Instituto Multidisciplinar para el Estudio del Medio "Ramón Margalef," Universidad de Alicante, 03690 San Vicente del Raspeig, Alicante, Spain.
Institut de Biología Evolutiva (UPF-CSIC), 08003 Barcelona, Spain.
Science. 2020 Feb 14;367(6479):787-790. doi: 10.1126/science.aay5958.
Aridity, which is increasing worldwide because of climate change, affects the structure and functioning of dryland ecosystems. Whether aridification leads to gradual (versus abrupt) and systemic (versus specific) ecosystem changes is largely unknown. We investigated how 20 structural and functional ecosystem attributes respond to aridity in global drylands. Aridification led to systemic and abrupt changes in multiple ecosystem attributes. These changes occurred sequentially in three phases characterized by abrupt decays in plant productivity, soil fertility, and plant cover and richness at aridity values of 0.54, 0.7, and 0.8, respectively. More than 20% of the terrestrial surface will cross one or several of these thresholds by 2100, which calls for immediate actions to minimize the negative impacts of aridification on essential ecosystem services for the more than 2 billion people living in drylands.
由于气候变化，全球干旱地区正在变得更加干燥。干旱化影响了旱地生态系统的结构和功能。干旱化是否会导致逐渐（而非突然）和系统（而非特定）的生态系统变化，在很大程度上尚不清楚。我们研究了全球旱地中 20 种结构和功能生态系统属性如何对干旱化做出响应。干旱化导致了多种生态系统属性的系统和突然变化。这些变化在三个阶段中依次发生，其特征分别为：在干旱值分别为 0.54、0.7 和 0.8 时，植物生产力、土壤肥力和植物覆盖度和丰富度突然下降；到 2100 年，超过 20%的陆地表面将跨越其中一个或多个阈值，这要求立即采取行动，将干旱化对生活在旱地中的 20 多亿人所依赖的基本生态系统服务的负面影响降到最低。
