Dissertations / Theses on the topic 'Wetland biodiversity conservation'

Despite reductions in species diversity, few studies in wetlands investigate the relationship between biodiversity and ecosystem function (BEF). My research explores the BEF relationship in a recently restored salt marsh in Long Beach, California. I hypothesized that: (1) increasing plant diversity would result in higher primary productivity and decreased recruitment of native salt marsh plants, (2) observed variation in responses would be correlated with species-specific variation in individual demographic parameters, and (3) variation in demographic parameters and resulting ecosystem processes would be correlated with functional traits. I found that while survival over one year was correlated with elevation, overall percent cover and recruit species richness were positively affected by diversity. Performance patterns reveal variation by species in photosynthetic rate, leaf mass per area and chlorophyll a/b ratios. After one year, I found that the overall diversity patterns were driven by selection effect compared to complementarity.

The study explores the possibility of conflicts between conservation of wetlands and semi-natural grasslands in the county of Stockholm. Both habitats are important to protect from a biodiversity perspective. The species rich semi-natural grasslands have been created by agricultural practices like grazing and mowing. At the same time, wetlands have diminished due to earlier drainage in order to increase the area of arable land. Both habitats are incorporated in the Swedish Environmental Objectives and are parts of the EU’s Agri-Environmental Schemes (AES), where farmers get financial support to maintain or restore valuable habitats. Wetland conservation/restoration often requires raised water tables, but also maintenance with cattle grazing in certain areas. On the other hand, raised water tables can act as hinder for grazing animals and lead to conflict situations. Using a mixed method approach, this study scrutinized if the use of different management tools can result in conflicts between actors and objectives. The study is based on a literature review, interviews and the use of Geographical Information Systems (GIS). Institutionalism and the Institutional Analysis and Development framework are used to analyze and evaluate the situation in the county of Stockholm. The quantitative results reveal that 12,8 % of all semi-natural grasslands of high biological value intersects with wetlands. However, these areas are maintained with environmental support to a larger extent than semi-natural grasslands outside wetlands. This indicates there is no conflict between wetland and semi-natural grassland conservation, a perception shared by authorities. From farmers’ perspective the situation is described differently, rule compliance for environmental support is hard to obtain specifically in wet areas. Increased dialogue between authorities and farmers rather than harsh inspections would be preferable as the county of Stockholm needs more farmers and grazing cattle to maintain biologically important habitats. Grazing in wetlands is needed from a biodiversity perspective but can at the same time disturb the wetlands functioning of nutrient reduction. There is a risk of authorities prioritizing water quality in front of biodiversity in conflicting situations. Water, as a common-pool recourse, is surrounded by stricter regulation and also easier to monitor.

Dans le contexte du déclin général des zones humides temporaires méditerranéennes et du manque de connaissances à leur sujet en Tunisie, l'étude pluridisciplinaire et multiscalaire de leur structure et de leur fonctionnement a été entreprise dans les Mogods (Tunisie septentrionale). (1) A l'échelle régionale, l'inventaire et la typologie de ces milieux permettent d'en définir les enjeux conservatoires. Ces résultats montrent, d'une part l'intérêt biogéographique majeur de la zone d'étude, qui abrite des milieux rares et exceptionnels (zones tourbeuses, lacs semi-permanents, Garâa Sejenane), et d'autre part sa diversité spécifique et biocénotique reflétant l'hétérogénéité spatiale des conditions hydrologiques et pédologiques. (2) A l'échelle paysagère, l'étude des communautés végétales de trois mares temporaires permet de caractériser leur composition, leur structure et leur dynamique intra- et interannuelle, et de montrer l'influence majeure du pâturage. Les résultats obtenus mettent en évidence la nécessité d'une politique de gestion intégrant le maintien de l'hétérogénéité paysagère et le fonctionnement des zones humides en métapopulations. (3) A l'échelle locale, l'étude d'une espèce rare récemment découverte en Tunisie (Pilularia minuta) permet de caractériser pour la première fois la morphologie de ses organes reproducteurs, de mettre en évidence l'ancienneté de sa présence locale, de confirmer son caractère pionnier et d'évaluer sa dépendance vis-à-vis des conditions hydrologiques.Les résultats obtenus révèlent la diversité, la richesse et l'importance conservatoire des zones humides temporaires des Mogods, presque totalement méconnues et ignorées à l'heure actuelle. Ils mettent en évidence leur vulnérabilité face au développement socio-économique de la région, et soulignent l'urgence de développer une gestion conservatoire rationnelle, adaptée et durable, à différents niveaux d'organisation (région, commune, site)
In the context of the general decline of Mediterranean temporary wetlands and of the lack of knowledge about them in Tunisia, the pluridisciplinary and multi-scale study of their structure and functioning has been undertaken in the Mogods region (N. Tunisia). (1) At the regional scale, the survey and the typology of these habitats allow defining the conservatory stakes. These results show, first the major biogeographical interest of the study zone, which harbours rare and exceptional wetlands (peaty zones, semi-permanent lakes, Garâa Sejenane), and second its species and community diversity that reflects the spatial heterogeneity of hydrological conditions and soils. (2) At the landscape scale, the study of plant communities of three temporary pools allows characterising their composition, structure, and intra- and inter-year dynamics, and to show the major influence of grazing. The obtained results highlight the need for a management policy i ntegrating the conservation of the landscape heterogeneity and the pools' functioning in metapopulations. (3) At the local scale, the study of a rare species recently discovered in Tunisia (Pilularia minuta) allows characterising for the first time its reproduction organs, revealing its ancient local origin, confirming its pioneer character, and evaluating its dependence on hydrological conditions.The obtained results highlight the diversity, the richness and the conservatory importance of temporary wetlands of Mogods region, today almost completely unknown and ignored. They reveal their vulnerability to the socio-economical development of the region, and underline the urgency to develop a rational, adapted and sustainable conservatory management at different organisation levels (region, city, site)

This study aimed to analyse the potential and challenges for ecotourism development and how it can be applied as an integrated tool to provide economic incentives and better opportunities for community development, while improving natural resource management and conservation in Isimangaliso. The capital assets, the context of vulnerability of the local communities along with other significant attributes of the supply side were investigated in-depth. In addition, the potentials and challenges for ecotourism development in the selected Isimangaliso, Khula Village were studied. The impacts of ecotourism on local livelihood improvement, biodiversity resources and natural environment, and management and conservation of the area were also explored through sustainability concepts. However, the focus of the study was not only on ecotourism potentials and opportunities but was also on the development of sound guiding principles for planning and management of ecotourism development in Isimangaliso in a sustainable manner. It was found that community‟s willingness to participate in local development and natural resource management remains a questionable issue to be achieved. This is because local communities are strongly influenced by vertical network of the state administration. The study reveals that there is a strong interaction and interdependency between local livelihoods or poverty and the status and effectiveness of natural resource management in Isimangaliso. The study indicates that the area has plenty of potential natural and cultural resources. These resources signify three fundamental elements for ecotourism destination: quantity, quality, and fascination. The natural attractions consist of vital and sensitive biological and scenic values of the destination area.

East African papyrus Cyperus papyrus swamps have undergone wide-scale drainage and are used intensively by resources harvesters. They also support a unique biota, notably six inadequately protected bird species. In this thesis, the results of a study examining the socio-economic benefits of and avian responses to wetland drainage and resource use are presented. The species richness of bird communities in heavily disturbed papyrus stands was higher than in nearby stands that were not disturbed, but contained fewer species and individuals of specialised species. However, even the six most specialised species were tolerant of low-intensity disturbance. Using a time-series of Landsat ETM images covering southern Uganda and adjoining countries wetlands were mapped and regional variations in drainage quantified. Using land coverage and occurrence data, the abundance and decline of bird species in c. 30,000 Eas1 African wetlands was predicted. The species studied were found to have declined substantially more than predicted by ecological theory because population densitie~ were higher in regions in which most drainage has occurred. Although averag( drainage was only c. 9% over 15 years, drainage in regions in which bird densit) was highest exceeded 75% over this period. The socio-economic value of crops grown in reclaimed swamps and goods derive( from swamps were determined by interviewing rural householders. Result: indicated that although drainage always served to reduce the net present valU! (NPV) of goods derived from swamps, NPV was maximised when 25-30% of th swamp was used for harvesting. Drainage and harvesting exceeded these levels, il part because property rights structures have shifted from common ownership tl open-access and in part because income equality is low and poorer people are mor inclined to use and drain swamps. The results of this study suggested that ther were similarities between swamp use that maximises socio-economic benefits an management that favours specialist bird species. This would imply th, conservation action designed to protect papyrus avian communities could also be ( benefit to rural inhabitants using swamp resources. However mutual benefits t birds and people are dependent upon reducing poverty.

This doctoral dissertation was produced in a cooperation between Halmstad University (Wetland Research Centre, School of Business and Engineering) and Lund University (Limnology & Marine Biology, Department of Ecology). Abstract . Wetland creation at large, regional scales is implemented as a measure to abate the biodiversity loss in agricultural landscapes and the eutrophication of watersheds and coastal areas by non-point source nutrient pollution (mainly nitrogen). The consequences of creating many new wetlands for biodiversity conservation and nutrient reten- tion (ecosystem functioning) in agricultural landscapes are still relatively unknown, both on local (per wetland) and regional (per landscape) scales. In Sweden, wetland creation has progressed already since the 1990s, and by now larger numbers of created wetlands are present, mainly in the intensively farmed landscapes of southwestern Sweden. This thesis aimed to investigate the following aspects in these systems: (i) their large-scale effects on biodiversity, (ii) their functional diversity of bacterial denitrifiers, (iii) the abiotic and biotic influences on wetland ecosystem functioning, (iv) the potential for biodiversity-function links, and (v) the potential for functional links and joint functioning.(i) Created wetlands hosted diverse assemblages of macroinvertebrates and plants. They maintained a similar com- position and diversity as natural ponds in agricultural landscapes. The environmental conditions per wetland did hardly affect macroinvertebrate and plant assemblages, and the prerequisites for nutrient retention did neither. In landscapes were wetland creation efforts had increased the total density of small water bodies by more than 30%, macroinver- tebrate diversity of created wetlands was facilitated on both local and regional scales. (ii) Diverse communities of denitrifying bacteria with the capacity for conducting different denitrification steps (functional types) were present in all investigated wetlands. The richness of denitrifying bacteria communities was affected by nitrate concentration and hydraulic loading rate, which may potentially be relevant for the nitrogen retention function of created wetlands. The diversity across different functional types of bacterial denitrifiers increased with nitrate concentration. (iii) Both abiotic and biotic factors influenced ecosystem functions of created wetlands. Variation in nitrogen retention was associated to nitrate load, but even to vegetation parameters. In wetlands with constant nitrate load, planted emergent vegetation facilitated nitrogen retention compared to other vegetation types. In wetlands with variable loads, nitrogen retention was facilitated if nitrate load was high and many different vegetation types were present; nitrogen load could explain the majority of the variation in nitrogen retention compared to vegetation parameters. Phosporus retention of created wetlands was best explained by vegetation parameters. Litter decomposition was inhibited at high nitrate to phosphorus ratios. Methane production increased with age and decreased with plant cover. (iv) Biodiversity may facilitate wetland ecosystem functions, particularly in dynamic wetland ecosystems. Nitrogen retention increased with vegetation type diversity, phosphorus retention capacity with plant richness, and litter decomposition with macroinvertebrate diversity. (v) Created wetlands have the capacity of sustaining several parallel ecosystem services. Some wetland functions were coupled; nitrogen retention increased with fast litter decomposition. On the other hand, methane emission and nitro- gen retention were independent of each other, as were nitrogen and phosphorus retention.In conclusion, created wetlands have the potential to at least partly abate the lost biodiversity and multifunctionality caused by the past extensive destruction of natural wetlands in agricultural landscapes.

[Paper II] Milenkovski S., Thiere G., Weisner S.E.B., Berglund O. & Lindgren P.-E. Variation of eubacterial and denitrifying bacterial biofilm communities among constructed wetlands. Submitted manuscript. [Paper V] Thiere G. & Weisner S.E.B. Influence of biotic and abiotic parameters on ecosystem functioning of created wetlands. Manuscript.

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Universidade Federal de Sao Carlos
Wetlands are prioritary ecosystems for conservation due to their vast biological diversity and productivity, besides their many functions and value. In southern Brazil conservative data show that about 90% of the original wetlands are already destroyed due to agricultural expansion, mainly the irrigated rice fields. On the other hand, rice is the most important cereal grown in developing countries, being the main food source for more than half of the world population. Also, a high diversity of plants and animals has been found in these agricultural areas. The main goal of this study was to assess the structure and diversity of macroinvertebrates in rice fields and irrigation canals over the different hydrological phases of the cultivation cycle in an important rice cultivation area in Rio Grande do Sul to preserve the biota in these agroecosystems. Six collections were carried out along a cultivation cycle (June 2005 June 2006) in six rice fields and four irrigation canals in the Coastal Plain of Rio Grande do Sul. Quantitative samples of macroinvertebrates were obtained with a corer inserted 10 cm deep into the sediment, and also qualitative samples with a kick net.The main results obtained were: a total of 26,579 individuals assigned into 119 invertebrate taxa were collected in rice fields and irrigation canals; the maintenance of the dry fields and the flooded fields in the fallow phase favors the setting of a greater amount of macroinvertebrate taxa in the agricultural landscape; the irrigated rice fields can store and keep egg banks and other resistance structures of aquatic invertebrates viable along their cultivation cycle, and the irrigation canals work as habitats for the aquatic invertebrate community, thus assisting to keep the aquatic diversity in these agricultural areas. These results can be used in management plans which aim at reconciling agricultural production and biodiversity conservation in Rio Grande do Sul.
As áreas úmidas são ecossistemas prioritários para a conservação em vista de sua grande diversidade biológica e produtividade, além de suas inúmeras funções e valores. No Sul do Brasil, dados conservativos apontam que aproximadamente 90% das áreas úmidas originais já foram destruídas principalmente devido à expansão agrícola, especialmente de lavouras de arroz irrigado. Por outro lado, o arroz é o cereal mais importante cultivado em países em desenvolvimento, sendo o principal alimento para mais da metade da população mundial. Além disso, uma alta diversidade de espécies de plantas e animais tem sido encontrada nessas áreas agrícolas. O objetivo geral deste estudo foi avaliar a estrutura e a diversidade de macroinvertebrados em lavouras de arroz e em canais de irrigação nas diferentes fases hidrológicas do ciclo de cultivo em uma importante região orizícola do Rio Grande do Sul, visando a conservação da biota nestes agroecossistemas. Foram realizadas seis coletas ao longo de um ciclo de cultivo (junho de 2005 a junho de 2006) em seis lavouras de arroz e quatro canais de irrigação na Planície Costeira do Rio Grande do Sul. Foram obtidas amostras quantitativas de macroinvertebrados utilizando o amostrador do tipo core inserido nos 10 cm superficiais do sedimento, e amostras qualitativas, utilizando uma rede de mão. Os principais resultados obtidos foram: as amostragens resultaram em um total de 26.579 indivíduos distribuídos em 119 táxons de invertebrados coletados nas lavouras de arroz e canais de irrigação; a manutenção de lavouras de arroz com água e sem água no período de resteva favorece o estabelecimento de um maior número de táxons de macroinvertebrados dentro da paisagem agrícola; as lavouras de arroz irrigado são capazes de armazenar e manter viáveis os bancos de ovos e outras estruturas de resistência de invertebrados aquáticos ao longo de seu ciclo de cultivo; e os canais de irrigação funcionam também como hábitats para a comunidade de macroinvertebrados aquáticos, auxiliando na manutenção da biodiversidade aquática nessas áreas agrícolas. Esses resultados podem ser utilizados em planos de manejo que busquem conciliar a produção agrícola com a conservação da biodiversidade no Rio Grande do Sul.

Lewisville Lake Environmental Learning Area (LLELA) is an 809-hectare property in Denton County, TX. A study of the vegetation community identified 466 species in 104 families, with 25% of the species from only two families, Asteraceae and Poaceae. The property demonstrates the characteristics of an early successional community, dominated by weedy species. Prairie communities are dominated by Johnson grass and ragweed, with climax tall grass prairie communities only in areas that have been planted with native grass seed. Forest communities are similarly in an early successional stage, dominated by the hackberry-elm-ash alliance, with small remnants of native Cross Timbers found in isolated patches. Species richness and diversity were highest in the forests and lowest in the wetlands; evenness, though not different across ecosystems, demonstrated a strong seasonal component. The species list was compared with previously reported lists for Denton County, and 256 species identified had not been previously reported for the county. A wetland restoration study was conducted to determine if there was a difference in survival and growth between potted transplants with intact root systems and bare-root transplants. Two different mesh sizes were used for protection, and the success of the different caging was evaluated. Of eight species, only four survived through the second growing season. There was no significant difference in the success of the propagule types for Sagittaria latifolia. The treatments planted with intact root systems showed significantly higher growth and reproduction than the bare-root treatments for Eleocharis quadrangulata, Heteranthera dubia, and Vallisneria americana. There was no survival recorded in the coarse mesh cages, likely due to the presence of crayfish that are able to get through the coarser mesh and feed on the transplants.

This study examined the current plant diversity status and the impact of drivers of change on the peat basins of the Kromme River peatland. It was conducted at six sites over sixty one years in the Eastern Cape Province of South Africa. I reviewed the rapid habitat and biodiversity loss of wetlands globally and discussed the distribution of wetlands and specifically peatlands in South Africa. Plant species diversity was assessed using Modified- Whittaker plots. The influence of environmental variables on floristic composition and distribution was investigated using ordination techniques (DCA and CCA). Land use dynamics were assessed by applying GIS techniques on orthorectified aerial images. Six different peat basins were subjectively classified into good, medium and poor condition peat basins. The good condition peat basin (Krugersland) was the most diverse in plant species (4.1 Shannon-Weiner’s index) (p> 0.20; F = 11.04; df = 2), with the highest mean number of plant species (32.5 ± 3.4). This was followed by the medium condition class (Kammiesbos) (26.5 ± 9.0) and poor condition class (Companjesdrift) (22.5 ± 8.9). On average, species composition was not evenly distributed across the peat basins (p> 0.21; F = 0.94; df = 2), since 77.8% of the Shannon-Weiner evenness index obtained were less than one. However, there were variations in plant species richness across six peat basins as confirmed by Oneway ANOVA test (p= 0.0008, F = 1241.6, df = 4). Key environmental variables that influenced plant species distribution and structure were erosion and grazing intensity, potassium, phosphorus, soil pH and calcium. Total species variance accounted for in the first two axes for ground cover and plant height were 40.7% and 56.4% respectively. Alien species (e.g. Acacia mearnsii and Conyza scabrida) were common in degraded peat basins, whereas good condition peat basins supported indigenous species (e.g., Cyperus denudatus, Chrysanthemoides monolifera and Digitaria eriantha). Analysis of aerial images revealed a general progressive decrease in the peatland area between 1942 and 1969 in the good (Krugersland) and poor (Companjesdrift) condition class, with a marginal increase from 1969 to 2003. Peatland area in the good and poor condition class decreased by 5.3% and 8.3% respectively between 1942 and 1969, with a marginal increase of 1.5% and 4.1% respectively from 1969 to 2003. Annual net rate of change in peatland area over the 61 year period was -0.32% (good condition class) and - 0.79% (poor condition class). Transformed lands were impacted by drivers of change such as alien invasives, agricultural activities, erosion and sediment transport. The area under alien invasives increased by 50% between 1942 and 2003, with an annual net rate of change of +0.82 (good condition class) and +1.63% (poor condition class).

Ecosystem degradation and subsequent biodiversity loss has plagued freshwater environments globally. Wetland ecosystems, such as the depressional wetlands found in the Prairie Pothole Region of North America, have been heavily impacted by historical land-use change and continue to be vulnerable to continued landscape modifications and climate change. Using existing literature, I summarized how recent shifts in climate coupled with historic and contemporary landscape modifications have driven a shift in wetland ecohydrological variability. However, clear trends in biodiversity were often limited by the spatial and temporal resolution of published research. I used 24 years (1992–2015) of hydrologic and aquatic-macroinvertebrate data from a complex of 16 prairie-pothole wetlands located in North Dakota to relate wetland ecohydrological variability to biodiversity. I used structural equation modeling techniques to test a set of causal hypotheses linking a wetland’s hydrogeologic setting and local climate conditions (i.e., the Wetland Continuum) to changes in hydrology, water chemistry, and biology, with an emphasis on aquatic-macroinvertebrate community response. I then examined the temporal synchrony of aquatic-macroinvertebrate populations to examine the relative importance of landscape-scale controls (e.g., climate, metacommunity dynamics) and wetland-specific controls on community assembly. Using this information, I then quantified among-wetland and amongyear changes in aquatic-macroinvertebrate beta diversity to investigate patterns of biotic homogenization. I found that spatial and temporal variability in aquatic-macroinvertebrate composition was strongly influenced by ponded-water dynamics. In addition to hydrologic controls, the high levels of temporal coherence of aquatic-macroinvertebrate compositional turnover supported the hypothesis that wetland biodiversity is also dependent on metacommunity dynamics. Analyses of spatio-temporal patterns in beta diversity did not reveal climate driven homogenization of aquatic-macroinvertebrate taxa among wetlands. However, shifts towards more permanently ponded water regimes corresponded with lasting shifts in aquatic-macroinvertebrate community composition. The communities of temporarily ponded wetlands maintained high levels of both temporal and spatial beta diversity. My collective findings indicate that the conservation of aquatic-macroinvertebrate diversity is dependent on the conservation of heterogenous, wellconnected, wetland complexes.

Cette thèse porte sur l'étude de la relation Homme-Mare temporaire dans la région de Benslimane. Une approche pluridisciplinaire intégrant l'écologie et la sociologie a été adoptée, afin d'apporter des réponses adaptées aux problématiques liées à ces habitats et de permettre leur développement durable. Le premier volet a pour but d'évaluer les facteurs clés déterminant la richesse de la végétation des mares de cette région. Les résultats obtenus révèlent l'influence prédominante des facteurs locaux, avec un effet significatif des facteurs régionaux et de la vulnérabilité des mares aux usages, sur l'expression de la richesse floristique. Les activités anthropiques affectent différemment la richesse en espèces Préférentielles. Le second volet se focalise sur les causes de régression des mares, en couplant l'évaluation des menaces à une enquête socio-économique. Les résultats montrent la prédominance d'une perception anthropocentrique des mares temporaires. Ce constat traduit le haut niveau de menace qui pèse sur les mares de cette région. L'évaluation de ces menaces, qui indique que 22 % des mares sont vulnérables et que 23 % sont menacées de destruction à court terme, soulignent le besoin urgent de nouvelles politiques environnementales et d'approches innovantes de gestion des mares temporaires. Enfin, le troisième volet s'intéresse à l'impact du pâturage sur la végétation des mares. Les résultats montrent que cette perturbation affecte la végétation des mares, à l'échelle régionale et locale. Ces résultats sont interprétés comme résultant de l'effet sélectif des herbivores et la tolérance différentielle des espèces aux perturbations. Au terme de cette étude, la gestion intégrée des mares apparaît comme le moyen le plus approprié pour le développement durable de cet "éco-socio-système" complexe, en conciliant développement économique et bon état écologique des ressources, et en liant les questions environnementales, économiques et sociales
This thesis focuses on the study of the relationship Man-Temporary pool. A multidisciplinary approach integrating ecology and sociology has been adopted to provide appropriate responses to the problems related to these ecosystems and to allow their sustainable development. The first section aims at evaluating the key factors determining the vegetation richness within regional pools. The obtained results reveal the predominant influence of local factors, with a significant effect of regional factors and the vulnerability of pools to use, on the expression of the vegetation. Human activities affect differently the richness in preferential pool species. The second section focuses on the major causes of the regression of pools, by coupling threats assessment and a socio-economic survey. The results point out the anthropocentric perception of pools. This translates the high level of threat concerning the temporary pools of Benslimane region. The thr eat assessment, which shows that 22 % of pools are vulnerable, and 23 % are threatened of destruction of the short term, highlights the urgent need for new environmental policies and innovative approaches of temporary pools management. Finally, the third section concerns the impact of grazing on the vegetation of temporary pools. The results demonstrate that grazing affects the vegetation of pools, both at the regional and the local scale. These results are interpreted as a result of the selective influence of herbivores, and the differential tolerance of species to disturbance. At the end of the present study, the integrated management of pools appears as the most appropriate means for the sustainable development of this complex eco-socio-system, by combining the economic development and the ecological status of resources, and by linking environmental, economic and social issues

La Corse abrite une grande diversité de zones humides soumises à des pressions et menaces d’origine anthropique qui n’ont cessé de croître et de se diversifier au cours de ces dernières décennies. La conservation de ces milieux à forte valeur patrimoniale et du peuplement d’odonates original qui s’y développe, représente aujourd’hui d’importants enjeux environnementaux et sociétaux afin de préserver les services écologiques essentiels rendus par ces éléments clefs des écosystèmes aquatiques et terrestres. Le projet de recherche appliquée développé dans le cadre de cette thèse s’est attaché à améliorer les connaissances disponibles sur les libellules de Corse, afin de proposer des mesures de conservation et de gestion concrètes en faveur de ce groupe et de ses principaux habitats naturels sur l’île. Dans cet objectif, la première partie de ces travaux s’est employée à combler les principales lacunes de connaissance identifiées par les études antérieures sur la situation des espèces, notamment en intensifiant l’effort de prospection consenti à l’échelle régionale. Les particularités, la répartition, les exigences et habitats écologiques de nombreuses libellules se développant en Corse ont pu être décrits avec précision. Les informations disponibles sur certains taxons à forte valeur patrimoniale ont particulièrement augmenté comme l’illustre la définition très complète de la situation éco-biogéographique de Chalcolestes parvidens. La deuxième partie de ces travaux s’est attachée à évaluer et comparer l’efficacité des principales méthodes d’échantillonnage couramment utilisées pour l’étude des populations d’odonates. Dans ce cadre, les nombreuses informations récoltées sur l’organisation spatiale et la dynamique des populations étudiées ont notamment été employées afin de proposer aux principaux gestionnaires d’espaces naturels de l’île (Conseils départementaux, PNRC, Communes…) des méthodes adaptées pour l’évaluation et le monitoring des espèces à fort enjeu de conservation, dont l’emblématique et menacé Lestes macrostigma.La troisième partie de ces travaux est consacrée au développement d’outils pour le suivi de la qualité des principaux habitats d’odonates. Elle a permis d’aboutir à l’élaboration d’un tout nouvel indice biologique adapté à l’évaluation de l’état écologique des rivières de Corse : « Odonata Community Index – Corsica » (OCIC). Cet outil innovant, basé sur l’étude du peuplement caractéristique des libellules des cours d’eau, s’est montré particulièrement performant lors de sa confrontation aux autres indices biologiques actuellement utilisés sur l’île. L’indice OCIC et le groupe des odonates apparaissent aujourd’hui clairement comme des solutions alternatives prometteuses, en vue d’améliorer l’efficacité du système d’évaluation de la qualité écologique des rivières de Corse, compte tenu des failles de représentativité mises en évidence par les expérimentations réalisées.La dernière partie de cette thèse, basée sur des évaluations patrimoniales et écologiques du peuplement insulaire d’odonates réalisées à l’aide des informations produites, se conclue par le développement de nouveaux dispositifs régionaux de conservation en lien avec les services de l’Etat : un Plan Régional d’Actions, une liste rouge d’espèces menacées ainsi qu’une liste actualisée d’espèces déterminantes pour les Zones Naturelles d’Intérêt Ecologique Faunistique et Floristique. Ces dispositifs permettront d’améliorer l’état de conservation des libellules de Corse et des principales zones humides qui les abritent.Au final, ces travaux de thèse qui ont permis de plus de tripler les données disponibles jusqu’alors sur les libellules de Corse, fourniront un nouveau cadre de développement pour l’odonatologie insulaire
Corsica is home to a great diversity of wetland subject to anthropogenic pressures and threats which have continued to grow and diversify in recent decades. The conservation of these environments with high heritage value and of the original Odonata community that develops in it, today represents significant environmental and societal challenges in order to preserve essential ecological services provided by these key elements of aquatic and terrestrial ecosystems. The applied research project developed as part of this thesis is focused on improving the knowledge available on the corsican dragonfly’s community, to propose concrete conservation and management measures for this group and its main insular natural habitats.In this objective, the first part of this work has sought to fill principal knowledge gaps identified by previous studies on the situation of listed species, including by greatly intensifying exploration effort at the regional level. The special features, distribution, habitat requirements and ecological of many dragonflies growing in Corsica have been described with great precision. The information available on some taxa with high heritage value increased as illustrated by the comprehensive definition of eco-bio-geographical situation of Chalcolestes parvidens.The second part of this work has sought to evaluate and compare the effectiveness of the main sampling methods commonly used for the study of dragonfly’s populations. In this context, the informations collected on the spatial organization and dynamics of the populations studied were especially used to propose appropriate methods for evaluation and monitoring the species to high conservation issue to main managers of natural areas of the island (County Councils, PNRC, municipalities ...), including the emblematic and threatened Lestes macrostigma.The third part of this work is devoted to the development of tools for monitoring the quality of the main Odonata habitats. It lead to the development of a new biological index adapted to assess the ecological status of corsican rivers: "Odonata Community Index - Corsica '(OCIC). This innovative tool, based on the study of characteristics of Odonata community of watercourses, was particularly effective during its confrontation with other biological indicators currently used on the island. The OCIC index today appear clearly as an alternative solution to improve the efficiency of the ecological quality assessment system of the Corsican rivers, given the representativeness vulnerabilities which have been highlighted by the tests performed.The final part of this thesis, based on heritage and environmental assessments of the insular dragonfly’s community made with all the information produced, ended with the development and the proposal of several regional conservation devices whose implementation is encouraged by the state services: a first regional actions plan, a first red list of threatened species and an updated list of species determinative for natural areas of ecological, flora and fauna interest. These important features are intended to contribute to improve the overall state of conservation of Corsican dragonflies and main wetlands that support them. They should enable the implementation of truly operational management actions and ensure better consideration of the main regional conservation and valuation issues identified.In the end, the thesis work that increased more than triple the previously available data on dragonflies of Corsica, will provide a new framework to developpe the isular odonatology

Les zones humides sont des écosystèmes dynamiques en perpétuel changement, dans le temps et dans l'espace et demeurent parmi les plus menacés au monde. Ce travail de thèse est une contribution à la connaissance et la conservation des zones humides. Nous avons étudié la végétation de différents milieux, appartenant à un réseau de zones humides de Gironde, allant des landes humides aux prairies alluviales. Nous les avons choisies pour leur intérêt patrimonial et les enjeux de gestion qu'elles représentent dans le département. Nous avons utilisé plusieurs approches descriptives et expérimentales. La première partie vise à étudier l’organisation des communautés des deux grands systèmes, les landes humides et les prairies alluviales, le long de gradients environnementaux. Dans un deuxième temps, une approche combinant données anciennes et récentes, nous a permis de caractériser les changements de végétation à long terme selon différentes stratégies d’étude de la végétation. La troisième partie, par une approche expérimentale a été conduite sur une communauté végétale à fort enjeu patrimonial : les prairies à Molinie (code 6410 de la Directive Natura 2000). Cette troisième partie a permis de mettre en évidence la part respective des filtres stochastiques (dispersion de graines) et déterministes (compétition) dans une communauté soumise à de fortes contraintes environnementales (inondation). Enfin, dans une analyse prospective, nous avons considéré les enjeux de biodiversité ainsi que les services écosystémiques, cette fois, à l'échelle du département. Cette analyse envisage les outils à développer pour une approche multi-taxon et multi-services sur l'ensemble des zones humides de Gironde. L’ensemble de ce travail a permis de construire un dispositif de suivi de la biodiversité végétale au niveau départemental. Les résultats de ce travail contribuent aujourd’hui à considérer la gestion de ces communautés végétales de façon intégrée et proposent des outils d’aide à la décision pour la gestion de ces espaces
Wetlands are dynamic ecosystems, constantly changing in time and space, and remaining among the most threatened ecosystems in the world. This thesis contribute to wetland knowledge and conservation. We studied the vegetation of different communities belonging to a network of wetlands in Gironde and ranging from wet heathlands to alluvial meadows. Wetlands were selected from the department council historical interest and management issues. We used several descriptive and experimental approaches. The first part aims to study the organization of the communities of the two major systems, heathlands and alluvial grasslands, along environmental gradients. Then, in a second time, an approach combining old and recent data allowed us to characterize long-term vegetation changes according to different strategies of vegetation study. The third part was conducted on a plant community with a strong conservation issue: Molinia caerulea wet meadow (Code 6410 of the Natura 2000 Directive) with an experimental approach. We highlight here the importance of stochastic filters (seed dispersion) and deterministic filters (competition) in a community controlled by environmental constraints (flooding). Finally, within a prospective analysis, we considered biodiversity issues and supply in ecosystems services at the departmental level. This analysis investigate tools to develop for a multi-taxon and multi-service approach in any Gironde wetlands. This work allowed us to create a monitoring device for plant biodiversity in the department. These results lead to consider nowadays the management of these plant communities in an integrated way and offer tools of decision support for the management of these communities

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Wetlands are ecosystems which embrace a great number of botanical species and they may include endangered and endemic species and others with economic potentialities. However, the studies of these environments are still in their beginnings, mostly those about Santa Catarina‟s South Plateau. The main aims of this study were: 1. to test digital classification techniques on wetlands mapping and to analyze their size pattern, the forms and density of their landscape occurrence; 2. to list botanical species, their ecological aspects and their economic potentialities; 3. to establish the spatial distribution of species. In order to mapping, a Landsat-5 image and some digital ortoimages were used, they were processed with ArcGIS 9.3, ENVI 4.7 and ENVI EX softwares; metrics in landscape were analyzed with FRAGSTATS 4.0 software. The floristic survey was made in Aug./2011-Jan./2013 in three areas: Bom Jardim da Serra, Lages (Coxilha Rica) and Painel cities. Habits, life forms, frequency of species, stature classes, species economical potential uses and conservation status indicators were analyzed. Data about species distribution were collected in Jan.-Feb./2012, by means of six transects (4x27 m), placed in the three research wet areas, from border to center (n=168). The ordering analysis applied was non-metric multidimensional scaling (NMDS), used in two stages: among areas and in the transections, using R 2.15 software. Digital classification showed up as a satisfactory one and wetlands represented 12% of the landscape; frequency of one wetland/10 hectare; the area occupied by wetlands presented a great largeness (0,01-37 ha.), most with less than 2 ha. Total richness was of 156 species, distributed in 96 genera and 47 families. Families with greater richness, were Poaceae (26 spp.), Asteraceae (23) and Cyperaceae (23), while 24 families were represented by one specie each. The most common habit was herbaceous (124), life forms were amphibians (107) and emergent (30); the majority of species had a regular frequency classification (77); the stature class with a bigger number of species was class III (≥ 50 e < 100 cm). Among species with economical uses (61), pointed out the bioactive ones (30) and also were observed endangered (four) and endemic species (three); as well as some high land grasslands conservation status indicator species (38) and turf indicator species (four). Floristic diversity was considered high (Shannon: 3.32; 3.53 e 3.62), and the three areas showed 17 species in common. Regarding to the ordination analyses, two zones were observed: border (≤ 7 m) and center (> 7 m), border species represented 70%, of total species collected. Dates achieved in this study shall be important helping to recognize the preservation significance of these ecosystems, as well as helping to understand the ecological processes that occur in these environments
As áreas úmidas são ecossistemas que apresentam um grande número de espécies vegetais, podendo incluir espécies ameaçadas, endêmicas e de interesse econômico. Entretanto, os estudos sobre esses ambientes ainda são incipientes, sobretudo no Planalto Sul de Santa Catarina. Os objetivos deste estudo foram: 1. Testar técnicas de classificação digital para mapear áreas úmidas e analisar o seu padrão de tamanho, forma e densidade de ocorrência na paisagem; 2. Levantar as espécies botânicas, seus aspectos ecológicos e potencialidades econômicas; 3. Analisar a distribuição espacial das espécies. Para o mapeamento utilizou-se uma imagem Landsat-5 e ortoimagens digitais, que foram processadas nos programas ArcGIS 9.3, ENVI 4.7 e ENVI EX; as métricas da paisagem foram analisadas no programa FRAGSTATS 4.0. O levantamento florístico foi realizado em ago/2011-jan/2013, em três áreas: municípios de Bom Jardim da Serra, Lages (localidade de Coxilha Rica) e Painel. Foram analisados os aspectos sobre o hábito, a forma de vida, a frequência, a classe de altura e a citação de potencial de uso econômico e indicação de status de conservação das espécies. Os dados sobre a distribuição das espécies foram coletados em jan-fev/2012, em seis transecções (4x27 m), alocadas no sentido margem-centro de três banhados (n= 168). A análise de ordenação utilizada foi Non-metric Multidimensional Scaling (NMDS), aplicada em duas etapas: entre áreas e nas transecções, utilizando o programa R 2.15. A classificação digital se mostrou satisfatória e os banhados representaram 12% da paisagem; frequência de um banhado/10 hectares; a área ocupada por banhado apresentou grande amplitude (0,01-37 ha), sendo em sua maioria com < 2 ha. A riqueza total foi de 156 espécies, distribuídas em 96 gêneros e 47 famílias. As famílias de maior riqueza foram Poaceae (26 spp.), Asteraceae (23) e Cyperaceae (23), enquanto 24 famílias foram representadas por uma espécie cada. A maior parte das espécies foi classificada como de hábito herbáceo (124); as formas de vida mais comuns foram anfíbias (107) e emergentes (30) e a freqüência foi a comum (77). A classe de altura que abrigou o maior número de espécies foi a III (≥ 50 e < 100 cm). Entre as espécies com potencial de uso (61), se destacaram as bioativas (30) e foram observadas também espécies ameaçadas de extinção (quatro), endêmicas (três), espécies caracterizadas como indicadores de estado de conservação de campos de altitude (38) e espécies indicadoras de turfeiras (quatro). A diversidade florística encontrada foi considerada alta (Shannon: 3,32; 3,53 e 3,62) e as áreas apresentaram 17 espécies em comum. Com relação à análise de ordenação, foi observada a formação de duas zonas: marginal (≤ 7 m) e central (> 7 m), e as espécies encontradas na zona marginal representaram 70%, do total de espécies amostradas. Os dados obtidos neste estudo são importantes para o reconhecimento da importância da conservação desse ecossistema, assim como para o entendimento dos processos ecológicos que ocorrem nesses ambientes

Wetlands are among the most threatened habitats on Earth. They are essential components of functional landscapes, providing habitat for native flora and fauna as well as supporting critical ecosystem services. Loss of wetland biodiversity threatens these values. There is an urgent need to understand patterns of wetland biodiversity, the processes creating these and the risk of species loss to plan effective intervention. Species-area relationships have a successful, although controversial, history of quantifying the risk of extinction in terrestrial biomes, and can provide rapid estimates of extinction risk at a range of scales without the need for extensive datasets. Prior to my research, applications of species-area relationships in extinction risk were limited to island archipelagos and formerly continuous terrestrial habitats that had become fragmented. Naturally occurring, discrete habitat types—such as wetlands—have been ignored. I address this gap, demonstrating that area-based methods can, with some modification, be successfully applied to predict extinction risk in wetland communities. Before considering extinction risk I analysed patterns of wetland plant diversity and occupancy and how competing community-assembly processes produce more or less unique combinations of species among wetlands. I showed that much of the plant community diversity in seasonal wetlands in South Australia is driven by rare terrestrial species of wetland fringes, which assemble from a much larger available species pool. The distribution of these rare species was not correlated with total species richness or wetland size, suggesting that changes in the number or total area of wetlands could result in different extinction dynamics, depending on how they affected endemic species. I therefore compared risks associated with loss of complete wetlands (patch loss), with loss of the equivalent wetland area while maintaining the total number of wetlands. To implement the latter scenario, I developed a novel approach consisting of three steps: (i) a generalized empirical endemics-area relationship to predict the number of species lost within each wetland as a function of a reduction in wetland area; (ii) I selected the identities of the predicted number of species lost at each wetland probabilistically; (iii) I compred the number of wetlands from which each species was lost with its regional occupancy, and I considered any species predicted to be lost from all known sites as extinct. I then repeated steps (ii) and (iii) many times to obtain a distribution of regional-scale species loss for a given loss of area in each wetland. Step (ii) allowed for different scenarios to be tested by adjusting the sampling probability for each species. I found that a higher extinction risk was associated with the loss of complete wetlands than the equivalent area loss shared among all wetlands. Moreover, for a given area loss, small wetlands had a much higher risk of species loss due to the distribution of endemic species. The approach I developed could be readily applied to any discrete habitat type, providing predictions of risk for a range of ecosystems that have received little attention.
Thesis (M.Phil.) (Research by publication) -- University of Adelaide, School of Biological Sciences, 2016.

abstract: It’s no secret that wetlands have dramatically declined in the arid and semiarid American West, yet the small number of wetlands that persist provide vital ecosystem services. Ciénega is a term that refers to a freshwater arid-land wetland. Today, even in areas where ciénegas are prominent they occupy less than 0.1% of the landscape. This investigation assesses the distribution of vascular plant species within and among ciénegas and address linkages between environmental factors and wetland plant communities. Specifically, I ask: 1) What is the range of variability among ciénegas, with respect to wetland area, soil organic matter, plant species richness, and species composition? 2) How is plant species richness influenced locally by soil moisture, soil salinity, and canopy cover, and regionally by elevation, flow gradient (percent slope), and temporally by season? And 3) Within ciénegas, how do soil moisture, soil salinity, and canopy cover influence plant species community composition? To answer these questions I measured environmental variables and quantified vegetation at six cienegas within the Santa Cruz Watershed in southern Arizona over one spring and two post-monsoon periods. Ciénegas are highly variable with respect to wetland area, soil organic matter, plant species richness, and species composition. Therefore, it is important to conserve the ciénega landscape as opposed to conserving a single ciénega. Plant species richness is influenced negatively by soil moisture, positively by soil salinity, elevation, and flow gradient (percent slope), and is greater during the post-monsoon season. Despite concerns about woody plant encroachment reducing biodiversity, my investigation suggests canopy cover has no significant influence on ciénega species richness. Plant species community composition is structured by water availability at all ciénegas, which is consistent with the key role water availability plays in arid and semiarid regions. Effects of canopy and salinity structuring community composition are site specific. My investigation has laid the groundwork for ciénega conservation by providing baseline information of the ecology of these unique and threatened systems. The high variability of ciénega wetlands and the rare species they harbor combined with the numerous threats against them and their isolated occurrences makes these vanishing communities high priority for conservation.
Dissertation/Thesis
Masters Thesis Plant Biology 2016