Disturbance legacies in arid environments shape recovery of former agricultural land

Introduction Increasingly, arid agricultural land is being permanently taken out of irrigated production due to more frequent drought, higher temperatures, and the overconsumption of groundwater, with important ramifications for ecological recovery.Objectives We aimed to study the consequences of intensive cultivation in an arid climate, which are less understood relative to more temperate areas.Methods We investigated a chronosequence of time-since-cultivation of former agricultural sites in the Colorado Desert in the Southwestern United States to assess the recovery of the vegetation community and soil characteristics and to identify key environmental drivers that shape this process.Results Recovery timescales varied widely for different variables; soil salinity was estimated to recover to a non-saline level within approximately 22 years, while native species richness could require an estimated 130 years to approach reference conditions. The primary drivers of recovery included a decline in soil salinity and a corresponding decline in non-native species richness, and the influence of episodic water flow, which enhanced landscape complexity.Conclusions These findings emphasize the slow pace of natural recovery in arid systems and the benefit of active restoration to overcome persistent abiotic barriers on former agricultural land to hasten recovery.