The Causes and Consequences of Variation in Dispersal Distance

像人一样，野生动植物可以在它们出生的地方附近度过一生，也可以离开。科学家称这种终生运动为“分散”。短距离的扩散是常见的，远距离的扩散是罕见的。然而，长距离传播在自然界中扮演着重要的角色——它可以帮助物种在栖息地被破坏时生存下来，并可以传播它们适应新环境所需的基因。长距离传播也会使入侵物种迅速传播，导致巨大的管理成本并威胁到本地物种。科学家们还没有完全了解导致扩散距离不同的因素，部分原因是很难追踪远距离扩散者。这项研究将通过关注生活在小山涧中的蝾螈，帮助人们了解传播距离差异的原因和后果。因为蝾螈是沿着溪流散布的，而且即使是长距离的散布者也不会走很远（不到500米），所以有可能收集到关于散布的信息（距离、时间、前后情况），而在其他物种身上收集这些信息是困难和昂贵的。有了这些信息，科学家和管理者可以更好地促进本地物种的扩散，或防止入侵物种的扩散。这项研究将测试扩散距离是否会影响个体的表现（生存和生长），以及环境因素（栖息地稳定性和捕食）如何影响这些影响。然后，研究人员将测试个体表现结果是否能预测种群在扩散距离（即扩散核）、相关形态、行为和生理表型以及种群连通性和范围扩张的新兴模式方面的种群水平变化。由于研究问题集中在基本的性能结果、尺度关系和生物地理过程上，结果将在分类群中提供信息。特别是，这项工作将有助于弥合植物和动物的扩散研究，填补我们对扩散数据尺度的理解中的一个共同空白——从个体特征到种群水平的扩散分布，再到景观和生物地理后果。

Like people, wild animals and plants can spend their lives close to where they were born or move away. Scientists call these lifetime movements "dispersal". While short-distance dispersal is common, long-distance dispersal is rare. Long-distance dispersal, however, plays an important role in nature -- it can help species survive when their habitat is destroyed, and can spread genes that they need to adapt to new conditions. Long-distance dispersal can also allow invasive species to spread quickly, leading to significant management costs and threatening native species. Scientists do not fully understand the factors that cause differences in dispersal distance, in part because it is difficult to track long-distance dispersers. This research will help people understand the causes and consequences of differences in dispersal distance by focusing on a salamander that lives in small, mountain streams. Because salamanders disperse along streams, and because even long-distance dispersers don't go very far (less than 500 meters), it is possible to collect information on dispersal (distance, timing, conditions before and after) that would be difficult and expensive to collect in other species. With this information, scientists and managers can better promote dispersal by native species, or prevent dispersal by invasive species. This research will test whether dispersal distance affects individual performance (survival and growth), and how environmental factors (habitat stability and predation) influence those effects. The researcher will then test whether individual performance consequences predict population-level variation in dispersal distances (i.e., dispersal kernels), associated morphological, behavioral, and physiological phenotypes, and emergent patterns of population connectivity and range expansion. Because the research questions center on fundamental performance consequences, scaling relationships, and biogeographic processes, results will be informative across taxa. In particular, this work will help bridge plant and animal studies of dispersal by filling a common gap in our understanding of the scaling of dispersal data -- from individual traits to population-level dispersal distributions, and further to landscape and biogeographic consequences.