Dead shrub patches as ecosystem engineers in degraded drylands  

枯死灌木斑块对退化旱地生态系统的调节作用

作　　者：Ilan STAVI Eli ZAADY Alexander GUSAROV Hezi YIZHAQ 

机构地区：[1]Dead Sea and Arava Science Center,Yotvata 88820,Israel [2]Eilat Campus,Ben-Gurion University of the Negev,Eilat 88100,Israel [3]Department of Natural Resources,Agricultural Research Organization,Gilat Research Center,85280 Negev,Israel [4]Department of Solar Energy and Environmental Physics,Blaustein Institutes for Desert Research,Ben-Gurion University of the Negev,Sede Boqer Campus 84990,Israel

出　　处：《Journal of Geographical Sciences》2021年第8期1187-1204,共18页地理学报（英文版）

基　　金：funded by the Israel Science Foundation(ISF),grant number 1260/15。

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 productivity.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 highlights the complex and unpredicted impacts of prolonged droughts on dryland ecosystems.

关 键 词：allogenic ecosystem engineers climate change legacy mechanism patchy vegetation small-scale geodiversity vegetation transition 

分 类 号：X171.1[环境科学与工程—环境科学]