DISSERTATION RESEARCH: Effects of Host Community Structure on Amphibian Disease Risk

两栖动物是脊椎动物中最受威胁的一群，主要原因是森林砍伐和一种真菌疾病在全球蔓延，造成了种群规模的毁灭性下降，导致一些物种灭绝。为了在野外实施有效的保护策略，我们需要了解栖息地变化和疾病威胁是如何相互作用的。根据最近的发现，简单地保护自然栖息地并不是保护两栖动物的答案，因为新出现的真菌病原体感染原始森林中的两栖动物比生活在农业和城市地区的两栖动物更多。这种双重威胁使两栖动物几乎没有避难所，因为大多数患病的物种在受到干扰的栖息地无法逃脱感染。这种矛盾模式的一个假设是，自然栖息地中两栖动物的数量和多样性越高，病原体传播和传播的可能性就越大。该项目将检验这一假设，方法是检查巴西原始栖息地和改良栖息地的青蛙群落，并在受控的实验室条件下用真菌病原体对每个群落的个体进行实验感染。来自原始栖息地和受干扰栖息地的青蛙将被监测感染模式的变化，这些疾病动态将与物种的数量和特征、个体密度和体型相关。了解由土地利用变化引起的青蛙种群变化如何影响疾病动态，将为森林砍伐和新出现的疾病之间的相互作用提供更完整的图景，这是两栖动物衰退危机的两个主要因素。该项目将加强与巴西科学家研究两栖动物物种丧失的研究合作。这项工作的结果将有助于制定保护热带两栖动物物种多样性的策略。巴西拥有世界上最多的两栖动物物种，因此，该项目将有助于管理一个巨大的动物多样性。该项目将为本科生提供进行实地研究的机会，并将有助于研究生的博士研究。

Amphibians are the most threatened group of vertebrate animals, due primarily to deforestation and a fungal disease that has spread globally and is causing devastating declines in population sizes that has driven some species to extinction. To implement effective conservation strategies in the wild, we need to understand how habitat change and disease threats interact. According to recent findings, simply protecting natural habitats is not the answer for amphibian conservation, because the emerging fungal pathogen infects amphibians in pristine forests more than those living in agricultural and urban areas. This double threat leaves amphibians little refuge, as most species that suffer from disease cannot escape infections in disturbed habitats. One hypothesis for this paradoxical pattern is that higher amphibian numbers and diversity in natural habitats hold a greater potential for pathogen transmission and spread. This project will test this hypothesis by examining frog assemblages in both pristine and modified habitats in Brazil and experimentally infecting individuals from each assemblage with the fungal pathogen under controlled laboratory conditions. Frogs from both pristine and disturbed habitats will be monitored for changes in infection patterns, and those disease dynamics will be correlated with number and identity of species, density of individuals, and body size. Understanding how changes in frog assemblages caused by land use change can affect disease dynamics will provide a more complete picture of the interaction between deforestation and emerging diseases, the two main factors at the root of the amphibian decline crisis.The project will strengthen research collaborations with Brazilian scientists studying amphibian species loss. Results from this work will be useful in developing strategies to conserve the diversity of amphibian species in the tropics. Brazil has the highest number of amphibian species anywhere in the world, thus, this project will contribute to the management of a mega-diverse fauna. This project will provide research opportunities for undergraduate students to conduct field research and will contribute to the doctoral research of a graduate student.