Parasitism in aquatic communities- environmental influences and multiple stressors

在过去的25年里，两栖动物已经成为世界上最濒危的脊椎动物。这种下降的原因是多种多样的，包括栖息地丧失、入侵物种、气候变化和传染病的挑战，其中一些或全部可能通过复杂的机制相互作用。我和我的学生将致力于了解世界范围内两栖动物数量下降中病原体参与的重要性和机制，并探索将这些知识更广泛地应用于其他水生生物。最近越来越多的注意力集中在环境变化如何影响宿主-寄生虫相互作用的问题上。现在人们认识到，寄生虫可以对两栖动物的幼虫产生特别重要的影响，例如由吸虫Ribeiroa ondatrae（一种扁形蠕虫）引起的肢体畸形。最近的研究表明，某些环境因素（如农业农药）与两栖动物的寄生虫感染之间存在明确的联系。这项研究和培训计划将有助于确定农业农药的影响是一般性的还是特异性的，这些影响是否更有可能在特定条件下发生，这些影响的持续时间有多长，以及这些影响是否对宿主和/或寄生虫有特异性。这些工作将需要公开翻译，以帮助制定适当的两栖动物保护指导方针。这项工作还将包括现实的考虑，因为自然种群经常同时暴露于一个以上的压力源，并对宿主产生潜在的相互影响。最近的研究表明，寄生虫对宿主状况的影响是高度依赖于环境的。建议的工作将集中在寄生虫感染对宿主对未来感染的易感性的影响，受感染的两栖动物幼虫抵御池塘干燥的能力，以及蓝藻毒素对受感染两栖动物的影响。这些压力源的各种组合可能是观察到的两栖动物数量下降的潜在原因，并且可能同样影响其他水生生物。

In the last 25 years, amphibians have become the most imperiled class of vertebrates worldwide. The causes of such declines are diverse, including challenges from habitat loss, invasive species, climate change, and infectious disease, some or all of which might interact through complex mechanisms. My students and I will aim to understand the importance of and mechanisms behind pathogen involvement in worldwide amphibian declines, as well as explore the broader applications of this knowledge to other aquatic organisms. Growing attention has recently focused on the question of how environmental change affects host-parasite interactions. There is now recognition that parasites can exert particularly important effects on larval amphibians, such as limb malformations due to the trematode Ribeiroa ondatrae, a platyhelminth (flatworm). Recent research has demonstrated clear links between certain environmental factors, such as agricultural pesticides, and parasite infection in amphibians. This program of research and training will help to determine whether effects of agricultural pesticides are general or specific, whether these effects are more likely to occur in specific conditions, how long-lived these effects are, and if effects are host and/or parasite-specific. Such work will need to be publically translated to aid in the development of appropriate guidelines for amphibian conservation. This work will also include realistic considerations, as natural populations are often exposed to more than one stressor concurrently with potential interactive effects on hosts. Recent work has shown that parasite effects on host condition are highly context-dependent. The proposed work will focus on the influence of parasitic infection on host susceptibility to future infections, the ability of infected larval amphibians to withstand pond drying, and the effects of cyanobacterial toxins on infected amphibians. Various combinations of such stressors could be an underlying cause of observed amphibian declines, and may similarly impact other aquatic organisms.