Data from: Natural enemies govern ecosystem resilience in the face of extreme droughts

Severe droughts are on the rise in many regions. But thus far, attempts to predict when drought will cause a major regime shift or when ecosystems are resilient, often using plant drought tolerance models, have been frustrated. Here we show that pressure from natural enemies regulates an ecosystem’s resilience to severe droughts. Field experiments revealed that in protected salt marshes experiencing a severe drought, planting-eating grazers eliminated drought-stressed vegetation that could otherwise survive and recover from the climate extreme, transforming once lush marshes into persistent salt barrens. These results provide an explicit experimental demonstration for the obligatory role of natural enemies across the initiation, expansion and recovery stages of a natural ecosystem’s collapse. Our study highlights that natural enemies can hasten an ecosystem’s resilience to drought to much lower levels than currently predicted, calling for integration into climate change predictions and conservation strategies.

诸多区域的严重干旱正呈频发之势。迄今为止，依托植物耐旱模型开展的、旨在预测干旱何时引发重大生态系统状态转换（regime shift），或是评估生态系统恢复力的各类尝试均以失败告终。本研究表明，天敌（natural enemies）带来的调控作用可调节生态系统对严重干旱的恢复力。野外实验显示，在遭遇严重干旱的受保护盐沼（salt marshes）中，植食性牧食者会清除受干旱胁迫的植被——而这类植被本可存活并从极端气候中恢复，最终将原本繁茂的盐沼转变为持久性盐裸地。上述结果通过实验明确证实了天敌对自然生态系统崩溃的起始、扩张及恢复阶段均具有不可或缺的调控作用。本研究凸显出，天敌可将生态系统对干旱的恢复力削弱至远低于当前预测的水平，呼吁将天敌因素纳入气候变化预测与生态保护策略之中。