Genetic estimates of immigration and emigration rates in relation to population density and forest patch area in Peromyscus leucopus
Genetic estimates of immigration and emigration rates in relation to population density and forest patch area in Peromyscus leucopus
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DOI：
10.1007/s10592-009-0033-8
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发表时间：
2010-10-01
影响因子：
2.2
通讯作者：
Meikle, Douglas B.
中科院分区：
文献类型：
--
作者：
Anderson, Christine S.;Meikle, Douglas B.
一个新出现的模式是，人口密度的通才啮齿动物是更高的小相比，大型森林斑块在破碎的景观。我们使用基于遗传学的补丁之间的迁移措施，以测试两个基于扩散的假设，这种负密度-面积关系：（1）移民率从小补丁应该是相对较低的相比，大补丁（“抑制扩散假说”），或（2）移民率应该是更高的小补丁比大（“移民假说”）。这两种假设都没有得到支持，使用数据推断的8个微卫星位点的Peromyscus leucopus在6个小（1.3-2.7公顷）和6个大（8-150公顷）森林斑块的12个种群的扩散。移民率并不低于和移民率并不高于小的比大的补丁。事实上，与这两种假设相反，小斑块中的白背飞虱种群的迁移率高于大斑块。基于遗传和现场数据相结合，我们推测，更高的繁殖在较小的补丁导致更高的密度，从而导致更高的移民率从这些补丁。繁殖率（可能是由较小斑块中更好的栖息地条件驱动的），而不是分散，似乎导致了森林斑块的密度差异。我们的结论是，较小的森林斑块内的农业矩阵作为一个来源的个人，和迁移率是相当高的森林斑块之间，无论大小。
An emerging pattern is that population densities of generalist rodents are higher in small compared to large forest patches in fragmented landscapes. We used genetically based measures of migration between patches to test two dispersal-based hypotheses for this negative density-area relationship: (1) emigration rates from small patches should be relatively lower compared to large patches ("inhibited dispersal hypothesis''), or (2) immigration rates should be higher into small than large patches ("immigration hypothesis''). Neither hypothesis was supported using data on dispersal inferred from eight microsatellite loci for 12 populations of Peromyscus leucopus in six small (1.3-2.7 ha) and six large (8-150 ha) forest patches. Emigration rates were not lower from and immigration rates were not higher into small than large patches. In fact, contrary to both hypotheses, emigration rates were higher from populations of P. leucopus in small compared to large patches. Based on a combination of genetic and field data, we speculate that higher reproduction in smaller patches resulted in higher densities which led to higher emigration rates from those patches. Rates of reproduction (presumably driven by better habitat conditions in smaller patches), rather than dispersal, seems to drive density differences in forest patches. We conclude that smaller forest patches within an agricultural matrix act as a source of individuals, and that migration rates are fairly high among forest patches regardless of size.