Department of Biology, North Carolina State University, Raleigh, NC 27695, USA.
Conserv Biol. 2011 Oct;25(5):1022-31. doi: 10.1111/j.1523-1739.2011.01720.x. Epub 2011 Aug 16.
Understanding the way in which habitat fragmentation disrupts animal dispersal is key to identifying effective and efficient conservation strategies. To differentiate the potential effectiveness of 2 frequently used strategies for increasing the connectivity of populations in fragmented landscapes-corridors and stepping stones-we combined 3 complimentary methods: behavioral studies at habitat edges, mark-recapture, and genetic analyses. Each of these methods addresses different steps in the dispersal process that a single intensive study could not address. We applied the 3 methods to the case study of Atrytonopsis new species 1, a rare butterfly endemic to a partially urbanized stretch of barrier islands in North Carolina (U.S.A.). Results of behavioral analyses showed the butterfly flew into urban and forested areas, but not over open beach; mark-recapture showed that the butterfly dispersed successfully through short stretches of urban areas (<500 m); and genetic studies showed that longer stretches of forest (>5 km) were a dispersal barrier, but shorter stretches of urban areas (≤5 km) were not. Although results from all 3 methods indicated natural features in the landscape, not urbanization, were barriers to dispersal, when we combined the results we could determine where barriers might arise: forests restricted dispersal for the butterfly only when there were long stretches with no habitat. Therefore, urban areas have the potential to become a dispersal barrier if their extent increases, a finding that may have gone unnoticed if we had used a single approach. Protection of stepping stones should be sufficient to maintain connectivity for Atrytonopsis new species 1 at current levels of urbanization. Our research highlights how the use of complementary approaches for studying animal dispersal in fragmented landscapes can help identify conservation strategies.
理解生境破碎如何干扰动物扩散对于确定有效和高效的保护策略至关重要。为了区分两种常用于增加破碎景观中种群连通性的策略（廊道和踏脚石）的潜在有效性，我们结合了 3 种互补的方法：在栖息地边缘进行行为研究、标记-重捕和遗传分析。这些方法中的每一种都涉及到单个密集研究无法解决的扩散过程中的不同步骤。我们将这 3 种方法应用于北卡罗来纳州（美国）部分城市化的屏障岛狭长地带特有罕见蝴蝶 Atrytonopsis 新种 1 的案例研究。行为分析的结果表明，蝴蝶会飞入城市和森林地区，但不会飞越开阔的海滩；标记-重捕表明，蝴蝶成功地穿过了短距离的城市地区（<500 米）；遗传研究表明，较长的森林（>5 公里）是扩散的障碍，但较短的城市地区（≤5 公里）则不是。尽管这 3 种方法的结果都表明景观中的自然特征而不是城市化是扩散的障碍，但当我们结合这些结果时，我们可以确定障碍可能出现的地方：只有当没有栖息地的长距离时，森林才会限制蝴蝶的扩散。因此，如果城市地区的范围扩大，它们有可能成为扩散的障碍，如果我们只使用单一方法，这一发现可能会被忽视。保护踏脚石应该足以维持 Atrytonopsis 新种 1 在当前城市化水平下的连通性。我们的研究强调了在破碎景观中研究动物扩散时使用互补方法的重要性，这有助于确定保护策略。
