Droughts are predicted to increase in frequency and intensity for large parts of Africa. It is unclear how this may impact native grazers in protected areas, and how these outcomes may differ under contrasting management approaches. Reducing artificial water sources and increasing the size of protected areas have been proposed as management responses that could possibly increase system resilience and buffer herbivores against large-scale mortality during droughts. Long-term spatially explicit buffalo, elephant and hippo census data from the Kruger National Park and adjacent private protected areas during three droughts (1982/1983, 1991/1992 and 2015/2016) provided a unique opportunity to explore how a range of management actions influenced megaherbivore responses across six regions. Drought responses varied significantly at a regional scale for all three megaherbivores, supporting the notion that size, and the associated emergent property of spatio-temporal heterogeneity, provides a buffer during droughts. Furthermore, regional buffalo population declines (as a function of mortality, movement and birth rates) were highest in areas with high waterhole density and concomitant low levels of herbaceous biomass, compared with areas that experienced similar rainfall, but had lower waterhole density and higher herbaceous biomass. Elephant mortalities were negligible, but elephants displayed regional movement patterns, seemingly attracted to higher water provision densities during the drought. Our results highlight that drought interacts with spatio-temporal environmental gradients and management actions and illustrates how the Greater Kruger National Park is increasingly functioning as an integrated ecosystem for megaherbivores.

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大型食草动物在不同管理制度下对干旱的反应：来自非洲大草原的教训

预计非洲大部分地区的干旱频率和强度都会增加。目前尚不清楚这会如何影响保护区内的本地食草动物，以及在不同的管理方法下这些结果可能有何不同。减少人工水源和扩大保护区的规模已被提议作为管理对策，可能会提高系统恢复能力并缓冲食草动物在干旱期间免受大规模死亡的影响。在三次干旱（1982/1983、1991/1992 和 2015/2016）期间，来自克鲁格国家公园和邻近私人保护区的长期空间明确的水牛、大象和河马普查数据提供了一个独特的机会来探索一系列管理行动影响了六个地区的大型食草动物的反应。所有三种大型食草动物的干旱反应在区域范围内都有显着差异，这支持了这样一种观点，即规模和相关的时空异质性的紧急特性在干旱期间提供了缓冲。此外，与经历类似降雨但具有较低水坑密度和较高草本生物量的地区相比，区域水牛种群下降（作为死亡率、移动和出生率的函数）在水坑密度高且草本生物量水平较低的地区最高。生物质。大象的死亡率可以忽略不计，但大象表现出区域性的运动模式，似乎被干旱期间更高的供水密度所吸引。