Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / We study the richness and the spatial distribution of anuran amphibians recorded in Parque Estadual do Turvo (PET), the largest remnant of Mesophytic Semideciduous Forest in the state of Rio Grande do Sul, Brazil. In this study we (1) describe the composition of community of amphibians in PET, (2) compare the composition of species with those recorded in other localities of Seasonal Forests, testing the hypothesis that localities nearest the Misiones Nucleus support the current proposal of a new phytogeographic unit, known as Seasonal Rain Forest Region , and (3) we tested if the occurrence of breeding pond anurans differed from a null model of random placement, as well as we hypothesized that the environmental heterogeneity and spatial distribution of ponds influences the structure of anuran communities in southern Brazil. The species inventory was carried out using complementary sampling techniques (surveys at breeding sites, casual encounters, pitfall traps and search at scientific collections). To check the spatial distribution, we monitored 14 ponds with variable heterogeneity. We recorded 32 species of amphibians in the Park area, belonging to two orders: Anura, 30 native and one exotic species, and Gymnophiona, one species. The analysis of similarity among the localities of seasonal forests evidenced three groups with similarity of 45%: the former group was composed by localities of southeast and central-western Brazil, the second group was composed by southern localities, and the third group was composed by localities of the transition area with the Atlantic Forest sensu stricto. The second group supports the proposal of a new phytogeographic unit, known as 'Tropical Seasonal Forests Region'. We recorded 15 anuran species at the monitored ponds, and the species occurrence was clearly not random, corroborating our hypothesis that the anuran composition of species is influenced by environmental heterogeneity. The main descriptors of pond heterogeneity correlated with abundance of anuran species were area, depth, hydroperiod, percentage of vegetation cover on water surface, and distance of pond in relation to the nearest Park edges. The community structure of anurans was not affected by the geographical distribution of ponds. The results of the present study demonstrate that the heterogeneity of water bodies is a strong regulator of community structure of breeding pond amphibians and this information has implications for conservation strategies of Neotropical Austral anurans. / Estudamos a riqueza e a distribuição espacial da anurofauna registrada no Parque Estadual do Turvo (PET), maior remanescente de Floresta Estacional Semidecidual do estado do Rio Grande do Sul, Brasil. Nesse trabalho, (1) descrevemos a composição da comunidade de anuros do PET, (2) comparamos a composição da anurofauna com a de outras localidades de Florestas Estacionais, testando a hipótese de que as localidades próximas ao Núcleo Misiones corroboram a nova unidade fitogeográfica, conhecida como Região das Florestas Tropicais Sazonais , e (3), testamos se a ocorrência de espécies de anuros em poças é diferente de um modelo nulo de distribuição randômica, hipotetizando que a heterogeneidade ambiental e a distribuição espacial das poças têm influência sobre a estrutura das comunidades de anuros no sul do Brasil. Para o inventariamento das espécies foram empregadas diferentes técnicas (amostragens em sítios de reprodução, encontros ocasionais, armadilhas de interceptação e queda e consulta a coleções científicas). Para verificar a distribuição espacial, monitoramos 14 poças com heterogeneidade ambiental variável. Foram registradas 32 espécies de anfíbios no Parque e arredores, pertencentes a duas ordens: Anura, 30 espécies nativas e uma exótica e Gymnophiona, uma espécie. A análise de similaridade entre as localidades de Florestas Estacionais apresentou a formação de três grupos com 45% de similaridade entre eles: o primeiro grupo composto pelas localidades do sudeste e centro-oeste, o segundo grupo composto pelas localidades do sul e o terceiro grupo pelas localidades da porção de transição com a Floresta Atlântica sensu stricto. A formação do segundo grupo corrobora a proposta de uma nova unidade fitogeográfica, conhecida como Região das Florestas Tropicais Sazonais . Foram registradas 15 espécies de anuros nas poças, e sua distribuição foi claramente não randômica, corroborando a nossa hipótese de que a composição das espécies é influenciada pela heterogeneidade ambiental. As principais variáveis que estão correlacionadas com a estruturação das poças são: a área, a profundidade, o hidroperíodo, a porcentagem de cobertura vegetal no espelho d água e a distância que se encontravam em relação à borda mais próxima do Parque. A estrutura das comunidades de anuros não foi influenciada pela distribuição espacial das poças. Esse resultado indica que as poças estudadas foram independentes quanto à composição da anurofauna. Os resultados do presente estudo demonstraram que a heterogeneidade dos corpos d água é uma forte reguladora da estrutura de comunidades de anfíbios anuros e essa informação tem implicações para estratégias de conservação da anurofauna Neotropical Austral.

Un des enjeux importants de l’écologie est de comprendre comment les pratiques anthropiques affectent la biodiversité et quelles en sont les conséquences sur le fonctionnement des écosystèmes. L’objectif de cette thèse est d’améliorer la compréhension des mécanismes régissant les communautés végétales aquatiques, et plus particulièrement ceux liés aux perturbations anthropiques et aux phénomènes d’eutrophisation. Les méta-écosystèmes constitués de réseaux d’étangs agro-piscicoles sont des modèles d’étude adaptés à notre problématique car ils sont sous forte pression anthropique et présentent une forte variabilité environnementale. Dans un premier temps, nous avons étudié l’impact des modes de gestion des bassins versants sur l’eutrophisation des étangs. Dans un second temps, nous avons mesuré l’effet de l’eutrophisation sur la productivité et la diversité des communautés phytoplanctoniques. Enfin, nous avons relié 3 types de contraintes générées par les pratiques anthropiques (l’eutrophisation, l’assèchement et la connectivité entre les étangs) sur les communautés de plantes aquatiques en termes de diversité spécifique et fonctionnelle. L’effet de l’eutrophisation, le recrutement et l'établissement des communautés des plantes aquatiques a été abordé au travers de la relation entre la banque de graines et la végétation établie. L’eutrophisation est le facteur majeur responsable de la diminution de la biodiversité végétale dans les étangs. Cependant les perturbations récurrentes constituées par les assecs, engendrent une succession cyclique qui contribue à maintenir une forte biodiversité dans les étangs. / One important issue of research in Ecology is to understand how anthropogenic activities are influencing biodiversity and what are the consequences on ecosystem functioning. The aim of the study is to improve the knowledge of the mechanisms governing aquatic plant communities, particularly those related to human disturbance and eutrophication. Meta-ecosystems constituted by networks of fish-farming shallow lakes are study models adapted to our problematic because they are submitted to a strong anthropogenic pressure and because they show a high environmental variability. First, we studied the impact of watershed management practices on shallow lakes eutrophication. In a second step, we measured eutrophication effect on productivity and on diversity of phytoplankton communities. Finally, we were able to link 3 types of constraints generated by human practices (eutrophication, drying and connectivity between shallow lakes) to aquatic plant communities in terms of specific and functional diversity. The impact of eutrophication, recruitment and establishment of aquatic plant communities has been approached through the relationship between the seed bank and established vegetation. Eutrophication is the major factor responsible for the loss of plant biodiversity in shallow lakes. However frequent disturbances due to drying events induce a cyclic succession that helps maintain a high biodiversity.

L'objectif de cette thèse a été de mesurer comment les modifications des régimes hydrologiques, plus particulièrement les exondations, régissent 1) certains aspects du fonctionnement des zones humides, 2) l'organisation et la dynamique à court terme des communautés végétales aquatiques et 3) la survie et la réponse plastique des végétaux aquatiques. Cette thèse aborde les questions à des échelles spatio-temporelles différentes. Premièrement, à l'échelle de la décennie, j'ai mesuré la conséquence de la baisse de la hauteur d'eau des zones humides péri-fluviales sur leur physico-chimie. Deuxièmement, à l'échelle de la saison, j'ai mesuré l'influence des caractéristiques sédimentaires des zones humides sur la réponse à court terme des communautés végétales à l'exondation. Enfin, à l'échelle de quelques semaines, je me suis intéressée à l'aptitude des espèces d'angiospermes aquatiques à mettre en place un ajustement plastique face à l'exondation, en conditions expérimentales de laboratoire et in situ, j'ai recherché les déterminismes de cette réponse (écologiques, morphologiques, phylogénétiques). En termes de caractéristiques physico-chimiques des eaux de surface, l'étude sur 15 ans de la dynamique de zones humides péri-fluviales subissant des exondations, ne conclue pas, comme cela est habituellement décrit dans la littérature, à une augmentation de la teneur en nutriments de la masse d'eau, mais plutôt des changements suggérant des variations du fonctionnement hydrogéologique des zones humides, en faveur d'une plus grande influence de la nappe de versant dans leur alimentation. La réponse in situ des communautés végétales à l'exondation diffère selon le type de sédiment. La résistance et la résilience des communautés décroissent toutes deux avec la capacité de rétention d'eau du sédiment. La capacité des plantes aquatiques à tolérer l'exondation, en conditions expérimentales, semble différer selon leur position phylogénétique, mais pas selon leur forme de croissance (rosettes ou caulescentes) / The objective of this thesis was to measure how changes in hydrological regimes, particularly dewatering govern 1) aspects of the functioning of wetlands, 2) the organization and short-term dynamics of aquatic plant communities and 3 ) survival and plastic response of aquatic plants. This thesis addresses issues at different spatial and temporal scales. First, at the decade scale, I measured the effect of water-level decreases in riverine wetlands on their physico-chemistry characteristics. Second, at the season scale, I measured the influence of sedimentary characteristics of wetlands on short-term response of plant communities to dewatering. Finally, at the scale of a few weeks, I was interested in the ability of aquatic angiosperm species to develop a plastic adjustment to dewatering, in experimental laboratory conditions and in situ, and I looked determinism of this response (ecological, morphological, phylogenetic). In terms of physico-chemical characteristics of surface waters, the 15- year study of the dynamics of riverine wetlands undergoing dewatering, not reached, as is usually described in the literature, with an increase of water body nutrient contents, but rather changes suggesting variations of the hydrogeological functioning of wetlands in favor of a greater influence of the hillslope groundwater table in their water supply. In situ response of plant communities to dewatering differs according to sediment type. Both, resistance and resilience of communities decrease with the sediment water retention capacity. The ability of aquatic plants to tolerate dewatering, in experimental conditions, seems to differ according to their phylogenetic position, but not according to their growth form (rosettes or caulescentes). Species tolerating dewatering show phenotypic adjustments such as denser aerial organs and high plasticity of the leaves, which may explain the maintenance of a similar growth rate in terrestrial and aquatic conditions in these species

Several mechanisms mediate the richness, diversity, abundance and distribution of tadpoles in the ponds. The purpose of this study was to characterize the composition of tadpoles of an area of Caatinga in the State of Sergipe and evaluate it with respect to use temporal (time of occurrence) and spatial (within the preferred local water bodies) in the dams. Looking for understand the influence of some environmental parameters and predators on the abundance of tadpoles. The study was conducted at the Natural Monument Grota Angico in the period September 2011 to August 2012. The sample of tadpoles and predators were doing in nine dams of the locality. The biotic and abiotic factors were collected monthly in the dams that had water. 2117 tadpoles and 710 predators were collected. The alpha diversity was similar between the dams and the beta diversity was considered relatively low. Most tadpoles had high spatial niche breadth showing a general use of space. The spatial and temporal overlaps showed segregation between species in the use of micro-habitats and seasons. None of the species showed association between their abundances and the physical-chemical and structural of the dams. The richness and abundance were correlated to rainfall. Tadpoles and predators differed on the use of micro-habitat and only three species showed a positive correlation with the predators. The results were in some ways similar to other studies in the Caatinga biome and in dry areas of the country. Studies in the Caatinga are still a challenge to researchers, especially about the frogs of the Biome, and studies should be encouraged, so that you can know more about the biology of these species and so you can get better conservation strategies for the group. / Diversos mecanismos mediam a diversidade, riqueza, abundância e distribuição dos girinos nos corpos d água. O objetivo do estudo foi caracterizar a composição de girinos de uma área de Caatinga no Estado de Sergipe e avaliá-la em relação ao uso temporal (períodos de ocorrência) e espacial (locais preferenciais dentro dos corpos d água) nos açudes. Buscando ainda, compreender a influência de alguns parâmetros ambientais e de predadores, em potencial, sobre a abundância dos girinos. O estudo foi realizado no Monumento Natural Grota do Angico, no período de Setembro de 2011 a Agosto de 2012. A coleta dos girinos e predadores foi realizada em forma de parcela em nove açudes da localidade. Os fatores bióticos e abióticos foram coletados mensalmente nos açudes que possuíam água. Foram coletados 2117 girinos e 710 predadores. A diversidade alfa foi semelhante entre as lagoas e a beta foi considerada relativamente baixa. A maioria dos girinos teve amplitude de nicho espacial elevada mostrando um uso generalista do espaço e, as sobreposições espacial e temporal demonstraram uma segregação entre as espécies no uso de micro-habitat e dos períodos de ocorrência. Nenhuma das espécies apresentou relação entre suas abundâncias e os fatores físico-químicos e estruturais dos açudes. A riqueza e abundância estiveram relacionadas a pluviosidade. Girinos e predadores diferiram quanto ao uso do micro-habitat e apenas três espécies apresentaram correlação positiva com os predadores. Os resultados obtidos foram em alguns aspectos semelhantes a outros estudos realizados no bioma Caatinga e em áreas secas do país. Evidenciou-se a importância dos açudes na manutenção das populações locais e a necessidade de preservação dos mesmos. Estudos na Caatinga ainda perfazem um desafio aos pesquisadores, principalmente a cerca da anurofauna do Bioma, e estudos devem ser incentivados, tanto para que se possa conhecer mais sobre a biologia larval dessas espécies quanto para que se possa obter melhores estratégias de conservação para o grupo.

No description available.

The prevalence of hypoxia in aquatic systems has increased in recent decades and climate change is expected to worsen the extent and severity of hypoxic phenomena worldwide. Moreover, aquatic hypoxia has produced adverse ecological consequences and stimulated research interest within the Laurentian Great Lakes. The physiological stress imposed by hypoxia reduces habitat quality for most aquatic biota and causes changes in patterns of resource use and food web dynamics. We conducted a review of the primary literature to identify trends in prevalence of Great Lakes hypoxia research and broadly classify the unique hypoxic conditions afflicting Great Lakes ecosystems. We found that the majority of research effort toward Great Lakes hypoxia is focused on the Lake Erie central basin. Our review further revealed that this does not characterize the breadth of hypoxic phenomena that occur throughout the Great Lakes region. We then utilized a long-term monitoring dataset provided by the U.S. Environmental Protection Agency Great Lakes National Program Office to quantify the impact of Lake Erie central basin hypoxia on habitat quality of several fish species. We found that bioenergetics-based growth-rate potential models have a potential application as the framework for the development of biological endpoints that measure the effects of hypoxia on aquatic biota. Finally, we utilized stable isotope analysis to look for broad spatial and temporal trends in resource utilization within distinct regions of the Lake Erie central basin, with hypoxia and large-scale hydrodynamic patterns serving as potential driving patterns for spatial differences.

<p dir="ltr">North American beaver are ecosystem and habitat altering mammals with a wide distribution in North America. Beaver are associated with bodies of fresh water while utilizing riparian habitat by foraging on woody and herbaceous, terrestrial and aquatic vegetation, as well as creating lodges, dams, dens, and scent mounds. Chain O’Lakes State Park was chosen as a study area for surveying beaver activity and woody species communities. The aim of the study was to better understand the relationship between beaver, and specifically, the woody vegetation in their foraging and home range. There is a large swath of habitat that beaver can utilize and alter within Chain O’Lakes State Park including the lakes, streams, and forests that attract visitors. The factors that have been found to influence beaver utilization in Chain O’Lakes State Park (and North America at large) are woody species community composition, abundance of heavily preferred woody species, as well as a combination of both an absence of predators and an abundance of aquatic vegetation. Based on the distribution of heavily, occasionally, and rarely preferred woody species across the understory (new individuals) and overstory (mature individuals) stratum an inference can be made that most of the riparian habitat around the lakes will continue to and/or shift into a higher proportion of species that beaver heavily select. A minority of the habitat shall shift away from those species and towards rarely and/or occasionally selected species. I will provide USDA APHIS Wildlife Services that play a wildlife management role in Chain O’Lakes State Park with the survey information detailing how beaver and their structures interact with the ecosystem, hypothesized methods for preserving the woody species that are targeted by beaver foraging within the park, and supplementary information that may aid in maintaining the riparian habitats for the benefit of park’s biodiversity and wildlife persistence while continuing to provide an enriched experience within Northwest Indiana with the potential to inform the greater collection of parks and maintained land at large.</p>

<p dir="ltr">The lichen-feeding tiger moth tribe Lithosiini (Erebidae: Arctiinae) represent the largest radiation of invertebrate lichenivory. Caterpillars feed on lichen and as they feed, also sequester lichen polyphenolics, a behavior unique to these insects. The role of these compounds is believed to defend lithosiines against predators as larvae have been found to be protected against predators such as ants and moths to predators such as birds and bats. Experimental testing with controlled diets is necessary to fully make this connection, however little is known about host specifics for lithosiines. Furthermore, although lithosiines are monophyletic, the lack of a fully resolved phylogeny hampers investigation into many of the shallower level relationships, e.g. those among genera and species, within the group.</p><p dir="ltr">I addressed these knowledge gaps using the subtribe Cisthenina. Members of this group have been used to investigate predator-prey interactions and been included in morphological and molecular studies. Thus, while the group still needs attention, there is an ample amount of legacy loci data available for its members. I used these data to investigate the evolutionary relationships at the genus level, but to increase resolution in my analyses I additionally sampled taxa throughout the group with a recently developed anchored hybrid enrichment (AHE) probe set. I combined it with the legacy loci to both increase taxon sampling and resolution. I confirmed that trees made strictly from the legacy loci were unsuccessful and resulted in poorly supported relationships that made little sense. The addition of the AHE data greatly helped resolve relationships, however, there remained areas that were poorly supported and they appear to be genera with only a few loci. Thus, there is still room for improvement, but this offers a way for moving forward in lithosiine research, particularly to involve others who may have limited funding, equipment, and/or personnel and may only be able to afford legacy loci in diverse collaborations.</p><p dir="ltr">As the AHE probe set worked well with genus-level relationships I further attempted to use it in species delimitation of the notorious <i>Hypoprepia fucosa</i>-<i>miniata </i>species complex. Members of this group are varying shades of yellows, oranges and reds and have a convoluted taxonomic history. I gathered and organized over 4,000 specimens and using the AHE probe set found support for five distinct species. Interestingly, I used other morphological characters such as genitalia, but found no differences between species and a large amount of intraspecific variation. This suggests other courtship behaviors may be present and external morphology, i.e., color patterns, remain the best way to identify species. As part of this I am describing a new species and raising one from subspecies and as species are now readily distinguishable, they can be used for further investigations into lithosiines.</p><p dir="ltr">I used a member of this complex, <i>H</i>. <i>fucosa</i> to then evaluate the use of species distribution models (SDMs) to better understand their niche and how it relates to plausible lichen hosts. I evaluated 17 lichen species from two lichen genera, <i>Physcia </i>(13 species) and <i>Myelochro</i><i>a </i>(4 species)<i>. </i>These genera were selected based on previous feeding assays and the metabolites found in them have also been found in <i>H</i>. <i>fucosa </i>further suggesting caterpillars may feed on them. SDMs typically only use environmental factors to define and predict species niches. I compared the niches described by traditional SDMs to assess how similar they were, but I also investigated the use of lichens as biotic factors in the models. I assessed the influence each lichen had on the moth’s distribution found the niche of every lichen to be significantly different than that of the moth and their inclusion in SDMs of <i>H</i>. <i>fucosa </i>to improve model performance. This suggests <i>H</i>. <i>fucosa </i>caterpillars to be polyphagous, but to have some connection with these lichens. Further investigation with live specimens is needed, but these results support this as an effective way to describe lithosiine niches to better understand lichen feeding.</p>

Biodiversity is being lost around the world and anthropogenic activities, like non-native species introductions and urbanization, are among the leading causes of decline. Broadening our understanding of human-driven impacts on biodiversity can lead to more effective solutions and contribute towards stemming biodiversity losses. In this thesis, I explored the impacts of non-native species introductions and urbanization on butterfly-plant communities. I evaluated potential factors influencing the range expansion of a newly introduced species (Chapter 1), examined the role of urbanization in structuring biological communities (Chapter 2), and identified important ecological interactions between native and non-native species (Chapter 3). In my first chapter, I found that the newly introduced European Common Blue butterfly (Polyommatus icarus) was more abundant in urban and disturbed habitat that was unmown and where their preferred larval host plant (Lotus corniculatus), a non-native species, was present. I also found that P. icarus was not a strong flier relative to other butterfly species, suggesting that adult dispersal may not be a driving factor in range expansion. Instead, this species could expand its range in the future by colonizing habitats in developed regions across Canada given the association I found between P. icarus and disturbed habitat. In my second chapter, I found that urbanization led to the biotic homogenization of butterfly communities around Montréal, QC, favouring a few, highly abundant, non-native species. Homogenization was detected at both the taxonomic and functional levels and was driven by increases in P. icarus abundance in the more urban sites. In my third chapter, I found that non-native plants were well integrated into native butterfly nectar diets in an at-risk oak savanna ecosystem on Vancouver Island, BC and that usage of non-native plants increased when they were more available during the season. I also found that native butterflies visited non-native plants more often than flower availability predicted on its own, suggesting that butterflies may even prefer non-native nectar. Findings from my thesis research broaden our understanding of the ways in which butterfly communities can be influenced by human activities like urbanization and the introduction of non-native species, informing conservation efforts and directing future research needs.

No description available.