Dissertation Research: Impacts of Logging on Patterns and Processes in a Parasite-Host Association

9701128 Sousa 尽管许多研究已经讨论了人为干扰对自由生活物种的影响，但很少有人考虑到这些影响可能如何破坏寄生虫与其宿主之间的紧密联系。在这项研究中，PI 调查了伐木引起的干扰对一组溪流栖息物种的密度和分布的影响，并询问这些变化如何改变它们共有的吸虫寄生虫的动态。吸虫寄生虫 Cephalouterina dicamptodoni 会依次感染太平洋大鲵 (Dicamptodon tenebrosus) 幼虫、常见水生蜗牛 (Juga silicula) 和若虫石蝇 (Calineuria californica)。这项研究分为三个阶段：1）记录伐木对每个寄主物种的密度和分布的影响； 2) 检查已伐木和未伐木溪流中每种寄主物种的寄生虫流行率和丰度模式； 3）对干扰引起的宿主分布和密度变化改变寄生虫传播过程并进而改变寄生虫种群动态的假设进行实验研究。 这项工作首次探讨了伐木对寄生虫与宿主相互作用的模式和机制的影响。

9701128 Sousa Though many studies have addressed the impacts of anthropogenic disturbances on free-living species, few have considered how these impacts might disrupt the tight links between parasites and their hosts. In this study the PIs investigate the impacts of logging-induced disturbance on the density and distribution of a suite of stream-dwelling species and ask how these changes can alter dynamics of their shared trematode parasite. The trematode parasite, Cephalouterina dicamptodoni, obligately and sequentially infects larval Pacific giant salamanders (Dicamptodon tenebrosus), a common aquatic snail (Juga silicula) and a nymphal stonefly (Calineuria californica). This study consists of three phases: 1) documentation of the effects of logging on the density and distribution of each host species; 2) examination of the patterns of parasite prevalence and abundance within each host species from both logged and unlogged streams; and 3) experimental investigation of the hypothesis that disturbance-induced changes in host distributions and densities alter parasite transmission processes and in turn parasite population dynamics. This work is the first to explore the impacts of logging on both patterns and mechanisms of parasite-host interactions.