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. Understanding the interactions between traditional habitats, novel habitats, and species of conservation interest is important when planning successful conservation strategies. 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 snail kites; they would not have been viable foraging areas prior to the introduction of the exotic island apple snail (Pomacea maculata). By examining the differences between snail kite behavior in traditional and novel habitats, we were able to identify some characteristics of novel habitats that may be important in determining their value to snail kites. The novel wetland areas were highly attractive to snail kites, likely due to the high snail capture rates. The survival of snail kite nests occurring within the novel areas appeared to be similar to that of 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 these areas. The snail kites’ dynamic use of the novel habitat demonstrates both the value of a novel ecosystem and the importance of traditional habitats to a species of conservation concern.

新型生态系统（novel ecosystem）的形成源于多种因素，其中尤以非本土物种的引入最为显著。在规划卓有成效的保护策略时，明晰传统生境、新型生境与受保护关注物种之间的相互作用至关重要。在美国，螺鸢（snail kite，学名*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。我们在托霍普卡利加湖（Lake Tohopekaliga，简称Lake Toho）开展繁殖期螺鸢的觅食行为研究时，意外发现该湖周边的受干扰临时湿地竟被螺鸢利用。此类湿地是螺鸢的新型生境：在引入外来岛屿苹果螺（Pomacea maculata）之前，它们并不具备作为觅食场所的可行性。通过对比螺鸢在传统生境与新型生境中的行为差异，我们得以明确部分可用于判定新型生境对螺鸢价值的关键特征。该类新型湿地对螺鸢具有极强的吸引力，这大概率源于其极高的螺类捕获效率。新型生境中螺鸢巢穴的存活率，与托霍普卡利加湖周边更为传统的生境中的巢穴存活率大致相当。但螺鸢是否将新型生境作为筑巢区域，似乎取决于该区域内的水深与筑巢基质的可获得性。螺鸢对新型生境的动态利用，既彰显了新型生态系统的生态价值，也凸显了传统生境对受保护关注物种的重要意义。