Landscape vulnerability assessment driven by drought and precipitation anomalies in sub-Saharan Africa

Abstract

Global climate extremes are increasingly frequent and intense, especially in Africa, which is most vulnerable to climate change (de Sherbinin 2013 Clim. Change 123 23-37). However, the vulnerability of the landscapes composed of diverse ecosystems to climate extremes is far from being clearly understood. This study constructed a set of index systems based on the 'exposure-sensitivity-adaptive capacity' framework to assess landscape vulnerability driven by abnormal drought and precipitation in sub-Saharan Africa. In addition, correlation analysis was used to discover factors affecting landscape vulnerability. The results showed that a high level of landscape vulnerability was determined by high exposure and high sensitivity, as adaptive capacity exhibited little difference. The drought and wet events occurred in 80.9% and 51.3% of the climate change-dominated areas during 2001-2020, respectively. In areas where drought anomalies occur, about 8% of the landscapes, primarily formed by sparse vegetation and grasslands, were susceptible to drought. Moreover, in areas with abnormal precipitation, high vulnerability occurred only in about 0.6% of landscapes mostly covered by grasslands and shrubs. In addition, the intensity of landscape vulnerability driven by drought was higher than that driven by precipitation anomalies in the areas that experienced both dry and wet anomalies. Furthermore, the greater the deviation of landscape richness, diversity, and evenness from the normal climate state, the stronger the landscape vulnerability. The results add new evidence for landscape instabilities - an obvious contrast driven by drought and wetness - from the perspective of landscape vulnerability. The methodology of assessing landscape vulnerability established in this study can provide a new way to guide the regulation of landscape composition in response to frequent climate extremes on a macro level.