Fragmentation of Atlantic Forest has not affected gene flow of a widespread seed-dispersing bat

Habitat loss and resultant fragmentation are major threats to biodiversity, particularly in tropical and subtropical ecosystems. It is increasingly urgent to understand fragmentation effects, which are often complex and vary across taxa, time and space. We determined whether recent fragmentation of Atlantic forest is causing population subdivision in a widespread and important Neotropical seed-disperser: Artibeus lituratus (Chiroptera: Phyllostomidae). Genetic structure within highly fragmented forest in Paraguay was compared to that in mostly contiguous forest in neighboring Misiones, Argentina. Further, observed genetic structure across the fragmented landscape was compared with expected levels of structure for similar timespans in realistic simulated landscapes under different degrees of reduction in gene flow. If fragmentation significantly reduced successful dispersal, greater population differentiation and stronger isolation-by-distance would be expected in the fragmented than in ...生境丧失（habitat loss）及其引发的生境破碎化（habitat fragmentation）是生物多样性面临的主要威胁，在热带与亚热带生态系统中尤为突出。理解破碎化效应已愈发紧迫，这类效应通常极为复杂，且会随分类群（taxa）、时间与空间尺度发生变化。本研究旨在探究近期大西洋森林（Atlantic Forest）的破碎化是否正导致一种广泛分布且具有重要生态价值的新热带区（Neotropical）种子传播者——Artibeus lituratus（翼手目：叶口蝠科）出现种群分化。我们对比了巴拉圭境内高度破碎化森林与毗邻的阿根廷米西奥内斯省（Misiones）近乎连续森林中的种群遗传结构。此外，我们还将破碎化景观中观测到的遗传结构，与不同基因流（gene flow）降低程度下、相似时间尺度内真实模拟景观中预期的遗传结构水平进行了对比。若破碎化显著降低了成功扩散事件的发生，那么相较于连续森林种群，破碎化种群应表现出更强的种群分化与更显著的距离隔离（isolation-by-distance）效应。