Savanna megafauna have become scarce outside of protected areas in Africa, largely because of land conversion for farming (smallholders and agribusiness) and expansion of settlements and other infrastructure. Intensification also isolates protected areas, even affecting natural processes within reserve boundaries. Here, we used satellite imagery from the past 32 years in the iconic Maasai Mara ecosystem to assess the capacity of different land tenures to prevent degradation. We compare unprotected land with two types of conservation management: fully protected land without livestock (land sparing) and semi-protected community-based conservation – protected land with regulated livestock densities (land sharing). On unprotected land (61% of the area), we detected massive and accelerating degradation and fragmentation of natural vegetation, with large losses of woodland (62%) and grassland (56%), resulting in the expansion of bare ground. In contrast, directional change was minimal in both types of protected areas. Vegetation resistance to drought was lowest on unprotected land, intermediate under community-based conservation and highest under full protection. Our results show that the Mara ecosystem is under heavy pressure, but that conservation management counteracts negative trends. Importantly, semi-protected community-based land-sharing conservation offers clear, partial buffering against degradation.

稀树草原大型动物已经在非洲保护区之外变得稀缺，这主要是因为用于农业（小农和农业综合企业）的土地转换以及定居点和其他基础设施的扩大。集约化还将隔离保护区，甚至影响保护区边界内的自然过程。在这里，我们使用了标志性的马赛马拉生态系统中过去32年的卫星图像来评估不同土地保有权防止退化的能力。我们将无保护土地与两种类型的保护管理进行了比较：没有牲畜的完全保护土地（保留土地）和基于社区的半保护土地–牲畜密度受到管制的保护土地（土地共享）。在未受保护的土地（占该地区的61％）上，我们发现了自然植被的大规模加速退化和破碎化，林地（62％）和草原（56％）的大量损失，导致裸露土地的扩张。相反，在两种类型的保护区中方向变化最小。在未保护的土地上，植被的干旱抵抗力最低，在社区保护下处于中等水平，而在全面保护下则最高。我们的结果表明，马拉生态系统承受着沉重的压力，但是保护管理抵消了负面趋势。重要的是，基于社区的半保护土地共享保护提供了清晰，部分的缓冲，以防止退化。在基于社区的保护下处于中等水平，在完全保护下处于最高水平。我们的结果表明，马拉生态系统承受着沉重的压力，但是保护管理抵消了负面趋势。重要的是，基于社区的半保护土地共享保护提供了清晰，部分的缓冲，以防止退化。在基于社区的保护下处于中等水平，在完全保护下处于最高水平。我们的结果表明，马拉生态系统承受着沉重的压力，但是保护管理抵消了负面趋势。重要的是，基于社区的半保护土地共享保护提供了清晰，部分的缓冲，以防止退化。