Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ, USA.
Station Biologique de Roscoff, UMR 7144 CNRS-Sorbonne Université, Roscoff, France.
Nat Ecol Evol. 2020 May;4(5):712-724. doi: 10.1038/s41559-019-1068-y. Epub 2020 Jan 13.
Trophic rewilding seeks to rehabilitate degraded ecosystems by repopulating them with large animals, thereby re-establishing strong top-down interactions. Yet there are very few tests of whether such initiatives can restore ecosystem structure and functions, and on what timescales. Here we show that war-induced collapse of large-mammal populations in Mozambique's Gorongosa National Park exacerbated woody encroachment by the invasive shrub Mimosa pigra-considered one of the world's 100 worst invasive species-and that one decade of concerted trophic rewilding restored this invasion to pre-war baseline levels. Mimosa occurrence increased between 1972 and 2015, a period encompassing the near extirpation of large herbivores during the Mozambican Civil War. From 2015 to 2019, mimosa abundance declined as ungulate biomass recovered. DNA metabarcoding revealed that ruminant herbivores fed heavily on mimosa, and experimental exclosures confirmed the causal role of mammalian herbivory in containing shrub encroachment. Our results provide mechanistic evidence that trophic rewilding has rapidly revived a key ecosystem function (biotic resistance to a notorious woody invader), underscoring the potential for restoring ecological health in degraded protected areas.
trophic rewilding 旨在通过重新引入大型动物来恢复退化的生态系统，从而重新建立强大的自上而下的相互作用。然而，很少有研究测试这些举措是否能够恢复生态系统的结构和功能，以及需要多长时间。在这里，我们表明，莫桑比克戈龙戈萨国家公园因战争导致的大型哺乳动物种群崩溃加剧了入侵灌木含羞草的木质化入侵——被认为是世界上 100 种最具入侵性的物种之一——而十年的协同 trophic rewilding 将这种入侵恢复到了战前的基线水平。含羞草的出现从 1972 年到 2015 年增加了，这一时期包括莫桑比克内战期间大型食草动物几乎灭绝。从 2015 年到 2019 年，随着有蹄类动物生物量的恢复，含羞草的丰度下降。DNA metabarcoding 显示反刍动物食草动物大量食用含羞草，实验围栏证实了哺乳动物食草作用在控制灌木入侵方面的因果关系。我们的研究结果提供了机制证据，表明 trophic rewilding 已经迅速恢复了一个关键的生态系统功能（对臭名昭著的木质入侵生物的生物抗性），这突显了在退化的保护区恢复生态健康的潜力。
