Data from: Assessing the value of novel habitats to snail kites through foraging behavior and nest survival

Novel ecosystems arise for a variety of reasons, most notably from the introduction of non-native species. To be successful, conservation strategies must both focus on traditional habitats and acknowledge the interplay between novel habitats and species of conservation interest. In the United States, the snail kite (Rostrhamus sociabilis plumbeus) is a federally endangered species whose population in Florida has undergone declines within the past decade. While studying the foraging behavior of breeding snail kites on Lake Tohopekaliga (Lake Toho), we discovered the unexpected use of disturbed ephemeral wetlands adjacent to the lake. These wetlands represent a novel habitat for kites in that they would not have been viable foraging areas prior to the introduction of the exotic island apple snail (Pomacea maculata). The novel wetland areas were highly attractive to kites, likely due to the high snail capture rates in such areas. The survival of kite nests occurring within the novel areas appeared to be similar to that of kite nests occurring in more traditional, nearby areas on Lake Toho. However, whether or not snail kites used novel habitats as nesting areas appeared to be dependent upon water depth and availability of nesting substrate within the novel areas. By examining the differences between snail kite behavior in traditional and novel habitats, we are able to identify some characteristics of novel habitats that may be important in determining the value of novel wetlands to snail kites. More broadly, this study demonstrates the care with which the management and monitoring of novel ecosystems and invasive species should be undertaken, especially when a species of conservation concern is involved.

新型生态系统的形成缘由多样，其中以外来物种引入最为显著。若要达成有效保护，保护策略既需聚焦传统栖息地，也需正视新型栖息地与受保护物种间的相互作用。在美国，螺鸢（Rostrhamus sociabilis plumbeus）是联邦一级濒危物种，其在佛罗里达州的种群数量在过去十年间持续下滑。在对托霍普卡利加湖（Lake Tohopekaliga，简称Lake Toho）上繁殖期螺鸢的觅食行为开展研究时，我们意外发现该湖周边的受干扰暂时性湿地被螺鸢用作觅食地。这类湿地是螺鸢的新型栖息地——在福寿螺（Pomacea maculata）被引入之前，此类区域并不具备作为螺鸢觅食地的可行性。该类新型湿地对螺鸢具有极强的吸引力，这大概率源于此类区域内较高的螺类捕获率。在新型湿地中筑巢的螺鸢，其巢的存活率与托霍普卡利加湖周边传统栖息地内的螺鸢巢存活率大致相当。不过，螺鸢是否会将新型栖息地作为筑巢场所，似乎取决于该新型区域内的水深与筑巢基质的可获得性。通过对比螺鸢在传统与新型栖息地内的行为差异，我们得以明确部分新型栖息地的特征——这些特征或对判定新型湿地对螺鸢的保育价值具有关键意义。从更宏观的视角来看，本研究凸显了在管理与监测新型生态系统及入侵物种时需秉持严谨态度，尤其是当涉及受保护物种时。