Community ecology and conservation are complementary disciplines under the umbrella of ecology, providing insight into the factors that determine where and how communities exist, and informing efforts aimed at sustaining the diversity and persistence of the organisms that comprise them. Conservation ecologists apply the principles of ecology and other disciplines, to the maintenance of biodiversity. This thesis uses this approach to assess the status of freshwater crayfish in south-central Ontario and investigate potential anthropogenic drivers of crayfish community change. I start with a temporal analysis of crayfish relative abundance over a period of 18 years and find that all species have experienced significant population declines across the sampled range, resulting in reduced species distributions and crayfish community diversity. Next I employ multivariate statistical techniques to relate changes in crayfish communities between the two time periods to ecological and anthropogenic changes. I identify a number of threats in the region that are correlated with crayfish decline and are likely to pose a threat to aquatic ecosystems more broadly in the region, including calcium (Ca) decline, metal pollution, human development, and species introductions. In the latter two chapters I look more closely at Ca decline as a mechanism driving crayfish declines. First, laboratory analysis of the effect of Ca availability on juvenile Orconectes virilis (a Shield native) reveals that survival is significantly reduced below 0.5-0.9 mg·L-1, which is one of the lowest ever reported Ca requirement thresholds for a crustacean. Second, a correlative study using adult inter-moult crayfish collected from lakes that range broadly in their Ca concentrations, indicates that for O. virilis, carapace Ca content is significantly related to lake Ca concentration, and is under-saturating below 8 mg·L-1. This collective body of work identifies significant anthropogenic threats to crayfish and their aquatic ecosystems in south-central Ontario.

Salamanders are critical components of forest ecosystems, in terms of total biomass, as well as for their value as indicators of ecosystem stress. Considering the worldwide decline in amphibian populations, the known effects of timber harvest on salamander populations, and the importance of the forest products industry in Kentucky and elsewhere, the impacts of silvicultural operations on salamander communities cannot be overlooked. The objective was to investigate the effects of three different silvicultural treatments, each involving different streamside management zone (SMZ) characteristics, on salamander communities in ephemeral streams. Data were collected by regular checks of pitfall traps, coverboards, and transect searches. Using both pre- and post-harvest data, abundance estimates were acquired using binomial mixture models. Declines in some species of terrestrial and stream-breeding salamanders were detected, and were shown to be likely related to characteristics of the corresponding silvicultural treatment. Applying modest SMZ regulations to ephemeral streams would likely alleviate these declines significantly.

Over the past five decades, populations of the Cerulean Warbler (Setophaga cerulea) have declined precipitously and the response of populations to silviculture has been identified as a high-priority research need. This species was studied in nine forest management units in Southern Indiana following a harvest that took place in 2008. Males were detected, territories were demarcated, and male age-class was determined to identify settlement patterns. Vegetation was measured in all territories and associated random non-use sites. Data analyzed in ArcMap (ArcGIS 10) show that Cerulean Warbler territory size was smallest and density was highest in even-aged units. Territories contained a greater number of small woody species than non-use sites but no vegetative differences existed between male age-classes. Instead, males appeared to select areas by relying on social cues from experienced neighbors. It is possible that “social attraction” management techniques could influence male Cerulean Warbler settlement patterns, providing a valuable tool for the conservation of this species. / Forest management effects on cerulean warbler territory size in southern Indiana -- Conspecific social cues strongly influence cerulean warbler male settlement patterns in a managed forest. / Department of Biology

The sudden appearance of chytridiomycosis, as the cause of amphibian deaths and population declines in several continents suggests that its etiological agent, the amphibian chytrid fungus Batrachochytrium dendrobatidis, was introduced into the affected regions. However, the origin of this virulent pathogen is unknown. Efforts were directed to determine the occurrence of chytridiomycosis in Africa, whether the disease had been introduced into South Africa in recent years and how wild frog populations were affected by infection. A chytridiomycosis survey of 2,300 archived and live specimens involving members of the Pipidae family in sub-Saharan Africa, as well as a number of unrelated frog species in South Africa was conducted by histological diagnosis of skin samples. The epidemiological evidence indicated that chytridiomycosis has been a stable endemic infection in southern Africa for 23 years before any positive specimens were found outside Africa. The occurrence of chytridiomycosis in South Africa can be described as widespread both in terms of geographical distribution and host species and generally infection is not associated with adverse effects at the individual or population level. It was proposed that the amphibian chytrid originated in Africa and that the international trade in the African clawed toad Xenopus laevis that commenced in the mid 1930s was the means of dissemination. A risk assessment of the X. laevis trade demonstrated that chytridiomycosis could spread through this pathway and culminated in the development of a management protocol to reduce the risks of spreading disease through this animate commodity. Initial comparative genetic analysis of B. dendrobatidis strains isolated from South African frogs with a global set of 35 strains, suggests that analysis of a more geographically diverse set of southern African strains is needed before this line of argument can support or reject the "out of Africa" hypothesis. / Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2005.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 95-104). Also available on the World Wide Web.

Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 82-92).

Dissertation (Ph.D.)--Auburn University,2009. / Abstract. Vita. Includes bibliographic references (p.222-226).

Orientador: Luís Felipe de Toledo Ramos Pereira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-25T14:12:31Z (GMT). No. of bitstreams: 1 Lambertini_Carolina_M.pdf: 6513639 bytes, checksum: 76f60b46e28d803521c2f06db67818b3 (MD5) Previous issue date: 2014 / Resumo: Os anfíbios são os animais mais ameaçados do planeta, tendo como fatores mais impactantes a perda de habitat e a quitridiomicose. Esta doença em anuros é causada pelo fungo Batrachochytrium dendrobatidis (Bd), que já foi registrado em todos os continentes e no Brasil estende-se por toda a Mata Atlântica, e já foi encontrado no Cerrado e na Amazônia. Existem diversos fatores que podem influenciar a dinâmica de infecção na natureza, e como fatores intrínsecos ao Bd podemos citar a variação genotípica, morfológica, variação na virulência e taxas de crescimento. Com isso, o presente estudo teve como objetivos realizar a caracterização genotípica e fenotípica de cepas de Bd provenientes de um gradiente de elevação na Mata Atlântica, e verificar se existem associações entre o tamanho dos zoósporos e zoosporângios das cepas isoladas com dados de prevalência e intensidade de infecção e taxa de crescimento do Bd. Adicionalmente, foi analisado se as taxas de infecção aumentam conforme o aumento da elevação. Para tanto, foram isoladas e genotipadas cinco cepas de Bd. Foi realizado o diagnóstico e quantificação da doença, assim como a confecção de suas curvas de crescimento. Com base nos resultados foram desenvolvidos dois índices relacionados à variação em tamanho e dados de prevalência e intensidade de infecção. Todas as cepas isoladas pertencem à linhagem Bd-GPL2. Foi detectada variação fenotípica entre as cepas e associações entre tamanho das cepas com prevalência e intensidade de infecção, e não houve associação com as taxas de crescimento. A prevalência e intensidade de infecção não aumentaram com a altitude. Os índices de tamanho e infecção também foram associados. Com isso, a variação fenotípica pode ser considerada preditora da dinâmica de infecção do Bd na natureza. Isto poderá ser utilizado como eficiente ferramenta de baixo custo para estudos que busquem reconhecer áreas nas quais o fungo pode ser mais prevalente e apresentar maior intensidade de infecção. Estes fatores podem ser cruciais para determinar populações de anfíbios ameaçadas / Abstract: Amphibians are the most threatened animals of the world. Habitat loss and chytridiomicosys are considered the main causes for their declines. Chytridiomycosis is a disease caused in anurans by the fungus Batrachochytrium dendrobatidis (Bd), detected worldwide. In Brazil it was registered all over the Atlantic rainforest and in some localities of the Cerrado and Amazonia. Several factors influence this disease dynamics, such as intrinsic factors related to Bd: different lineages, morphology, virulence, and growth rate. Given these factors, the present study aimed to genotype and analyze Bd strain¿s size from an elevational range, and verify if these factors were correlated to Bd size, prevalence, infection load, growth rate, and elevation. We isolated and genotyped five strains, and quantified growth rates. We developed two indexes related to Bd size, prevalence, and infection load. The five strains were Bd-GPL2. We found size variation and correlations between Bd size, prevalence, and infection load, but not with growth rate. Prevalence and infection load did not increase with elevation. The size and infection indexes were correlated. The phenotypic variation can be considered as a predictor to disease dynamics on environment. It can be used in other studies as a tool to efficiently (cheap and fast) identify areas where the fungus can develop faster and be more deleterious to amphibian populations / Mestrado / Biodiversidade Animal / Mestra em Biologia Animal

Magister Scientiae (Biodiversity and Conservation Biology) / Since the late 1970 there has been increased concern of amphibian decline and extinction. Several causes for the worldwide declines have been suggested and include ultraviolet radiation, predation, pollution, climate change, diseases and habitat modification. To counter this, more research on the subject has been encouraged of which long term monitoring has been suggested as a research method. The study was conducted in Kakamega Forest in Kenya, which is the country's remnant of the once vast Guineo-Congolian forest. A rectangular transect whose sides measured 600 m in total was established and transect walks were carried out every two weeks for two consecutive days between 2002 and 2006. 24 species were targeted in the study and were sampled through VES and AES and data recorded in a GPS and later downloaded. In this study I examined the influence of rainfall, temperature, habitat and moon phases on the activity of frogs in Kakamega Forest. I also determined under which weather conditions sampling was more efficient. When monitoring was carried out by two observers I tested whether their data were similar. Data were analysed using non-parametric methods (Kruskal-wallis and Tukey test), species abundances analysed using EstimateS..Out of the 24 targeted species only 14 were recorded, with a total of 535 specimens being counted mostly at night. Most frogs in Kakamega Forest were more active in temperatures between 20 and 25oC. There was not much variation and there was no frog activity when the temperature was extremely high. There was rainfall throughout the year and there was no significant differences in the number of frogs counted in rainfall above 200 mm or below 200 mm. There was no significant difference in the number of specimens found in the different vegetation segments in the forest. More amphibians were caught under cloudy, rainy and clear conditions at night than under any weather condition during the day. During the day, more amphibians were caught during cloudy conditions than when it rained or when there was no cloud cover. There was no difference in catch among night conditions and there was no difference between clear and rainy days In Kakamega Forest, night is the best time to sample amphibians. In terms of weather it is best to sample when it is cloudy both during the day and at night. There were no differences in sampling abilities between two observers tested under similar weather conditions.

AN ABSTRACT OF THE DISSERTATION OF GRETCHEN ELIZABETH PADGETT-FLOHR for the Doctor of Philosophy degree in Zoology, presented on March 5, 2009 at Southern Illinois University of Carbondale. TITLE: BATRACHOCHYTRIUM DENDROBATIDIS IN CENTRAL CALIFORNIA AMPHIBIANS MAJOR PROFESSOR: Eric Schauber Amphibian chytridiomycosis has been identified as a disease responsible for the decline and extinction of many amphibian taxa world wide, but little research has been conducted on the disease in Mediterranean climates. To address this gap in the data I studied the amphibian assemblage present across a ~6,475 ha site in central California and investigated the occurrence of the etiological agent, Batrachochytrium dendrobatidis (BD) from organismal, community, landscape and historical perspectives. I initially tested the accuracy and reliability of a proposed diagnostic screening test for BD in four larval species that occur on the site. The screening test proposed by Fellers et al. (2001) and Vredenburg and Summers (2001) consisted of examining larval amphibian mouthparts for abnormalities and or defects, based on their hypothesis that mouthpart defects are clinical signs of BD infection. Sensitivity and specificity of the diagnostic screening test were 76% and 58%, respectively, indicating that the proposed screening test was not a reliable diagnostic test for BD infection for the four species I examined. I conducted controlled laboratory experiments to examine the consequences of BD infection in the two threatened California species that occur on my study site: Rana draytonii and Ambystoma californiense. Both species were susceptible to infection, but all infected animals survived the 18-month study. Infected A. californiense sloughed skin at three times the rate of uninfected salamanders, a pattern that may have long-term energetic costs potentially leading to population-level consequences of sublethal infection by BD. I conducted a retrospective survey of the California Academy of Sciences' (San Francisco, California, USA) amphibian collection, testing for BD in four amphibian species collected from central California between 1897 and 2005 to assess whether the pathogen is novel versus endemic. The earliest detection of BD was in two Rana catesbeiana collected in 1961, and the data support the hypothesis that BD was a novel pathogen introduced into central California prior to 1961 that spread geographically and taxonomically from at least one point of introduction and is now endemic throughout most of central California. I analyzed how environmental factors, amphibian community composition, land use practices, and landscape structure affect the dynamics of the pathogen's distribution on my study site in central California. The distribution of BD in ponds within the landscape varied markedly between years and increases were associated with precipitation, mean minimum and maximum temperatures, and presence of particular species. Pseudacris regilla infection patterns were highly indicative of overall patterns of pond BD status. Fourteen ponds were identified as BD hotpots (BD-positive three of four years). Occurrences of the pathogen within the landscape were spatially autocorrelated and ponds in close proximity to BD hotspots were more likely to test positive. Local land use, (presence/absence of grazing or recreational activity and developed lands), apparently did not influence BD status of a pond. My studies show that BD was likely a novel pathogen introduced into California ca. 1961 that has since become established as an endemic pathogen throughout most of central California. The listed amphibian species that occur in central California can be infected with BD but appear to be resistant to manifesting amphibian chytridiomycosis, and the data from the studies herein could support one of two hypotheses: that natural selection acting over the past 48 years has selected for those individuals that were resistant to the disease; or that the species on my site have always been resistant to BD. The research I conducted further supports the hypothesis that BD is locally vectored by native amphibians (e.g. P. regilla) moving between ponds and that local ecological constraints likely limit vectoring of BD by non-native species. These findings contribute substantially to elucidating and understanding the responses of amphibian populations to disease/pathogen introduction and lay groundwork for future investigations into the host-pathogen-environment relationship as it relates to declining amphibian populations.