PDF(Pubmed)
Abstract：
Despite seawalls becoming ubiquitous coastal features, and having some physical similarities to natural rocky shores, it remains unclear how these urban habitats influence predator-prey interactions. Predators can affect intertidal mobile prey densities through two pathways: (1) successful predation directly influences prey mortality rates, and (2) direct and indirect effects of predation can scare and induce motile prey to seek safer areas. In this study, we investigated whether intertidal predators affect the density of the marine gastropod, Nerita undata, at four seawall sites in Singapore. Using a tethering method that we developed, we monitored the mortality and other evidence of predation (shell state) of tethered N. undata. Field experiments revealed high (22.5%-82.5%) predation potential of N. undata across the four sites, with significantly higher predation risk at lower shore heights and for snails with mixed shell coloration. Observations and analysis of the shell state after 3 days showed that predation on seawalls was primarily by crushing predators such as fish. Other predators of N. undata include predatory snails, with various feeding methods that left behind different predator signatures. Our results add substantially to the limited knowledge on predator-prey interactions on seawalls, particularly for Nerita undata, and suggest that seawall systems are more dynamic than previously thought. This further highlights the role of these artificial structures as important habitats and feeding grounds in urban coastal ecosystems.
摘要：
尽管海堤成为无处不在的沿海特征，与天然岩石海岸有一些物理相似性，目前尚不清楚这些城市栖息地如何影响捕食者-猎物的相互作用。捕食者可以通过两种途径影响潮间带移动猎物的密度：（1）成功的捕食直接影响猎物的死亡率，（2）捕食的直接和间接作用可以吓and并诱导活动猎物寻求更安全的区域。在这项研究中,我们调查了潮间带捕食者是否影响海洋腹足动物的密度，Nerita没有数据，在新加坡的四个海堤站点。使用我们开发的网络共享方法，我们监测了系留N.无数据的死亡率和其他捕食证据(壳状态)。现场实验显示，四个地点的N.undata具有很高的捕食潜力（22.5％-82.5％），在较低的海岸高度和具有混合壳颜色的蜗牛的捕食风险明显更高。3天后对壳状态的观察和分析表明，海堤上的捕食主要是通过压碎鱼类等捕食者。N.Undata的其他掠食者包括掠食性蜗牛，用各种喂养方法留下了不同的捕食者签名。我们的结果大大增加了关于海堤上捕食者-猎物相互作用的有限知识，特别是对于Neritaundata，并表明海堤系统比以前认为的更具活力。这进一步突出了这些人工结构作为城市沿海生态系统中重要的栖息地和觅食地的作用。
