Data from: Trophic sensitivity of invasive predator and native prey interactions: integrating environmental context and climate change

Climate change is predicted to intensify the impacts of invasive species by enhancing their performance relative to their native counterparts. However, few studies have compared the performance of invasive predators and native prey, despite the fact that non-native predators are well known to disrupt native communities.
The ‘trophic sensitivity hypothesis’ suggests that predators are less tolerant of increasing environmental stress than their prey, whereas the ‘tolerant invaders hypothesis’ suggests that invaders are more tolerant than native species due to selection during the introduction process. It is therefore unclear how invasive predators will respond to increasing climate stressors.
We coupled physiological measurements (thermal tolerance, thermal optima, salinity tolerance, predation rate) with environmental time-series data to assess the effects of warming and extreme low salinity events on non-native predators (gastropods) and native prey (oysters) from a coastal ecosystem.
In general support of the trophic sensitivity hypothesis, we found that both non-native predators exhibited lower thermal optima relative to native prey, lower salinity tolerance and one predator was less tolerant of warming. However, because warming tolerance was extremely high (i.e. habitat temperature is 7·9–21 °C below thermal tolerance), near-term warming may first increase predator performance (consumption and growth rates), with negative effects on prey. Low salinity will likely produce heterogeneous effects on predator–prey interactions due to varying watershed sizes among estuaries that control the duration of low salinity events.
The trophic sensitivity hypothesis may be a useful framework for understanding community responses to extreme climate change, which portends a decoupling of predator–prey interactions. However, we conclude that this hypothesis must be evaluated in environmental context and that coupling physiological metrics with in situ environmental data offers the best predictive power of near-term climate change impacts on invaded communities. Within our study system, warming is likely to intensify the impacts of both invasive predators, which may greatly reduce the abundance of the native oyster, a species of conservation and restoration focus.

据预测，气候变化将通过提升入侵物种相较于本土同类的适合度表现，加剧其危害程度。然而，尽管人们早已熟知非本土捕食者会破坏本土群落，但鲜有研究对比入侵捕食者与本土猎物的适合度表现。

营养敏感性假说（trophic sensitivity hypothesis）提出，捕食者相较于猎物对增强的环境胁迫的耐受能力更弱；而耐受入侵者假说（tolerant invaders hypothesis）则认为，由于引入过程中的选择压作用，入侵者比本土物种具有更强的胁迫耐受能力。因此，目前尚不清楚入侵捕食者将如何响应日益加剧的气候胁迫因子。

本研究将生理测定指标（热耐受能力、最适温度、盐度耐受能力、捕食速率）与环境时间序列数据相结合，以评估气候变暖和极端低盐事件对某沿海生态系统中非本土捕食者（腹足类（gastropods））及本土猎物（牡蛎）的影响。

总体而言，研究结果支持营养敏感性假说：相较于本土猎物，两种非本土捕食者的最适温度均更低，盐度耐受能力更弱，且其中一种捕食者对气候变暖的耐受能力更差。然而，由于变暖耐受量极高（即栖息地温度较热耐受温度低7.9~21℃），短期气候变暖可能首先提升捕食者的适合度表现（捕食与生长速率），进而对猎物产生负面影响。由于不同河口的流域面积存在差异，会调控低盐事件的持续时长，因此低盐事件可能对捕食者-猎物相互作用产生异质性影响。

营养敏感性假说或可作为理解群落对极端气候变化响应的有效研究框架，该假说预示着捕食者-猎物相互作用将发生解耦。然而，本研究认为，该假说需结合具体环境背景进行验证，且将生理指标与原位环境数据相结合，是预测短期气候变化对入侵群落影响的最优方案。在本研究的生态系统中，气候变暖可能加剧两种入侵捕食者的危害，这将大幅降低本土牡蛎的种群丰度——而该物种正是当前保护与修复工作的重点对象。