He Qiang, Silliman Brian R, Liu Zezheng, Cui Baoshan
School of Environment, State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China.
Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, 135 Duke Marine Lab Road, Beaufort, NC, 28516, USA.
Ecol Lett. 2017 Feb;20(2):194-201. doi: 10.1111/ele.12721. Epub 2017 Jan 6.
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, plant-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.
许多地区的严重干旱正在增加。但到目前为止，试图预测干旱何时会导致重大的状态转变或生态系统何时具有恢复力的尝试往往受挫，这些尝试通常使用植物耐旱模型。在此，我们表明天敌的压力调节着生态系统对严重干旱的恢复力。野外实验表明，在遭受严重干旱的受保护盐沼中，食草动物清除了原本可以在这种气候极端情况下存活并恢复的受干旱胁迫的植被，将曾经繁茂的沼泽变成了永久性的盐滩。这些结果为天敌在自然生态系统崩溃的起始、扩展和恢复阶段所起的不可或缺的作用提供了明确的实验证明。我们的研究强调，天敌会使生态系统对干旱的恢复力加速降至远低于目前预测的水平，这就要求将其纳入气候变化预测和保护策略之中。
