Water hyacinth (Eichhornia crassipes) is a floating non-native plant that has been reoccurring in Lake Chapala, Jalisco, Mexico for more than 100 years. In this research, I explore the effects of water hyacinth on freshwater ecosystems worldwide and specifically on Lake Chapala. In chapter 1, I reviewed studies conducted on water hyacinth worldwide and found that the effects of water hyacinth on water quality are similar but the magnitude of effects is dependent on the percent cover and potentially the spatial configuration of water hyacinth mats. Water hyacinth's effect on aquatic invertebrates, fish, and waterbirds is less predictable and dependent on conditions prior to invasion. In chapter 2, I tested for relationships between percent water hyacinth cover and waterbird abundance, species diversity, community composition, and habitat use. In general, I found a weak positive relationship or no relationship between these variables. In Chapter 3, I monitored habitat use by American Coots (Fulica americana) in a variety of habitats around Lake Chapala. I found that the time spent in water hyacinth positively corresponded to the percent water hyacinth cover and that the time foraging in water hyacinth was positively related to the time spent in water hyacinth. In Chapter 4, I compared invertebrate assemblages in open water to those within and at the edge of water hyacinth mats, emergent vegetation, and submerged trees. I also examined invertebrate assemblages within the roots of water hyacinth plants and compared assemblages between patch and shoreline water hyacinth plants. I found that density and taxonomic richness of water column invertebrates were generally higher in association with water hyacinth, but that mean percent cover of water hyacinth affected the magnitude of differences among habitats and vegetation types. I did not find significant differences in root invertebrate density and taxonomic richness between patch and shoreline water hyacinth plants. In chapter 5, I discuss how water hyacinth affected dissolved oxygen and water transparency on a small, localized scale, but was not the driving factor for seasonal differences. The overall results suggest that water hyacinth had a minimal ecological effect on Lake Chapala during this study. / Ph. D.

During December-April in 2016/2017, five wetlands in near proximity to the city of Halmstad and four stretches along the stream Trönningeån were investigated regarding their use by birds during winter and spring. At one of the wetlands it was investigated whether non-entry rules are set accordingly to the breeding period. Furthermore, the recreational values of two of the wetlands were calculated. The five wetlands were used by a total of 37 species during the months December-April and they were occupied by mainly the same bird species with a few exceptions, showing some differences in numbers of individuals and species composition depending on wetland. The wetlands seemed to be of importance for a few wintering species as there were at least 12 species and 190 individuals at the near-coastal wetland Trönninge ängar during months December-February. The inland wetland Stjärnarps norra våtmark attracted 6 species and a surprising amount of 153 individuals during the same period. Especially the near-coastal wetlands also created for bird purposes (Trönninge ängar and Larssons våtmark) served as very important spots for migrating birds and were visited by a large number of species and attracted 1531 and 1314 individuals between months March-April. The no-entry rules regarding Trönninge ängar seemed to be up-to-date in terms of when the birds show signs of breeding. The recreational value was calculated to be almost three times higher for Trönninge ängar than for Larssons våtmark. The turnover rate for the birds in two of the wetlands showed some differences and/or patterns regarding how and when different bird species use the wetlands. / Under månaderna december-april 2016/2017 inventerades fem våtmarker nära Halmstad för att få information angående hur fåglar använder dessa våtmarker under vintermånaderna och våren samt undersöktes fyra åsträckor av Trönningeån med avseende på hur dessa används av vissa vadare vintertid. En av våtmarkerna undersöktes angående huruvida datumen för tillträdesförbud stämde överens med fåglarnas häckningstider och dessutom undersöktes rekreationsvärdet för två våtmarker. Totalt använde 37 olika arter våtmarkerna under perioden december-april och de användes huvudsakligen av samma arter med vissa undantag. Det fanns även vissa skillnader i antalet individer samt variationer i artsammansättning beroende på våtmark. Våtmarkerna verkade ha betydelse för ett antal övervintrande fåglar då den kustnära våtmarken Trönninge ängar besöktes av åtminstone 12 arter och 190 individer. Inlandsvåtmarken Stjärnarps norra våtmark besöktes av 6 arter och ett oväntat stort antal på 153 individer. Särskilt våtmarkerna närmast kusten som dessutom är fågelvåtmarker (Trönninge ängar och Larssons våtmark) spelade en viktig roll för flyttfåglar då de användes av totalt 1531 respektive 1314 individer under perioden mars-april. Tiderna för tillträdesförbud gällande Trönninge ängar verkade vara aktuella ännu i relation till när fåglar i våtmarken uppvisar tecken på häckning. Det uträknade rekreationsvärdet visade sig vara nästan tre gånger högre för Trönninge ängar än för Larssons våtmark. Undersökningen angående hur och när olika fågelarter använder två av våtmarkerna visade på att det finns vissa skillnader mellan hur och när olika fågelarter utnyttjar dem.

Areas of wetland have for the last century declined globally, mostly as a cause of anthropogenic activitities. Since many bird species are depending on wetlands, this have affected their populations negatively, and today many of the remaining wetlands are protected. This study has investigated the status and trends of Gialova lagoon in Greece, both as a stopover for spring migrating birds and as a wetland for wintering waterbirds. This has been done by doing an own field inventory for two weeks in March, and by compiling and analysing data from winter censuses from the last thirty years. Results showed that Gialova supported many migrating birds during the inventory, and several of these are threatened in Europe. The eastern parts of the lagoon are the most important and sensitive areas, due to the suitable habitat for foraging and protection. The analysis of winter data showed that only one species was increasing, while the rest and the total amount of waterbirds were stable or decreased. The number of birds during winter did not reach thresholds for qualifying as a Ramsar-site of international importance. However, the wetland’s geographical location and context makes it a important area to protect for migrating birds, and it also has values for the local community in terms of different ecosystem services.

Rice not collected by harvesters and natural seeds are important foods for waterfowl. Estimation of abundance of these seeds is necessary for calculating waterfowl habitat conservation needs in the Louisiana Chenier Plain (LCP) and Texas Mid-Coast (TMC). My objectives were to quantify dry mass of rice and other seeds from August-November 2010, and estimate waterbird abundances on farmed and idle ricelands in these regions from December 2010-March 2011. Rice abundance in farmed ricelands ranged from 159.7 kg/ha (CV = 66.6%) to 1,014.0 kg/ha (CV = 8.3%). Natural seed abundance in idle ricelands ranged from 99.7 kg/ha (CV = 32.9%) to 957.4 kg/ha (CV = 17.2%). Greatest waterbird densities occurred in shallowly flooded (i.e., ¡Ü30 cm) disked ricelands (mean = 7.35 waterbirds/ha, 90%; CI = 2.37-19.70). Ratoon, disked, and shallowly flooded ricelands are important habitat for non-breeding waterbirds but variable estimates of seed and waterbird abundances warrant continuation of this study.

Les activités humaines menacent gravement la biodiversité. Sous le terme de changements globaux, la sur-exploitation des populations et la destruction/dégradation des habitats arrivent en tête de liste des facteurs responsables de l’érosion de la biodiversité. Le changement climatique gagne en magnitude et ajoute une pression supplémentaire sur les espèces. En réponse à l’augmentation des températures du globe, les communautés se réorganisent suite au déplacement de la distribution géographique des espèces vers les pôles. Mais l’accumulation des pressions anthropiques est susceptible de produire des effets d’interaction limitant l’ajustement des communautés au réchauffement climatique. Dans ce contexte critique, la biologie de la conservation a pour but de concilier les activités humaines avec la conservation de la biodiversité. Dans cette thèse j’ai cherché à comprendre comment l’accumulation des pressions anthropiques peut limiter l’ajustement des communautés au réchauffement climatique et à identifier les solutions qui pourraient être mises en place pour faciliter leur adaptation à ce réchauffement. J’ai pris pour modèle d’étude les espèces d’oiseaux d’eau hivernants dans les pays du bassin méditerranéen. Ces espèces emblématiques bénéficient d’un dénombrement international destiné à suivre leurs populations en réponse aux prélèvements par la chasse et à la dégradation des zones humides dont elles dépendent. La Méditerranée est une région fortement anthropisée où l’utilisation des ressources naturelles exerce d’importantes pressions sur les zones humides et leur biodiversité. En réponse, les pays ont différentes stratégies pour protéger ces écosystèmes, ce qui fait de cette région un plan expérimental intéressant pour mesurer l’impact dans changements globaux sur l’assemblage des espèces en fonction des mesures de conservation mises en oeuvre. En étudiant la réponse des communautés au réchauffement climatique sous un gradient de perte/dégradation d’habitat, je montre que l’ajustement des communautés est réduit, voire empêché, par la dégradation des zones humides. La Convention Ramsar vise justement à protéger les zones humides et leur biodiversité en maintenant une exploitation raisonnée des ressources naturelles. En évaluant l’effet de cette convention, je montre que son efficacité à conserver les populations d’oiseaux est dépendante de l’implémentation d’autres outils de protection, mais que son rôle est crucial dans les pays où la législation environnementale est faible. Enfin, j’évalue la capacité des conventions internationales à faciliter l’ajustement des communautés au réchauffement climatique grâce à la réduction des pressions qui s’exercent sur les populations. J’ai comparé la réponse des communautés entre les pays ayant ratifié la Convention de Berne, ceux ayant engagé son application strictement réglementaire sous la Directive Oiseaux (Union Européenne) et ceux n’ayant pas ratifié ces conventions. Le résultat est clair, plus la réglementation est précise et strictement réglementaire, plus les communautés et les espèces strictement protégées s’ajustent à l’augmentation des températures.En conclusion, les activités humaines sont une menace pour la biodiversité, mais les mesures de conservation, en réduisant les pressions sur les populations facilitent leur adaptation au changement climatique. La conservation des oiseaux d’eau nécessite une collaboration internationale et l’établissement de lois strictement réglementaires protégeant les zones humides et les espèces, tout en assurant une utilisation durable des ressources. / Human activities seriously threaten biodiversity. In terms of global changes, overexploitation of populations and habitat destruction/degradation are at the top of the list of factors responsible for biodiversity loss. Climate change is increasing in magnitude and adding additional pressure on species. In response to the increase in global temperatures, communities are changing as a result of the shift in the geographical distribution of species towards the poles. But the accumulation of anthropogenic pressures is likely to produce interaction effects that limit community adjustment to global warming. In this critical context, conservation biology aims to reconcile human activities with biodiversity conservation. In this thesis I have investigate how the accumulation of anthropogenic pressures can limit the adjustment of communities to global warming and to identify solutions that could be put in place to facilitate their adaptation to this warming. I have used the wintering waterbird species in the countries of the Mediterranean basin as a model for my study. These iconic species benefit from an international census to monitor their populations in response to hunting and the degradation of the wetlands on which they depend. The Mediterranean is a highly anthropized region where the use of natural resources exerts significant pressures on wetlands and their biodiversity. In response, countries have different strategies to protect these ecosystems, making this region an interesting experimental plan to measure the impact in global changes on species assemblage based on conservation measures implemented. By studying the response of communities to global warming under a gradient of habitat loss/degradation, I show that community adjustment is reduced or even prevented by wetland degradation. The Ramsar Convention aims to protect wetlands and their biodiversity by maintaining a rational use of natural resources. In assessing the effect of this convention, I show that its effectiveness in conserving bird populations depends on the implementation of other protection tools, but that its role is crucial in countries where environmental legislation is weak. Finally, I assess the capacity of international conventions to facilitate community adjustment to global warming by reducing population pressures. I compared the communities' response between countries that have ratified the Bern Convention, those that have started its strictly regulatory application under the Birds Directive (European Union) and those that have not ratified these conventions. The result is clear, the more precise and strictly regulatory the regulations, the more communities and strictly protected species adjust to the increase in temperatures.In conclusion, human activities are a threat to biodiversity, but conservation measures, by reducing pressures on populations, facilitate their adaptation to climate change. Waterbird conservation requires international collaboration and the establishment of strictly regulatory laws to protect wetlands and species, while ensuring sustainable use of resources.

Conservation of intertidal habitats in the UK is vital in order to continue to support nationally and internationally important populations of non-breeding waterbirds. Historic reclamation for agriculture and industry has resulted in the loss and degradation of large areas of these intertidal habitats in estuaries and they continue to be threatened by sea-level rise. Managed realignment is one method which is increasingly being used to restore intertidal habitats. As managed realignment is a relatively new restoration technique, the extent to which knowledge of the biology of estuaries is applicable to managed realignment sites is unclear. Habitat restoration is often unsuccessful or incomplete, so a detailed knowledge of both the natural system and the characteristics of restored systems will usually be necessary to recreate fully-functional estuarine habitats. This thesis focuses on Nigg Bay Managed Realignment Site (Nigg Bay MRS), the first managed realignment site in Scotland, and follows the first four years of ecological development to gain an understanding of how breached realignment can be used to restore intertidal habitats to support non-breeding waterbirds. This thesis has six major aims: (i) to describe the development of saltmarsh, (ii) to describe the development of intertidal flat, (iii) to describe the colonisation by non-breeding waterbirds (iv) to determine how tidal cycle and weather affect patterns of waterbird use, (v) to determine which factors affect the spatial distribution of waders and finally (vi) to determine the patterns of use by individual birds. Four summers after the re-establishment of tidal conditions, almost all of the saltmarsh species recorded on the nearby saltmarsh had colonised Nigg Bay MRS, although recognisable communities had yet to establish. Three winters after the re- establishment of tidal conditions in Nigg Bay MRS, the sediments had a significantly smaller particle size and higher organic matter content compared to the fine sands of the adjacent intertidal flats. The intertidal invertebrate community also differed from the adjacent intertidal flats. Nigg Bay MRS attracted large numbers of non-breeding waterbirds and supported each of the most common wader and wildfowl species present in the wider estuary. Nigg Bay MRS performs a number of important functions for non-breeding waterbirds by: (i) providing a foraging and resting habitat when the tide is absent and intertidal sediments in Nigg Bay are exposed; (ii) providing a foraging resource as the tide passes over the intertidal sediments within the site once the intertidal flats in Nigg Bay are inundated; and (iii) providing a high tide roosting site. On days with low temperatures and high wind speeds, more waterbirds use Nigg Bay MRS, suggesting that it is likely to be providing sheltering benefits. Nigg Bay MRS also provides top-up feeding habitat. The factors that often influence the spatial distributions of waders in estuaries appear to be operating within Nigg Bay MRS. Wader densities are greater on the intertidal flats when they are accessible than on the saltmarsh. Wader densities are also greatest close to creeks and drainage channels, possibly due to higher invertebrate densities, more accessible prey or sheltering benefits. Colour-ringing and radio-tracking of Common Redshank established that Nigg Bay MRS has a subset of regular users, including both adults and juveniles, and the wader assemblage at night may differ from the assemblage during the day. These findings are discussed in terms of the implications for locating, designing and managing future managed realignment projects.

Made available in DSpace on 2015-03-05T16:19:35Z (GMT). No. of bitstreams: 0 Previous issue date: 27 / Nenhuma / O Parque Nacional da Lagoa do Peixe (PNLP), na zona costeira do Rio Grande do Sul, protege amostras importantes de quase todos os ecossistemas de áreas úmidas e espécies de aves aquáticas da região. Os movimentos migratórios e os deslocamentos entre áreas úmidas determinam importantes variações temporais de composição e abundância das assembléias de aves aquáticas. Os objetivos deste estudo foram descrever os padrões de composição e abundância de aves aquáticas em 27 áreas úmidas naturais, distribuídas no entorno do Parque Nacional da Lagoa do Peixe; descrever os padrões de variação temporal das assembléias associados às variações de pluviosidade; avaliar o efeito do tamanho dos fragmentos, do tipo de área úmida, do tipo de matriz circundante e da disponibilidade de áreas úmidas na paisagem na composição, riqueza e abundância de aves aquáticas e discutir a importância dos remanescentes de áreas úmidas do entorno do Parque para a conservação de aves aquáticas. Foram realizados 12 censos mensais de aves aquátic / The Lagoa do Peixe National Park (LPNP), in the coastal plain of Rio Grande do Sul, protect important samples of almost all wetland ecosystems and waterbird species in the region. The surrounding areas also harbor remnant natural wetlands, scattered in a matrix of drained meadows or rice fields, of which the conservation significance is unknown. The structure of waterbird assemblages in these remnants is expected to vary with their spatial attributes and with the characteristics of the surrounding matrix. The aim of this study was to describe the composition, richness and abundance of waterbird assemblages of 27 remnant wetlands; to describe the seasonal variation in the structure of these waterbird assemblages and it’s relation with pluviosity; to evaluate the effect of the remnant’s area, type of wetland, type of matrix and wetland availability in the landscape on the composition, richness and abundance of waterbirds; and to discuss the importance of the remaining wetlands nearby the Park for the conservat

Marine and coastal ecosystems are subject to diverse and increasingly intensive anthropogenic activities, making understanding cumulative effects critically important. However, accurately accounting for the cumulative effects of human impacts can be difficult, with the possibility of multiple stressors interacting and having greater impacts than expected, compounding direct and indirect effects on individuals, populations, communities and ecosystems. Assessment of multiple stressors therefore requires extensive scientific research that directly tests how single or multiple ecological components are affected by stressors, both singly and when combined, and as a consequence, cumulative effects assessments are now increasingly included in environmental assessments. Currently, there is a need to assess these at larger spatial scales, with additional research also urgently needed on the responses of ecological components, processes and functions to single and cumulative stressors. As cumulative environmental impacts could be better addressed by regional stressor effects assessments that combine methods for predicting multiple pressures on ecosystem recovery alongside degradation, this study used several separate approaches that can be used in parallel to give support for local management measures. I tested four completely different methods - a range of multi-metric indices, a food web model (Ecopath), a predictive model (Ecosim) and a Bayesian Belief Network model. Each approach was tested and compared in two shallow water estuarine systems, in Scotland and England, initially concerning the impact of nutrient enrichment and subsequent recovery and was followed by an investigation of how the addition of multiple stressors (nutrient levels, temperature and river-flow rates) would impact the future state of each system. The response to stressors was highly context dependent, varying between and within geographic locations. Overall, each of the four different approaches complemented each other and gave strong support for the need to make big reductions in the pressures and to consider trade-offs between impacting pressures. The models and tools also indicate that in order to reach an improved overall environmental state of each ecosystem, a focus on nutrient reductions are likely to be the most effective of the controls on stressors explored and that cumulative effects of the management of nutrient inputs and increased water temperatures and river-flow are likely to exist.

Made available in DSpace on 2016-06-02T20:20:30Z (GMT). No. of bitstreams: 1 3280.pdf: 5102569 bytes, checksum: f511b08e43998ea79e0f9b0ac5ed969b (MD5) Previous issue date: 2010-08-06 / Universidade Federal de Sao Carlos / Population genetic parameters and genetic relatedness estimates were carried out for Roseate Spoonbill (Platalea ajaja), Wood Stork (Mycteria americana) and Great Egret (Ardea alba egretta) reproductive colonies in Amapa, Pantanal and Rio Grande do Sul (RS), Brazil. Microsatellite genotypes were used to investigate kinship patterns between nestlings sampled inside the same nests, using a variety of analytical approaches. Unrelated nestling-pairs were observed in Roseate Spoonbill nests (6.12% of analyzed nests) and in Wood Stork nests (11.34%); half-siblings were present in Roseate Spoonbill nests as well (1.36%). Only full-siblings were detected inside Great Egret nests. Conspecific brood parasitism (CBP) and extra-pair paternity were proposed to account for the presence of unrelated nestmates and half-siblings, respectively, in Roseate Spoonbill and Wood Stork nests. Those results suggest the occurrence of a mating system different than genetic monogamy in natural populations of those waterbirds. Genetic relatedness was also investigated for adults and offspring, as well as for supposed siblings in Roseate Spoonbill families kept in three zoological facilities in the U.S. Paternity and maternity allocation analyses through maximum-likelihood revealed that errors were present in zoo‟s studbooks in relation to the familial records. We also identified mating between related individuals that were not detected previously by zookeepers. Population genetic parameters were also estimated and demographic processes were assessed for Great Egret reproductive colonies in the Pantanal and Rio Grande do Su, Brazil. Bayesian clustering analyses, assignment tests, analysis of molecular variance, F-statistics estimates, allelic frequency distribution and the G-W index revealed that: i) Pantanal reproductive colonies are genetically differentiated from Rio Grande do Sul colonies; ii) an IBD-like pattern alone cannot explain that differentiation; and iii) genetic signal of a reduction of population size was present for two colonies in the Pantanal and one in Rio Grande do Sul. Results were discussed considering a metapopulation dynamic and also considering that populations from both Brazilian regions represent distinct units and deserve to be treated separately when planning and carrying out conservation and management programs that aim to preserve the species‟ genetic diversity. / Estudos de genética de populações e de parentesco genético foram desenvolvidos em colhereiro (Platalea ajaja), cabeça-seca (Mycteria americana) e garça-branca-grande (Ardea alba egretta), de colônias reprodutivas do Amapá, Pantanal e Rio Grande do Sul (RS), Brasil. Genótipos em locos de microssatélites foram utilizados para se investigar os padrões de relacionamento entre ninhegos amostrados dentro dos mesmos ninhos com diferentes metodologias de análise. Pares de ninhegos não-relacionados foram encontrados nos ninhos de colhereiro (6,12% dos pares analisados) e de cabeça-seca (11,34%); meio-irmãos foram observados nos ninhos de colhereiro (1,36%). Em garça branca grande foi detectada apenas a presença de irmãos-completos dentro dos ninhos. Parasitismo de ninho intraespecífico e paternidade extra-par podem explicar a presença de ninhegos não-relacionados e meio-irmãos nos ninhos de colhereiro e cabeça-seca, o que indica a presença de um sistema de acasalamento diferente da monogamia genética nas populações naturais dessas espécies. Relações de parentesco entre adultos e filhotes e entre supostos irmãos foram determinadas em famílias de colhereiro de três zoológicos dos EUA. Análises de atribuição de maternidade e paternidade por máxima verossimilhança revelaram erros nos registros dos zoológicos quanto às relações progenitor-progênie e identificaram acasalamentos entre indivíduos aparentados que não tinham sido registrados. Parâmetros genético-populacionais e processos demográficos foram investigados em populações de garça-branca-grande do Pantanal e do Rio Grande do Sul. Análises Bayesianas, testes de alocação de indivíduos, análises de variância molecular, estimativa de estatísticas F, exame da distribuição das freqüências alélicas e cálculo do índice de G-W permitiram identificar que: i) há diferenciação genética significativa entre colônias reprodutivas do Pantanal e do Rio Grande do Sul; ii) o padrão de isolamento pela distância não explica essa diferenciação; e iii) duas populações no Pantanal e uma população no RS apresentaram sinais genéticos de redução demográfica. Os resultados foram discutidos considerando que as populações de garça-branca-grande localizadas no Pantanal e no Rio Grande do Sul são unidades populacionais independentes e devem se tratar separadamente no planejamento e desenvolvimento de programas de manejo para a conservação da diversidade genética total da espécie.