DISSERTATION RESEARCH: The effects of dendritic structure on parasite metacommunities in stream networks

论文研究：树突结构对河流网络中寄生虫元群落的影响

• 批准号: 1501487
• 负责人: Lisa Belden
• 金额: $ 2.09万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1501487&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; effects; dendritic; structure

Ecological communities are composed of many interacting species and provide valuable ecosystem services ranging from clean water to pollination. To maintain these ecosystem services, it is important to understand the processes that determine where, when and which species occur together. Dispersal, or the movement of organisms across the landscape, is an important process in determining what species exist at a specific site; however, the importance of dispersal is likely to vary for different types of organisms and for different habitats. To date, most research examining the role of dispersal has focused on habitats with distinct boundaries, such as forest fragments or ponds. The primary goal of this research is to explore the role of dispersal in structuring communities of wildlife parasites live in streams. A second goal of the research is to develop methods to use new DNA sequencing technologies to quantify the abundance of parasites in water samples, making it possible to rapidly survey parasite communities and identify areas of high and low infection. Streams and rivers can be important channels for the movement of pathogens, and this research will increase our understanding of infectious disease dynamics in freshwater ecosystems while also contributing new methods for assessing the distribution and abundance of freshwater parasites. Trematodes, also known as flukes or parasitic flatworms, are obligate endoparasites of mollusks and all classes of vertebrates. They have complex life cycles requiring multiple hosts, and because the hosts disperse at different spatial scales (e.g., fish vs. birds), they represent a valuable system for examining the role of dispersal in local community structure. This research will employ field surveys and molecular analyses to characterize trematode abundance and diversity within and across multiple stream networks in the southeastern U.S. Proceeding from mainstem to headwaters, investigators will quantify trematode infection in first-intermediate hosts (snails) from 15 sites within each stream network. As the obligate first-intermediate hosts of multiple trematode species, snails integrate information on the entire community of hosts involved in trematode life cycles. Investigators hypothesize that: i) there will be an increasing downstream gradient of overall trematode prevalence and diversity due to the continuous movement of free-living parasite stages and infected hosts downstream; and ii) that trematodes with mammalian or avian hosts will have a less pronounced downstream gradient of prevalence and diversity than those with fish hosts, due to greater host mobility across the landscape. By focusing on a diverse community of parasites that all use the same snail species as a first-intermediate host but that vary in vertebrate host use and thus dispersal potential, this research will provide new insights into the importance of dispersal in structuring local communities.

生态群落由许多相互作用的物种组成，提供从清洁水到授粉等宝贵的生态系统服务。为了维持这些生态系统服务，重要的是要了解决定在何处、何时以及哪些物种一起出现的过程。扩散，或生物在景观中的移动，是确定特定地点存在何种物种的重要过程;然而，扩散的重要性可能因不同类型的生物和不同的生境而异。迄今为止，大多数研究扩散作用的研究都集中在有明显边界的栖息地，如森林碎片或池塘。本研究的主要目的是探讨传播的作用，在构建社区的野生动物寄生虫生活在流。该研究的第二个目标是开发使用新的DNA测序技术来量化水样中寄生虫丰度的方法，从而能够快速调查寄生虫群落并确定高感染和低感染区域。溪流和河流可能是病原体移动的重要渠道，这项研究将增加我们对淡水生态系统中传染病动态的了解，同时也为评估淡水寄生虫的分布和丰度提供新的方法。吸虫，也称为吸虫或寄生扁形虫，是软体动物和所有脊椎动物的专性体内寄生虫。它们具有复杂的生命周期，需要多个宿主，并且由于宿主分散在不同的空间尺度上（例如，鱼类与鸟类），它们代表了一个有价值的系统，研究分散在当地社区结构中的作用。这项研究将采用实地调查和分子分析，以表征吸虫丰度和多样性内，并在美国东南部的多个流网络从mainstem到源头，调查人员将量化吸虫感染的第一中间主机（蜗牛）从15个网站内的每个流网络。螺类作为吸虫的第一中间宿主，整合了吸虫生活史中整个宿主群落的信息。 研究者假设：i）由于自由生活的寄生虫阶段和受感染宿主不断向下游移动，整体吸虫流行率和多样性的下游梯度将不断增加;以及ii）由于宿主在整个景观中的流动性更大，以哺乳动物或鸟类为宿主的吸虫的流行率和多样性的下游梯度将不如以鱼类为宿主的吸虫明显。通过关注一个不同的寄生虫社区，所有使用相同的蜗牛物种作为第一中间宿主，但不同的脊椎动物宿主使用，从而分散潜力，这项研究将提供新的见解分散在构建当地社区的重要性。