Dead shrub patches as ecosystem engineers in degraded drylands

• 作者: Ilan STAVI Eli ZAADY Alexander GUSAROV Hezi YIZHAQ
• 来源期刊: 地理学报（英文版）
• 年，卷（期）: 2021,（8）
• 所属期刊栏目: Regular Articles
• 页码范围: 1187-1204
• 页数: 18页
• 语种: 英文
• DOI: 10.1007/s11442-021-1892-2

摘要

A long-term drought has led to the mass mortality of shrubs in the semi-arid Israeli Negev.The most impacted shrub species is the Noaea mucronata (Forssk.) Asch.and Schweinf.In a four-year study,we found that herbaceous vegetation growth was greater in the dead shrub patches than in the surrounding inter-patch biocrusted spaces,suggesting that the dead shrub patches encompass improved micro-habitats.However,unexpectedly,the soil moisture in the dead shrub patches was consistently lower than that of the inter-patch biocrusted spaces.At the same time,soil quality in the dead shrub patches was higher than that in the inter-patch spaces.Therefore,it seems that the overall better soil conditions in the dead patches overcome the scarcity of soil-water,supporting increased herbaceous produc-tivity.For explaining the discrepancy between herbaceous vegetation and soil-water,we formulated a conceptual framework,which highlights the key factors that regulate soil-water dynamics in this dryland ecosystem.We demonstrate that herbaceous vegetation is facilitated in the dead shrub patches by a legacy effect that takes place long after the shrubs have died.The dead shrub patches encompass a unique form of ecosystem engineering.The study high-lights the complex and unpredicted impacts of prolonged droughts on dryland ecosystems.