Hastings Alan, Botsford Louis W
Department of Environmental Science and Policy, University of California, Davis, CA 95616, USA.
Proc Natl Acad Sci U S A. 2006 Apr 11;103(15):6067-72. doi: 10.1073/pnas.0506651103.
There is a need for better description and heuristic understanding of the sustainability of populations connected over space by a dispersing stage, both for management purposes and to increase our basic knowledge of the dynamics of these populations. We show that persistence of such a population of connected subpopulations depends on whether the sum of the reproductive gains through all possible closed, between-patch reproductive paths through multiple generations, relative to the shortfall in self-persistence in each path, exceeds unity plus extra terms, which only appear if there are four or more patches. These extra terms have the heuristic explanation that they avoid double counting of reproductive paths that arise with four or more patches because there can be nonoverlapping subnetworks. Thus only those patterns of reproduction and connectivity which eventually lead to descendants returning to the patch from which they originate contribute to persistence. This result provides the basis for evaluating connectivity and habitat heterogeneity to understand reserve design, the effects of human fragmentation, the collapse of marine fisheries, and other conservation issues.
为了管理目的以及增进我们对这些种群动态的基础知识，需要对通过扩散阶段在空间上相互连接的种群的可持续性进行更好的描述和启发式理解。我们表明，这种相互连接的亚种群的持久性取决于通过多代所有可能的封闭的斑块间繁殖路径所获得的繁殖增益之和，相对于每条路径中自我持久性的不足，是否超过一加额外项，这些额外项仅在有四个或更多斑块时出现。这些额外项有这样的启发式解释，即它们避免了因四个或更多斑块产生的繁殖路径的重复计算，因为可能存在不重叠的子网络。因此，只有那些最终导致后代回到其起源斑块的繁殖和连接模式才有助于持久性。这一结果为评估连通性和栖息地异质性以理解保护区设计、人类碎片化的影响、海洋渔业的崩溃以及其他保护问题提供了基础。
