Dissertations / Theses on the topic 'Biodiversity hotspots'
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Prendergast, John Richard. "Biodiversity hotspots in Britain." Thesis, Imperial College London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300123.
Full textNorström, Paananen Marcus, Magnus Boström, and Christian Ahlgren. "Power Lines - Wasteland or Biodiversity Hotspots?" Thesis, Mälardalen University, School of Sustainable Development of Society and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-4541.
Full textDet svenska kulturlandskapet har förändrats radikalt under de senaste 200 åren från ett varierat och heterogent landskap till ett mer monotont, homogeniserat landskap som följd av att olika former av mänskligt resursutnyttjande har effektiviserats. Detta har lett till en fragmentering av livsmiljöerna för flera av kulturlandskapets arter. Kraftledningsgator kan tänkas hysa naturtyper som påminner om vissa av de nu försvunna eller fragmenterade livsmiljöerna (t ex betad skogsmark och vissa typer av ängsmarker) och skulle kunna ha en viktig betydelse som reträttplats och/eller spridningskorridor för dessa arter.
I en fallfällsinventering i Köpings och Strängnäs kommun i Mälardalen undersöktes förekomst och abundans av marklevande evertebrater i kraftledningsgator, skog och betesmark. Jämförelser i förekomst och abundans gjordes mellan dessa marktyper (d v s kraftledningsgator, skog och betesmark), samt mellan positioner inom kraftledningsgator (centrala och distala delar) och närliggande skogsmark. Jämförelserna innefattade dels analyser av artantal (eller snarare antal taxa) och flera olika biodiversitetsindex och dels analyser av likhet i artförekomst och individantal med "likhetsindex" (similarity index). Separata analyser gjordes inom olika taxonomiska grupper (t ex alla taxa, endast inom insekter, endast inom spindeldjur). Antalet replikat tillät statistisk testning av eventuella mönster i antal taxa och biodiversitetsindex.
Inga signifikanta skillnader dokumenterades, varken mellan de olika marktyperna eller mellan positioner inom kraftledningsgator och närliggande skog. Vi tolkar dessa resultat som att kraftledningsgator med avseende på antal taxa respektive biodiversitet inte är (signifikant) sämre än skogs- eller betesmark. Det kan betonas att det inte heller fanns något konsekvent (icke-signifikant) mönster som pekade på att så skulle vara fallet. Antal taxa och biodiversitetsindex tar ingen hänsyn till vilka arter eller taxa som ingår i analyserna. En naturtyp som hyser en individ- och artrik fauna bestående av oönskade arter (introducerade arter, "skadedjur" etc.) registrerar t ex ett högre biodiversitetsindex än en naturtyp med fåtaligt förekommande rödlistade, skyddsvärda arter. Likhetsindex belyser bättre vilka arter som är inblandade. Visserligen tas inte heller här hänsyn till exakt vilka arter som ingår (eller deras eventuella önskvärdhet eller skyddsvärde), men ett högt index indikerar att samma arter förekommer i de jämförda naturtyperna. I denna studie indikerar ett högt likhetsindex dessutom att antalet individer av de inblandade arterna är likartat, eftersom ett index som tar hänsyn till abundans användes.
Resultaten visade överlag höga likhetsindex, speciellt verkade kraftledningsgator och skogsmark hysa likartad evertebratfauna medan likheten mellan kraftledningsgator och betesmark var mindre uttalad. Sammanfattningsvis indikerar studien att kraftledningsgator inte verkar vara lågvärdiga livsmiljöer för de marklevande evertebrat-taxa som ingått i studien. Vi föreslår att kraftledningsgator med väl avvägda rutiner för röjning och skötsel skulle kunna spela en viktig roll i skapandet av artrika kantzoner eller marker som liknar ängs- eller betesmarker med svag hävd.
As a consequence of the intensification of various forms of human resource utilization rural Sweden has changed radically over the past 200 years from offering a varied and diverse landscape to a more monotonous, homogenised type of environment. This has led to fragmentation of habitats for many of the species occurring. Power line corridors might harbour habitats that resemble some of the now lost or fragmented habitats (e.g. grazed forest land and certain types of meadow), and could have important functions as refuge habitats and / or distribution corridors for these species.
In a pitfall trap study in Köping and Strängnäs municipalities in Mälardalen, the occurrence and abundance of ground-living invertebrates were investigated in power line corridors, adjoining forest and pastures. Comparisons were made between these habitat types, and between positions within the power line corridor (central and distal parts) and the nearby forested area. The comparisons included analysis of number of species (or rather the number of taxa) and several biodiversity indexes, as well as analysis of the similarity of the occurrence of certain species and individual numbers by use of "similarity index". Separate tests were made in different taxonomic groups (e.g. all taxa, only within insects, only within spiders). The number of replicates allowed statistical testing of patterns in the number of taxa and biodiversity index.
No significant differences were documented, neither between the different habitat types, nor between positions in the power line corridors and nearby forest. There was also no consistent (non-significant) pattern indicating that this would be the case. We suggest these results to indicate that power line corridors at least are not (significantly) poorer quality habitats than are forest or pasture land with regard to number of taxa and biodiversity. Number of taxa and biodiversity indices take no account of the species or taxa included in the analysis. Thus the same weight is assigned to an unwanted species (e.g. an invasive pest species or parasite) as to a red-listed, highly valued species. Similarity index takes more heed to the species involved. Although similarity indices do not consider the exact identity of involved species (or their possible value or desirability), a high index value indicates that the same species occur in the compared habitats. In this study, where an index that takes into account the abundance of species was used, a high similarity index value also indicates that the numbers of individuals are similar.
Overall, the results showed high similarity between habitat types. This would suggest that, to a large extent, power lines, forest and pasture land had the same composition of taxa, and that the taxa had similar abundances. Power lines and forest seemed to exhibit particularly high similarities, whereas the similarity between power lines and pasture land was less pronounced. Thus, this study indicates, in contrast to several previous suggestions, that power line corridors do not seem to be low quality habitats. We also suggest that power line corridors with well designed management routines could play an important role creating edges and habitats resembling meadow or low intensity grazed pasture land.
Pulliam, Robert. "Evolutionary history of amphibians in biodiversity hotspots." Connect to resource, 2006. http://hdl.handle.net/1811/6021.
Full textTitle from first page of PDF file. Document formattted into pages: contains 32 p.; also includes graphics. Includes bibliographical references (p. 17-19). Available online via Ohio State University's Knowledge Bank.
Martin, Thomas Edward. "Avifauna and anthropogenic forest disturbance in two biodiversity hotspots." Thesis, Lancaster University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543999.
Full textSchnitzler, Jan. "Biotic interactions and species diversification in Southern African biodiversity hotspots." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/5946.
Full textGrocott, Michael. "Hydrology of paraglacial catchments in a changing climate : impacts on biodiversity hotspots." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6978/.
Full textSoccodato, Alice. "Planktonic biodiversity hotspots in the open ocean : detection, drivers and implications at the global scale." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066549/document.
Full textPatterns of biodiversity and the mechanisms that maintain them have always interested biologists and have been addressed considering geological, evolutionary and ecological factors. Ecological processes that determine the co-occurrence of species differ according to the physical environment of the ecosystem. Many theories have proposed relationships between patterns in species diversity and large-scale physical features. In terrestrial and aquatic environments, the impact of temperature on the distribution of biodiversity is among the most influent and studied factors. However, many marine taxa are exceptions in the primary influence of temperature, since a large fraction of marine species is planktonic or with dispersible larvae. In the marine environment, dispersal through physical transport has a major impact on patterns of species abundance. Some ocean currents can indeed determine the distribution of planktonic stages of some species, even when demographic and physiological features of the species are unaffected by water properties. Transport mechanisms may therefore influence the distribution of diversity at all scales, from the individual to populations and species. Contrarily to the terrestrial environment, marine ecosystems are characterized by a variability that has spatial and temporal scales defined by specific biophysical processes of turbulent transport. This aspect makes it challenging to provide synoptic information on the distribution of marine species at the global level and at high resolution, features that are essential to understand patterns of biodiversity and the mechanisms involved in their changes. Moreover, hotspots of biodiversity are of primary concerns for conservation efforts. The objectives of this study are therefore: to identify biodiversity hotspots of pelagic primary producers on a global scale and at high resolution; to determine the physical ocean processes that control the spatial and temporal dynamics of such hotspots, focusing on transport-driven mechanisms like dispersion, advection and mixing; study the role of these mechanisms in the structuring of biodiversity at higher trophic levels.To obtain these results, information on water masses with coherent biophysical characteristics ('fluid-dynamical niches') obtained by remote sensing are used to identify hotspots of microbial biodiversity as regions of strong spatial patchiness. These hotspots and the role of transport in shaping their structure are studied by analysing ecological and biophysical global circulation models (Model-ECCO2 Darwin), together with molecular and morphological data on the structure of the community, obtained using in-situ data collected during the Tara-Oceans expedition and Atlantic Meridional Transect. The possible bottom-up effects of the diversity of primary producers on the upper levels of the food chain are evaluated by comparing them with global models integrated with data collected in situ.The ecological models coupled with ocean circulation, identified as biodiversity hotspots of primary producers the most dynamic areas of the global ocean characterized by increased turbulence, mixing and the presence of vortices. These oceanographic features can improve local productivity by transporting nutrients in the photic zone and increase biodiversity by the mixing of species typical of different water masses. In addition, maps of microbial biodiversity suggest a bottom up propagation of biodiversity across the ecosystem, hotspots for primary producers being positively correlated with regions where highest number of top predator species are observed
Soccodato, Alice. "Planktonic biodiversity hotspots in the open ocean : detection, drivers and implications at the global scale." Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066549.
Full textPatterns of biodiversity and the mechanisms that maintain them have always interested biologists and have been addressed considering geological, evolutionary and ecological factors. Ecological processes that determine the co-occurrence of species differ according to the physical environment of the ecosystem. Many theories have proposed relationships between patterns in species diversity and large-scale physical features. In terrestrial and aquatic environments, the impact of temperature on the distribution of biodiversity is among the most influent and studied factors. However, many marine taxa are exceptions in the primary influence of temperature, since a large fraction of marine species is planktonic or with dispersible larvae. In the marine environment, dispersal through physical transport has a major impact on patterns of species abundance. Some ocean currents can indeed determine the distribution of planktonic stages of some species, even when demographic and physiological features of the species are unaffected by water properties. Transport mechanisms may therefore influence the distribution of diversity at all scales, from the individual to populations and species. Contrarily to the terrestrial environment, marine ecosystems are characterized by a variability that has spatial and temporal scales defined by specific biophysical processes of turbulent transport. This aspect makes it challenging to provide synoptic information on the distribution of marine species at the global level and at high resolution, features that are essential to understand patterns of biodiversity and the mechanisms involved in their changes. Moreover, hotspots of biodiversity are of primary concerns for conservation efforts. The objectives of this study are therefore: to identify biodiversity hotspots of pelagic primary producers on a global scale and at high resolution; to determine the physical ocean processes that control the spatial and temporal dynamics of such hotspots, focusing on transport-driven mechanisms like dispersion, advection and mixing; study the role of these mechanisms in the structuring of biodiversity at higher trophic levels.To obtain these results, information on water masses with coherent biophysical characteristics ('fluid-dynamical niches') obtained by remote sensing are used to identify hotspots of microbial biodiversity as regions of strong spatial patchiness. These hotspots and the role of transport in shaping their structure are studied by analysing ecological and biophysical global circulation models (Model-ECCO2 Darwin), together with molecular and morphological data on the structure of the community, obtained using in-situ data collected during the Tara-Oceans expedition and Atlantic Meridional Transect. The possible bottom-up effects of the diversity of primary producers on the upper levels of the food chain are evaluated by comparing them with global models integrated with data collected in situ.The ecological models coupled with ocean circulation, identified as biodiversity hotspots of primary producers the most dynamic areas of the global ocean characterized by increased turbulence, mixing and the presence of vortices. These oceanographic features can improve local productivity by transporting nutrients in the photic zone and increase biodiversity by the mixing of species typical of different water masses. In addition, maps of microbial biodiversity suggest a bottom up propagation of biodiversity across the ecosystem, hotspots for primary producers being positively correlated with regions where highest number of top predator species are observed
Bellard, Céline. "Effets des changements climatiques sur la biodiversité." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112269/document.
Full textGlobal biodiversity is changing at an unprecedented rate due to loss of habitat, biological invasions, pollution, overexploitation. Furthermore, climate changes and their synergies with other threats will probably become the main drivers of biodiversity loss in the next century. Nowadays, the multiplicity of approaches and the resulting variability in projections make it difficult to get a clear picture of the future of biodiversity due to climate change. Yet, the majority of models indicate alarming consequences for biodiversity, with the worst- case scenarios leading to an increase of extinction rates. The aim of this thesis was to improve the knowledge about of the different consequences of climate change on biodiversity worldwide. To do that I mainly used modelisation and meta-analyses approaches. The first part of my work was to investigate the consequences of sea level rise for the ten insular biodiversity hotspot and their endemic species, during which I highlighted that between 6 and 19% of the islands would be entirely submerged. Then I studied the effects of climate and land use changes on biological invasions worldwide. The results showed that invasives species response to climate and land use changes depend on region, taxa and species considered. We also emphasized that some regions could lose a significant number of invasive alien species. Besides, we also found that hotspot that are mainly islands or group of islands are highly suitable for invasive species. Finally, in the last part, I quantified the exposure of biodiversity hotspots to the combined effects of climate change, land use change and biological invasions. This work highlighted the pressing need to consider different drivers of global change in conservation planning. In addition, we established some prioritization framework among the hotspot. Finally, conservation strategies to protect habitat and species under global changes, can only be achieved through closed collaboration with park managers. Overall, implementation of effective adaptation strategies to climate change can only succeed with public support
Banu, S. "Molecular marker based genetic diversity in symplocos spp. from the two biodiversity hotspots in India." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2008. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2699.
Full textHaydu, Kristie. "Mapping Plant Biodiversity Hotspots at the County Scale: A New Tool for Establishing Resource Conservation Strategies." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/749.
Full textToroitich, Faith Jebet. "Biodiversity assessment of tetranychid mites in Kenya and the conservation hotspots of Tanzania / Faith Jebet Toroitich." Thesis, North-West University, 2011. http://hdl.handle.net/10394/9708.
Full textThesis (PhD (Environmental Sciences))--North-West University, Potchefstroom Campus, 2012.
Apte, G. S. "Genetic diversity analysis in gaultheria fragrantissimia wall. from the two biodiversity hotspots in India using molecular markers." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2004. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2895.
Full textMalviya, Shruti. "Global Diatom Biodiversity : An Assessment Using Metabarcoding Approach." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112075/document.
Full textDiatoms (Stramenopiles, Bacillariophyceae) are an ecologically important and one of the most diverse phytoplanktonic groups, with an estimated ~1,800 marine planktonic species. Although widely studied, their diversity and biogeographic distribution patterns are not well known. The advent of high-throughput DNA sequencing has revolutionized molecular biodiversity studies facilitating the understanding of biogeography, community assembly and ecological processes. The two major goals of this thesis are (1) to investigate global biodiversity patterns and structure of marine planktonic diatom communities across the world’s oceans, and (2) to understand the mechanisms and processes determining their community structure and assembly. This thesis also presents an initial attempt to discern the distribution of rare species in protist communities. The study was conducted using the metabarcoding data generated from the biological samples and associated environmental data collected during the Tara Oceans (2009-2013) global circumnavigation covering all major oceanic provinces. A total of ~12 million diatom V9-18S rDNA tags from 46 sampling stations, constituting 293 size fractionated samples represent the study material for the thesis. Using 63,371 unique diatom metabarcodes, this study presents an in-depth evaluation of global diatom distribution and diversity. The analyses study draw a number of revelations related to diatom biogeography, e.g. a new estimate of the total number of planktonic diatom species, a considerable unknown diversity, exceptionally high diversity in the open ocean, complex diversity patterns across oceanic provinces. The thesis then looks into the factors determining the beta-diversity patterns. The results suggest that diatoms represent biogeographically structured ecological communities regulated by both environmental heterogeneity and spatial processes. Nonetheless, the majority of the total variation in community composition remained unexplained by either the examined measured environmental factors or spatial distances, which warrants future analyses focusing on biological interactions, historical events, and other factors that are not considered. The thesis further outlines an approach to characterize significantly associated clusters of co-occurring ribotypes. Finally, a preliminary study of size-fractionated protistan communities reveals that the tail (of their rank-abundance distributions) appears to follow a power-law behavior in almost all protistan communities. This observation may indicate a potential universal mechanism which can explain the organization of marine planktonic communities. In general, this work has presented a global comprehensive perspective on diatom distribution and diversity in the world’s oceans. The thesis offers an overall framework for metabarcoding-based global diversity assessments which in turn can be employed to study distribution and diversity of other taxonomic lineages. Consequently, this work provides a reference point to explore how microbial communities will respond/change in response to environmental conditions
Betzin, Anja [Verfasser], and Marcus [Akademischer Betreuer] Koch. "The Laurel Forest: An Example for Biodiversity Hotspots threatened by Human Impact and Global Change / Anja Betzin ; Betreuer: Marcus Koch." Heidelberg : Universitätsbibliothek Heidelberg, 2015. http://d-nb.info/1180301447/34.
Full textPECCI, ANGELO. "Geoinformatic methodologies and quantitative tools for detecting hotspots and for multicriteria ranking and prioritization: application on biodiversity monitoring and conservation." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/1341.
Full textWho has the responsibility to manage a conservation zone, not only must be aware of environmental problems but should have at his disposal updated databases and appropriate methodological instruments to examine carefully each individual case. In effect he has to arrange, in advance, the necessary steps to withstand the foreseeable variations in the trends of human pressure on conservation zones. The essential objective of this Thesis is methodological that is to compare different multivariate statistical methods useful for environmental hotspot detection and for environmental prioritization and ranking. The general environmental goal is the conservation of the biodiversity patrimony. The individuation, through multidimensional statistical tools, of habitats having top ecological priority, is only the first basic step to accomplish this aim. Ecological information integrated in the human context is an essential further step to make environmental evaluations and to plan correct conservation actions. A wide series of data and information has been necessary to accomplish environmental management tasks. Ecological data are provided by the Italian Ministry of the Environment and they refer to the Map of Italian Nature Project database. The demographic data derives from the Italian Institute of Statistics (ISTAT). The data utilized regards two Italian areas: Baganza Valley and Oltrepò Pavese and Ligurian-Emilian Apennine. The analysis has been carried out at two different spatial/scale levels: ecological-naturalistic (habitat level) and administrative (Commune level). Correspondingly, the main obtained results are: 1. Habitat level: comparing two ranking and prioritization methods, Ideal Vector and Salience, through important ecological metrics like Ecological Value (E.V.) and Ecological Sensitivity (E.S.), gives results not directly comparable. Being not based on a ranking process, Ideal Vector method seems to be used preferentially in landscapes characterized by high spatial heterogeneity. On the contrary, Salience method is probably to be preferred in ecological landscapes characterized by a low degree of heterogeneity in terms of not large differences concerning habitat E.V. and E.S.. 2. Commune level: Being habitat only a naturalistic partition of a given territory, it is necessary, for management decisions, to move towards the corresponding administrative units (Communes). From this point of view, the introduction of demography is an essential element of novelty in environmental analysis. In effect, demographic analysis makes the goal at point 1 more realistic introducing other dimensions (actual human pressure and its trend) which allows the individuation of environmentally fragile areas. Furthermore this approach individuates clearly the environmental responsibility of each administrative body for what concerns the biodiversity conservation. In effect communes’ ranking, according to environmental/demographic features, clarify the responsibilities of each administrative body. A concrete application of this necessary and useful integration of ecological and demographic data has been developed in designing an Ecological Network (E.N.).The obtained E.N. has the novelty to be not “static” but “dynamic” that is the network planning take into account the demographic pressure trends in the individuation of the probable future fragile points.
Waseem, Muhammad. "Biodiversité et stratégies adaptatives des bactéries mycorhizosphériques associées aux Tristaniopsis spp. dans les écosystèmes ultramafiques de Nouvelle-Calédonie." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20220.
Full textNew Caledonian ultramafic (serpentine) ecosystems are considered as hotspots of biodiversity, partly because of the adaptative pressure exerted by drastic edaphic conditions. Indeed these soils resulting from natural weathering of oceanic mantle could be composed of up to 85 % of iron oxides and are deficient in N.P.K., unbalance for the Ca/Mg ratio and rich in heavy metals Ni, Cr, Mn, Co. Both plant and soil microbes play a vital role in the adaptation to soil conditions mainly heavy metal uptake and tolerance. In our study, we choose endemic species of the genus Tristaniopsis (Myrtaceae) as model plant to study the role of ectomycorrhizal fungi and associated bacteria in plant adaptation to nickel. To investigate the effect of ultramafic soils on ectomycorrhiza and mycorrhizosphere bacteria diversities as well as on the genetic determinants of resistance/adaptation of associated mycorrhizosphere bacteria, 200 ectomycorrhizas were sampled from four different ultramafic sites (3 in Koniambo and 1 in Desmazures forest) vs two non-ultramafic ones from volcano-sedimentary soils (Arama). Molecular characterization of ectomycorrhiza (rRNA ITS) and associated mycorrhizosphere bacteria (16S rRNA) from these samples showed the presence of different fungi (Pisolithus albus, Russula spp., Boletellus spp.) and bacteria (Burkholderia spp., Bacillus spp., Pseudomonas spp.) that can be found in both soils. However, bacteria isolated from ultramafic soils could grow in the presence of Ni up to 20 mmol L-1 and contained cnrA and nreB genes, known to confer heavy metal tolerance, contrary to bacteria isolated from non-ultramafic soils. Moreover, we found a strong positive correlation between heavy metal tolerance and P-solubilizing ability. Further knowledge on functional diversity of ectomycorrhiza-mycorrhizosphere bacteria associations and its role in the adaptation of plants to ultramafic soils would help in the understanding of plant functioning on New Caledonian mine sites
Peixoto, Franciele Parreira. "Diversidade evolutiva de morcegos: padrões geográficos e aplicações em conservação." Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/3151.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Aim: To investigate global patterns of phylobetadiversity (PBD) in bats, with the purpose to better understand the mechanisms underlying current biodiversity patterns. We also aimed to use a metric that allows partitioning PBD into two components to distinguish the relative roles of local (e.g. lineage filtering) and regional processes (e.g. speciation) in shaping broad-scale patterns of PBD. Furthermore, we analyzed the distance-decay relationship of phylogenetic beta diversity to provide more information about factors that act in the PBD patterns. Location: global, delimited by biogeographic regions. Methods: Using the global distribution of bats and a supertree available for most species, we calculated PBD using the complement of phylosor index. We used a null model to test if two assemblages were more or less phylogenetically dissimilar than expected by chance. In addition, we decoupled PBD into turnover and nestednessresultant components, providing information about two factors that produce differences in assemblage phylogenetic composition. We also performed a Mantel analysis to analyze the distance-decay patterns of PBD and its two components. Results: The most striking difference in PBD was found between the Old and New World “phylogenetic composition”. We found the lowest values of PBD between adjacent regions (i.e., Neotropical/Neartic; Indo-Malay/Paleartic), revealing a strong geographical structure in PBD. These values were even lower when the turnover component was analyzed, demonstrating the differences in the role of regional processes in shaping regional diversity. On the other hand, we found out that for some adjacent regions (e.g., Afrotropical/Paleartic), the observed PBD was higher than expected by chance and comparatively different from expected by the distance decay relationship. This value remained high, even when we analyzed just the PBD turnover component. This demonstrates that although these regions are relatively close in space, there are other factors driving phylogenetic differences between them (e.g. an environmental barrier). Main conclusions: Our analyses revealed differences in the expected patterns of bat PBD among regions, suggesting that at broad scales, besides the effects of distance and geographic barriers, we also have to consider the importance of environmental gradients when studying the phylogenetic origin of bat assemblages.
A abordagem mais comum no uso de PD (diversidade filogenética) para conservação é selecionar locais com maior diversidade evolutiva. Essa estratégia parte do pressuposto de que locais com maior quantidade de PD indicam maior potencial para respostas evolutivas a mudanças ambientais futuras. No entanto, há um crescente debate sobre se as prioridades de conservação deveriam também ser voltadas para locais com baixo valor de PD, que podem representar centros de diversificação de espécies ou “berçários de diversidade”. Alguns trabalhos têm testado se os hotspots globais de biodiversidade, baseados em riqueza, também representam locais de desproporcional concentração de história evolutiva. Nós testamos aqui se os hotspots contêm mais, menos ou igual diversidade filogenética (PD) que o esperado por uma amostragem ao acaso de espécies em qualquer posição na filogenia, para a ordem Chiroptera. Buscamos responder qual a real contribuição de cada hotspot para a conservação de padrões e processos relacionados à diversidade filogenética. Nós utilizamos uma supertree disponível para a maioria das espécies da ordem, e dados de distribuição das espécies. Nós calculamos o PD para cada hotspot separadamente e utilizamos um modelo nulo para obter os valores esperados dado a riqueza. De 34 hotspots, apenas um apresentou maior PD do que o esperado, treze apresentaram valores menores e o restante valores iguais ao esperado. Nós demonstramos que a relação entre PD e riqueza varia entre regiões biogeográficas, de modo que não há como fazer generalizações acerca da contribuição dos hotspots para a conservação de diversidade evolutiva. De modo geral nossos resultados demonstram que devido ao fato da história evolutiva variar regionalmente, também devem ser estabelecidas as prioridades de conservação nessa escala.
Beddek, Menad. "Déficit de connaissances de la biodiversité et biologie de la conservation : le cas de l’herpétofaune d’Algérie." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT167/document.
Full textAlgeria is a case study of biodiversity ignorance. To date, there are neither complete inventories for any taxa nor atlas across the country! Yet, Algeria is of great importance for global biodiversity. The coastal area of Algeria is part of the global biodiversity hostpot which is the Mediterranean perimeter and has several regional red spots of biodiversity. Moreover, the Saharan part encompasses a diversity of endemic organisms adapted to the strong conditions of drought. The Algerian authorities are deploying an ambitious project for conservation aiming to reach 50% of the country's surface as protected areas! However, the location of these protected areas and their management don’t obey to a scientific evidence based, but are rather based on experts opinion. The main aim of this thesis is the study of the biodiversity ignorance distribution in Algeria by focusing on the "Linnean, Wallacean, and Darwinian Shortfalls" and to contribute to reduce them. The first chapter aims at reducing the Linnean Shortfall by proposing 1) a first checklist of reptiles and amphibians of Algeria which is the result of an accurate review of scientific publications on these taxa in North Africa. 2) a first pre-assessment of the conservation status of reptiles and amphibians of Algeria for the production of the first national red list. The second part of this manuscript deals with the ignorance of the geographical distribution of species. The purpose of this part is to map the ignorance which is defined as the difference between the expected specific richness diversity and the observed specific richness. The predicted species richness was modelled with two approaches: 1 ecological niche modeling with the maximum entropy method (MaxEnt) to predict the suitable habitats for each species and then add the different binary layers of species presence to calculate the specific richness. 2) Minimum convex polygon method was used to create range maps of each species and were auditioned to obtain predicted species richness. Both approaches have shown the same trend at a national scale: the concentration of the richest areas along the Saharan Atlas and the high plateaux which are the transition zone between the Sahara and the the Mediterranean part of Algeria. The opposition of the Saharan with a low species richness and the northern part with a higher species richness. Finally, the Saharan massifs of the Hoggar and Tassili form a very distinct zone with a much greater wealth compared to the rest of the Sahara. In terms of gaps, in the northern part, Kabylie, El Kala National Park and the Oran region are fairly well surveyed. In the Sahara, only a few points are clearly well prospected as Biskra, Bechar and some areas of the Hoggar and Tassili. The third part deals with the distribution of genetic llineages in the Maghreb. The aim of this section is to locate the phylogeographic breaks between the divergent eastern and western populations of the Maghreb and to try to understand the mechanisms that led to this pattern of genetic diversity. To answer these questions, I carried out a comparative phylogeography on 11 species of reptiles and amphibians with continuous and wide distribution in the Maghreb. Two suture zones have been identified: one zone on the border of Algeria and Morocco, the other in Kabylia west of the Soummam valley. The divergences between the eastern clades and the western clades occurred between the pre-Messinian periods up to the plio-pleistocene boundary and were maintained in climatic refugia in the east and west of the Maghreb
Kurzweg, Sabine Eva Maria Johanna. "Standardizing quarter degree grid data for plant species in the Western Central Bushveld for more explicit use in spatial models / Sabine Eva Maria Johanna Kurzweg." Thesis, North-West University, 2011. http://hdl.handle.net/10394/9516.
Full textThesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2012
Venevskaia, Irina. "Modeling of vegetation diversity and a national conservation planning: example of Russia." Phd thesis, Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2005/210/.
Full text1) Wie lässt sich Vegetationsvielfalt in grober Auflösung auf Basis abiotischen Faktoren einschätzen?
2) Wie ist der Ansatz 'globaler Hotspots' für die Eingrenzung nationaler Biodiversitäts-Hotspots zu übernehmen?
3) Wie erfolgt die Auswahl von quantitativen Schutzzielen unter Einbezug der Unterschiede nationaler Hotspots bei Umweltbedingungen und durch den Menschen Bedrohung?
4) Wie sieht der Entwurf eines großflächigen nationalen Naturschutzkonzepts aus, das die hierarchische Natur der Artenvielfalt reflektiert? Die Fallstudie für nationale Naturschutzplanung ist Russland.
Die nachfolgenden theoretischen Schlüsse wurden gezogen:
· Großräumige Vegetationsdiversität ist weitgehend vorhersagbar durch klimabedingte latente Wärme für Verdunstung und topographische Landschaftsstruktur, beschrieben als Höhendifferenz. Das klimabasierte Modell reproduziert die beobachtete Artenanzahl von Gefäßpflanzen für verschiedene Gebiete auf der Welt mit einem durchschnittlichen Fehler von 15%
· Nationale Biodiversitäts-Hotspots können auf Grundlage biotischer oder abiotischer Daten kartographiert werden, indem als Korrektur für ein Land die quantitativen Kriterien für Planzenendemismus und Landnutzung des Ansatzes der 'globalen Hotspots' genutzt wird
· Quantitative Naturschutzziele, die die Unterschiede zwischen nationalen Biodiversitäts-Hotspots in Bezug auf Umweltbedingungen und der Bedrohung durch den Menschen miteinbeziehen, können mit nationalen Daten über Arten auf der Roten Liste gesetzt werden
· Ein großräumiger nationaler Naturschutzplan, der die hierarchische Natur der Artenvielfalt berücksichtigt, kann durch eine Kombination von abiotischer Methode im nationalen Bereich (Identifikation großräumiger Hotspots) und biotischer Methode im regionalen Bereich (Datenanalyse der Arten auf der Roten Liste) entworfen werden
The overall objective of the study is an elaboration of quantitative methods for national conservation planning, coincident with the international approach ('hotspots' approach). This objective requires a solution of following problems:
1) How to estimate large scale vegetation diversity from abiotic factors only?
2) How to adopt 'global hotspots' approach for bordering of national biodiversity hotspots?
3) How to set conservation targets, accounting for difference in environmental conditions and human threats between national biodiversity hotspots?
4) How to design large scale national conservation plan reflecting hierarchical nature of biodiversity?
The case study for national conservation planning is Russia.
Conclusions:
· Large scale vegetation diversity can be predicted to a major extent by climatically determined latent heat for evaporation and geometrical structure of landscape, described as an altitudinal difference. The climate based model reproduces observed species number of vascular plant for different areas of the world with an average error 15%
· National biodiversity hotspots can be mapped from biotic or abiotic data using corrected for a country the quantitative criteria for plant endemism and land use from the 'global hotspots' approach
· Quantitative conservation targets, accounting for difference in environmental conditions and human threats between national biodiversity hotspots can be set using national data for Red Data book species
· Large scale national conservation plan reflecting hierarchical nature of biodiversity can be designed by combination of abiotic method at national scale (identification of large scale hotspots) and biotic method at regional scale (analysis of species data from Red Data book)
Thiers, Laurie. "Utilisation des prédateurs supérieurs pour déterminer les zones d'importance pour la biodiversité : comparaison de différentes méthodes de mise en évidence de "hotspots"." Thesis, La Rochelle, 2014. http://www.theses.fr/2014LAROS025/document.
Full textThe numerous threats that marine environment face, coupled with the evidence for a global biodiversity loss during last decades have lead to an increasing need for setting up conservation measures. Particularly, delimiting Marine Protected Areas (MPAs) within the French Southern Territories, which are home to an exceptional biodiversity and extensive human activities through industrial fisheries, would be extremely beneficial for species conservation. In order to identify areas of ecological significance for biodiversity, which could be good MPA candidates, the use of distribution data from top marine predators seems to be ideal. Thanks to their high position in trophic network, they are likely to integrate lowers trophic level species distribution. Moreover, they are easy to observe trough at-sea observation campaigns, and easy to equip with telemetric devices thank to their central place foraging that lead them to return regularly to their colony during breeding season. Here, we analyse distribution data and develop habitat models from several top predators species in both subantarctic and tropical regions to highlight biodiversity hotspots within the French Southern Territories. This work could thus be use as a basis to define potential boundaries for a future MPA
Dafreville, Stéphanie. "Diversité et structuration génétique des sapotacées endémiques de l'archipel des Mascareignes à différentes échelles spatiales et temporelles." Thesis, La Réunion, 2013. http://www.theses.fr/2013LARE0033.
Full textMadagascar is among the top five priorities "hotspots" for global biodiversity conservation. In Madagascar, melliferous flora is diverse and abundant; the endemic honey bee Apis melliferaunicolor inhabits all areas regardless of the climatic conditions and topography. As other islands, Madagascar is fragile and susceptible to invasions of alien species. In 2010, Varroa destructor has been reported parasitizing A. m. unicolor. The ectoparasite is not only a serious threat to beekeeping in Madagascar but it may also alter ecosystems balance.The objectives of this thesis were i) to study the genetic diversity and population structure of both A. m. unicolor and V. destructor in Madagascar, ii) to estimate the impact of V. destructor on honey bee colonies, and iii) to investigate the hygienic behaviour of honey beeOur results confirm that all honey bees collected in Madagascar belonged to the African evolutionary lineage and more than 99% were identified as A. m. unicolor. Despite its lownuclear genetic diversity, two genetic clusters have been detected, corresponding to geographic regions.In Madagascar, only one genetic strain of V. destructor was detected, the Korean haplotype (K1-1) which is the most widespread lineage in the world and the one present in Africa. Genetic studies showed a higher proportion of homozygous genotype (69.5%) and also a high number of MLG (Multi- Locus Genotypes) in the High Lands compared to the East coast. The presence of particular MLG on the High Land reinforces the assumption of its introduction into the capital. The spread of V. destructor in Madagascar is relatively slow in comparison with those observed in African countries. Its presence remains confined to the High Land and the East coast. The impact of the parasite on A. m. unicolor was severe; with about 60% of colony losses in a year reported in 2012. Nevertheless, this is less than observed in Europe, where many more colonies died at the early stage of infestation.Based on the percentage of cleaned cells observed 6 hour after pin killing the brood, the efficiency of A. m. unicolor colonies to detect and uncap cells was comparable to those of Africanised hygienic honey bees and was much higher than those of European honey bees. In Madagascar, the detection of highly hygienic colonies of A. m. unicolor is a great opportunity to develop a programme of selection of tolerant honey bee strains
Burke, Antje. "Spotlight on a Global Biodiversity Hotspot - Namibia's Sperrgebiet." University of Arizona (Tucson, AZ), 2006. http://hdl.handle.net/10150/555885.
Full textWarren-Thomas, Eleanor. "Rubber plantations in the Indo-Burma biodiversity hotspot : habitat loss, biodiversity and economics." Thesis, University of East Anglia, 2017. https://ueaeprints.uea.ac.uk/66569/.
Full textGreen, Jonathan Michael Halsey. "Incorporating costs and processes into systematic conservation planning in a biodiversity hotspot." Thesis, University of Cambridge, 2012. https://www.repository.cam.ac.uk/handle/1810/245104.
Full textAgius, Jessica. "Combating a Novel Pathogen Threatening Critically Endangered Reptiles in a Biodiversity Hotspot." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/25893.
Full textEluvathingal, Lilly M. "An Ecological Study of the Anurans in Tea Plantations in a Biodiversity Hotspot." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/3029.
Full textStrijk, Joeri. "Species diversification and differentiation in the Madagascar and Indian Ocean Islands biodiversity hotspot." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/921/.
Full textThe Madagascar and Indian Ocean Islands biodiversity hotspot is renowned for its high levels of species diversity and endemism. Yet despite many hypotheses and a considerable literature, we still know relatively little about the mechanisms of species diversification within the region. Until recently, the major role for high levels of species diversity was attributed solely to breakup of East Gondwana and the isolation of Madagascar and India (120-160Mya). However, an increasing number of studies, employing recent advances in analytical methods, have shown that the origin for many groups post-dates the isolation of Madagascar. Furthermore, Madagascar is embedded in a wider geographical setting of oceanic and microcontinental islands that vary distinctly in origin, age and structure, and that are also home to highly diverse flora and fauna assemblages. Most of these islands are young (2-10My) and the high levels of endemism on these islands therefore can't be explained by Gondwanan vicariance, but only by recent long distance dispersal followed by extensive in-situ diversification processes. In addition, some groups of organisms show higher levels of diversity on young volcanic islands than on Madagascar, which runs counter to expectations given the greater surface area and habitat diversity of Madagascar. Taking into account the disparity in geological ages among the land fragments in the Indian Ocean, theory suggests that diversification on geologically young islands would have proceeded via high levels of diversification rates and rapid shifts over time after new ranges and habitat became available upon colonization. In this thesis we compare major plant lineages (Asteraceae, Myrsinaceae, Monimiaceae) that have undergone extensive diversification in the region. In each of these families we selected highly speciose genera that are characterized by single island endemism, phenotypic diversity and presence on Madagascar and a range of Indian Ocean islands. We found evidence of significant shifts in diversification rates and repeated long distance dispersals to Indian Ocean islands where Madagascar played a central role as a disperser source. .
DOBROVOLSKI, Ricardo. "Biogeografia da conservação frente à expansão agrícola: conflitos e prioridades." Universidade Federal de Goiás, 2012. http://repositorio.bc.ufg.br/tede/handle/tde/2640.
Full textAgriculture is the human activity with the greatest impact on the environment. Specifically, it represents the greatest threat to biodiversity. In the future, this activity should expand due to population growth, increased consumption and production of biofuels from food. To understand the possible impacts of this expansion on biodiversity, we used scenarios of land use change between 1970 and 2100 from IMAGE (Integrated Model to Access Global Environment) to test the following hypotheses: (i) areas considered as global priorities for conservation by international NGOs will be preferentially impacted by agricultural expansion in the XXI century, (ii) there is a conflict between the priority areas for carnivores conservation and agricultural expansion, and this conflict can be reduced by incorporating information on agricultural expansion in the prioritization process, (iii) the integration among countries for conservation planning may benefit both biodiversity and agricultural productivity, (iv) Brazilian protected areas will be impacted by agricultural expansion in the future and this impact will differ between protected areas of integral protection and those of sustainable use. We found that: (i) the impact on priority areas for conservation depends on the criteria by which they were set, so that areas defined by its high vulnerability are currently most affected than those of low vulnerability. Throughout the XXI century this impact is expected to increase, although the difference between the two types of priorities remains, except for High Biodiversity Wilderness Areas, defined by their low vulnerability in current time, but for which most pessimistic scenarios forecast an impact similar to priority areas of high vulnerability, (ii) there is a high spatial congruence between areas with high agricultural use in the future and priority areas for conservation of carnivores. This conflict can be reduced if the prioritization process include information on agricultural expansion; this incorporation, however, causes a profound change in the distribution of priority areas and reduces the number of protected carnivore populations, (iii) the integration of countries to create a set of priority areas for conservation that represents 17% of the land surface can protect 19% more mammal populations without reducing food production, compared to a strategy in which each country seeks to protect its territory independently, and (iv) the impact of agriculture in Brazil is expected to increase until the end of the century, threatening even the protected areas and their surroundings. This impact, however, should not be different between areas of sustainable use and those of integral protection. We conclude that agricultural expansion should remain a major threat to biodiversity in the future, even in areas of special interest for conservation. Conservation actions should be planned taking into account this threat in order to reduce their potential impacts. For this, countries like Brazil should strengthen its surveillance on agricultural expansion and on how this activity is developed. Furthermore, the integration of international conservation efforts should be pursued, given its benefits for biodiversity and food production. Finally, humanity must choose methods of agricultural production that reduce its impacts, including avoiding its future expansion, so as to meet the increasing needs of a human population globally.
A agricultura é a atividade humana com maior impacto sobre o ambiente. Particularmente, ela representa a maior ameaça à biodiversidade. No futuro, essa atividade deve expandir-se com o aumento populacional humano, o aumento do consumo e a produção de biocombustíveis a partir dos alimentos. Para entender os possíveis impactos dessa expansão sobre a biodiversidade, nós utilizamos cenários de mudança de uso do solo entre 2000 e 2100 do IMAGE (Integrated Model to Access Global Environment) para testar as seguintes hipóteses: (i) as áreas consideradas como prioridades globais de conservação pelas ONGs internacionais serão preferencialmente impactadas pela expansão agrícola no século XXI; (ii) há um conflito entre áreas prioritárias para a conservação de carnívoros e a expansão agrícola e esse conflito pode ser reduzido com a incorporação da informação sobre expansão agrícola no processo de priorização; (iii) a integração entre os países para o planejamento da conservação pode ser favorável à proteção da biodiversidade e à produção agrícola; (iv) no Brasil, as áreas protegidas serão impactadas pela expansão agrícola no futuro e esse impacto será diferente entre áreas de proteção integral e áreas de uso sustentável. Nós encontramos os seguintes resultados: (i) o impacto sobre as áreas prioritárias para a conservação depende dos critérios pelos quais elas foram definidas, assim, as áreas definidas por sua alta vulnerabilidade estão atualmente mais impactadas do que áreas de baixa vulnerabilidade. Ao longo do século XXI, o impacto geral da agricultura deve aumentar, mas a diferença entre os dois tipos de prioridades se mantém, exceto para as High Biodiversity Wilderness Areas, definidas por sua baixa vulnerabilidade, mas que nos cenários mais pessimistas podem ter um impacto agrícola semelhante ao das áreas de alta vulnerabilidade; (ii) há uma alta congruência espacial entre áreas com elevado uso agrícola no futuro e áreas prioritárias para a conservação de carnívoros; esse conflito pode ser reduzido se o processo de priorização incluir as informações sobre a expansão agrícola; a incorporação dessa informação, entretanto, provoca uma profunda alteração na distribuição das áreas prioritárias e reduz o número de populações de carnívoros protegidas; (iii) a integração entre os países para a criação de um conjunto de áreas prioritárias para conservação que represente 17% da superfície terrestre pode proteger 19% mais populações de mamíferos sem reduzir a produção de alimentos, se comparada a uma estratégia em que cada país busque proteger seu território independentemente; (iv) o impacto da agricultura no Brasil deve aumentar até o fim do século XXI, ameaçando inclusive as áreas protegidas e o seu entorno. Esse impacto, porém, não deve ser diferente entre as áreas de uso sustentável e aquelas de proteção integral. Assim, a expansão agrícola deve continuar a ser uma importante ameaça à biodiversidade no futuro, atingindo inclusive áreas de especial interesse para a conservação. As ações de conservação devem ser planejadas levando em consideração essa ameaça, a fim de reduzir seus impactos potenciais. Para isso, países como o Brasil devem reforçar sua vigilância sobre a expansão agrícola e a maneira como essa atividade é desenvolvida. Além disso, a integração internacional dos esforços de conservação deve ser buscada, dados seus benefícios para a biodiversidade e para a produção de alimentos. E por fim, a humanidade deve optar por formas de produção agrícola que reduzam seus impactos, inclusive evitando sua expansão futura, mas que possam satisfazer as necessidades da população humana globalmente.
Whitman, Karie L. "Improving Conservation Outcomes in a Biodiversity Hotspot: Alternative Agriculture Techniques in Maromizaha Forest, Madagascar." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1493822021804859.
Full textJust, Michael. "Understanding the seed ecology of southwest Australian Rutaceae to improve restoration in a biodiversity hotspot." Thesis, Curtin University, 2022. http://hdl.handle.net/20.500.11937/88660.
Full textSor, Ratha. "Modélisation des changements spatio-temporels des communautés de macroinvertébrés benthiques dans les rivières d'Asie et d'Europe." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30148/document.
Full textOverall aims: Freshwater tropical and temperate river systems are known to support different biotic communities. In this study, I investigated benthic macroinvertebrate community composition and diversity and its spatial and temporal variation both in tropical Asian and temperate European regions. I also examined the influences of physical-chemical water quality variables on community composition, variations and diversity, and modelled the occurrence of selected species. Locations: Tropical Asia: the Lower Mekong Basin (LMB), covering an area of 609,000 km2; Temperate Europe: Western Europe, Flemish rivers (Belgium), covering an area of 13,787 km2. Materials and Methods: For the LMB, data collected from 2004 to 2008 were used, and median values of this period were analysed. For Flemish rivers, data collected from 1991 to 2010 were used. The data were divided into 4 periods: D1: 1991-1995, D2: 1996-2000, D3: 2001-2005 and D4: 2006-2010. The medians of each period were used for detailed spatial analyses. Multivariate analyses were applied to relate community composition and diversity to physical-chemical variables. Five modelling techniques namely Logistic Regression (LR), Random Forest (RF), Support Vector Machine (SVM), Artificial Neural Network (ANN) and Classification Tree (CT) were used to model the occurrence of selected species. Main results: Community composition variations, diversity and relationship with environmental variables From the LMB, 299 macroinvertebrate taxa belonging to 196 genera and 90 families were identified: 131 insects, 98 molluscs, 38 crustaceans, and 32 annelids
Sholihah, Arni. "Diversification des biotas aquatiques de Sundaland : accumulation de la biodiversité chez les poissons d'eau douce et distribution dans un hotspot de biodiversité." Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTG024.
Full textSundaland is one of the most threatened biodiversity hotspots, experiencing a fast increase of threat levels during last decades. Covering Malayan Peninsula, Sumatra, Java and Borneo, this hotspot has one of the highest species richness and endemism for vertebrates in SEA, including freshwater fishes. This level of biodiversity has long attracted the attention of evolutionary biologists, particularly by considering effects of Sundaland complex geological history. This study addressed it by exploring time frame of vicariance and dispersal during diversity build-up of freshwater fish species in Sundaland. To support this, we first aimed to assess the match between distribution of molecular lineages from multiple taxa with palaeoriver boundaries using metadata analysis of existing molecular dataset with representative biological and spatial coverage in Southeast Asia (especially in Sundaland). Second, we focussed on estimating clades’ age and geographic distribution of Rasbora lineages in relation to the Pleistocene Palaeoriver Hypothesis by utilising newly generated empirical data for Rasborinae, a widespread and extremely diversified group of primary freshwater fishes in Sundaland. On both steps, we questioned: 1) if palaeorivers served as corridors of dispersal between islands during Pleistocene sea levels low stands; 2) if palaeoriver watersheds initiated allopatric divergence across their boundaries; and 3) if Pleistocene climatic fluctuation increased rates of species diversification. Overall, this study detected high level of cryptic diversity. Ancestral area reconstructions revealed that Sundaland freshwater fish lineages originated from Mainland Asia, and further colonised the region since Oligocene. This result validated the pre-Pleistocene settlement hypothesis. These lineages entered Sundaland mainly through North Sunda palaeoriver in contemporary Borneo and dispersed to other parts of Sundaland via long distance dispersal, often followed by in situ diversification. These results suggest Bornean part of North Sunda palaeoriver is the most likely centre of origin for Sundaland freshwater fishes. Contrary to the initial hypothesis, we found that although lowered sea level during glacial periods reconnected watersheds within palaeorivers, it did not necessarily open up inter-island dispersal channels for freshwater fishes. Corridors of savanna and seasonal forest ecosystems in the interior of Sundaland served as barrier to dispersal. Also, permeability of the physical boundaries of palaeoriver’s watersheds as well as geomorphological and habitat variabilities within palaeoriver created respectively gene flow between palaeorivers and allopatric speciation within palaeoriver. Moreover, although significant proportion of Sundaland freshwater fish lineages originated during Pleistocene, we found that Pleistocene dynamics did not affect diversification rate as sea level-dependent diversification models poorly account for species proliferation patterns for all clades excepting Channa. Besides, none of the taxa examined has declining diversification rates as suggested by diversity-dependent diversification (DDD) model. It is suggested then that global Pleistocene eustatic fluctuation and regional paleoriver dynamics are not sole drivers for Sundaland freshwater fish diversification, but only a part of abiotic aspects affecting it. Pleistocene Climatic Fluctuations likely interacted with other factors such as: landscape geomorphology, local ecosystem/habitat variability and life history traits of organisms
Kieck, Marius Burger. "Comparative impacts of fragmentation on birds in two bioregions in a biodiversity hotspot, the Cape Floristic Region." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1627.
Full textHabitat loss and fragmentation are two of the most pressing threats to biodiversity. Avifaunal diversity and integrity is under immense pressure from these two processes. We have made major advances in our understanding of avifaunal responses to habitat fragmentation, but mostly focus on either fragment scale and/or landscape scale influences of fragmentation on birds. A more comprehensive approach to assessing the impacts of fragmentation was used in this study. The avifaunas of two different geographical regions and bioregions were surveyed and a multiscale analysis of avifaunal responses to fragmentation was attempted. The study sites include the West Coast and East Coast Renosterveld Bioregions in the Cape Floristic Region, South Africa. Assemblage shifts, feeding guild compositional changes, species abundance variation and species persistence were examined at the three spatial scales. Time- and distance-restricted point counts were used to document birds that were directly dependent on the habitat fragments. Forty fragments were selected in each bioregion and a once-off snapshot of the avifaunal richness and diversity was obtained. Results indicate that the avifauna of the two bioregions responded differently to habitat fragmentation. In the East Coast Renosterveld Bioregion, the assemblages, guild composition and species abundances were most accurately predicted by landscape configuration. An assemblage shift occurred at 20 ha fragment area, compared to the 50 ha fragment area threshold of the West Coast Renosterveld Bioregion’s avifauna composition. In the West Coast Renosterveld Bioregion, fragment area was the better predictor of assemblage, guild composition and species abundances. However in both bioregions, the persistence of common species was equally sensitive to area and landscape scale effects.
Nakamura, Nodoka. "Dissecting the Japanese hotspot : refining evaluation of biodiversity in forests at different scales in the Japanese landscape." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:c625c75e-b983-48ab-b8c8-fbe0cea0d53e.
Full textBriñas, Garcia Berta. "Mapping and identification of hotspot areas for biodiversity and ecosystem services in cork oak woodlands of southern Portugal." Master's thesis, ISA/UL, 2014. http://hdl.handle.net/10400.5/8313.
Full textCork oak woodlands or montados are ecosystems of high conservation and socio-economic importance. The present work aimed at 1) identifying and mapping biodiversity and Ecosystem Services in main area of distribution of cork oak montado in Southern Portugal 2) assessing how the distribution of these conservation values relates with the distribution of the network of classified areas and 3) assessing how the distribution of identified conservation values relates with the area of cork oak montado under forest certification. I mapped biodiversity values (presence of species of amphibians, reptiles and threatened birds) and Ecosystem Services (carbon storage and aquifer recharge rates) within the study area. For achieving this I used the open source Q-GIS 2.0.1. software together with the open access online geographic information system WebGIS Hotspot Areas for Biodiversity and Ecosystem Services (HABEaS: www.habeas-med.org). With the exception of Natura 2000 sites the distribution of Biodiversity and Ecosystem Services is largely not coincident with that of classified areas. In relation to forest certified areas, these are presently covering a significant area of cork oak montados where biodiversity values and Ecosystem Services overlap
Bradshaw, Peter L. "Endemism and richness in the Cape floristic region : phytogeographic patterns and environmental correlates in a global biodiversity hotspot." Doctoral thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/19036.
Full textThis study reports on an investigation of the phytogeographical patterns retrieved within the exceptionally species rich Cape Floristic Region (CFR), a global biodiversity hotspot in South Africa. Modern Analytical techniques, including a novel approach developed within this study, were used to identify Phytogeographical Centres. Moreover, the efficiency and optimality of these techniques were tested against each other using several different datasets. Endemism and species richness in the core CFR were assessed against contemporary environmental conditions, using a spatially sensitive regression technique. A combined dataset of 4414 taxa was analysed, of which 4000 were recorded in the general CFR area. This represented 44.4% of the 9087 total taxa recorded in the CFR, and the largest dataset examined to date on floristic patterns in the CFR. The combined data (Combined Dataset), a relatively representative sample of the CFR flora, was used to establish overall phytogeographic patterns of endemism. Further, derivative subsets, based predominantly on phylogeny/taxonomy including taxa from eleven plant families, and two ecological guilds, Geophytes and Red Data Listed (RDL) Taxa, were also analysed. Differences between the derivative datasets revealed insights into taxonomically distinct floristic patterns, determined by the dominance of particular floristic/biotic elements within each dataset. This helped explain phytogeographical differences between previous CFR phytogeographical studies, which focused on different floristic/biotic elements. In the Combined Dataset, nearly all Quarter Degree Square (QDS) cells were assigned to PCs in the core CFR, indicating endemism is common throughout the CFR. However, endemic taxa were concentrated in the high winter rainfall west, and southwest areas. The large size of the dataset, and detailed analyses revealed additional finer phytogeographical sub-division, not previously recorded, including six Phytogeographical Provinces, 16 Centres, and 36 Sub-Centres; compared to five equivalent Phytogeographical Provinces and nine equivalent Centres of Weimarck. Hierarchical analyses of the Combined Dataset displayed congruent patterns to the previous two comprehensive phytogeographical studies of Goldblatt and Manning, (2000) and Weimarck (1941). Within the core CFR phytogeographical provinces, common patterns across studies included choria being strongly associated with TMS mountain ranges. This highlighted the importance of substrate and topography explaining floristic patterns, consequent PC formation, and the numeric dominance of montane TMS 'fynbos' taxa. The latter was confirmed through habitat analysis of endemic taxa. However, PC development was also noted on the lower lying areas, notably the Agulhas Plains, and the lowland areas neighbouring the mountains of the Southwest Phytogeographical Province, and to a lesser extent, the Northwest Province. The five analytical methods used to determine candidate PCs were evaluated for performance optimality. Bell Shaped Curve Weighting using UPGMA proved marginally more optimal than the other four methods, but differences between various weighting and clustering algorithms were less than anticipated. However, weighting was seen to be substantially better than not weighting. The novel technique of using a multiple clustering analysis approach was found to highlight areas of conflict, where floristic/biotic elements overlapped, and to supplement occasional poorly resolved trees. In addition, the approach of using GIS interrogation of candidate centres, substantially enhanced the endemic composition and size of PCs, and is strongly recommended. Moreover, post clustering GIS analyses may correct any marginal disadvantages of any single approach. Significant correlations between endemism and PC size, and richness of non-endemics and PC size were found. However, certain PCs still contained more taxa than predicted by area alone, while others contained fewer. In these PCs with over- or under-represented richness, alternative explanations (either historical and/or environmental) were required to explain why these PCs differ from other PCs in the CFR, which was subsequently investigated. Analyses of patterns of endemism and taxon richness against contemporary climatic and environmental variables using a regression technique which accounted for spatial variation in parameter estimates highlighted the importance of both the energy-water hypothesis, and the habitat heterogeneity hypothesis in the CFR. Potential evapo-transpiration and various measures of topographic heterogeneity provided much explanatory power. In addition, length of growing/rain season was particularly important in the western winter rainfall portion of the CFR, and is here retrieved for the first time as a strong predictor variable. Different input units and different floristic components of the dataset required different models for optimisation. The models were adequately able to account for much of the variability in richness (~ = 78.3- 91.2%). The Cape Floristic Region (CFR) -a global hotspot- proved an excellent area to study patterns of endemism, taxon richness, floristic patterns, and how environmental conditions affect richness because of its exceptionally high concentration of both richness because of its exceptionally high concentration of both richness and endemism, and high levels of beta and gamma diversity over relatively short geographic distances.
Ribeiro, Martins Renata Filipa [Verfasser], and Jörns [Akademischer Betreuer] Fickel. "Deciphering evolutionary histories of Southeast Asian Ungulates : comparative phylogeography in a biodiversity hotspot / Renata Filipa Ribeiro Martins ; Betreuer: Jörns Fickel." Potsdam : Universität Potsdam, 2017. http://d-nb.info/1218403004/34.
Full textWulff, Adrien. "Le micro-endémisme dans un hotspot de biodiversité : approche globale sur la flore vasculaire de la Nouvelle-Calédonie et analyse comparative au sein du genre Scaevola." Nouvelle Calédonie, 2012. http://portail-documentaire.univ-nc.nc/files/public/bu/theses_unc/TheseAdrienWulff2012.pdf.
Full textOsorio, Popiolek Christian Thomaz. "Wild carnivore habitat use and community ecology in a biodiversity hotspot and human-wildlife conflict with pumas and dogs across Chile." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103440.
Full textDoctor of Philosophy
Landscape transformation and human-wildlife conflict (HWC), which often result in retaliatory killing of wildlife in response to livestock predation, is one of the main global threats to wild cats, including pumas (Puma concolor). Medium-sized carnivores (mesocarnivores or mesopredators) are more abundant than large carnivores, live closer to human settlements and, like large predators, impact ecosystem structure and function significantly. Understanding habitat use of these carnivores is key to their conservation and management and to biodiversity preservation. Thus, there is need to investigate the ecological roles of carnivores (including invasive ones like free-ranging dogs and cats) to determine how interactions with other carnivore species and with the physical environment influence ecological roles of such species. This is especially important in my study area, which was severely burned by a catastrophic mega-wildfire in 2017, and for which there is scant information on wildlife responses to the mega-fire. I determined the distribution and causes of HWC across 52 provinces for 8 years in Chile and found that free-ranging dogs accounted for higher livestock depredation than pumas, killing substantially more livestock. Occurrence of HWC for both dogs and pumas increased with the sheep density of the province. Unexpectedly, dog HWC increased in less degraded habitats, indicating that dogs may travel far to prey on livestock in remote areas. The emergence of puma HWC in a site where it did not occur in the previous year increased with human-caused disturbance. Countrywide, dog HWC was higher than pumas in 43 out of the 49 provinces where both pumas and dogs occurred. I discuss livestock vulnerability, management strategies, and policy changes to address HWC, and discuss the threats that free-ranging dogs pose to biodiversity conservation and even to human public health. I also used remotely-triggered, camera-trap records to explore distribution of three mesocarnivores (guignas, culpeo foxes and chilla foxes across the landscapeand in response to mega-wildfires in southern-central Chile. I found that guignas, a small and vulnerable wild cat, avoided burned sites, preferring sites with native, dense vegetation while culpeo foxes were intermediate in being able to use plantations, but avoiding burned areas. Chilla foxes were most tolerant to landscape change with no response to burns, and they were found closer to human settlements and rivers. Finally, I examined overlap in space and time of day between native species pairs and native and exotic species pairs. I found that dogs were the most widely distributed species across the landscape, but were mostly diurnal while native species were primarily nocturnal. Cats however had high temporal overlap with guinas and chilla foxes, highlighting the potential for competition between them.. Thus, exotic species are damaging to wildlife, livetock and even huan health. I discuss the management implications and urge dialog between government authorities, wildlife managers, and scientists to generate a legal and public policy framework to properly managing habitat and HWC in southern-central Chile.
McCoy, Neil L. "The Geographical Mosaic of Myrmecochory in a Global Biodiversity Hotspot and the Fate of Myrmecochorous Seeds Dispersed by a Keystone Seed Disperser." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-12112008-142107/.
Full textPop-Ristova, Petra [Verfasser], Antje [Akademischer Betreuer] Boetius, and Gerhard [Akademischer Betreuer] Bohrmann. "Biogeochemical activity and associated biodiversity at reduced deep-sea hotspot ecosystems / Petra Pop Ristova. Gutachter: Antje Boetius ; Gerhard Bohrmann. Betreuer: Antje Boetius." Bremen : Staats- und Universitätsbibliothek Bremen, 2012. http://d-nb.info/1072076888/34.
Full textPrendergast, Kit Stasia. "Urban native bee assemblages and the impact of the introduced European honeybee on plant-pollinator networks in the southwest Australian biodiversity hotspot." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/84947.
Full textGardee, Muhammed Nizaar. "Recovery of vegetation and bees after removal of pine forests by fire in the Limietberg region of the Cape Floristic Region biodiversity hotspot." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97796.
Full textENGLISH ABSTRACT: The present global biodiversity crisis is characterized mostly by loss of species due to habitat destruction but there other major threats – notably invasive alien species. The term “biodiversity hotspot” has been coined to emphasize areas for conservation prioritization – areas that have high biodiversity under threat from habitat destruction, invasive species, etc. The Cape Floristic Region (CFR) in the Western Cape (WC) Province of South Africa has the highest biodiversity of all Mediterranean-type climate regions globally and is classified among global biodiversity hotspots. The CFR, a Mediterranean-type climate heathland with a naturally high fire frequency, faces threat from transformation by development, disturbed (increased) fire frequencies and intensities, and invasive organisms, most notably invasive trees. Such threats disturb keystone species and keystone processes including insect pollinator assemblages and associated insect flower visitation webs and frequencies. Invasive pines are a serious threat to insect flower visitation as pine trees (Pinus spp.) shade out much indigenous vegetation in the CFR. Little is known of their long-term effects on insect flower visitors and vegetation recovery in post-pine restoration and recovery areas after such trees are removed. I investigated the recovery of vegetation and the most important insect pollinator, bees, after the removal of pines by fire and passive recovery in a CFR valley in the Western Cape. In 1999, a wildfire burned much of the WC Limietberg Nature Reserve along with an adjacent pine tree forestry stand - which was then left to recover, providing an ideal opportunity to investigate the enduring effects of pine afforestation in the CFR. In two data chapters, I compared the post-fire passive recovery of vegetation (Chapter 2) and bee diversity (Chapter 4) in areas which had previously been planted with pines vs. those which had contained natural fynbos. To improve on sampling methodology, I conducted an experiment that demonstrated the Observer Effect in bee sampling with a sweep net (Chapter 3), and I developed a novel sampling device (Chapter 5) for insect flower visitors. Sampling of vegetation and bee diversity was conducted in a paired sampling design, where fynbos (Natural) sub-sites were paired with sub-sites which had previously been afforested with pines (Post-Pine Recovery; PPR) and the two sub-sites were separated by a distinct, linear boundary (Natural/PPR boundary). Sampling was conducted along transects parallel to the boundary and extending in both directions from the boundary into the Natural and in the opposite direction into PPR sub-sites. Five transects were positioned at 3, 10, 20, 30, and 40 m from the boundary (Ecotone) and three were positioned at 60, 80, and 100 m from the boundary (Deep). In Chapter 2, I found that natural sub-sites consistently had higher total plant species abundance and species richness than PPR sub-sites. Approximately two thirds of plant species were more abundant in Natural sub-sites than in PPR sub-sites. There was no significant correlation in species richness or abundance with distance from the Natural/PPR boundary. Some genera are cautiously indicated as having lower success in recovery after pine afforestation: Erica spp., Restio spp., Hypodiscus spp. while Helichrysum spp. is also tentatively indicated to recover well in PPR sub-sites. Soil disturbance and concomitant disruption of normal ecosystem functions, including pollination, is indicated as a probable reason for disruption of plant recovery. In Chapter 3, sweep netting methodology was tested for the Observer Effect. A noticeable increase in bee visitation frequency to a common generalist plant species in bloom, Metalasia densa, was correlated with longer waiting periods after I stopped moving indicating the presence of an Observer Effect. This suggests that sweep netting for bees should only be commenced after a waiting period of five minutes during which the sweep netter is motionless. In Chapter 4, using a flight-intercept modified pan trap, I compared bee species richness and bee species abundance across different seasons and in both mass-flowering and sparser flower patches. There was no significant difference in bee species richness between Natural and PPR sub-sites. All bee species, except one complex, were more abundant in Natural sub-sites. Nearly two thirds of all bee species (n=37 of 56) caught with sweep netting and the modified pan trap are undescribed species. Similar to the vegetation, the effects of soil disturbance as a result of decades of pine forest shading and pine forest litterfall followed by an unusually hot pine forest fire are indicated as the most likely reasons for lower bee abundance in PPR sub-sites. This is due to the difficulty associated with viable nest establishment and suitable pollen and nectar forage availability in disturbed areas. In Chapter 5, the newly developed Pan and Flight Intercept Combination (PAFIC) trap’s design, pilot testing, and comparison with the traditional pan trap is discussed. A preliminary test suggests that the PAFIC trap is more efficient (with higher abundance) than the traditional pan trap. In Chapter 6, I discuss the implications of the disturbance of pine forestry and unusual pine fire to plant species and bee species assemblages. Bee-pollination webs in PPR sub-sites are indicated as being substantially simpler than those in Natural areas as well as compositionally different. The recovery of pollination as a keystone process in post pine-afforestation areas faces a substantial challenge given the disturbance to soil that decades of pine afforestation followed by pine forest fire can cause. Some suggestions are made for the restoration of fynbos areas recovering from pine afforestation including a discussion of augmenting re-vegetation measures (fynbos seed dispersal and seedling planting) with methods of restoring of healthy pedogenesis, epigaeic arthropod communities, and fynbos seedbanks.
AFRIKAANSE OPSOMMING: Die huidige globale biodiversiteit krisis is gekenmerk meestal deur die verlies van spesies as gevolg van die vernietiging van habitat. Maar daar is ook ander groot bedreigings – veral merkbaar indringerspesies. Die term “biodiversiteit brandpunt” is geskep om gebiede vir bewaring prioritisering te beklemtoon - gebiede wat 'n hoë biodiversiteit bevat wat bedreig word deur die vernietiging van habitat, indringerspesies, ens. Die Kaap Floristiese Streek (KFS) in die Wes-Kaap (WK) Provinsie van Suid-Afrika het die hoogste biodiversiteit van alle Mediterreense tipe klimaat streke wêreldwyd, en is onder die globale biodiversiteit brandpunte geklassifiseer. Die KFS, 'n Mediterreense-tipe klimaat heideveld met 'n natuurlike hoë brand frekwensie, word bedreig as gevolg van transformasie deur ontwikkeling, versteurde (verhoogde) vuur regimes, en indringer organismes, veral indringerbome. Sulke bedreigings versteur hoeksteen spesies en die hoeksteen prosesse, insluitende insek bestuiwer samestelling en verwante insek blom besoekings webbe en frekwensies. Indringer dennebome (Pinus spp.) is 'n ernstige bedreiging vir insek blom besoeking want dennebome verskaf skaduwee aan baie inheemse plantegroei in die KFS. Min is bekend oor die langtermyn effekte op insek blom besoekers en plantegroei restorasie na denneboom verwydering en restorasie gebiede na sodanige bome verwyder word. Ek ondersoek die restorasie van plantegroei en die belangrikste insek bestuiwer, bye, na die vernietiging van dennebome deur vuur en passiewe herstel in 'n KFS vallei in die Wes-Kaap. In 1999 het'n veldbrand baie van die WK Limietberg Natuurreservaat saam met 'n aangrensende denneboom bosbouplantasie gebrand - wat toe gelaat is om te herstel via intermediêre suksessie na inheemse fynbos plantegroei. Dit bied 'n ideale geleentheid om die blywende gevolge van denneboom aanplanting in die KFS te ondersoek. In twee data hoofstukke, vergelyk ek die passiewe herstel van plantegroei na ‘n brand (Hoofstuk 2) en by diversiteit (Hoofstuk 4) in gebiede wat voorheen geplant is met dennebome teenoor diegene wat natuurlike fynbos vervat het. Om te verbeter op steekproefmetodiek, het ek 'n eksperiment onderneem wat demonstreer hoe die Waarnemer Effek by monsterneming met 'n vee-net beïnvloed (Hoofstuk 3), en het ek 'n nuwe monsterneming toestel ontwerp (Hoofstuk 5) vir insek blom besoekers. Monsterneming van plantegroei en by diversiteit is uitgevoer in 'n gegroepeerde steekproef ontwerp, waar fynbos (Natuurlik) sub-terreine gegroepeer is met sub-terreine wat voorheen aangeplant was met dennebome (Na Denneboom Verwydering Herstel; NDVH) en die twee sub-terreine is geskei deur 'n duidelike, lineêre grens (Natuurlik / NDVH grens). Steekproefneming is gedoen langs transekte parallel tot die grens en versprei in albei rigtings van die grens tot binne die natuurlike fynbos en in die teenoorgestelde rigting tot binne NDVH sub-terreine. Vyf transekte is geposisioneer binne 50 m van die grens (Oorgang sone) en drie is ver geplaas van die grens (Diep). In Hoofstuk 2 het ek gevind dat natuurlike sub-terreine konsekwent hoër totale getal plant individue en spesierykheid as NDVH sub-terreine gehad het. Ongeveer twee derdes van plantspesies was meer volop in natuurlike sub-terreine as in NDVH sub-terreine. Daar was geen beduidende korrelasie in spesierykheid of totale hoeveelheid plant individue met betrekking tot afstand van die Natuurlike /NDVH grens. Sommige genera word versigtig aangedui as met laer sukses in die restorasie terreine na denneboom aanplanting: Erica spp., Restio spp., Hypodiscus spp. terwyl Helichrysum spp. voorlopig aangedui is as goed herstel in NDVH sub-terreine. Grondversteuring en gepaardgaande ontwrigting van normale funksionering van die ekosisteem, insluitend bestuiwing, word aangedui as 'n waarskynlike rede vir die ontwrigting van die herstel van plantegroei. In Hoofstuk 3 is vee-net metodologie getoets vir die Waarnemer Effek. 'N merkbare toename in by besoeking frekwensie van 'n algemene plantspesie in blomtyd, Metalasia densa, is gekorreleer met langer wagtydperke nadat ek gestop het om te beweeg, en dui dus op die teenwoordigheid van 'n Waarnemer Effek. Dit dui daarop dat die vee-net vir bye eers gebruik moet word na 'n wagtydperk waartydens die waarnemer bewegingloos verkeer. In Hoofstuk 4, met behulp van 'n vlug-onderskep gewysigde pan lokval, het ek by spesierykheid en totale by hoeveelheid vergelyk oor verskillende seisoene en in beide massa-beblomde en yler blom kolle. Daar was geen beduidende verskil in by spesierykheid tussen natuurlike en NDVH sub-terreine. Alle by spesies, behalwe een spesie kompleks, was meer volop in natuurlike sub-terreine. Byna twee derdes van alle by spesies (n = 37 van 56) gevang met vee-nette en die van die gewysigde pan lokvalle is onbeskryfde spesies. Soortgelyk aan die plantegroei, is die gevolge van grondversteuring as gevolg van dekades van denneboom bos skadu en denneboom bos blaar afval gevolg deur 'n buitengewoon warm denneboom bos brand as die mees waarskynlike redes vir laer by hoeveelheid in NDVH sub-terreine aangedui. Dit is as gevolg van die probleme wat verband hou met lewensvatbare nes vestiging en geskikte stuifmeel en nektar voer beskikbaarheid in versteurde gebiede. In Hoofstuk 5 is die nuut ontwikkelde Pan en Vlug Onderskep Kombinasie (PEVOK) lokval ontwerp, aanvanklike toetsing, en vergelyking met die tradisionele pan lokval bespreek. 'N Voorlopige toets dui daarop dat die PEVOK lokval meer doeltreffend (met 'n hoër oorvloed) is as die tradisionele pan lokval. In Hoofstuk 6 bespreek ek die implikasies van die versteuring van denneboom bosbou en ongewone denneboom vuur met betrekking tot plant spesies en by spesies samestelling. By-bestuiwing webbe in NDVH sub-terreine word aangedui as wesenlik eenvoudiger as dié in natuurlike areas asook verskillend in samestelling. Die herstel van bestuiwing as 'n hoeksteen in na denneboom-aangeplante gebiede staar 'n aansienlike uitdaging in die gesig, gegee die versteuring van grond wat dekades van denneboom aanplanting gevolg deur denneboom bos brand kan veroorsaak. Sommige voorstelle is gemaak vir die herstel van fynbos gebiede wat herstel van denneboom aanplanting, insluitend 'n bespreking van die aanvulling van plantegroei hervestiging maatreëls (fynbos saadverspreiding en saailinge plant) met die metodes van die herstel van 'n gesonde pedogenese, bogrondse geleedpotige gemeenskappe, en fynbos saadbanke.
Kehinde, Temitope Olatayo. "Effects of vineyard management and landscape context on taxonomic diversity and interaction networks of flower-visiting insects in the Cape Floristic Region biodiversity hotspot." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17980.
Full textENGLISH ABSTRACT: Both taxonomic diversity and diversity of species interaction networks are experiencing declines as a result of agricultural intensification at habitat and landscape scales. Reversing this trend is a key conservation issue, particularly for important functional groups such as flower-visiting insects and the networks within which they interact. This is of great concern in regions of high conservation priority such as the Cape Floristic Region (CFR), known for its high level of floral and faunal endemism and exceptional species turnover. Holistic approach to conservation in agricultural landscapes involves both preservation of natural land and wildlife friendly management of the farm land to achieve conservation targets. The value of these extensive management approaches is yet to be fully assessed, especially in perennial systems such as vineyards. I examined here the effects of vineyard management and landscape context on species richness and abundance of flower-visiting insects and their species interaction networks. Possible taxon specific effects were verified. I also investigated whether vineyards under organic and conventional management homogenized insect-flower interaction networks and whether vineyards with different management practices vary in patterns of species turnover. I sampled flower-visiting insects and their interactions in organic and conventional vineyards, and in natural reference sites. Inclusion of natural reference sites enabled me to make management recommendations for patches of natural vegetation in CFR agricultural landscape. Statistical models showed taxon-specific benefit of organic farm management, and of landscape (distance to natural habitat). There was benefit to monkey beetles (Scarabaeidae) but not to bees (Apidae). Organic vineyards had a higher number of insect-flower interactions than conventional ones, but vineyards under the two types of management were similar in terms of other important network indices. However, networks of the vineyards were more nested than the natural sites, indicating that they may be potentially more stable to perturbation and random extinctions. Multivariate dispersion tests revealed insect-flower interaction networks were not homogenized by both organic and conventional vineyards across the landscapes. I also found, through additive partitioning, that organic and conventional vineyards were similar in terms of species turnover of bees and flowering plants. The findings of this study provide heuristic value to current debates on the value of vineyard habitats for insect conservation. Both organic and conventional vineyards that promote sustainable management of the non-crop floral vegetation between vineyard rows are potential solutions for conservation of flower-visiting insects and their interactions. Also, attention has to be paid to the quality and connectivity of the natural habitat patches that are within CFR agricultural landscape. Site specific management and assessment of the value of these landscape elements is important. Management approaches such as carefully controlled burning may be beneficial, as the CFR natural vegetation is a fire-driven community.
AFRIKAANSE OPSOMMING: Taksonomiese diversiteit en diversiteit van spesies-interaksie netwerke ondervind beide afnames as gevolg van landboukundige intensifikasie op habitat en landskap skaal. Om die neiging terug te swaai, is ’n sleutel bewaringsaangeleentheid, veral vir belangrike funksionele groepe soos blom-besoekende insekte en die netwerke waarbinne hulle op mekaar inwerk. Dit is van groot kommer in streke met hoë bewaringsprioriteite soos in die Kaapse Floristiese Streek (KFS), bekend vir sy hoë vlak van plant- en dierendemisme en buitengewone spesies kentering. ’n Holistiese benadering tot bewaring van landboukundige landskappe behels beide die bewaring van natuurlike land en natuurlewe-vriendelike bestuur van die plaasgrond om bewaringsdoelwitte te bereik. Die waarde van hierdie ekstensiewe bestuursbenaderings moet nog volledig bepaal word, veral in meerjarige sisteme soos wingerde. Ek het die uitwerkings van wingerdbestuur en landskapsamehang op spesiesrykheid en volopheid van blombesoekende insekte en hulle spesies interaksie netwerke ondersoek. Moontlike takson-spesifieke uitwerkings is nagegaan. Ek het ook ondersoek ingestel of wingerde onder organiese en gebruiklike bestuur ooreenstemmende insek-blom interaksie netwerke met wingerde met verskillende bestuurspraktyke in patroon van spesies kentering gewissel het. Ek het blom-besoekende insekte en hulle interaksies in organiese en konvensionele wingerde, asook in natuurlike verwysingsgebiede gemonster. Insluiting van natuurlike verwysingsgebiede het my in staat gestel om bestuursvoorstelle vir gebiede van natuurlike plantegroei in KFS landboulandskappe voor te stel. Statistiese modelle toon takson-spesifieke voordeel van organiese plaasbestuur en van die landskap (afstand van natuurlike habitat) self. Daar was voordeel vir bobbejaankewers (Scarabaeidae), maar nie vir bye (Apidae) nie. Organiese wingerde het ’n groter getal insek-blom interaksies as konvensionele wingerde gehad, maar wingerde onder beide tipes van bestuur was soortgelyk in terme van ander belangrike netwerk aanduiders. Netwerke van wingerde was egter meer geklomp dan natuurlike gebiede wat aandui dat hulle potensieel meer stabiel betreffende versteuring en lukrake uitsterwings is. Multivariate verspreidingstoetse het aangetoon dat insek-blom interaksie netwerke by beide organiese en konvensionele wingerde oor landskappe nie eenvormig was nie. Ek het ook bevind deur aanvullende verdeling dat organiese en konvensionele wingerde gelykwaardig was in terme van spesies kentering van bye en blomplante. Die bevindings van hierdie studie verskaf heuristise waarde tot huidige debatte oor die waarde van wingerdhabitatte vir insekbewaring. Beide organies en konvensionele wingerde wat volhoubare bestuur van die nie-gewas plantegroei binne wingerdrye bevorder, is moontlike oplossings vir die bewaring van blom-besoekende insekte en hulle wisselwerkings. Bykomend moet aandag gegee word aan die kwaliteit en verbindings van en tussen natuurlike habitat gebiede binne die KFS landboulandskap. Plekspesifieke (plaaslike) bestuur en bepaling van die waarde van hierdie landskapelemente is belangrik. Bestuursbenaderings, soos noukeurig beheerde brand, mag voordelig wees aangesien die KFS natuurlike plantegroei ’n vuurgedrewe gemeenskap is.
Zuiddam, Sharon Angela. "A revision of the Western Australian species of the Australian harvestman genus Nunciella (Opiliones: Triaenonychidae)." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2015. https://ro.ecu.edu.au/theses/1636.
Full textRodrigues, Rodolpho Credo. "Influência da estrutura da vegetação sobre a diversidade e detectabilidade das espécies de aves do Cerrado." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-11012017-102836/.
Full textIn several studies around the globe, the structure and diversity of vegetation have been shown to be a determining factor in the diversity of species of birds and also other groups of animals. The Cerrado is the second most extensive and most threatened biome occurrence in Brazil. This biome is also characterized by an obvious environmental gradient of vegetation structure and heterogeneity. In this thesis we analysed the influence of the structure and diversity of the vegetation on the diversity in the Cerrado bird communities. Our expectation was to support the “Habitat Heterogeneity Hypothesis” which suggests that the higher the structure and diversity of vegetation, the greater the diversity of species. In the first chapter, we conducted a systematic compilation of published studies on the diversity of birds in areas occupied by some typical physiognomy of Cerrado textit lato sensu, in order to analyze the knowledge obtained so far about the relationship between diversity of birds and the structure of the vegetation in the Cerrado. We selected 72 samples from 22 studies, and these samples varied as the sampled vegetation physiognomy, the sampling method used, and they also are available in different articles and be carried out in different geographical regions. We performed the analysis of generalized linear mixed effects models (model poisson distribution errors), which allows us to analyse the effects of fixed and random variables on the explanatory variable (species richness). Fixed variables were the type of sampled vegetation (grassland, savanna and forest) and the sample method employed (fixed point, transect and mist nets). The random variables used were the study where the data were published, the author of each study and geographic location. These random variables could only affect the intercepts of the relationship between fixed and variable explanatory variable or could alter the relationship between fixed and explanatory variables. We built several models from the combination of fixed and random effects variables and selection the most parsimonious model was made by the AIC criterion (Akaike information criterion corrected for small samples). The model that showed lower value of AIC (more parsimonious) was the one that included the effects of both fixed effect variables (physiognomy and sampling method) and also an effect of the interaction between these two variables. In this model were also included the effects of random variables study and geographic location of the intercepts of the relationship between the fixed effect variables and the explanatory variable. These results showed that the bird species richness in our study varied not only in terms of physiognomy and sample method, but depending on the sampling method used the relationship between richness and physiognomy has also changed. Therefore, this interaction does not allowed us to estimate the relationship between physiognomy and richness without considering the effect of the methods. Since the effects of random variables showed that the variation in the estimated intercept between studies was twice larger than the estimated variation between geographic locations. The effect of interaction between the vegetation physiognomy and sampling method variables pointed to the existence of heterogeneity detection between locations with different physiognomies, in addition also of an effect of the physiognomies in the effectiveness of different sampling methods. The influence of the sampling method in the number of species observed in each physiognomy may be expected due to intrinsic differences in the methods, since fixed point counts and transect are based on visual and aural contacts with the species, while the mist net method consists in passive capture of species flying at the time of the networks. Thus, mist nets may be more effective in less structured environments (eg. Clean and dirty fields) where the net reaches virtually all vegetation layers. However, transect method can be more effective than the fixed point method in areas of forests since in these habitats species tend to have smaller territory areas, and the observer movement provides the observer cover greater areas. On the other hand, the point counts can be more advantageous not to produce noise and chase species, which may be a disadvantage of transect method. Other factors, such as experience and number of observers, the number of sampling points, the number of nets used and length of transects, may explain the wide variation between studies estimated. One of the ways to overcome these methodological effects is to use methods developed especially to deal with different probabilities of detection of species, between sites and sampling methods, which could yield more reliable data for the ecological study of the species and the development of management plans and/or conservation. In the second chapter, the relationship between diversity of birds and vegetation structure was analysed from data collected in the field and using a specific sampling protocol to estimate and consider the effects of vegetation on the detection of species. The samples were taken in one of the largest and well preserved remnants of Cerrado (Grande Sertão Veredas National Park-PARNA GSV) and consisted of the record of bird speciesin 32 areas arranged in a Cerrado vegetation gradient, ranging from grasslands, open and dense savannas. The calculation of the bird species richness at each site was conducted using occupancy-detection models adapted to estimate the number of species in communities. The vegetation, in turn, was measured from estimates of the presence of vegetation in height intervals between 0 and 4 m (16 intervals of 22.5 cm each) and two structure variables were obtained from a principal component analysis applied to summarize the variation of the vegetation presence in height intervals. These vegetation variables were related to both the occupation and detection of species, since the vegetation structure could influence not only the occurrence but also the detection of species. The day of sampling and also the temperature at the time of sampling were also included as covariates that may a_ect the detection. After the estimation of species richness by model occupancy detection for communities, this estimated richness was related by a quadratic function with the vegetation structure using a Bayesian meta-analysis model, which allowed us include uncertainty in richness estimates. By way of comparison, we also fit a quadratic model GLM (normal distribution errors) to the observed richness data. The results showed that the richness estimated from the data of the 38 most detected species during sampling had a weak relationship with both covariates vegetation structure, and there was a greater number of species at sites with intermediate vegetation height and greater bird species richness in places where there was a greater presence of vegetation below 2 m in height. However, relations between estimated richness and these covariates was less intense but qualitatively similar to the relationship between observed richness and vegetation covariates. The lowest intensity in the estimated richness relationship was observed mainly at both ends of the vertical gradient of vegetation and also in areas with less presence of vegetation below 2 m. These results showed that the effect of detection can change the effect of the relationship between species richness and vegetation structure. Moreover, at least for the 38 species most commonly found in the study area, the results point to the importance of the entire vegetation structure gradient to maintain the bird species richness in Cerrado. Future studies aiming to improve the use of these models of occupation and detection for communities are essential to allow the use of data of all species in the community. In addition, other studies that propose to analyse the dynamics and composition of bird communities in these vegetation structure gradients are fundamental for a better understanding of the ecology and conservation of Cerrado birds
Pereira, Ismael Martins. "Ecologia, conservação e aspectos taxonômicos do gênero neotropical Davilla Vand. (Dilleniaceae)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/59/59139/tde-30072014-110731/.
Full textIn this study was realized to study the distribution, richness and conservation of the Davilla Vand. (Dilleniaceae) in the neotropics. For this purpose was used to distribution model of species with Maxent algorithm. This produces species distribution in geographic in space based on environmental and occurrence data. Species in accordance with biome of occurrence were studied: Atlantic Forest; Cerrado; and the Amazon. This group is represented by 25 species in the neotropics. For the Cerrado was included in addition to the Davilla species all species of Dilleniaceae family. The results indicated that in the Cerrado this group is represented by nine species of Davilla, and Curatella americana L. and three species of Doliocarpus Rol., to these five are endemic (Doliocarpus elegans Eichler and 4 Davilla spp.). For Atlantic Forest occur 12 Davilla species, eight of which are endemic, including an endangered species. For the Amazon are known nine species, five of these endemic. Two other neotropical species are therefore shared by all biomes mentioned above. The other species are occurring in at least two biomes. For these three biomes produced the distribution and species richness in order to compare the results with the protected areas, aiming to discuss issues relating to the conservation of this group. Conservationists parameters as rare species, areas of endemism, areas of high species richness, conservation areas, were confronted aiming indicate priority areas for conservation of biodiversity and too this group. The results indicated three centers of diversity for this group. The main one is located in the Atlantic Forest in coastal forests of Bahia. Another center of diversity is located in central region of Cerrado, especially in the states of Goias and Bahia. The other area of diversity is located near the mouth of the Amazon River and along its course. Due to the prevailing habit of the species are lianas, these are important components of forests, of which we use this framework to discuss issues relating to the conservation of these habitats, their species and biodiversity. Full details are presented in chapters according to their biomes addressed.
Longo, Luccas Guilherme Rodrigues. "Análise da Avifauna da RPPN Rio dos Pilões (Santa Isabel, SP), visando à conservação das espécies de um "Hotspot" da Mata Atlântica." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-08082007-163301/.
Full textThe most of global biodiversity is intent in the tropical forests. One of the main factors that they cause the disappearance of this diversity is the loss of habitats for the anthropic actions, as the deforestation and the disordered urban growth. Forest fragments that possess high biodiversity, high taxes of endemism and forts anthropics pressures, are called hotspots. The Atlantic Forest is a Brazilian hotspots more deforested. By being sensible the alterations of the environment, the birds are considered the most important bioindicators of the quality of ecosystems. The present study River of the Piloes was carried through in the Particular Reserve of Patrimony Natural (RPPN), in an anthropic region and with remainders of Atlantic Forest, located in the city of Santa Isabel, State of Sao Paulo. The RPPN belongs to a real estate enterprise that aims at the integration enters the activities of protection of the natural resources with the actions human beings. Whit the intention to know and to analyze the community of birds of the RPPN one studied three main environments: environment of anthropic field (ACA), anthropic environment flooded (AAI) and the anthropic forest environment (AFA). The study has been at the May of 2006 to May of 2005, using the capture method with mist-nets and the method of irregular courses, being the first one applied in the AFA, and as in the ACA and the AAI. They had been registered 141 species of birds in a total of 1.824 working hours. These are distributed in 20 orders, 46 families, 125 genders, resulting in 2.243 observed individuals, 184 captured and 17 recaptured. The accumulated curve of species as soon as did not show to trend to the stabilization, suggesting that the expended effort of collection has not been enough to show to all the community, indicating new species can be registered. The Non- Passeriformes had added 56 species, with bigger representation in the families Ardeidae and Trochilidae. The Passeriformes had been most representative, with 85 species and in Tyrannidae are the bigger. The environment that presented greater wealth was the AAI with 85 species, AFA with the 72 and the ACA with 52 species. The most frequent species (FR) had been Patagioenas picazuro in ACA, Thraupis sayaca in AAI and Chiroxiphia caudata in AFA. The analysis of the occurrence frequency (FO) showed that the majority of the species had FO below of 25%, whereas few species had presented bigger FO that 75%. The bigger with FO had been Vanellus chilensis, Pitangus sulphuratus, T. sayaca and Basileuterus leucoblepharus. The community was grouped in 13 trophic guilds, being the insectivora of the bigger predominance in all environments. Of the registered species, 04 are migrants and 03 are threatened of extinguishing. Although the RPPN presents one high degree of degradation, it possess high wealth and diversity of species of birds, it is the factor that can contribute to not only increase its value of conservation, as well as auxiliary in the implantation of projects of ecological restoration of the remainders.