Using a Bayesian network to understand the importance of coastal storms and undeveloped landscapes for the creation and maintenance of early successional habitat

Coastal storms have consequences for human lives and infrastructure but also create important early successional habitats for myriad species. For example, storm-induced overwash creates nesting habitat for shorebirds like piping plovers (Charadrius melodus). We examined how piping plover habitat extent and location changed on barrier islands in New York, New Jersey, and Virginia after Hurricane Sandy made landfall following the 2012 breeding season. We modeled nesting habitat using a nest presence/absence dataset that included characterizations of coastal morphology and vegetation. Using a Bayesian network, we predicted nesting habitat for each study site for the years 2010/2011, 2012, and 2014/2015 based on remotely sensed spatial datasets (e.g., lidar, orthophotos). We found that Hurricane Sandy increased piping plover habitat by 9 to 300% at 4 of 5 study sites but that one site saw a decrease in habitat by 27%. The amount, location, and longevity of new habitat appeared to be influenced by the level of human development at each site. At three of the five sites, the amount of habitat created and the time new habitat persisted were inversely related to the amount of development. Furthermore, the proportion of new habitat created in high-quality overwash was inversely related to the level of development on study areas, from 17% of all new habitat in overwash at one of the most densely developed sites to 80% of all new habitat at an undeveloped site. We also show that piping plovers exploited new habitat after the storm, with 14–57% of all nests located in newly created habitat in the 2013 breeding season. Our results quantify the importance of storms in creating and maintaining coastal habitats for beach-nesting species like piping plovers, and these results suggest a negative correlation between human development and beneficial ecological impacts of these natural disturbances.

海岸风暴不仅会对人类生命与基础设施造成破坏，同时也会为众多物种创造重要的早期演替生境。例如，风暴引发的越岸冲刷会为笛鸻（piping plover, Charadrius melodus）这类滨鸟提供筑巢生境。本研究针对2012年繁殖季过后飓风“桑迪”登陆的情况，探究了纽约州、新泽西州与弗吉尼亚州障壁岛的笛鸻生境范围与空间分布变化。我们基于包含海岸地貌与植被特征的筑巢位点存在/缺失数据集，对筑巢生境进行建模；借助贝叶斯网络（Bayesian network），我们基于遥感空间数据集（例如激光雷达（lidar）、正射影像（orthophotos）），预测了2010/2011年、2012年以及2014/2015年各研究样地的筑巢生境分布。研究结果显示，飓风桑迪使得5个样地中的4个的笛鸻生境面积提升了9%至300%，但剩余1个样地的生境面积减少了27%。新生境的面积、分布位置与存续时长似乎受到各研究样地人类开发强度的影响：在5个样地中的3个，新生境的面积与存续时长均与开发强度呈负相关关系。此外，高质量越岸冲刷区域形成的新生境占比同样与研究样地的开发强度呈负相关——在开发程度最高的样地中，该类新生境仅占全部新生境的17%，而在未开发样地中这一比例高达80%。我们还发现，风暴过后笛鸻会利用新生境：在2013年繁殖季，所有筑巢位点中有14%至57%均位于风暴形成的新生境中。本研究量化了风暴对于笛鸻这类海滩筑巢物种的海岸生境创建与维持的重要性，同时表明人类开发活动与这类自然扰动带来的有益生态效应之间存在负相关关系。