Global amphibian decline: emerging infectious diseases and local extinctions

全球两栖动物数量下降：新出现的传染病和局部灭绝

• 批准号: 312126-2007
• 负责人: Lesbarrères, David
• 金额: $ 1.4万
• 依托单位: Laurentian University of Sudbury
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2009
• 资助国家: 加拿大
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=428062
• 关键词: Global; amphibian; decline; emerging; infectious

Extinction is a common fate to any species. However, determining the causes and processes is often difficult. Increasing evidence suggests that amphibians are actually facing a global decline representing a singular opportunity to study the biology of extinction. Among other causes, emerging infectious diseases are involved in this decline. They consist of a fungal infection responsible in extinctions all around the world as well as another group of amphibian pathogens, ranaviruses, which have been shown to only cause local mortality but no known extinction. While the physiological mechanisms of these pathogens are well understood, the ecological and genetic components of the host-pathogen relationship remain to be studied. Understanding infectious disease ecology and evolution is a key to the more general investigation of extinction. Therefore amphibians are an excellent model for studying such a process in the wild. Not only do they suffer from these emerging infectious diseases but they also face anthropogenic and ecological pressure in many of their habitats. Only by exploring the role of these diseases in broad context will we be able to both test pathogen-induced extinctions and address appropriate conservation solutions. To this end, I will establish a long-term program in northern Ontario, where a matrix of disturbed and undisturbed habitats are present, and the diseases have been recently recorded. Using a combination of field observations and experiments, I will be able to investigate the pathogen mechanisms leading to the decline of local populations. Considering the current knowledge and theory on population genetics and EIDs, the hypotheses that will be tested in this application are (1) host differences in susceptibility and mortality have a significant genetic component (2) EIDs are not only causing mass mortalities within populations, but also affect individual development and (3) environmental factors affect the extensive spread of the diseases and the susceptibility of infection. In the context of the global amphibian decline, the program can be viewed as an attempt to bridge ecology and genetics to create a field that might be termed as evolutionary conservation genetics.

灭绝是任何物种的共同命运。然而，确定原因和过程往往是困难的。越来越多的证据表明，两栖动物实际上正面临全球衰退，这为研究灭绝生物学提供了一个难得的机会。在其他原因中，新出现的传染病与这种下降有关。它们包括一种导致世界各地灭绝的真菌感染，以及另一组两栖病原体--RANAV，它们已被证明只导致局部死亡，但没有已知的灭绝。虽然这些病原菌的生理机制已被很好地了解，但寄主-病原菌关系的生态和遗传成分仍有待研究。了解传染病的生态和进化是更全面地研究物种灭绝的关键。因此，两栖动物是在野外研究这一过程的极好模型。它们不仅遭受这些新出现的传染病的折磨，而且在它们的许多栖息地也面临着人为和生态压力。只有在广泛的背景下探索这些疾病的作用，我们才能既测试病原体诱导的灭绝，又解决适当的保护解决方案。为此，我将在安大略省北部建立一个长期计划，那里有一系列受干扰和未受干扰的栖息地，最近记录了这些疾病。通过实地观察和实验相结合，我将能够调查导致当地人口下降的病原体机制。考虑到目前关于种群遗传学和EID的知识和理论，将在这一应用中检验的假设是：(1)宿主在易感性和死亡率方面的差异具有显著的遗传成分(2)EID不仅在种群中造成大规模死亡，而且还影响个体发育，(3)环境因素影响疾病的广泛传播和感染的易感性。在全球两栖动物数量减少的背景下，该计划可以被视为一种尝试，试图在生态学和遗传学之间架起一座桥梁，创建一个可以被称为进化保护遗传学的领域。