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危险的脊椎动物类别。造成这种下降的原因是多种多样的，包括栖息地丧失、入侵物种、气候变化和传染病带来的挑战，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病原体参与全球两栖动物衰退的重要性和背后的机制，并探索将这一知识更广泛地应用于其他水生生物。最近，人们越来越关注环境变化如何影响宿主-寄生虫相互作用的问题。现在人们认识到，寄生虫可以对幼虫两栖动物产生特别重要的影响，例如由于吸虫Ribeiroa ondatrae(扁虫)造成的肢体畸形。最近的研究表明，某些环境因素，如农业杀虫剂，与两栖动物中的寄生虫感染之间存在明确的联系。这一研究和培训计划将有助于确定农业杀虫剂的影响是一般的还是特定的，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，以及影响是否因宿主和/或寄生虫而异。这种工作将需要公开翻译，以帮助制定适当的两栖动物保护准则。这项工作还将包括现实的考虑，因为自然人口经常同时暴露在一个以上的应激源中，并对宿主产生潜在的交互影响。最近的工作表明，寄生虫对寄主条件的影响高度依赖于上下文。拟议的工作将集中在寄生感染对宿主对未来感染的易感性的影响，受感染的幼虫两栖动物抵抗池塘干燥的能力，以及蓝藻毒素对受感染的两栖动物的影响。这些应激源的各种组合可能是观察到的两栖动物数量下降的根本原因，并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.