Dissertations / Theses: 'Arthropoda – Ecology'

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Pravia-Fernández, Ainoa. "The response of arthropod assemblages to peatland restoration in formerly afforested blanket bog." Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=240202.

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The restoration of drained afforested blanket bogs is a cost-effective management approach in peatland conservation that aims to restore key ecosystem functions such as biodiversity and carbon storage and sequestration. Although arthropods are one of the most abundant and widespread animal groups in peatlands, little research has been carried out to assess their response to the variety of restoration management techniques that have been applied in afforested blanket bogs. We assessed the effectiveness of restoration by investigating the restoration trajectory of arthropod assemblages in formerly afforested blanket bog. We first looked at the long-term trajectory of arthropod assemblages, as well as carabid and moth taxa, in a chronosequence of tree-felled/drain-blocked treatments. Then, we looked at the short-term response of arthropod and carabid assemblages in treatments under varying regimes of brash management. General arthropod assemblages, and the functional traits of carabids and moths, were used to further investigate what type of biotic and abiotic parameters might be of importance during restoration. Lastly, we looked at potential biondicators of restoration progress to be used in restoration monitoring. The long-term restoration trajectory showed that typical bog assemblages are yet to be achieved due to persistence of generalists, as well as absence of bog specialists. Divergence in assembly trajectory was found at 18 years since onset of restoration, suggesting the emergence of an alternative state. Short-term restoration shows that brash might act as temporary habitat at early stages, where carabids favour lower structurally complex habitats than arthropods. Broad patterns of moth distribution revealed trait syndromes associated with blanket bog, whilst abiotic components such as vegetation structure, temperature, plot perimeter and blanket bog connectivity were found to be key for arthropod assemblages. The latter suggests potential legacy and edge effects associated with the restoration process. Arthropods and carabids showed high habitat specificity and fidelity, providing high bioindicator potential for restoration progress. This thesis shows that typical bog arthropod assemblages largely rely on habitat microstructure, particularly Sphagnum mosses, and associated microclimates for survival. Management can provide temporary refuge for arthropods, but the re-establishment of peat-forming vegetation and water table depth is essential for the return of typical bog assemblages. Though trade-offs might be encountered in the long-term restoration of peatland functions, a restoration framework is provided for the monitoring of arthropod assemblages.

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Roets, Francois. "Diversity and ecology of ophiostomatoid fungi and arthropods associated with proteaceae infructescences." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52807.

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Thesis (MSc)--University of Stellenbosch, 2002.
ENGLISH ABSTRACT: Five new species of ophiostomatoid fungi, colon ising the infructescences of serotinous Protea species, have recently been discovered in South Africa. Prior to this, ophostomatoid fungi were thought to be restricted to the Northern Hemisphere. The discovery of these five species thus extensively expanded the known geographical range of these fungi, now also to include the Southern Hemisphere. Since this discovery, few studies have focused on the interesting ecology of this group, which is uniquely adapted for spore dispersal by arthropods. Studies focussed on ophiostomatoid fungi provide an unique opportunity to study inter-organism interactions between fungi, their host plants and the arthropods responsible for their spore dispersal. Very few similar studies have been undertaken, particularly in the Fynbos Biome, to which most of our economically important Protea species are confined. The current study provides insight into some ecological aspects of these complex interactions. The seasonal distribution of the ophiostomatoid fungi associated with the infructescences of members of the Proteaceae was investigated. Definite seasonal patterns were observed, with peak fungal colonisation occurring during the wetter winter months. While determining the host specificity of these fungi, a new Protea host for Ophiostoma splendens was identified, and a new species of Rhyncomeliola was discovered. All ophiostomatoid species native to Fynbos in the Stellenbosch region are exclusively associated with the infructescences of species in the plant genus Protea. By employing a multiplex Polymerase Chain Reaction (PCR), a set of group specific primers was developed for the identification of South African Ophiostoma and Gondwanamyces fungal DNA. This newly developed method was used to scan arthropods collected from the infructescences of P. repens for the presence of 0. splendens and G. proteae spores. By using these group-specific primers, three insects possibly responsible for long range dispersal of fungal spores were identified. Three further insect species, possibly contributing to the short-range dispersal of ophiostomatoid spores, were also implicated through this method. All arthropods associated with the fruiting structures of selected members of the Proteaceae were also investigated. A total of 62 pseudospecies (ca. 7500 individuals), belonging to 45 different arthropod families, were collected. Proteaceae species with larger fruiting structures housed more arthropod species and higher numbers of individuals than Proteaceae taxa with smaller fruiting structures. Some plant species housed similar arthropod communities, while others housed unique suites of arthropods. Seasonal patterns in arthropod numbers were observed, and it was found that, in most instances, arthropod numbers peaked during the autumn and winter months. Twenty-five fungal taxa were isolated from various Proteaceae arthropods, many of which are genera known to include Proteaceae pathogenic species. Ophiostomatoid fungi have a saprophytic relationship with their Protea hosts, and may deter some of these potentially harmful fungi from colon ising the infrutescences. Some fungi showed a high degree of specificity towards potential vectors, while others were found on a diverse range of arthropods. This study highlights the existence of complex inter-organismal interactions within the Fynbos Biome, a study area where the interactions between plants, fungi and insects have been grossly neglected. The few studies that have been conducted in this field have mostly focussed on a limited number of organisms, and no wide-scale attempts, such as presented here, have been published. It is important to obtain a holistic view in any ecological study that focuses on interactions between different suites of organisms. Ultimately this will aid in the development of better conservation strategies. This study thus provides a muchneeded start in studies on multi-organismal interactions in the Fynbos Biome.
AFRIKAANSE OPSOMMING: Vyf nuwe ophiostoma-agtige fungus spesies is onlangs in die vrug-liggame van Suid Afrikaanse Protea plante ontdek. Voor hierdie ontdekking, was die algemene opvatting dat ophiostoma-agtige fungi beperk is tot die Noordelike Halfrond. Die ontdekking van hierdie vyf spesies het dus die bekende geografiese verspreiding van hierdie tipe fungi vergroot om nou ook die Suidelike Halfrond in te sluit. Sederdien het min studies gefokus op die interesante ekologie van hierdie groep, wat aangepas is vir spoorverspreiding deur geleedpotiges. Studies wat fokus op die ophiostoma-agtige fungi voorsien 'n unieke geleentheid om die inter-organismiese-interaksies tussen fungi, hul gasheer plante en die geleedpotiges wat hul spore versprei, te bestudeer. Baie min soortgelyke studies is al voorheen in die Fynbos Bioom, waar die meeste van ons ekonomies-belangrike Protea spesies voorkom, onderneem. Die huidige studie verleen meer inligting oor sommige ekologiese aspekte van hierdie komplekse interaksies. Seisoenale verspreidingspatrone van ophiostoma-agtige fungi geassosieer met die vrug-liggame van lede van die Proteaceae, is ondersoek. Daar is defnitiewe seisoenale patrone in die aanwesigheid van fungi gevind, met 'n piek in fungi kolonisasie-getalle gedurende die vogtiger wintermaande. 'n Nuwe Protea gasheer vir Ophiostoma splendens en 'n nuwe fungus spesie (Rhyncomeliola sp.), is ontdek. Alle Fynbos ophiostoma-agtige spesies in die Stellenbosch area, is beperk tot Protea spesies. 'n Multipleks Polimerase Ketting Reaksie is ontwikkel om die spesifieke DNS van ophiostoma-agtige fungi te herken. Hierdie metode is gebruik om te toets vir die aanwesigheid van spore van hierdie fungi op die liggame van geleedpotiges (geassosieerd met P. repens). Hierdeur is drie insekte wat waarskynlik verantwoordelik is vir die langafstand verspreiding van spore geidentifiseer. Drie verdere insekte wat moontlik verantwoordelik is vir die kortafstand verspreiding van ophiostoma-agtige fungi is ook aangewys. Alle geleedpotiges geassosieer met die vrugstrukture van geselekteerde lede van die Proteaceae is ondersoek. 'n Totaal van 62 pseudo-spesies (omtrent 7500 individue), wat tot 45 families behoort, is versamel. Proteaceae spesies met groter vrugstrukture het meer geleedpotige spesies en individue gehuisves as taksa met kleiner vrugstrukture. Sommige plant spesies het soortgelyke geleedpotige gemeenskappe gehuisves, terwyl unieke groepe geleedpotiges in ander plante voorgekom het. Alhoewel die geleedpotiges seisonale variasies in getalle geopenbaar het, het die meeste groepe 'n piek in getalle getoon gedurende die herfs- en wintermaande. Vyf-en-twintig fungi taksa is geïsoleer vanaf verskeie Proteaceae geleedpotiges. Sommige van hierdie is genera wat Proteaceae patogeniese spesies insluit. Sommige fungi het 'n hoë graad van spesifisiteit teenoor potensiële vektore getoon, terwyl ander weer algemeen op verskeie geleedpotige spesies gevind is. Hierdie studie dui op die bestaan van komplekse inter-organismiese-interaksies in die Fynbos Bioom, in 'n area waar die studie van interaksies tussen plante, fungi en insekte nog baie min aandag geniet het. Die beperkte aantal studies wat tot dusver in hierdie veld onderneem is, fokus gewoonlik slegs op 'n paar organismes. Geen grootskaalse studies, soos die een hier voorgelê, is al gepubliseer nie. In enige ekologiese studie wat fokus op interaksies tussen verskeie organismes, is dit belangrik om 'n holistiese siening te probeer verkry. Uiteindelik sal dit bydra tot die ontwikkeling van beter bewarings-strategië. Hierdie studie verleen dus 'n noodsaaklike begin tot studies op multiorganismiese- interaksies.

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Chan, Lai-chun, and 陳麗珍. "The ecology of marine plankton in Tai Tam Bay, Hong Kong, with specialreference to barnacle (arthropoda : cirripedia) larvae." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31234112.

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Chan, Lai-chun. "The ecology of marine plankton in Tai Tam Bay, Hong Kong, with special reference to barnacle (arthropoda : cirripedia) larvae /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B14709089.

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Brown, Grant R. "Garden life : the influence of garden age and area on the biodiversity of ground active arthropods." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/6815.

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Urbanisation is a global issue, and rapidly gaining attention from researchers as a major cause of biodiversity loss. Gardens represent a considerable proportion of the urban landscape in the UK and have significant potential to promote urban biodiversity and reduce species loss providing they can be designed and managed appropriately. This research focused on gardens in St Andrews, Scotland, and investigated the influence of environmental variables such as age and area on arachnid and beetle biodiversity with the aim of identifying key predictors of arthropod species richness in urban environments. The key result of this research was that the age and area of individual gardens was not a strong predictor of ground active arthropod biodiversity. This suggests that more recently developed or smaller gardens can contribute to the overall urban region species richness pool as well as larger or more ancient gardens. The most important predictor of ground active arachnid and beetle species richness was the proportion of porous (or 'green') habitat surrounding each garden, and suggested that urban density and habitat connectivity at the regional scale are of key importance. In general, variables measured within gardens (e.g. the provision of microhabitats such as leaf litter, non-managed vegetation, etc.) did not exert any measurable effect on the biodiversity of arachnids or beetles. The findings of this research suggest that the regional availability of heterogeneous greenspace habitat is of high importance for promoting and maintaining urban arthropod biodiversity.

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Ferreira, Aila Soares. "Varia??o temporal e descri??o de novas esp?cies de collembola (arthropoda, hexapoda) em uma ?rea de caatinga do nordeste do Brasil." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17353.

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Made available in DSpace on 2014-12-17T15:37:17Z (GMT). No. of bitstreams: 1 AilaSF_DISSERT.pdf: 2602874 bytes, checksum: 17786cedd4c6cf455a1bade82e0156e9 (MD5) Previous issue date: 2013-03-25
Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Collembola is one of the most abundant and diverse group of terrestrial arthropods, being at the base of the food chain operating in the decomposition process. They have a wide distribution in the world and can be found in practically all habitats. The knowledge of this distinctive fauna is still deficient in brazilian territory, especially in semi-arid region. The aim of this study was to investigate which climatic variables may act as predictors of species richness, abundance of individuals and compositional structure of the taxocenose of Collembola over 12 months in an area dominated by semi-arid Caatinga vegetation, northeastern Brazil and describe new species of the genus Seira found, more diverse taxon of Collembola in Brazil. Samples were collected in Jo?o C?mara, Rio Grande do Norte. Ten plots of 20 x 20 meters were established and the specimens were collected with collection effort of one hour/people using entomological aspirator. The identification and description of the species was carried out by studying the morphology and chaetotaxy. Was performed a multiple regression analysis between species richness and abundance of individuals with climatic variables. A total of 1231 individuals belonging to 15 species, 12 genera and nine families. The greatest richness and abundance of Collembola were found during the rainy season. The genus Seira was the most abundant. Rainfall explained the temporal variation in species richness and abundance of Collembola in the semi-arid region, which is consistent with the biology of these animals. The populations of Collembola showed grouped distribution. Three new species of Seira were described and illustrated and all show similarities with species already registered in the national territory
Collembola constitui um dos grupos mais abundantes e diversos de artr?podes terrestres, estando na base da cadeia alimentar e atuando no processo de decomposi??o. Possuem ampla distribui??o no mundo e podem ser encontrados em praticamente todos os habitats. O conhecimento desta distinta fauna ainda ? deficiente em territ?rio brasileiro, especialmente no semi?rido. O objetivo desse estudo foi investigar quais as vari?veis clim?ticas podem atuar como preditoras da riqueza de esp?cies, abund?ncia de indiv?duos e da estrutura composicional da taxocenose de Collembola ao longo de 12 meses em uma ?rea semi?rido dominada por vegeta??o de Caatinga, Nordeste brasileiro; e descrever novas esp?cies encontradas do g?nero Seira, t?xon mais diverso de Collembola no Brasil. As coletas foram realizadas em Jo?o C?mara, Rio Grande do Norte. Dez parcelas de 20 x 20 metros foram estabelecidas e os esp?cimes foram coletados com esfor?o de coleta de uma hora por pessoa utilizando um aspirador entomol?gico. A identifica??o e descri??o das esp?cies foram realizadas atrav?s do estudo da morfologia e quetotaxia dos exemplares. Foi realizada uma an?lise de regress?o m?ltipla entre a riqueza de esp?cies e a abund?ncia de indiv?duos com as vari?veis clim?ticas. Foi coletado um total de 1231 indiv?duos, distribu?dos em 15 esp?cies, 12 g?neros e nove fam?lias. As maiores riqueza e abund?ncia de Collembola foram encontradas durante a esta??o chuvosa. O g?nero Seira foi o mais abundante. A precipita??o explicou varia??o temporal da riqueza de esp?cies e abund?ncia de Collembola no semi?rido, o que condiz com a biologia desses animais. As popula??es de Collembola apresentaram distribui??o agrupada. Tr?s esp?cies novas de Seira foram descritas e ilustradas e todas apresentam semelhan?as com esp?cies j? registradas em territ?rio nacional

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Patrick, L. Brian. "Fertilization and plant litter effects on the plant and epigeal arthropod communities." [Kent, Ohio] : Kent State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1259588844.

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Thesis (Ph.D.)--Kent State University, 2009.
Title from PDF t.p. (viewed April 14, 2010). Advisor: Mark W. Kershner. Keywords: biodiversity; nitrogen; fertilization; plant litter; trophic dynamics; epigeal community. Includes bibliographical references.

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François, Sarah. "Diversité et écologie des virus associés aux arthropodes : des communautés aux génomes." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT106/document.

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Les nouvelles technologies de séquençage des génomes ont permis de révéler l’extraordinaire diversité des séquences virales dans des groupes d’hôtes jusque-là largement inexplorés. Ainsi, notre connaissance des virus d’arthropodes, infectant les animaux les plus diversifiés et abondants sur Terre, était jusque-là essentiellement réduite à des espèces d’intérêt économique et médical. Les nouvelles données de diversité virale chez les arthropodes illustrent le besoin d’étendre l’inventaire viral à l’échelle de l’écosystème et d’inclure les virus comme une composante essentielle de leur fonctionnement et de leur évolution.Dans ces travaux de thèse, j’ai développé et appliqué deux approches d’étude de la diversité virale chez des arthropodes, ainsi que de la circulation des virus dans des écosystèmes, en me focalisant sur des espèces d’intérêt agronomique : i) une approche virus-centrée par fouille de bases de données nucléotidiques, en recherchant la présence d’un groupe de petits virus à ADN inféodés aux arthropodes, les densovirus ii) une approche arthropode-centrée, utilisant une méthode séquençage haut débit de génomes viraux (métagénomique virale) pour analyser des communautés virales associées à des arthropodes de différents niveaux trophiques échantillonnés dans des agroécosystèmes.Mes résultats ont permis de :(i) Mettre en évidence que les densovirus sont largement présents dans l’ensemble du règne animal - notamment chez une grande diversité d’arthropodes - et qu’ils sont très diversifiés génétiquement, ce qui a permis de mieux appréhender histoire évolutive de ce groupe de virus ;(ii) Découvrir de nouveaux virus chez certains ravageurs de cultures : le tétranyque tisserand (Tetranychus urticae, Acarien) provenant de populations de laboratoires, ainsi que le puceron vert du pois (Acyrthosiphon pisum, Hémiptère), le phytonome de la luzerne (Hypera postica, Coléoptère) et l’armigère de la tomate (Helicoverpa armigera, Lépidoptère) provenant de populations naturelles échantillonnées dans des cultures de luzerne et des prairies. Ces études ont permis de mettre en évidence la présence de viromes spécifiques de chaque espèce d’arthropode et de caractériser la distribution de certains virus dans des communautés d’arthropodes d’un même écosystème. Plus de 60 nouvelles espèces de virus d’arthropodes et de plantes ont été découvertes. Leurs liens évolutifs avec des espèces de virus connues ont été caractérisés par des analyses phylogénétiques.(iii) Enfin, les travaux menés en (ii) ont également permis d’optimiser la méthodologie permettant d’obtenir et d’analyser des viromes obtenus à partir d’échantillons multiplexés, optimisant notamment l’étape d’attribution taxonomique des séquences obtenues par séquençage à haut débit, réduisant ainsi leur proportion en « matière noire » inhérente aux analyses des viromes
High throughput sequencing technologies have revealed the extraordinary diversity of viral sequences in hitherto largely unexplored host groups. Thus, our knowledge about arthropod viruses, infecting the most diverse and abundant animals on Earth, was hitherto essentially reduced to species of economical and medical interest. New data on viral diversity in arthropods illustrate the need to expand viral inventory at the scale of the ecosystem and to include viruses as an essential component of their functioning and their evolution.In my thesis, I developed and applied two approaches to study the diversity of viruses in arthropods and how virus circulate in ecosystems, focusing on species of agronomic interest: (i) a virus-centered approach by exploring nucleotidic sequence databases, searching for the presence of a group of small DNA viruses infecting arthropods, the densoviruses (ii) an arthropod-centered approach at the scale of the ecosystem, using a viral metagenomic method to analyze viral communities associated with arthropods from different trophic levels from the same agroecosystems.My results showed that:(i) Densoviruses are spread throughout the animal kingdom - particularly in a wide diversity of arthropods - and are highly diverse genetically, which led to a better understanding of the evolutionary history of this group of viruses;(ii) A number of new viruses can be described in pests: the spider mite (Tetranychus urticae, Acari) from laboratory populations, as well as the green pea aphid (Acyrthosiphon pisum, Hemiptera), the alfalfa weevil (Hypera postica, Coleoptera) and the cotton bollworm (Helicoverpa armigera, Lepidoptera) from natural populations sampled from alfalfa crops and grasslands. These studies also highlighted that specific viromes are associated with each pest species, and I characterized the distribution of some of these viruses in arthropod communities. In total, more than 60 new species of arthropod and plant viruses were discovered. Their evolutionary links with known virus species was characterized by phylogenetic analyzes.(iii) The work realized in (ii) also contributed to optimize a methodology to prepare and analyze viromes from multiplexed samples, that is particularly suitable to optimize the taxonomic allocation of sequences and thus reduce the "dark matter" that is inherent to viral metagenomics analyses

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Boonzaaier, Carmen. "Conservation in human-influenced areas : epigaeic arthropods in the Cape Floristic Region Lowlands." Thesis, Stellenbosch : Stellenbosch University, 2006. http://hdl.handle.net/10019.1/21551.

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Thesis (MSc)--University of Stellenbosch, 2006.
ENGLISH ABSTRACT: The conservation of biodiversity is becoming increasingly challenging as habitats are disturbed, fragmented or destroyed. Although nature reserves now cover more than 10 % of the earths’ surface it has become clear that more will have to be done to ensure the long-term survival of species. Therefore, focus is increasingly shifting towards conserving biodiversity in natural and semi-natural remnants in human-influenced areas. This study aimed to determine the contribution of remnants in human-influenced areas to the conservation of biodiversity in the Cape Floristic Region (CFR) lowlands, using ground-dwelling arthropods, specifically ants, as the focal taxon. Initially, base-line information of arthropods and in particular ants was obtained. Sampling arthropods generally involves a large sample effort. Therefore maximizing sampling effort for ants in the CFR was investigated by trapping ground-dwelling ants at a single locality. Doubling the number of grids of pitfall traps was found to be more effective in trapping a greater number of species than doubling the duration of sampling. Therefore increasing spatial sampling intensity rather than sampling duration maximizes sample effort for CFR ants. Also, the seasonal changes of ground-dwelling arthropods, including ants, were determined by sampling four times during the year at a single locality. Overall arthropod abundance was found to peak in summer while dropping to a minimum in winter. This pattern was mirrored by that of the ants, indicating that ant results have a broader relevance than to ants only. The ground-dwelling fauna was dominated by ants emphasizing their importance in the CFR lowlands, and demonstrating that ants are an appropriate flagship taxon for epigaeic arthropod diversity in the CFR. Finally the contribution of remnants in human-influenced areas to the conservation of the CFR was investigated. A nested hierarchical approach was used, where five localities were selected across the CFR, each containing one reserve site and one site with natural remnants. Ants were sampled, along with environmental variables, namely weather, vegetation and soil. Overall, remnants were found to support similar ant assemblages to those of reserves. However for individual localities some remnants were significantly different to their reserve counterparts. Differences in ant assemblages were found to be greater between localities than between reserves and remnants. The relatively high heterogeneity of ants found in this study emphasizes the conservation significance of invertebrates along with that of plants in the CFR. Remnants clearly show the potential to conserve ant assemblages, however correct management is needed for these areas to maximize their potential. Disturbances such as the presence of the invasive Argentine ant and increasing soil nutrients by fertilization, pose a distinct threat to the ability of remnants to conserve ant assemblages. This study has shown that remnants currently support ant assemblages representative of those present in the CFR today. Therefore, some remnant patches of habitat in agricultural areas currently do contribute highly to the conservation of a functional important taxon in this global biodiversity hotspot, and if managed correctly, may continue to do so in the future.
AFRIKAANSE OPSOMMING: Die vernietiging en fragmentering van habitatte maak die bewaring van biodiversiteit al hoe meer van ‘n uitdaging. Alhoewel natuur reservate reeds meer as 10 % van die aarde se oppervlak beslaan is dit duidelik dat meer gedoen sal moet word vir die lang-termyn voortbestaan van spesies. Dus word die fokus van biodiversiteit-bewaring toenemend gerig op bewaring van natuurlike en semi-natuurlike fragmente in menslik-beinvloede gebiede. Die doel van hierdie studie was om te bepaal wat die bydrae van fragmente van natuurlike veld in menslik-beinvloede gebiede is tot die bewaring van die streek. Dit is gedoen deur van grond-lewende geleedpotiges en spesifiek, miere in die Kaapse floraryk (CFR) gebruik te maak. Aanvanklik is kennis ingewin oor die geleedpotiges en spesifiek miere in die omgewing. Omdat die versameling van geleedpotige diere gewoonlik baie moeite vereis is ‘n maksimum steekproef gedoen by ‘n enkele lokaliteit. Daar is gevind dat ‘n verdubbling van die aantal ruitsteekproefnemings met vanggate meer effektief is om miere te vang as ‘n verdubbling in die tydperiode wat vanggate oop is. Dus, is ‘n hoër ruimtelike steekproef intensiteit meer effektief in vergelyking met ‘n langer tydsduur vir miere in die CFR. Die seisoenale veranderinge van grond-lewende geleedpotiges, sowel as miere, was ook bepaal. Dit was gedoen deur vier seisoenale steekproewe te doen by ‘n enkele lokaliteit. Die totale geleedpotige-talrykheid was die meeste gedurende die somer en die minste in die winter. Die miertalrykheid het ook hierdie patroon weerspieël. Dit dui daarop dat veranderinge in mier versamelings van breër belang is vir alle grondlewende geleedpotiges. Miere was die dominante grond-lewende geleedpotiges en beklemtoon die belangrikheid van miere in die CFR, sowel as hulle toepaslikheid as vlagskip taksa vir grond-lewende geleedpotige diversiteit in die CFR. Laastens was die bydrae van gefragmenteerde natuurlike veld in menslik–beinvloede gebiede tot die bewaring van die CFR ondersoek. ’n Krimpende/ genestelde hiërargies benadering is gebruik in vyf geselekteerde lokaliteite, elk het bestaan uit ‘n area in ‘n natuur reservaat en ‘n area in ‘n naasliggende fragment. Miere was versamel saam met ‘n verskeidenheid omgewings veranderlike, naamlik weer, plantegroei en grond. In die algemeen is gevind dat fragmente en reservate gelyksoortige mier versamelings het. Daar was wel gevind dat party fragmente aansienlik verskillend was van die reservaat teenstuk. Verskille in mier versamelings tussen lokaliteite was groter as verskille tussen reservate en fragmente. Die relatief hoë heterogeniteit van miere beklemtoon die bewaringsbelang van invertebrate saam met dié van plante in die CFR. Dit is duidelik dat fragmente wel ‘n potensiale bydrae kan maak om die mier versamelinge te bewaar, maar gepaste bestuur is nodig om hierdie potentiaal te maksimaliseer. Versteurings soos die teenwoordigheid van die indringer Argentynse mier en toenemende grondvoedingstofkonsentrasie as gevolg van bemesting is ‘n groot bedreiging tot die vermoë van fragmente om mier versamelings te bewaar. Hierdie studie wys dat mier versamelings in gefragmenterde areas verteenwordigend is van die algemene mier versamlings wat op die oomblik in die CFR is. Dus lewer party fragmente in landbou gebiede op die oomblik ‘n wesenlike bydrae tot die bewaring van ‘n funksioneel belangrike takson in hierdie globale biodiversiteitsbrandpunt en die bydra sal volhoubaar wees met korekte bestuur.

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Netchy, Kristin. "Epibenthic Mobile Invertebrates along the Florida Reef Tract: Diversity and Community Structure." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5085.

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Benthic mobile invertebrates are important components of coral-reef diversity and community structure, though, in most cases, their ecological contributions are poorly known. Baseline information on their diversity, prevalence, assemblages, and ecological roles is needed to aid in the conservation of coral-reef habitats. The objectives of this study are to 1) describe diversity and assemblages of epibenthic, mobile invertebrates in shallow water coral-reef communities in Florida, 2) evaluate their ecological roles by reviewing published literature on diet, and 3) measure the degree of linear dependence between mobile invertebrates and scleractinian corals. Underwater surveys were conducted in the summer of 2013 at 40 sites distributed along the Florida Reef Tract from Broward County to the Dry Tortugas. The presence/absence of all mobile, epibenthic invertebrate fauna observed were recorded and identified to the lowest level possible. The survey data include 618 records of 116 unique taxa, 83 species, 61 genera, 46 families, 19 orders, seven classes, and four phyla of mobile invertebrates, comprising herbivores, detritivores, carnivores, omnivores, and suspension feeders. These taxa represent 22% of the comparable taxa in a historical dataset that spans 60 years, plus an additional 18 taxa. The survey data also show that the percent composition of major phyla is similar to the historical dataset, despite taxonomic bias evident in the historical dataset. During the survey, novel unique taxa were encountered frequently, but were seldom recurrent, which highlights their cryptic nature. While regional patterns were not identified in the study, assemblages of dominant taxa were characteristic of reef type: echinoderms were the most diverse on patch reefs and southeast Florida reef complexes, mollusks were most diverse on shallow bank reefs, and arthropods were diverse on deep bank reefs, Southeast Florida reef complexes, and shallow bank reefs. Herbivorous mobile invertebrate diversity was negatively correlated with scleractinian coral diversity, underlining competition between corals and macroalgae, and association of herbivores with macroalgae. All of these results suggest that reef types are distinct, but interrelated communities of fauna having specific habitat requirements and important roles. This study also reinforces the challenges in assessing the diverse and often cryptic mobile invertebrate fauna and emphasizes the need for further research and monitoring to detect changes in their communities for the conservation of Florida reef systems.

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Meloni, Fernando. "Influência do desenvolvimento florestal sobre a comunidade edáfico-epígea de Arthropoda e a mirmecofauna: bases para a bioindicação do processo sucessional na restauração ecológica." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/59/59131/tde-02012013-120543/.

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A restauração ecológica visa o estabelecimento de ecossistemas semelhantes aos que originalmente ocupavam uma determinada área que foi degradada. Todavia, os resultados dos esforços envolvidos na restauração e no retorno dos processos ecológicos naturais são difíceis de serem medidos, pois faltam métodos apropriados. Os bioindicadores são ferramentas baratas e confiáveis para o diagnóstico das características ambientais e ecológicas, cujo princípio consiste em medidas simples de grupos biológicos especialmente sensíveis às mudanças no meio. Os Arthropoda que ocorrem no solo e na serapilheira, em especial as formigas, mediam processos ecológicos importantes e apresentam características que os tornam bioindicadores potenciais, mas seu uso ainda necessita de conhecimentos específicos. Assim, o presente estudo teve como objetivo testar o potencial indicador da comunidade de Arthropoda edáfico-epígea na restauração ecológica, com maior enfoque sobre as formigas. Foram avaliadas as comunidades de um gradiente sucessional formado por doze reflorestamentos com diferentes idades e três remanescentes florestais, localizados nas bacias dos rios Pardo e Mogi-Guaçu. O objetivo foi identificar quais os parâmetros que melhor refletem a resposta dessas comunidades ao desenvolvimento florestal. Os resultados indicaram que tanto a mirmecofauna como o restante da comunidade são influenciadas pelos estádios de desenvolvimento florestal. As comunidades variaram em composição e estrutura. A evolução das comunidades mostrou-se direcional, formando um padrão convergente de acordo com o avanço da sucessão. Os resultados indicaram forte efeito da sazonalidade e das técnicas de coleta na interpretação dos resultados. A comunidade edáfico-epígea encontrada no período seco mostrou-se especialmente sensível ao desenvolvimento florestal, enquanto a resposta da mirmecofauna foi mais evidente durante o período chuvoso. Os resultados indicaram também que as comunidades de diferentes regiões, Mogi-Guaçu e Ribeirão Preto, responderam ao processo sucessional, embora tenham apresentado diferenças na composição e no padrão de resposta. As análises com formigas classificadas em grupos funcionais indicaram que a resposta da mirmecofauna ao desenvolvimento florestal ocorre também no nível funcional. As mudanças nos padrões da comunidade e seus módulos estão relacionadas às mudanças nos filtros ambientais e à disponibilidade de nichos. Em conclusão, (1) a riqueza de espécies da fauna edáfico-epígea encontrada na serapilheira do período seco foi um bom preditor geral do desenvolvimento florestal; (2) a riqueza de grupos raros proporcionou o melhor modelo de prognóstico do estádio sucessional, indicando ainda que os reflorestamentos tendem a atingir patamares semelhantes aos encontrados nos remanescentes florestais por volta dos 27 anos após o plantio; (3) na comunidade edáfico-epígea, o avanço no desenvolvimento florestal levou à convergência entre padrões de composição, (4) enquanto na mirmecofauna a convergência ocorreu para os padrões de estrutura, sendo que em ambos os casos (3 e 4), quanto mais avançado o estádio sucessional, mais parecidos entre si são os padrões de locais diferentes; (5) a Equabilidade J das formigas amostradas por iscas decresceu ao longo do desenvolvimento florestal, sendo considerado também um indicador do processo sucessional (6) as classificações funcionais das formigas também permitiram boa predição dos estádios sucessionais, com destaque para formigas capturadas com iscas quando classificadas pelo sistema proposto por Andersen (1995), devido a boa relação custo/benefício. Portanto, foi confirmado o potencial bioindicador da mirmecofauna de comunidade edáfico-epígea geral, que podem ser utilizados como ferramentas de diagnóstico e monitoramento do processo sucessional. O uso mais apropriado deve ser feito por métodos comparativos, através de parâmetros provenientes de ecossistemas referência, ou por medidas repetidas ao longo do tempo, pela observação do deslocamento dos padrões da comunidade e interpretação da proporção dos grupos.
Ecological restoration objective is to promote the return of chemical, physical and biological natural properties as those similar to the native features as possible. However, the restoration projects cannot be well evaluated due to the fact that there are no appropriated tools to do that. Plantations using native species are a prominent technique used in São Paulo state, promoting the fast rising of a plant community, but it is very expensive and hard to measure if ecological processes are returning. Bioindicators are cheap tools to evaluate environmental conditions and ecological processes because they respond to all ecosystem characteristics acting together and the responses of a single group make possible to infer properties of the total biodiversity or the full ecosystem health. Epigeic and hipogeic Arthropoda, especially ants, are potential bioindicators, due to their high abundance, ubiquitousness and their straight relationship to some important ecological processes, even to other community components, but they have not been used because it lacks information about the local scale responses to successional process and which standards can be used as parameters. Hence, we have tried to understand the main standards and responses from soil and litter community, as well as the mirmecofauna responses, under a successional gradient constituted by twelve planted forests in different ages and three forest remainders (semi-deciduous forest), all located at the hydrographic basins, Pardo and Mogi-Guaçu, searching for trustful bioindicators of forest development. General fauna was sampled from litter and soil and ants were additionally sampled by attractive baits, using glucose and sardine. Results have showed that forest development makes influence on structure and composition of general communities and ant communities found in restoration sites, so that over time, these community parameters progressively have become more similar to those found in forest remainders, consisting in a directional shifting. Epigeic and hipogeic general fauna showed to be more sensitive to forest development through dry season, while ants presented critical responses in wet season. Communities from different regions were influenced by successional process but they have presented differences among fauna compositions. The analyses using ants classified in functional groups indicated that forest development makes influence also on fauna functional pattern. Groups occupying specialized niches tend to increase their relative amount throughout forest development. The shifting of ant community functionality may be related to changes in environmental filters plus the increase of niche availability through forest development. As conclusions, under experiment features (1) species richness of litter fauna of dry season is a good predictor of forest development; (2) the richness of rare taxa allowed the best prognosis about sucessional stage, also indicating that fauna found in forest plantations reaches similar fauna standards of forest remainders close to 27 years after the deployment; (3) over time, the composition of general edaphic-epigeic community found in restoration sites becomes more similar to composition of communities found in forest remainders, (4) while for ant communities, the structure standards found in restoration sites progressively become more similar of respective parameter found in forest remainders. (5) the Equitability J of ants communities sampled using baits decreases over forest development and it may be considered a bioindicator of sucessional process; (6) ant functional groups also provided good prediction of sucessional stages, highlighting ant sampling using baits and ant functional classification according to Andersen (1995), due to best benefit-cost ratio. For appropriated application of all bioindicators, the use of comparative techniques may be considered, including ecosystem references, and rather than it uses fixed values of fauna parameters (as fixed goals to be achieved), it is better to consider which parameters of the community are changing over time and if their tendencies are in accordance to the expected.

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Diniz, Suzana. "Influência da complexidade arquitetural de ramos vegetativos na riqueza e abundância de aranhas e outros artrópodes." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316023.

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Orientadores: João Vasconcellos Neto, Gustavo Quevedo Romero
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-18T01:27:37Z (GMT). No. of bitstreams: 1 Diniz_Suzana_M.pdf: 61632938 bytes, checksum: 7bcbe079e28a7f57357c4d6ecbb16e88 (MD5) Previous issue date: 2011
Resumo: A estrutura do hábitat tem sido um tema recorrente na literatura, havendo diversos estudos que correlacionaram uma maior complexidade estrutural do hábitat à riqueza e abundância dos mais variados taxa. Contudo, este é um tema de difícil generalização e as abordagens experimentais ainda são raras. A vegetação é um elemento que proporciona complexidade estrutural ao hábitat devido às diversas organizações arquiteturais de seus módulos. Diversos estudos demonstraram que os artrópodes associados às plantas são um dos grupos mais afetados pela arquitetura da vegetação, particularmente as aranhas. Logo, o objetivo deste estudo foi avaliar os possíveis efeitos da arquitetura da vegetação sobre a abundância e riqueza de guildas de artrópodes, com ênfase na comunidade de aranhas. O estudo foi dividido em duas partes: (1) uma pesquisa exploratória, cujo objetivo foi correlacionar diferentes elementos arquiteturais das plantas com a comunidade de artrópodes, de forma a avaliar se determinados grupos de artrópodes são mais ou menos abundantes em determinadas configurações arquiteturais da vegetação; (2) uma pesquisa experimental, cujo objetivo foi manipular a arquitetura vegetal agrupando e espaçando os ramos vegetativos, de forma a avaliar os efeitos da densidade vegetal sobre a comunidade de artrópodes. Um total de 17 espécies de plantas e oito características arquiteturais foi utilizado na pesquisa exploratória. Já o experimento foi feito para três espécies de plantas e repetido em duas estações climáticas diferentes (seca e chuvosa) para avaliação dos efeitos sazonais sobre a resposta da comunidade de artrópodes à manipulação arquitetural da vegetação. Todos os dados de abundância e riqueza de artrópodes foram expressos por unidade de biomassa de planta e a disponibilidade de presas para os predadores (i.e., o total de artrópodes exceto o grupo de predadores sendo estudado) foi colocada como co-variável. Os padrões de abundância da comunidade de aranhas foram fortemente correlacionados à arquitetura da vegetação, tanto na pesquisa experimental quanto na exploratória. Já as guildas de outros artrópodes, com algumas exceções, foram pouco afetadas pela arquitetura da vegetação. Algumas guildas de fitófagos tiveram padrões consistentes de distribuição em plantas com diferentes arquiteturas. Estes padrões, por sua vez, ocorreram tanto na pesquisa exploratória quanto na experimental. A abundância de parasitóides e predadores (exceto aranhas) foi mais explicada pela disponibilidade de presas do que pela arquitetura per se. O padrão de distribuição das aranhas sobre as plantas pode ser explicado, em grande medida, pelo favorecimento que determinadas arquiteturas proporcionam aos hábitos de forrageio de cada guilda. Já o padrão de abundância das guildas de fitófagos em plantas com diferentes arquiteturas provavelmente decorre de uma modulação da taxa de predação, uma vez que a arquitetura da planta está vinculada à disponibilidade de refúgios
Abstract: Habitat structure has been a recurrent subject in literature and there have been several researches that correlated a greater structural complexity of habitat to the richness and abundance of diverse taxa. However, this represents a subject of hard generalization and experimental approaches are still rare. Vegetation is an element that provides structural complexity to habitat due to diverse architectural organization of their modules. Many researches demonstrated that arthropods associated to plants are one of the most affected groups by the vegetation architecture, especially the spiders. Thus, the objective of present research was to evaluate possible effects of vegetation architecture on the richness and abundance of arthropod guilds, with special emphasis on spider community. The research was divided in two parts: (1) a survey research, whose objective was to correlate diverse architectural traits of plants with the arthropod community, this in order to assess whether certain groups of the arthropod community are more or less abundant in certain plant architectural configurations; (2) an experimental research, whose objective was to manipulate plant architecture by grouping and spacing the vegetative branches in order to evaluate the effects of plant density on the arthropod community. A total of 17 plant species and eight architectural traits was used in survey research, whereas the experiment was performed in three plant species and repeated in two seasons (dry and wet) for evaluation of seasonal effects on the arthropod community response to manipulation of the plant architecture. All data referring to arthropod abundance and richness were given per unit of plant biomass and the prey availability for predators (i.e., all arthropods except the group of predators being studied) was set as a covariate. The abundance patterns of spider community were strongly correlated to the plant architecture, both in experimental and in survey research. Nevertheless, the other arthropod guilds, with some exceptions, were weakly affected by vegetation architecture. Some phytophagous guilds had consistent patterns of distribution on plant with different architectural traits. These patterns, by the way, occurred as in survey as in experimental research. The abundance of parasitoids and predators (except spiders) was more explained by the prey availability than by the plant architecture per se. Patterns of spider distribution on plants can be quite explained by the advantages that some plant architectures provide to the foraging habits of each guild. Abundance patterns of phytophagous guilds on plants with different architectural traits, nevertheless, were probably due to modulation of predation rates, since the plant architecture could determine refuge availability
Mestrado
Mestre em Ecologia

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Ozanne, Claire Margaret Philippa. "The arthropod fauna of coniferous plantations." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303621.

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Caballero, López Berta. "La diversitat d'artròpodes als agro-ecosistemes: efectes del paisatge, la gestió agronòmica, i la composició de la flora arvense = Arthropod diversity in agro-ecosystems: the effects of landscape, management and assembly of weed communities." Doctoral thesis, Universitat de Barcelona, 2010. http://hdl.handle.net/10803/670836.

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La agricultura ecológica se ha planteado como una posible solución paliativa a las negativas consecuencias de la intensificación agrícola. Aunque los beneficios de una agricultura más sostenible y menos intensiva son claros para la flora arvense de los campos de cereales gestionados ecológicamente, no son tan obvios para grupos de artrópodos oportunistas como son los pulgones que pueden ocasionar grandes pérdidas económicas, ni para sus enemigos naturales. Los estudios que abordan el tema de planta-artrópodo son escasos y frecuentemente se ciñen a evaluar las abundancias de ciertos grupos en vez de estudiar el impacto de la comunidad vegetal entera sobre la comunidad de artrópodos. Así que es necesario evaluar la interacción entre grupos funcionales vegetales (gramíneas, dicotiledóneas (excluyendo leguminosas) y leguminosas) y grupos funcionales de artrópodos (herbívoros succionadores y masticadores, consumidores florales, saprófagos, omnívoros, parasitoides, y predadores) para poder evaluar la efectividad real de las medidas agro-ambientales aplicadas en estas últimas décadas en la búsqueda de una gestión más sostenible.

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Barnes, Katherine M. "Molecular and biochemical ecology of European arthropods found on corpses." Thesis, University of Lincoln, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508301.

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Jumeau, Philippe J. A. M. "Arthropod predation in a simple Antarctic terrestrial community." Thesis, University of York, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277219.

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Borges, Paulo Alexandre Vieira. "Pasture arthropod community in Azorean Islands of different geological ages." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285174.

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Welti, Ellen A. R. "Ecological networks of grassland plants and arthropods." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35284.

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Doctor of Philosophy
Division of Biology
Anthony Joern
John Blair
Ecological communities are comprised both of species and their interactions. The importance of species interactions is embraced by ecological network analysis, a framework used to identify non-random patterns in species interactions, and the consequences of these patterns for maintaining species diversity. Here, I investigated environmental drivers of the structure of plant-pollinator and plant-herbivore networks. Specifically, I asked: (1) Do global-scale climate gradients shape mutualistic and antagonistic networks? (2) At a landscape scale (within a 3,487 ha research site), how do contrasting regimes of major grassland disturbances - fire frequency and grazing by bison (Bison bison) - shape plant-pollinator network structure? (3) How do fire and grazing affect plant-grasshopper network structure? And, (4) What is the role of plant species diversity in determining plant-herbivore network structure? At the global scale, variability in temperature was the key climatic factor regulating both antagonistic and mutualistic network structural properties. At the landscape scale, fire and grazing had major consequences for plant-pollinator and plant-herbivore communities. In particular, bison grazing increased network complexity and resistance to species loss for both plant-pollinator and plant-herbivore systems. Results from an experimental grassland restoration that manipulated plant diversity suggest that plant diversity directly affects plant-herbivore structure and increases network stability. Collectively, these results suggest that environmental gradients and plant species diversity regulate the network structure of ecological communities. Determining how the structure of ecological interactions change with environmental conditions and species diversity improves our ability to identify vulnerable communities, and to predict responses of biodiversity to global change.

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Lagebro, Linda. "The Arthropod Assemblage of the Upper Devonian Strud locality and its Ecology." Doctoral thesis, Uppsala universitet, Paleobiologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-248153.

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The Devonian (419-359 million years ago) is the geological period when the terrestrial biota fully established. Early representatives from a terrestrial and continental aquatic biota have previously been reported from the Upper Devonian (Famennian) Strud quarry in Belgium, in the shape of seed-bearing plants and vertebrates (fish and early tetrapods). The palaeoenvironment is interpreted as a floodplain with slow accumulation of sediment in the river channels and adjacent shallow pools, subject to seasonal flooding and desiccation. This thesis presents the upper Famennian Strud ecosystem with representatives from the largest animal phylum – the Arthropoda. Pancrustaceans are dominating the arthropod assemblage by two eumalacostracans (previously described), three groups of branchiopods, and a putative insect, all collected in fine shales likely deposited in the shallow pools. The branchiopods from Strud comprise new members from all three extant clades, i.e. notostracans, anostracans, and spinicaudatan diplostracans. The notostracan Strudops goldenbergi is remarkable for its close resemblance with the extant genus Triops by the overall body plan and telson morphology. A phylogenetic analysis including modern and extinct notostracans and anostracans was performed, where Strudops appears as the earliest undisputed notostracan ever found. In addition, new genera of Anostraca (Haltinnaias serrata) and Spinicaudata (Gesvestheria pernegrei) are described herein. The insect Strudiella devonica consists of a single specimen and is interpreted to have been a nymph due to its minute size and wingless appearance. The chelicerates are represented by one or several species of eurypterids. So far unnamed juvenile eurypterid remains have also been found within the pool strata, and fragments of adult individuals in the coarser river deposits. The branchiopod community displays a unique insight to the ecosystem that these crustaceans inhabited. This is partly because of their co-occurrence, but mainly because they are preserved in close association to draught-resistant encysted eggs, in the same manner as modern day branchiopods do to survive and disperse during periods of drought and freezing. Altogether, the arthropod assemblage offers insight to Late Devonian freshwater ecosystems, and provides further understanding of the evolution of respective groups.

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McDermott, Molly Tankersley. "Arthropod Communities and Passerine Diet| Effects of Shrub Expansion in Western Alaska." Thesis, University of Alaska Fairbanks, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10616929.

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Across the Arctic, taller woody shrubs, particularly willow ( Salix spp.), birch (Betula spp.), and alder ( Alnus spp.), have been expanding rapidly onto tundra. Changes in vegetation structure can alter the physical habitat structure, thermal environment, and food available to arthropods, which play an important role in the structure and functioning of Arctic ecosystems. Not only do they provide key ecosystem services such as pollination and nutrient cycling, they are an essential food source for migratory birds. In this study I examined the relationships between the abundance, diversity, and community composition of arthropods and the height and cover of several shrub species across a tundra-shrub gradient in northwestern Alaska. To characterize nestling diet of common passerines that occupy this gradient, I used next-generation sequencing of fecal matter. Willow cover was strongly and consistently associated with abundance and biomass of arthropods and significant shifts in arthropod community composition and diversity. Key nestling prey items were positively associated with both willow and ericaceous shrubs. Diet composition varied significantly among bird species and spatially within species, however, I found that temporal variability in prey abundance did not have a strong relationship to the probability of consumption. I predict that the wide temporal window of prey availability and high diet diversity may protect these birds against negative impacts from climate-driven shifts in prey phenology and abundance. Taken together, my results suggest that shrub expansion could result in a significant shift in Arctic food-web structure and an increase in food availability for insectivores, although future ecosystem change in the Arctic is likely to be heterogenous as shrub types are expanding at different rates and in different places across the Arctic.

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Chapman, Paul. "Short-term effects of vegetation management on epigeal predatory arthropods in organic farming systems." Thesis, University of Aberdeen, 1997. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU094109.

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Predatory arthropods such as carabid beetles and spiders are generally thought to be favoured by crop management that results in dense vegetation. In grassland, silage production increases vegetarian density compared to grazed grass but involves disturbance from cutting, while intercropping with clover increases the vegetation density of vegetable crops, but causes yield loss through interspecific competition. The first part of this thesis compares the predatory arthropod fauna of silage with grazed grass. There were small differences between the carabid assemblages of the two habitats before the first silage cut, when the contrast between silage and grazed grass was greatest, and a general reduction in species richness following silage cutting. However, the responses of individual species varied greatly. Agonum muelleri and Calathus fuscipes were associated with grazing management, but no species were consistently favoured by silage production. For Loricera pilicornis, this may have been due to cool weather creating similar conditions in silage and grazed grass, while for Nebria brevicollis, which was susceptible to disturbance, the timing of cutting determined its distribution. Spiders showed a more uniform association with structurally complex vegetation and were thus generally found in higher numbers under silage management. The second part of the thesis investigates daily movements of predatory arthropods between dense vegetation, such as clover intercropped vegetables, and adjacent open, weeded crops. The results suggested that nocturnal carabids and spiders of the genus Erigone sheltered in dense vegetation by day and moved into the open at night. Thus intercropping only parts of a vegetable crop would enhance predatory arthropod activity throughout the crop, while reducing interspecific competition. These results showed that the relationship between increased vegetation density and predatory arthropod activity is less important in the habitats studied than other factors, such as disturbance and daily movements in determining the distribution of these animals.

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Lingbeek, Brandon James. "Arthropod diversity response to deforestation and desertification in the Sahel region of western Senegal." Thesis, Tarleton State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10149640.

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Biodiversity has decreased due to anthropogenic activities, and extinction rates are currently one hundred to one thousand times greater than the background rate. While the connection between deforestation and biodiversity loss is well documented within tropical rainforest ecosystems, comparatively little is known about the effects of desertification on biodiversity in dryland ecosystems. Drylands, which cover nearly half the terrestrial surface and are highly vulnerable to desertification, are among the most endangered ecosystems. To understand how biodiversity responds to environmental degradation in these fragile ecosystems, I studied arthropod diversity within a human-modified landscape suffering from deforestation and desertification in the Sahel of western Senegal. My specific objective was to determine whether arthropod, beetle, spider and ant diversity differed between protected areas of tropical dry forest and surrounding communal lands suffering from desertification. I established 12 quadrats spaced homogenously throughout each protected area as well as adjacent communal land at three different locations (Beersheba, Bandia and Ngazobil). Within each quadrat, I measured canopy closure, characterized vegetation and collected arthropods using pitfall traps during the 2014 dry (May) and rainy (September) seasons.

I collected 123,705 arthropods representing 733 morphospecies, 10,849 beetles representing 216 morphospecies, 4,969 spiders representing 91 morphospecies and 59,183 ants representing 45 morphospecies. Results showed protected areas contained greater arthropod and spider diversity than communal lands, beetle diversity varied depending on location and season, and communal lands contained greater ant diversity than protected areas (P ≤ 0.05). My results illustrate the importance of a multi-taxa approach in understanding biodiversity response to anthropogenic disturbances. Conserving arthropod diversity in the Sahel will require the creation and preservation of more protected areas of a variety of sizes and successional stages as well as the adoption and extension of land-restorative techniques such as Zai and farmer managed natural regeneration (FMNR).

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Gómez, Polo Priscila. "Molecular identification and feeding ecology of arthropod generalist predators present in Mediterranean lettuce crops." Doctoral thesis, Universitat de Lleida, 2014. http://hdl.handle.net/10803/285489.

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The aphid Nasonovia ribisnigri (Hemiptera: Aphididae) and the thrips Frankliniella occidentalis (Thysanoptera: Thripidae) are two of the main pests in Mediterranean lettuce crops. The general goal of this Doctoral Thesis is to deepen in the study of the trophic interactions present in Mediterranean lettuce crops, in order to develop, apply and improve conservation biological control (CBC) programs using molecular techniques. Results showed the most abundant predator were Orius laevigatus, O. majusculus and O. niger (Hemiptera: Anthocoridae), the hoverflies Eupeodes corollae, Episyrphus balteatus and Sphaerophoria scripta/S. rueppellii (Diptera: Syrphidae), the coccinelid Coccinella septempunctata (Coleoptera : Coccidellidae) and spiders (Araneae: Linyphiidae, Thomosidae). Moreover, coccinellids were only found in spring, syrphids mainly in spring, but also in summer and Orius were only found in summer. With these abundances, the coccinellids were the most efficient predators of N. ribisnigri in spring; syrphids were the most efficient predators of F. occidentalis in spring; and Orius were the most efficient control agents of F. occidentalis in summer. In conclusion, molecular analysis of predation has allowed the characterization of the trophic links present in Mediterranean lettuce crops, which is of a great importance in order to develop CBC programs in those crops.
El pulgón Nasonovia ribisnigri ( Hemiptera: Aphididae ) y el trips Frankliniella occidentalis (Thysanoptera: Thripidae) son dos de las principales plagas en cultivos de lechuga mediterráneos. El objetivo general de esta Tesis Doctoral es profundizar en el estudio de las interacciones tróficas presentes en cultivos de lechuga mediterráneos, con el fin de desarrollar, aplicar y mejorar programas de control biológico (CB) por conservación mediante métodos moleculares. Los resultados mostraron que los depredador más abundantes fueron Orius laevigatus, O. majusculus y O. níger (Hemiptera: Anthocoridae ), los sírfidos Eupeodes corollae , Episyrphus balteatus y Sphaerophoria scripta / S. rueppellii (Diptera: Syrphidae), el coccinélido Coccinella septempunctata (Coleoptera : Coccidellidae) y arañas (Araneae: Linyphiidae, Thomosidae). Además los coccinélidos se encontraron sólo en primavera, los sírfidos principalmente en primavera, aunque también en verano y los Orius sólo en verano. Con estas abundancias, los coccinélidos fueron los depredadores más eficientes de N. ribisnigri en primavera; los sírfidos fueron los depredadores más eficientes de F. occidentalis en primavera; y Orius fueron los agentes de control más eficiente de F. occidentalis en verano. En resumen, los análisis moleculares de depredación han permitido la caracterización de las relaciones tróficas presentes en cultivos de lechuga del Mediterráneo, lo cual es de gran importancia para el desarrollo de programas de CB de este cultivo en esta zona.
El pugó Nasonovia ribisnigri (Hemiptera : Aphididae) i el trips Frankliniella occidentalis (Thysanoptera : Thripidae) són dues de les principals plagues en cultius d'enciam mediterranis . L'objectiu general d'aquesta Tesi Doctoral és aprofundir en l'estudi de les interaccions tròfiques presents en cultius d'enciam mediterranis , per tal de desenvolupar , aplicar i millorar programes de control biològic (CB) per conservació . Els resultats van mostrar que els tàxons de depredador més abundants van ser Orius laevigatus , O. majusculus i O. níger (Hemiptera : Anthocoridae), els sírfids Eupeodes corollae , Episyrphus balteatus i Sphaerophoria scripta / S. rueppellii (Diptera : Syrphidae), el coccinélid Coccinella septempunctata (Coleoptera : Coccidellidae) i aranyes (Araneae: Linyphiidae, Thomosidae). A més els coccinélidos es van trobar només a la primavera , els sírfids principalment a la primavera , encara que també a l'estiu i els Orius només a l'estiu . Amb aquestes abundàncies , els coccinélidos van ser els depredadors més eficients de N. ribisnigri a la primavera ; els sírfids van ser els depredadors més eficients de F. occidentalis a la primavera ; i Orius van ser els agents de control més eficient de F. occidentalis a l'estiu.En resum, les anàlisis moleculars de depredació han permès la caracterització de relacions tròfiques presents en cultius d'enciam de la Mediterrània la qual cosa és de gran importància per al desenvolupament de programes de CB d'aquest cultiu a la zona estudiada.

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24

Jennings, David. "The Conservation and Ecology of Carnivorous Plants." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3169.

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As discussed in Chapter 1, although our understanding of the ecology and evolution of carnivorous plants has greatly improved in recent years, many fundamental questions remain unanswered. Unfortunately, at the present time, many carnivorous plants are increasingly threatened by anthropogenic activities. Indeed, over half of the carnivorous plant species assessed by the International Union for the Conservation of Nature (IUCN) are listed as `threatened', but the threats to carnivorous plants have not previously been quantified. In Chapter 2, I quantified the conservation threats to carnivorous plant taxa worldwide by searching peer-reviewed literature, and found data on the threats to 48 species of carnivorous plants from nine genera. The most common threat was habitat loss from agriculture, followed by the collection of wild plants, pollution, and natural systems modifications. As I found in Chapter 2, while agrochemical pollution is thought to be an important conservation threat to carnivorous plants, the effects of insecticides in particular on these taxa have not previously been quantified. Therefore in Chapter 3 I tested the effects of commercial and technical grades of three widely used insecticides (carbaryl, lambda-cyhalothrin, and malathion) on survival and the expression of traits associated with carnivory of pink sundews (Drosera capillaris) and Venus flytraps (Dionaea muscipula) using a combination of lab- and field-based experiments. Commercial grades were generally more harmful than technical grades under lab and field conditions, but all three insecticides were capable of causing negative effects on the plants within recommended application rates. Pink sundews appeared to be more susceptible to insecticides than Venus flytraps, perhaps because of larger numbers of digestive glands on the leaf surfaces. Given the effects observed, I suggest that the use of insecticides should be carefully managed in areas containing vulnerable carnivorous plant species. For Chapters 4 and 5, I explored the ecological role of carnivorous plants, specifically if they could compete with animals for shared prey resources. In Chapter 4 I characterized the ground-surface spider and arthropod assemblages of two mesic flatwood habitats in Florida, to resolve what the most likely animal competitor was for pink sundews. I identified 31 spider species from 27 genera in 12 families, with wolf spiders (Lycosidae) being the dominant spider family at both sites. Based on their abundance and the behavioral traits they exhibited, I determined that the funnel-web-building wolf spider Sosippus floridanus was the most likely potential competitor with pink sundews. Collembola and Formicidae were the most abundant arthropod taxa present, but ground-surface spiders were not strongly associated with any typical prey groups, suggesting that environmental factors might also be important in structuring this community. Subsequently, in Chapter 5 I examined the potential for competition between carnivorous plants and animals by studying dietary and microhabitat overlap between pink sundews and wolf spiders in the field, and by conducting a lab experiment examining the effects of wolf spiders on sundew fitness. In the field, I found that sundews and spiders had high dietary overlap with each other and with the available arthropod prey. Associations between sundews and spiders depended on spatial-scale: sundews and spiders were both found more frequently in quadrats with more abundant prey, but within quadrats spiders constructed larger webs and located them further away from sundews as the total sundew trapping area increased. Spiders also constructed larger webs when fewer prey were available. In the lab, my experiment revealed that spiders can significantly reduce sundew fitness. All of these results suggest that members of the plant and animal kingdoms can and do compete. These findings provided inspiration for Chapter 6, where I explored if phylogenetic distance was a good predictor of the strength of competition between taxa, using a meta-analytical approach. I collected data from studies published from 1998-2008 in eight ecology journals using the keyword `interspecific competition', gathering a total of 191 effect sizes. I found no significant relationship between phylogenetic distance and the strength of competition, contrary to the long-standing assumption that it should be greatest in strength between closely related species. However, these findings could presently be limited by publication bias, and I suggest several directions for future research.

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25

De, Vries J. L. "Impacts of a specialist diet on aardwolf ecology." Thesis, University of Pretoria, 2013. http://hdl.handle.net/2263/79702.

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The diet of an animal plays a fundamental role in its ecology, and the consequence of a specific diet may be more pronounced in mammals with a specialised diet that are more reliant on a specific food type. This can have a dramatic effect on its activity patterns, home range size and the interaction with heterospecifics. Investigating the diet of specialist mammals and the subsequent effects it will have on their ecology is thus vital to the management and subsequent conservation of the species, and crucial to our understanding of how the animal can survive and reproduce. In this thesis I investigate the effect that the diet of the aardwolf, a highly specialised myrmecophage, has on its ecology. Aardwolves feed predominantly on one genus of termite, Trinervoides spp., and are thus extremely dependent on the abundance and distribution of this arthropod. I firstly investigated the effect of temperature and rainfall on arthropod abundance and diversity, and further investigated the variation of arthropod abundance and diversity across the four habitat types at study site. This is one of a few studies that have been conducted on arthropod abundance and diversity in an arid environment and the findings show that in an arid environment arthropods are mainly influenced by temperature rather than rainfall. This is in contrast to studies in temperate and forest habitats where rainfall is the most important abiotic factor determining the abundance and diversity of arthropod assemblages. Habitat type still plays a major role in the abundance and diversity of arthropods, and habitat types that are more complex and diverse have both a higher diversity, and abundance of arthropods than other habitats. Due to the absence of prey items during the colder months of the year I investigated the diet of aardwolves to see if they display a switch in diet. This included an investigation into the seasonal variation of diet from a detailed scat analysis, using a newly developed method to assess scat content. The analysis of scats revealed that, contrary to previous studies, aardwolves showed no switch in diet and continued to feed on Trinervitermes. Using the data from the scat analyses and the information from the abundance and diversity of arthropods at the study site I expanded the study to investigate the functional responses of the aardwolf to change in prey abundance at the locality. Aardwolves demonstrate a Type I functional response to changes in prey abundance, a response that is normally found in plankton feeders. The expected functional response for specialist animals would be Type II response, and I propose that the Type I response seen in aardwolves is probably as a result of a limited handling time which reduces time spent foraging. The abundance of termites thus had a clear effect on the diet of aardwolves, showing that they feed on fewer when they are unavailable, and as such I investigated the effect of termite densities on home range sizes. The number of termite mounds in a home range influenced the size of the home range, and aardwolves with larger home ranges had a lower density of termite mounds. In contrast to previous studies, large overlaps between neighbouring individuals were recorded and indeed three male aardwolves shared a common den. I propose that the reason behind the overlap of home ranges is that a higher prey abundance during my study period occurred and as a consequence aardwolves did not need to defend an area to protect this resource. T. trinervoides has thus played a keystone role in driving the biology of the aardwolf and shaping many aspects of its ecology.
Thesis (PhD)--University of Pretoria, 2021.
South African Research Chair Initiative chair of Mammal Behavioural Ecology and Physiology
Zoology and Entomology
PhD
Unrestricted

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26

Folkard, Nicholas Francis Goring. "An experimental study of the plant-arthropod-bird food chain in the southwestern Yukon." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28985.

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I describe an experimental study of the importance of food limitation and predation at three trophic levels in a terrestrial food web. The study system was the herb layer vegetation - arthropod - insectivorous bird food chain in the boreal forest near Kluane Lake, southwestern Yukon. Since little is known about boreal bird communities, I conducted a descriptive study of the community of passerine and piciform birds at Kluane in addition to the main study. Variable circular plot point counts were used to estimate bird populations in 1987 through 1990. Species' habitat preferences, use of foraging substrates and diets were studied in 1988 and 1989. Population densities, species richness and evenness were all low. Yellow-rumped warblers (Dendroica coronata) and dark-eyed juncos (Junco hyemalis) dominated the community. Common species differed markedly in their habitat preferences, and showed generally low overlaps in their use of foraging substrates. There was little evidence of dietary specialization. There was rather little spatial variation in the community, and species composition and total density remained approximately the same through time. However, there were large fluctuations in some species' populations between 1987 and 1989. The experimental study was conducted at two scales. Chemical fertilizer was applied to two 570m x 570m areas in 1987, 1988 and 1989. I compared arthropod populations, bird populations and bird reproductive performance in these areas with those in two control areas. Two experiments using 5m x 5m plots were performed in 1988 to examine the effects of fertilization on plants and arthropods in more detail, and to study the responses of these trophic levels to the exclusion of passerine birds and mammalian herbivores. All three trophic levels responded positively to fertilization, but the results were variable and there were no very large increases in biomass or population size. Dark-eyed juncos nested one week earlier in fertilized areas, which may have enhanced their reproductive success. Passerine exclusion did not increase arthropod biomass, but exclusion of mammalian herbivores increased plant biomass. "Bottom-up" limitation by food appears to dominate this system, but "top-down" limitation also operates at at least one level. More work is needed to fully understand how the system functions.
Science, Faculty of
Zoology, Department of
Graduate

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27

Attah, P. K. "The insect pests and polyphagous arthropod predators associated with crops of oilseed rape in North Yorkshire and Humberside." Thesis, University of York, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373304.

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28

Sasa, Archbold. "Arthropods associated with commercial Proteaceae in the Western Cape Province, South Africa." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6805.

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Thesis (MSc)--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: The commercial cultivation of Proteaceae is an important industry in the Western Cape, however, farmers are challenged with arthropod infestation which compels them to solely rely on chemical pesticides. Past studies in South Africa have shown that Proteaceae comprise a rich and diverse arthropod fauna. However, as most of these studies were conducted on wild Proteaceae, they may not be representative of cultivated proteas. Moreover, most of these species remained unidentified due to lack of identification expertise. These past studies, however, form a useful baseline for arthropod studies in proteas, e.g. the feeding guilds found in proteas. The aim of this research was to conduct an intensive and extensive survey of the arthropod-fauna associated with commercially-cultivated proteas across an entire year. Specifically, this survey was designed to document the composition of the arthropod fauna (creating a comprehensive reference collection for pest management purposes) and to assess whether the arthropod fauna differed between seasons and pesticide treatments. Infructescences, inflorescences and foliage of mainly commercial Proteaceae were sampled for arthropods seasonally for a period of twelve months by collection of plant material and direct searching. Seven commercial protea blocks, and a wild protea block (remnant patch of fynbos vegetation), were used as the sampling sites, and two sprayed blocks were used for assessing pesticide efficacy. Individual arthropods were identified as far as possible, with 37% identified to species level. A species accumulation curve showed that rare (minor) arthropod species made up of 70% of arthropods occurring in cultivated proteas. More than 8 700 individuals from more than 140 species and about 80 families were collected and identified, revealing that cultivated proteas have a rich and diverse insect fauna. These arthropods represent the full range of plant-feeding guilds: leaf miners, leaf chewers, flower bud borers, sap suckers and seed feeders. Flower visitors/free living guild was the most abundant (72%) and speciose (25%). In addition to phytophages, there was a large suite of insect predators and parasitoids. A large number of the arthropods were endemic to the Cape Floristic Region (CFR) and some (7.86%) have a pest status, in that they cause significant damage to the protea plants (for example, 60% of Safari sunset cultivar (Leucadendron salignum x L. laureolum) new flush stems and leaves were affected by Epichoristodes acerbella (Tortricidae). Capys alphaeus (Lycaenidae) and Phyllocnistis sp. (Phyllocnistidae) appear to be specialist pests, as they attack mainly Protea cynaroides and Susara cultivar (Protea magnifica x P. susannae) respectively. Arthropod abundance did not differ significantly between seasons, although significant seasonal effects were observed in species richness when the protea cultivars were examined separately. Pesticide application did not affect arthropod abundance, but did decrease species richness in sprayed blocks. Pesticides appeared to negatively affect minor (rare) species disproportionately, probably due to their lack of prior exposure to pesticides and hence sensitivity. Due to this inefficacy of pesticides in cultivated proteas, an increasing emphasis on the importance of non-chemical control measures, and our improved knowledge of the predatory and parasitic species in this system, integrated pest management strategies deserve greater research attention. Monitoring and use of threshold values for arthropod pests were suggested here, as well as the use of biological, cultural, physical and chemical (optimal use) control. For instance, in cultural control, polycropping and intercropping in proteas to increase plant diversity in the monocultures to promote a higher density of predators and parasitoids can be used. Certain flowering plants are known to provide greater temporal and spatial distribution of nectar and pollen sources, which can increase parasitoid reproductive potential and abundance of alternative hosts/prey when the pest species are scarce or at an inappropriate stage.
AFRIKAANSE OPSOMMING: Die kommersiële verbouing van Proteaceae (proteas) is 'n belangrike bedryf in die Wes-Kaap. Menige plantasie wemel egter van artropodes, wat boere noop om slegs van chemiese plaagdoders gebruik te maak. Vorige studies in Suid-Afrika toon dat proteas die gasheerplant vir 'n ryke en diverse artropodefauna is. Aangesien die meeste van hierdie studies egter op wilde proteas uitgevoer is, weerspieël dit moontlik nie die stand van sake met verboude proteas nie. Weens 'n gebrek aan kundigheid om die artropodes te eien word baie van die spesies boonop nooit uitgeken nie. Dié studies voorsien egter 'n nuttige grondlyn vir 'n ondersoek na die artropodes op proteas, veral vir die bestudering van die gilde wat van die protea leef (“the feeding guild”). Hierdie navorsing het ten doel om 'n intensiewe en omvattende opname te maak van die artropodefauna wat oor die tydperk van 'n jaar op kommersieel verboude proteas voorkom. Die opname is meer bepaald ontwerp om die samestelling van die artropodefauna te bestudeer (deur 'n omvattende verwysingsversameling vir plaagbestuurdoeleindes te skep), en om vas te stel of seisoene en plaagbehandelings enige beduidende uitwerking op die artropodefauna het. Oor 'n tydperk van 12 maande is seisoenale monsters van die vrug- en bloeistadia, saadkoppe en blare van hoofsaaklik kommersiële proteas gesoek en ingesamel. Sewe kommersiële proteablokke sowel as 'n blok wilde proteas het as proefpersele gedien, en twee bespuite blokke is gebruik om die doeltreffendheid van plaagdoder te beoordeel. Individuele artropodes is so noukeurig moontlik uitgeken – 37% tot op spesievlak. Volgens 'n spesieakkumulasiekurwe maak seldsame (kleiner) artropodespesies sowat 70% van die artropodes uit wat op verboude proteas voorkom. Die meer as 8 700 individue van meer as 140 spesies en sowat 80 families wat ingesamel en uitgeken is, toon die rykheid en diversiteit van die artropodefauna op verboude proteas. Hierdie artropodes verteenwoordig die volle reeks plantvreterspesies – van blaardelwers en blaarkouers tot blomknopboorders, sapsuiers en saadvreters. Blombesoeker-/vrylewende spesies was die volopste (72%) en mees divers (25%). Buiten plantvreters was daar ook 'n groot aantal roofinsekte en parasitoïede. Baie van die artropodes was inheems, en sommige (7,86%) het boonop plaagstatus, aangesien hulle beduidende skade aan die proteaplant aanrig. [By ongeveer 60% van die Safari Sunset-kultivar (Leucadendron salignum x L. laureolum) is nuwe stamme en blare byvoorbeeld deur die Epichoristodes acerbella (Tortricidae) aangetas.] Capys alphaeus (Lycaenidae) en Phyllocnistis sp. (Phyllocnistidae) blyk spesialisplae te wees wat onderskeidelik hoofsaaklik die Protea cynaroides en die Susarakultivar (Protea magnifica x P. susannae) in die visier het. Artropodegetalle het nie juis tussen seisoene gewissel nie, hoewel 'n afsonderlike ondersoek van die proteakultivars 'n beduidende seisoenale uitwerking op spesierykheid aan die lig gebring het. Eweneens het die toediening van plaagdoder nie die artropodegetalle verminder nie, maar wel spesierykheid op die bespuite blokke verswak. Plaagdoders blyk besonder negatiewe uitwerking op kleiner (seldsame) spesies te hê – waarskynlik omdat dié spesies nie voorheen aan plaagdoders blootgestel was nie, en dus gevoelig is daarvoor. Weens die oënskynlike ondoeltreffendheid van plaagdoders op verboude proteas, verg 'n toenemende klem op die belang van niechemiese beheermaatreëls, 'n behoefte aan meer kennis van die roof- en parasitiese spesies in die stelsel, en die vraag na geïntegreerde plaagbeheerstrategieë, meer navorsing. Die studie moniteer en gebruik drempelwaardes vir artropodeplae, sowel as biologiese, kulturele, fisiese én chemiese (‘optimalegebruik’-) plaagbeheer. Met kulturele beheer kan poli- en interverbouing van proteas byvoorbeeld gebruik word om plantdiversiteit in die monokulture te verbeter, ten einde só 'n hoër digtheid van roofspesies en parasitoïede in die hand te werk. Sekere blomplante bied kenmerkend 'n wyer tyd- en ruimtelike verspreiding van nektar- en stuifmeelbronne, wat parasitoïede se voortplantingsvermoë en die getalle van alternatiewe gashere/prooi kan verbeter wanneer die plaagspesies skaars is of in 'n ontoepaslike stadium verkeer.

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29

Kielty, Jonathan Peter. "The effects of field margins on the distribution and biocontrol potential potential of polyphagous predatory arthropods in arable crops." Thesis, University of Hertfordshire, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314623.

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30

Lima, Iara Cristina da Silva. "Padrões de distribuição da diversidade de Collembola (Arthropoda, Hexapoda) no semiárido Paraíba." Universidade Estadual da Paraíba, 2015. http://tede.bc.uepb.edu.br/tede/jspui/handle/tede/2402.

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The Domain Caatinga spans much of the Northeast, the semiarid climate and xerophytic vegetation are striking characteristics of this area. Collembola are found in all zoogeographic regions of the Earth, are non-insect hexapods animals, edaphic and highly dependent on soil moisture. The diversity of this group is closely linked to seasonal and environmental characteristics.The aim of this paper was to verify the Collembola distribution patterns in three areas of environmental protection in the semiarid Paraiba, in the cities of São João do Cariri, São João do Tigre and Santa Teresinha. The search was conducted for two seasonal periods of the year, the dry season and rainy season. In each study area, they were drawn ten plots of 100m² and each plot was traced three distant points among themselves five meters for the removal and measurement of litter and phytosociological survey; in each plot was taken a soil sample. The organisms collected were screened and identified the species level. Absolute and relative abundances were estimated richness, diversity indices, equitability and similarity. To analyze the abundance of the regions between the samples was the Kruskal-Wallis test. The representativeness of the inventory was estimated using species accumulation curve. Within the Protected Areas and between areas: alpha diversity and estimated the beta diversity into two distinct scales was quantified. The diversity indices of Shannon-Wiener, α-Fisher, Margalef, Simpson and Whittaker were used; and the evenness index of Pielou. A cluster analysis was performed to verify the formation of groups among the studied areas. Multivariate as Canonical Correspondence Analysis were used to evaluate the composition of communities and associate this composition habitat. It was collected 6,226 individuals of Collembola during the two periods of collections, represented by 24 species, 17 genera and 9 families; where the dry season (PS) were recorded 50 individuals distributed in 4 families, 7 genera and 7 species During the rainy season (PC) were collected 6,176 individuals in nine families, 17 genera and 24 species. The most representative species were Brachystomella purma and B. agrosa totaling 83.74% of the individuals found. According to statistical analysis, areas of São João do Cariri and Santa Teresinha are most closely related and are more homogeneous than the areas of São João do Tigre. Therefore, any strategies for environmental conservation areas studied should take into account the spatial scales presented in this study, since the change in diversity was highest within each study area.
O Domínio da Caatinga se estende por grande parte da região Nordeste, o clima semiárido e a vegetação xerófila são características marcantes dessa área. Collembola são encontrados em todas as regiões zoogeográficas da Terra, são animais hexápodes não-insetos, edáficos e bastante dependentes da umidade do solo. A diversidade desse grupo está intimamente ligada às características sazonais e ambientais. O objetivo do trabalho foi verificar os padrões de distribuição de Collembola em três regiões de proteção ambiental no semiárido Paraibano, localizadas nas cidades de São João do Cariri, São João do Tigre e Santa Teresinha. A pesquisa foi realizada durante dois períodos estacionais do ano, o período de estiagem e período chuvoso. Em cada área de estudo, foram traçados dez parcelas de 100m² e em cada parcela foi traçados três pontos distantes entre si cinco metros para a retirada e medição do folhiço e levantamento fitossociólogico; em cada parcela foi retirada uma amostra de solo. Os organismos coletados foram triados e identificados a nível de espécies. Foram estimadas abundâncias absoluta e relativa, riqueza, índices de diversidade, equitabilidade e similaridade. Para analisar a abundância entre as amostras das regiões foi utilizado o teste de Kruskal-Wallis. A representatividade do inventário foi estimada por meio de curva de acumulação de espécies. Foi quantificada a diversidade alfa e estimada a diversidade beta em duas escalas distintas: dentro das Áreas de Proteção e entre as Áreas. Foram utilizados os índices de diversidade de Shannon-Wiener, α-Fisher, Margalef, Simpson e Whittaker; e o índice de equitabilidade de Pielou. Uma análise de agrupamento de cluster foi realizada para verificar a formação de grupos entre as áreas estudadas. Técnicas de análise multivariada como Análise de Correspondência Canônica foram usadas para avaliar a composição das comunidades e associar esta composição ao habitat. Foram coletados 6.226 indivíduos de Collembola durante os dois períodos de coletas, representados por 24 espécies, 17 gêneros e 9 famílias; no qual no período seco (PS) foram registrados 50 indivíduos distribuídos em 4 famílias, 7 gêneros e 7 espécies No período chuvoso (PC) foram coletadas 6.176 indivíduos distribuídos em 9 famílias, 17 gêneros e 24 espécies. As espécies mais representativas foram Brachystomella purma e B. agrosa que somaram 83,74% dos indivíduos encontrados. De acordo com as análises estatísticas, as áreas de São João do Cariri e de Santa Teresinha estão mais intimamente relacionadas e são mais homogêneas do que as áreas de São João do Tigre. Sendo assim, quaisquer estratégias voltadas à conservação ambiental das áreas estudadas devem levar em consideração as escalas espaciais apresentadas neste estudo, já que a variação da diversidade foi maior dentro de cada área estudada.

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Lima, Estevam Cipriano Araújo de. "Diversidade de collembola (Arthropoda, Hexapoda) do arquipélago Fernando de Noronha, Brasil." Universidade Estadual da Paraíba, 2014. http://tede.bc.uepb.edu.br/tede/jspui/handle/tede/2081.

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Made available in DSpace on 2015-09-25T12:22:56Z (GMT). No. of bitstreams: 1 PDF - Estevam Cipriano Araujo de Lima.pdf: 1780691 bytes, checksum: 6d96c61393940933aac44c66940be196 (MD5) Previous issue date: 2014-02-20
The terrestrial fauna on oceanic islands is highly vulnerability and diversity particular due to the geographical limited and unique space. Conservation Strategies of island must be strict to ensure the maintenance of diversity. The recognition of distribution patterns of diversity is important to determine the appropriate spatial scales for the development of conservation strategies biogeographic. This work, by partitioning the diversity of Collembola in Oceanic Islands of the Archipelago Fernando de Noronha, we present the distribution pattern the diversity of arthropods and also described a new species of Collembola endemic to this island environment. This work was structured in three chapters. In the first we present the state of the art, the objectives (general and specific), hypothesis, inquiry and characterization of the study area. The remaining chapters were developed in article format, respecting the proposed by the respective magazines format. The second chapter presents a study on the spatial distribution of Collembola, which determine the appropriate scale for the conservation of the Archipelago Fernando de Noronha and will be submitted for Diversity and Distributions ( IF 6.122 ) magazine and third present the first species of collembola endemic and restricted the sandy strand of the Archipelago Fernando de Noronha published in The Florida Entomologist (IF 1.163 ) in December 2013 (volume 96 , pages 1579-1587) titled " A New Species of Isotogastrura (Collembola : Isotogastruridae) from Northeastern Brazil " (PALACIOS - VARGAS et al., 2013) .
A fauna terrestre em ilhas oceânicas apresenta alta vulnerabilidade e diversidade particular, devido ao espaço geográfico restrito e único. As estratégias de conservação dos ambientes insulares devem ser rigorosas para garantir a manutenção da diversidade. O reconhecimento dos padrões de distribuição da diversidade é importante para determinar as escalas espaciais apropriadas para o desenvolvimento de estratégias de conservação biogeográfica. No presente trabalho, através do particionamento da diversidade de Collembola em Ilhas Oceânicas do Arquipélago Fernando de Noronha, apresentamos o padrão de distribuição da diversidade destes artrópodes e também descrevemos uma nova espécie de Collembola endêmica deste ambiente insular. Este trabalho foi estruturado em três capítulos. No primeiro apresentamos o estado da arte, os objetivos (gerais e específicos), hipótese, pergunta e a caracterização da área de estudo. Os demais capítulos foram desenvolvidos em formato de artigo, respeitando o formato proposto pelas respectivas revistas. O segundo capítulo traz um estudo sobre a distribuição espacial de Collembola, onde determinamos a escala apropriada para a conservação do Arquipélago Fernando de Noronha e será submetido à revista Diversity and Distributions (IF 6.122) e no terceiro apresentamos a primeira espécie de collembola endêmica e restrita ao cordão arenoso do Arquipélago Fernando de Noronha publicado na revista The Florida Entomologist (IF 1.163) em dezembro de 2013 (volume 96, páginas 1579-1587) intitulado A New Species Of Isotogastrura (Collembola: Isotogastruridae) From Northeastern Brazil (PALACIOSVARGAS et al., 2013).

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Camarinha, Inês Maria Ferreira. "Post-fire evaluation of shrub and arthropod communities." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/10245.

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Mestrado em Biologia Aplicada
Devido ao aumento da incidência de incêndios em Portugal, torna-se cada vez mais urgente uma avaliação dos efeitos deste fenómeno nas florestas, estando estas entre os ecossistemas mais afetados. As florestas de eucaliptos, de pinheiros e mistas, abundantes no centro do país, apresentam características distintas, sendo fundamental um estudo comparativo destas espécies. Este trabalho propôs-se a uma avaliação da regeneração da flora a médio prazo (5 anos após o evento), assim como da recuperação da comunidade de artrópodes, ambas componentes essenciais do meio florestal e severamente afetadas pelo fogo. Na regeneração da flora, registaram-se diferenças entre parcelas ardidas e não ardidas. Houve diferenças significativas entre as comunidades de artrópodes de pinhais e de eucaliptais. Os índices de diversidade obtidos indicam que a recuperação da comunidade foi mais elevada em florestas de pinheiro do que em florestas de eucalipto. A análise de redundância (RDA), demonstrou que as variáveis responsáveis pela distribuição de dados são as variáveis associadas com o horizonte orgânico do solo, nomeadamente a cobertura e profundidade da folhada, a percentagem de humidade e de matéria orgânica nesta camada. De forma global, os resultados indicaram diferenças significativas entre os povoamentos de eucaliptos e pinheiros, incluindo ao nível da regeneração pós-fogo das comunidades, que foi mais rápida em pinhais. Em geral, as diferenças encontradas foram sempre mais significativas entre parcelas ardidas e não ardidas, do que entre os diferentes tipos de povoamentos.
The incidence of fire in Portugal has been rising, and with it the urgency for a complete evaluation of the effects of these phenomena in forests, which are among the most affected ecosystems. Eucalypt, pine and mixed stands – the most abundant types of forest in the centre of the country – present distinct characteristics, being fundamental a comparative study of these different stands. This work is meant as a post-fire evaluation of the mid-term regeneration of the flora – 5 years after the event; as well as of the recovery of the arthropod community. Both these components are vital for the good functioning of a forest and are severely affected by fire. Regarding floristic regeneration, there were significant differences between burnt and unburnt plots. For the arthropod data, there were significant differences between pine and eucalypt stands. The results obtained from diversity indexes indicate that the recovery in pine stands was higher than in eucalypt stands. The redundancy analysis (RDA) revealed that the main variables responsible for the data variation were the ones associated with the organic horizon, namely litter depth and cover, humidity and organic matter percentage in this layer. Globally, results indicate that there are significant differences between pine and eucalypt stands, which include differences regarding the post-fire regeneration of communities, which was faster in pine stands. Nonetheless, differences were generally more profound between burnt and unburnt plots, than between types of stand.

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van, Schalkwyk Julia. "Biodiversity conservation in a fragmented landscape : arthropod assemblages in smaller corridors within a production landscape." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96752.

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Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Habitat loss and fragmentation are major threats to global biodiversity. A cornerstone of traditional conservation involves setting aside land as formally protected areas (PAs). However, for effective biological conservation in the long term there needs to be connectivity between these PAs. When possible, improved connectivity can be achieved using natural corridors at a landscape scale. Even better is to establish a network of corridors and nodes in the form of ecological networks (ENs). ENs are currently being employed by commercial forestry companies in South Africa. While larger corridors and nodes are considered optimum, factors other than design, such as management and environmental heterogeneity, have also been found to be important for species maintenance. This study aims to explore the role of corridor width in driving the composition of invertebrate assemblages across a transformed landscape in KwaZulu-Natal, South Africa, and to investigate other possible environmental variables significant for species distributions. In Chapter 2, I investigated the contribution of smaller grassland corridors within a timber production matrix to overall biodiversity conservation using two important bioindicator taxa. Ants and dung beetles were sampled in grassland corridors of three size classes, plantation blocks and a nearby PA, iMpendle Nature Reserve. The two taxa showed differential responses to landscape level fragmentation. Dung beetles showed a decrease in species richness and corresponding increase in species turnover with increased fragmentation, while ants were unaffected, although counter intuitively smaller corridors even contained more unique ant species compared to larger corridors. Dung beetle assemblages also showed strong differences between the PA and grassland corridors. While the conservation effectiveness of large corridors undoubtedly exceeds that of smaller corridors, for ants it seems that smaller corridors contribute to their overall conservation within this production landscape. In Chapter 3, I explore the importance of spatial and environmental factors for species distribution across this landscape. Dung beetles were split into functional guilds according to size and nesting behaviour for analyses. Within grassland corridors, tunnelling dung beetle species richness was sensitive to landscape level fragmentation, especially for larger species, while elevation and vegetation type influenced ant species richness. Since rolling dung beetles showed a close association with the PA, the marked difference in dung beetle assemblages between these two land-uses may be due to the presence of pellet producing grazers in the protected area and their replacement by pat producing cattle in the grassland corridors. Other environmental variables that were found to be important for dung beetle species composition were elevation, vegetation type, and soil hardness. For ant species composition, only elevation was found to be important. In conclusion, as large corridors were comparable to the PA in dung beetle and ant species richness, ENs act as extensions of formally PAs, given that they are large enough. Nevertheless, smaller corridors had surprisingly high species richness. Including additional information other than species data improved our knowledge of the underlying factors that drive dung beetle species composition. Even though dung beetle and ant species responded differentially to habitat fragmentation, environmental heterogeneity seemed important for both taxa. Incorporating habitat heterogeneity into the current management scheme may improve the conservation effectiveness within this transformed landscape.
AFRIKAANSE OPSOMMING: Die vermindering en fragmentasie van natuurlike habitat is ‘n groot bedreiging vir globale biodiversiteit. ‘n Belangrike tradisionele benadering tot natuurbewaring behels die afbakening van land vir formele beskermde areas (BAs). Ten einde effektiewe biologiese bewaring oor die langtermyn te verseker moet daar verbinding wees tussen hierdie BAs. Indien moontlik kan verbeterde verbinding verkry word deur die gebruik van natuurlike gange op ŉ landskaps-vlak. Nog beter is om ŉ netwerk van gange en nodes in die vorm van ekologies netwerke (ENe) saam te stel. ENe word tans deur kommersiële bosboumaatskappye in Suid Afrika aangewend. Terwyl groter gange en nodes as optimaal beskou word, is ander faktore behalwe ontwerp, soos bestuur en omgewingsheterogeniteit, ook al gevind as belangrik vir die onderhouding van spesies. Hierdie studie is gemik daarop om die rol van gangwydte as dryfkrag vir die samestelling van invertebraatversamelings oor ŉ getransformeerde landskap in KwaZulu-Natal, Suid-Afrika, te ondersoek, asook ander moontlike omgewingsveranderlikes wat belangrik vir spesiesverpreidings kan wees. In Hoofstuk 2 het ek die bydrae van kleiner gange tot totale biodiversiteit-bewaring ondersoek deur twee belangrike bio-indikator taxa te bestudeer. Miere en miskruiers is versamel in grasland-gange van drie grootte-klasse, plantasie blokke en ‘n naby geleë BA, iMpendle Natuurreservaat. Die twee taxa het verskillende reaksies tot landskaps-vlak fragmentasie getoon. Miskruiers het ‘n verlaging in spesiesrykheid en ‘n gesamentlike verhoging in spesiesomset met verhoogde fragmentasie gewys, terwyl miere nie geaffekteer is nie, alhoewel kleiner gange het trouens meer unieke mierspesies bevat as groter gange. Die miskruierversamelings in die BA het ook opmerklik verskil van dié in die grasland-gange. Alhoewel die bewaringsdoeltreffendheid van groot gange beslis dié van kleiner gange oorskry, kom dit voor dat kleiner gange wel bydra tot die totale bewaring van miere binne hierdie produksielandskap. In Hoofstuk 3 het ek die belangrikheid van ruimtelike en omgewingsfaktore vir spesiesverspreiding oor hierdie landskap ondersoek. Miskruiers is ook in funksionele groepe verdeel volgens grootte en nes-gedrag vir aparte analise. Binne grasland-gange was tonnellende miskruierspesies sensitief vir landskaps-vlak fragmentasie, veral groter spesies, terwyl hoogte bo seevlak en vegetasie tipe mier spesiesrykheid beïnvloed het. Aangesien rollende miskruierspesies ‘n nabye assosiasie met die BA gewys het, mag die opmerklike verskil in miskruier versamelings tussen hierdie twee grondgebruike ŉ gevolg wees van die aanwesigheid van korrel-mis produserend beweiders in die BA en hulle vervanging deur nat-mis produserende beeste in die grasland-gange. Omgewingsveranderlikes uitsluitende ganggrootte wat belangrik gevind is vir miskruier spesiessamestelling was hoogte bo seevlak, vegetasie tipe en grond-hardheid. Vir mier spesiessamestelling was slegs hoogte bo seevlak belangrik. Om af te sluit, aangesien groot gange vergelykbaar was met die BA in miskruier en mier spesiesrykheid, tree ENe op as uitbreidings van BAs, mits hulle groot genoeg is. Desnieteenstaande het kleiner gange ‘n verbasende hoë spesiesrykheid gehad, veral onder miere. Die insluiting van addisionele inligting buiten spesiesdata het ons kennis van die onderliggende faktore wat miskruier spesiessamestelling dryf verbeter. Alhoewel miskruier- en mierspesies verskillend gereageer het op habitat fragmentasie, het dit voorgekom asof omgewingsheterogeniteit belangrik was vir die spesiesverspreiding van beide taxa. Die insluiting van habitatheterogeniteit binne die huidige bestuursplan mag die doeltreffendheid van bewaring binne hierdie getransformeerde landskap verbeter.

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Gardner, Eric Ty. "Arthropod and plant communities as indicators of land rehabilitation effectiveness in a semi-arid shrub-steppe /." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2559.pdf.

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Becker, Jamie Erin. "The influence of urbanization on arthropod water demand and lipid and protein consumption in mesic environments." Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1510869685967938.

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Morse, D. R. "Fractals in ecology : The effect of the fractal dimension of trees on the body length distribution of arboreal arthropods." Thesis, University of York, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234971.

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Roets, Francois. "Ecology and systematics of South African Protea-associated Ophiostoma species." Thesis, Link to the online version, 2006. http://hdl.handle.net/10019.1/1469.

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Milano, Vittoria. "Effets de la mosaïque paysagère proche, de l’histoire et des pratiques de gestion locales sur les communautés taxonomiques et fonctionnelles des Collemboles du sol des parcs urbains méditerranéens : les cas de Naples (Italie) et Montpellier (France)." Thesis, Montpellier 3, 2017. http://www.theses.fr/2017MON30088/document.

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L’urbanisation aboutit à une grande diversité environnementale, paysagère, historique des espaces verts en ville, avec également des pratiques de gestion très variées, qui, peuvent affecter la biodiversité qu’ils abritent. Or, la composante du sol reste très peu étudiée et les communautés de Collemboles présentes dans les parcs urbains constitue une thématique de recherche jusqu’à présent relativement ignorée. Si ces Arthropodes sont de petite taille (de l’ordre du millimètre), ils sont en effet très nombreux dans les sols et aujourd’hui reconnus comme de bons indicateurs pour le monitoring des sols.Les effets de différents filtres abiotiques ont été testés en appliquant à la fois une approche taxonomique et fonctionnelle des communautés de Collemboles dans les parcs urbains de Naples et de Montpellier. La thèse se développe alors en trois axes correspondant à l’étude des effets:- de la composition et fragmentation de la mosaïque urbaine proche- des dynamiques temporelles propres aux parcs- des pratiques de gestion courantesL’analyse conduite à Montpellier a permis de mettre en évidence l’existence de plusieurs groupes homogènes de paysages auxquels étaient associées des structures de communautés différentes. En effet, les paysages urbains les plus hétérogènes favorisent le développement et le maintien de communautés mieux structurées et plus riches en espèces.Par ailleurs, l’étude menée à Naples a montré que le maintien d’un couvert végétal spécifique et principalement boisé, conjointement à la présence de litière au sol, apparaissent comme les facteurs les plus importants pour permettre l’établissement de communautés mieux structurées et plus riches en espèces. Dans une moindre mesure, l’âge des parcs et le précédant usage du sol étaient également déterminants.Enfin, une analyse fonctionnelle (étude de traits morphologiques et préférences de microhabitats) a été envisagée pour évaluer l’intensification de la gestion du sous-bois au sein des habitats boisés des parcs des deux villes. Un gradient abiotique clair a été observé. En revanche, contrairement aux hypothèses énoncées et à la littérature récente sur le sujet, les communautés de Collemboles étaient mieux discriminées du point de vue taxonomique que du point de vue fonctionnel. Il semblerait donc que l’intensification de la gestion du sous-bois ne soit pas un filtre environnemental imposant des changements dans les patterns de traits des espèces présentes.Si d’un côté les études développées dans cette thèse apportent des connaissances fondamentales sur l’écologie des Collemboles présents dans les parcs urbains, de l’autre elle vise à intégrer ces résultats pour un développement plus durable en termes d’aménagement et de gestion des espaces verts urbains
Urbanization causes a huge diversity in landscapes, environmental conditions and green spaces history. This phenomena also induces different vegetation management practices, which may affect urban fauna. However, scarce attention has been paid to belowground communities in cities and Collembola hosted by soils of urban parks represent a neglected research topic. These taxa are very common in most soils and have been recognized as proper indicators for soil monitoring programs.The effects of diverse abiotic filters on Collembola in Naples and Montpellier public parks has been studied from both taxonomic and functional points of view. In particular, the PhD work was developed based on three principal axes, aiming to test the effects of:- the neighboring landscape context,- the park historical dynamics,- the current park management.The analyses carried out in Montpellier showed different neighboring landscape patterns to which belonged diverse species communities. Indeed, more heterogeneous landscape patterns guarantee the richest and most structured species communities.The study conducted in Naples highlighted that maintaining a specific land cover, especially a canopy cover, jointly to a litter layer on soils are the main factors assuring more structured species communities. To a less extent, park age and the previous land use of the area were also important drivers in modelling species assemblages.Finally, a functional analysis (i.e. morphological traits and microhabitat preferences) was applied to evaluate the brushwood management intensification in woody areas of both cities parks. A clear abiotic gradient was observed. By contrast, functional responses of Collembola communities to brushwood management intensification contradicted our research hypothesis based on the recent literature. Thus, it seems that brushwood removal does not cause shifts in species trait patterns in urban parks.This PhD work increased fundamental knowledge on urban park Collembola ecology, and it strives to integrate these findings in a more suitable landscaping and management of urban green spaces

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Nighohossian, Cara B. "Arthropod Abundance and Diversity in Restored Longleaf Pine Savannas at Abita Creek Flatwoods Preserve." ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1826.

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The objective of this study is to determine whether changes in arthropod community structure in restored longleaf pine savannas corresponds to differences in vegetation structure often associated with burn frequency. Longleaf pine savannas are fire-maintained ecosystems characteristic of the southeastern United States and have experienced severe declines (around 97%) since European settlement. Changes in fire regime have been instrumental in the declines. Restoration of these ecosystems has involved reinstitution of periodic burnings to promote and maintain vegetative characteristics of the savannas. This study investigates trends in arthropod communities from areas heavily invaded by hardwood shrubs against those dominated by longleaf pines and associated vegetation. These data suggest that herb-dominated sites have higher overall diversity. While overall abundance differences were not found, significant differences have been detected at the order and family level, indicating that vegetation structure and periodic burning are important factors in maintaining arthropod communities characteristic of these savannas.

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Lawrence, Jessica. "Impact of the invasive shrub Lonicera maackii on shrub-dwelling arthropods in an eastern deciduous forest." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1289234685.

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Gaigher, Rene. "The effect of different vineyard management systems on the epigaeic arthropod assemblages in the Cape Floristic Region, South Africa." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/1565.

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Thesis (MScConsEcol (Conservation Ecology and Entomology)--Stellenbosch University, 2008.
In the Cape Floristic Region of South Africa, where wine grape production and biodiversity conservation are of major importance, innovative management of the landscape is necessary to integrate the two activities. Alternative farming, such as organic and biodynamic farming, focuses on the preservation of biological processes in agroecosystems with the aim of increasing the sustainability of these sytems. It has been demonstrated in other regions that alternative farming can enhance biodiversity. This study assessed the potential of alternative vineyard management to conserve biodiversity, in particular epigaeic arthropod diversity, relative to the more widespread integrated vineyard management in the CFR. A hierarchical design was used, consisting of three localities, with three land-uses nested within each locality. The land-uses were alternative vineyards, integrated vineyards and natural vegetation sites as reference habitats. Sampling was done in June and October 2006 using pitfall traps. Nested ANOVAs were used to test for differences in abundance and species richness of the total assemblages, functional feeding guilds and selected generalized predatory taxa. Assemblage patterns were assessed using hierarchical agglomerative clustering and non-metric multidimensional scaling. Canonical correspondence analyses were used to evaluate the effects of environmental variables, management practices and landscape variables on community composition. Alternative vineyards supported a significantly higher overall arthropod abundance and species richness, more diverse predatory, saprophagous, phytophagous and omnivorous guilds, as well as more abundant and speciose spider and rove beetle assemblages than the integrated vineyards. Integrated vineyards harboured a greater abundance of predators, whereas results for nectarivores, wood borers, parasitoids and carabid beetles were variable. The differences could be explained in part by higher non-crop vegetation complexity and reduced management intensity of the alternative vineyards. Community composition was influenced by a combination of management practices, the surrounding landscape and geographic locality, which highlighted the interdependence of the cultivated land and its surroundings.

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Schirmel, Jens [Verfasser]. "Arthropods in a changing environment : a multi-level and -species approach to diversity and ecology in coastal heathlands / Jens Schirmel." Greifswald : Universitätsbibliothek Greifswald, 2011. http://d-nb.info/1013465237/34.

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Bankroff, Timothy J. "Arthropod community response to high-intensity, low-frequency cattle grazing events and pasture succession." Miami University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1417541806.

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Meijer, Michael. "The role of wood ants (Formica rufa) in the Arctic tundra and how climate change may alter this role." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-171898.

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In the Arctic tundra, wood ants play an important ecological role in aerating the soil, cycling nutrients, for seed dispersal and, as biological control by preying on forest pest insects during outbreaks. The increase in temperature, caused by climate change, is positively associated with ant abundance. This could accelerate the wood ants’ effects on the ecosystem, with potentially dramatic consequences for associated taxa. It is, however, still unclear to what extent the ants influence the vegetation and arthropod community. The aim of this study is to investigate the effects ants have on the Arctic tundra ecosystem and how climate change may modify these effects. The study was conducted in Abisko national park, north Sweden, were two study sites were selected: one at low altitude and one at high altitude. I found that wood ants had a substantial effect on the vegetation community close to the mound, with a positive effect on different kind of vascular plant species, and a negative effect on rushes, mosses, and lichens. All the arthropods taxonomic orders and most of the families were positively affected by the presence of ant mounds. Ant mound abundance and volume were positively related with annual insolation and GPP, which indicates that climate change will increase ant abundance in the Arctic tundra. Thus, my results suggest that future climate change will have significant effects on Arctic tundra vegetation and arthropod communities, via positive effects on ant abundance.

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Foldi, Steven Edward. "The Arthropod Seedpod Community Of Mesquite (Prosopis Spp.): What Allows Many Species To Coexist On A Single Resource?" Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/565897.

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I studied the insect seed predator community on mesquite plants (Prosopis spp.) to investigate patterns of community composition in space and time, attempting to better understand the factors that led to the coexistence of many seed predator species on a single plant. This dissertation begins by testing the controversial species limits of Prosopis section Algarobía because hosts may act as environmental filters to insect seed predators. I found evidence for at least eight North American Prosopis species (section Algarobía). Second, I describe and add to the known natural history of 113 arthropod species among 315,174 individuals I collected from seedpod samples across the United States and Mexico. These samples included 187 trees from eight North American Prosopis species from section Algarobía and three from section Strombocarpa. Third, I examined reproductive timing in Prosopis and show that neighboring trees of the same species reproduce synchronously, whereas closely related species stagger reproduction. I found that photoperiod is the main cue that initiates flowering, but that multiple cues are involved. Thus, synchronous reproduction may act as an equalizing process that facilitates coexistence of seed predators in this system. Fourth, I tested for evidence of spatial and temporal niche partitioning among Prosopis seed predators. I found that the rank abundance of seed predators varies little over space and time, suggesting that this community exists in a homogeneous competitive environment. I also found that although a few species restrict the use of seeds to particular host plants or developmental stages of the pods, there is little evidence of niche partitioning. Finally, I looked for evidence of competition between seed predators and examined a number of factors that may allow for coexistence of these species. I found no evidence of interspecific competition or facilitation, suggesting that species somehow either avoid competition or that present patterns are the product of past competitive interactions. Natural enemies occur too sporadically to allow for apparent competition and I found no relationship between their occurrence or abundance and those of the seed predator species I studied. I found a positive correlation between rank abundance ability and fecundity, inconsistent with expectations of life-history or competitive-colonization trade-offs. Therefore, the only stabilizing process consistent with patterns found in this system is the niche regeneration hypothesis. I found that one seed predator species lays eggs most often away from both interspecific and intraspecific competitors, a pattern consistent with active avoidance as a second equalizing process within this system.

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Laux, Sara Ann. "A Multi-Taxonomic Approach to Assess the Impact of Overabundant White-Tailed Deer (Odocoileus virginianus) in Forest Ecosystems Across Northeast Ohio." Cleveland State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=csu1369088103.

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Botha, Nicola. "Plant- and arthropod diversity of vegetable gardens along a socio-economic gradient within the Tlokwe Municipal Area / Nicola Botha." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8651.

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Globally urbanization has increased to such an extent that more than half of the human population currently resides in cities. In the years to come, urban expansion will especially take place in developing countries through efforts to improve economic growth and poverty alleviation. This may have a negative effect on native biodiversity within and surrounding urban environments. However, residential areas with a high proportion of gardens form a significantly large part of urban environments and these domestic gardens contribute to the maintenance and preservation of biodiversity in cities. Although the preservation of biodiversity in these gardens is important in the overall conservation of urban green spaces, little is known about how these gardens can possibly contribute to conservation purposes in urban areas. Bearing in mind that anthropogenic activities are possible drivers of urban biodiversity, it is vital to quantify socio-economic aspects within urban ecological research. In developing countries, such as South Africa, the inclusion of socio-economic aspects are especially important because there is a wider gap between poor and wealthy households. There are also a larger number of people that are dependent on their gardens for subsistence purposes, such as vegetable gardening. In the Municipal Area of Tlokwe, South Africa, there exists a definite socio-economic gradient from the poorer western to the more affluent eastern part of the city. Five socio-economic status (SES) classes, primarily based on % unemployment, were used in this study. The ultimate aim of this study was therefore to determine the plant- and arthropod diversity within urban domestic gardens along a socio-economic gradient. Vegetable gardens within domestic gardens were selected to quantify plant- and arthropod biodiversity. Biodiversity of adjacent lawns were also sampled for comparative purposes. The study also attempted to determine to what extent socio-economic aspects of city residents may be possible drivers of biodiversity within the gardens. Various other factors that might have an effect on the plant and/or arthropod diversity were included such as soil characteristics, specific management factors of the gardens and other land-uses surrounding domestic gardens. Arthropod diversity was surveyd by means of pitfall traps and suction sampling in eight 0.25 m2 squares along an 8 m transect in each representative garden. Arthropods were identified up to morphospecies level. Vegetation was surveyed along the same transect and total species composition was determined. Plants were identified up to species level. The plant and arthropod surveys were conducted in both the vegetable gardens and lawns of all SES classes. For the soil samples a 1:2.5 water analysis was conducted. A social survey was conducted in all representative gardens by means of a questionnaire and a SPOT 5 satellite imagery was used to determine the land-use types in the areas surrounding the participating gardens. All the above mentioned factors were compared between the different SES classes. Diversity indices for the arthropods, multivariate statistical analyses and ANOVA analyses were applied to test for meaningful variables between socio-economic status classes as well as vegetable gardens and lawns. From the results it was evident that the more affluent SES classes had significantly higher arthropod diversity values, whilst the lower income classes had higher plant diversity. The factor analysis between the plants and arthropods with the surrounding land-uses revealed two significant factors. Firstly, arthropod diversity was influenced by domestic gardens in the surrounding landscape and there was a positive correlation between these two variables. This indicates that a high percentage of surrounding domestic gardens were possible drivers of arthropod diversity. No correlations were evident between plant and arthropod diversity. Secondly, the other significant factor showed that one SES class had a significantly higher percentage of woodlands and grasslands as opposed to two of the other classes that had a significantly higher percentage of built structures within the surrounding area. Differences were also apparent between the SES classes concerning management regimes, financial stability and level of education. The two more affluent SES classes had obtained a higher level of education and income and had management practices that were uncommon in the three poorer SES classes. This study proposes that domestic gardens are a means to conserve biodiversity in cities. Vegetable gardens in domestic gardens will also be able to harbour a larger diversity of plants and arthropods than the lawns. The socio-economic status of residents also had a significant effect on biodiversity and therefore it should be included in studies on urban domestic gardens. This study also provides additional knowledge to the fundamentals of the field of urban ecology and the importance of using domestic gardens as an urban green space for conservation purposes.
Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2013

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Nicholson, Mary E. "Habitat Characteristics Affecting Site Occupation in Wintering Henslow’s Sparrows at Mississippi Sandhill Crane National Wildlife Refuge." ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/1378.

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Henslow’s sparrow (Ammodramus henslowii) winters in recently burned sites in pine savannas of the Southeastern United States. Previous studies have suggested that factors such as seed abundance and litter depth are important to wintering Henslow’s sparrows. My study asked how habitat variables including vegetation structure, seed abundance, and arthropod abundance predict Henslow’s sparrow site occupancy at Mississippi Sandhill Crane National Wildlife Refuge. In this study, Henslow’s sparrow more often occupied sites burned one growing season earlier than sites burned two growing seasons earlier, and did not occupy sites burned three or more growing seasons earlier. Data indicated that mass of graminoid seeds borne on stalks in November and minimum total seed mass were higher in occupied sites vs. unoccupied sites while litter density was lower. This suggests that Henslow’s sparrow selects habitats that may maximize foraging efficiency and probability of survival based on information about litter density and seed availability.

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Ara?jo, Virg?nia Farias Pereira de. "Arthropoda de solo em um ecossistema semi-?rido da regi?o neotropical: composi??o, variabilidade temporal e estratifica??o." Universidade Federal do Rio Grande do Norte, 2009. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13047.

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Made available in DSpace on 2014-12-17T14:10:18Z (GMT). No. of bitstreams: 1 VirginiaFPA.pdf: 3161205 bytes, checksum: 32bf6716cae52aaaa41494cdf8ac9532 (MD5) Previous issue date: 2009-02-17
Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Caatinga is an important laboratory for studies about arthropods adaptations and aclimatations because its precipitation is highly variable in time. We studied the effects of time variability over the composition of Arthropods in a caatinga area. The study was carried out at a preservation area on Almas Farm, S?o Jos? dos Cordeiros, Para?ba. Samples were collected in two 100 m long parallel transects, separated for a 30 m distance, in a dense tree dominated caatinga area, between August 2007 and July 2008. Samples were collected in each transect every 10 m. Ten soil samples were taken from each transect, both at 0-5 cm (A) and 5-10 cm (B) depth, resulting in 40 samples each month. The Berlese funnel method was used for fauna extraction. We registered 26 orders and the arthropods density in the soil ranged from 3237 to 22774 individuals.m-2 from January 2007 to March 2008, respectively. There was no difference between layers A and B regarding orders abundance and richness. The groups recorded include groups with few records or that had no records in the Caatinga region yet as Pauropoda, Psocoptera, Thysanoptera, Protura and Araneae. Acari was the most abundant group, with 66,7% of the total number of individuals. Soil Arthropods presented a positive correlation with soil moisture, vegetal cover, precipitation and real evapotranspiration. Increases in fauna richness and abundance were registered in February, a month after the beginning of the rainy season. A periodic rain events in arid and semiarid ecosystems triggers physiological responses in edafic organisms, like arthropods. Edafic arthropods respond to time variability in the Caatinga biome. This fauna variation has to be considered in studies of this ecosystem, because the variation of Arthropods composition in soil can affect the dynamics of the food web through time
A Caatinga ? um importante laborat?rio para estudos sobre as adapta??es e aclimata??es de Arthropoda, devido a uma alta varia??o temporal da precipita??o. Foram verificados os efeitos da variabilidade temporal sobre a composi??o de Arthropoda em uma ?rea de caatinga. O estudo foi realizado na Reserva Particular do Patrim?nio Nacional (RPPN) Fazenda Almas, S?o Jos? dos Cordeiros, Para?ba. A coleta foi realizada em dois transectos paralelos de 100 m, distantes 30 m entre si, em ?rea de caatinga arb?rea densa, durante o per?odo entre agosto de 2007 e julho de 2008. Em cada transecto, foram determinados 10 pontos de coleta, distanciados 10 m entre si, onde se retiraram 10 amostras do solo entre 0 e 5 cm (A) e 5 e 10 cm (B) de profundidade, totalizando 40 amostras mensais. O m?todo do funil de Berlese foi utilizado na extra??o da fauna. Foram registradas 26 ordens e a densidade de Arthropoda do solo variou de 3237 a 22774 indiv?duos.m-2 em janeiro de 2007 e mar?o de 2008, respectivamente. N?o houve diferen?a significativa entre as camadas A e B com rela??o a abund?ncia e riqueza de ordens. Grupos com poucos registros ou que n?o haviam sido inventariados na regi?o da caatinga foram registrados, como Pauropoda, Psocoptera, Thysanoptera, Protura e Araneae. Acari foi o grupo mais abundante com 66,7% do total de indiv?duos. Os Arthropoda de solo apresentaram correla??o positiva com a umidade do solo, cobertura vegetal, precipita??o e evapotranspira??o real. Foram registrados aumento na riqueza e na abund?ncia da fauna em fevereiro, um m?s ap?s o in?cio das chuvas. A ocorr?ncia de chuvas peri?dicas em ecossistemas ?ridos ou semi-?ridos aciona respostas fisiol?gicas em organismos ed?ficos, como os Arthropoda. Portanto, os Arthropoda ed?ficos respondem a variabilidade temporal em ?rea de caatinga. Esta varia??o da fauna tem implica??es potencialmente importantes no estudo do ecossistema, pois as mudan?as na composi??o de Arthropoda do solo podem afetar a din?mica da rede alimentar ao longo do tempo

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Puga, João Ricardo Lavoura. "Mulching influence on the reestablishement of ground-dwelling arthropod communities after a wildfire." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/16408.

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Mestrado em Ecologia Aplicada
In the past decades Portugal has been one of the Mediterranean countries most affected by wildfires. In order to find better fire mitigation strategies for ecosystem recovery and land management a crescent number of studies all over the world have been conducted. The use of mulch is currently used to protect soils from erosion after a fire. However, the effects of mulching in communities such as ground-dwelling arthropods have been neglected. Hence, this study aimed to contribute to a better understanding of the long-term effects of chopped eucalypt bark mulch on the recovery of ground-dwelling arthropod communities five years after the wildfire and the respective mulching application. This study was conducted in a burnt Eucalyptus plantation located in north-central of Portugal, which was mulched immediately after the fire. The results of this study showed that five years after the wildfire and the mulching application the ground-dwelling arthropod communities are similar between mulched and untreated sites and among positions along the slope. In general, no significant relations were found between environmental variables and the ground-dwelling arthropod community. A high homogeneity of ground cover classes and ground-dwelling arthropod communities’ composition was obtained for both treatments. The most abundant orders were Hymenoptera and Collembola, associated with omnivore and microbial feeders that seem to be beneficiated by the high availability of litter. Coleoptera and Araneae had the higher richness of morphospecies, being mostly compodes by ground predatory families. Analysis of ecological function suggests that the high availability of litter could be an important and selective factor for the current ground-dwelling arthropod community in the study area. Globally it seems that the effects of mulching on the recovery of ground-dwelling arthropod communities in Eucalyptus plantations are diluted in a long-term after fire. However these findings do not discard potential short-term effects of mulching on particular groups of arthropods during the early period after its application on the burnt area, which are still ignored.
Nas últimas décadas Portugal tem sido um dos países da bacia mediterrânica mais afectado pelos incêndios. Um número crescente de estudos em todo o mundo têm vindo a ser realizados no sentido de melhor compreender os efeitos directos e indirectos do fogo e assim encontrar melhores estratégias de gestão e mitigação dos ecossistemas afectados pelos incêndios. O uso de mulching é actualmente utilizado para proteger os solos da erosão depois de um incêndio. No entanto, os efeitos do mulching sobre as comunidades de invertebrados do solo são pouco conhecidos. Actualmente é reconhecido o papel fundamental que as comunidades de invertebrados do solo desempenham na recuperação da maioria dos ecossistemas. Este estudo procura compreender os efeitos da utilização de um tipo específico de mulching (casca e desperdícios de eucalipto) na recuperação das comunidades de invertebrados do solo, uma vez que esta técnica é comummente utilizada como medida de mitigação após um incêndio. Este estudo foi realizado numa plantação de eucalipto no centro-norte de Portugal, que anteriormente havia ardido e na qual foi aplicado o mulching após o incêndio. Os resultados deste estudo mostram comunidades de invertebrados do solo semelhantes entre os locais tratados e não tratados e entre posições ao longo da encosta. Em geral, não foram encontradas relações significativas entre as variáveis ambientais estudadas e a comunidade de invertebrados do solo. Foi encontrado um elevado nível de homogeneidade entre as classes de cobertura do solo definidas e a composição da comunidade de invertebrados do solo nas áreas tratada e não tratada. As ordens Hymenoptera e Collembola foram as mais abundantes, estando associadas maioritariamente a famílias de hábitos omnívoros e microbianos e as ordens Coleoptera e Araneae apresentaram a maior riqueza de morfo-espécies, sendo na sua maioria formada por famílias de predadores terrestres. A análise da função ecológica de cada família, sugere que a grande disponibilidade de matéria orgânica no solo pode influenciar a abundância de formigas e colêmbolos, e fomentar uma maior diversidade de predadores terrestres.No global, a utilização de mulching não parece afectar a recuperação das comunidades de invertebrados do solo, após um período pós-fogo prolongado. Porém, os resultados deste estudo sugerem que o mulching poderá afectar alguns grupos de invertebrados, durante o período inicial após a sua aplicação na área ardida.

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Dissertations / Theses on the topic 'Arthropoda – Ecology'

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