Population dynamics of meta-population and ineraction among local population

灭绝-(再)殖民动态的概念适用于自然或人工碎片化的种群。我们研究了栖息地大小和隔离(到最近的占用栖息地的距离)对分布在个别支流的斑驳分布的溪流多莉·瓦登的存在或不存在的模式的影响。我们预测，发生的概率将1)随着生境的大小而增加，因为大生境的灭绝率很低；2)随着生境之间距离的增加而减少，因为在孤立的生境中，再殖化率很低。我们的第一个预测得到了Dolly Varden发生与栖息地大小的Logistic回归的支持，表明小种群可能特别容易灭绝。相反，距离最近种群的距离并不影响多莉·瓦登的发生。这表明，对无人居住的栖息地的殖民化是罕见的，与地理距离无关，灭绝速度可能超过重新殖民化速度。然而，之前的一项遗传研究发现，距离是隔离的，这一模式与目前的结果不一致。这种差异可能是由于关于发生时间波动的现有信息有限造成的，值得进一步关注。

The concepts of extinction-(re) colonization dynamics applies to naturally or artificially fragmented populations. We investigated the effects of habitat size and isolation (distance to nearest occupied habitat) on the patterns of presence or absence (occurrence) of patchily distributed stream-dwelling Dolly Varden in individual tributaries. We predicted that the probability of occurrence would 1) increase with habitat size because of low extinction rates in large habitats and 2) decrease with increasing distance among habitats because of low recolonization rates in isolated habitats. Our first prediction was supported by a logistic regression of Dolly Varden occurrence on habitat size, indicating that small populations may be especially prone to extinction. Oppositely, distance to nearest population did not affect Dolly Varden occurrence. This suggests that colonization of unoccupied habitats was rare and independent of geographic distance, and that extinction rates may exceed recolonization rates. However, a previous genetic study revealed isolation by distance, a pattern inconsistent with the present results. This discrepancy may result from the limited available information on temporal fluctuations of occurrence and deserves further attention.