RPG: Metapopulation Models at Two Spatial Scales Using Freshwater Mussels

元种群模型是了解大空间尺度上生物分布和丰度的重要工具。由于这些模型试图将当地种群动态与发生在不同地点之间的迁移和灭绝事件结合起来，它们在种群生态学（当地丰度）和生物地理学（区域发生）的传统分离领域之间形成了一座桥梁。河流中的淡水贻贝群落提供了一个范例系统，用于评估不同区域尺度上的超种群模型：河流本身（小流域）和河流网络（主要河流流域）。贻贝群落自然地呈斑块状分布，因为它们只出现在河流中适当的基质上。由于河流改道，泥沙会重新沉积，贻贝床也会消失，因此当地种群容易频繁灭绝。Vaughn博士将利用红河流域贻贝组合的历史（接近化石）数据，以及SCUBA促进的当前贻贝群落清单，以量化从地方到区域的时间和空间尺度上的殖民化和灭绝率。原始的元种群模型已经用强调当前物种组合的数据集进行了评估。要开始在区域空间尺度上量化殖民化和灭绝的速率和模式，就需要时间通量的数据。沃恩博士在一项研究计划资助下，开始集中研究红河流域的贻贝群落，收集这样的数据集。鉴于最近引进的一种外来的亚洲蛤蜊可能是该地区的一种咄咄逼人的竞争对手，这项工作变得更加紧迫。

Metapopulation models are important tools for understanding distribution and abundance of organisms at large spatial scales. Because these models attempt to integrate local population dynamics with immigration and extinction events occurring between sites, they form a bridge between the traditionally separate domains of population ecology (local abundance) and biogeography (regional occurrence). Freshwater mussel communities in rivers provide an exemplary system in which to assess metapopulation models across different regional scales: within a stream itself (small drainages) and within a network of streams (major river drainage). Mussel communities are naturally distributed in patches because they only occur on appropriate substrate within a river. Local populations are prone to frequent extinction because of the shifting course of rivers which redeposits sediment and eradicates mussel beds. Dr. Vaughn will take advantage of historical (near-fossil) data on mussel assemblages in the Red River drainage along with SCUBA- facilitated inventory of current mussel communities in order to quantify colonization and extinction rates through time and over spatial scales from local to regional. %%% Rudimentary metapopulation models have been evaluated with datasets that emphasize current assemblages of species. Data on temporal fluxes are needed to begin to quantify rates and patterns of colonization and extinction over regional spatial scales. Dr. Vaughn in a research planning grant is beginning to assemble such datasets by concentrating on mussel communities in the Red River drainage. The work takes on added urgency in light of the recent introduction of an alien asian clam that may prove an aggressive competitor in the region.