Sensitivity of global pasturelands to climate variation

Abstract

Pasturelands are globally extensive, sensitive to climate, and support livestock production systems that provide an essential source of food in many parts of the world. In this paper, we integrate information from remote sensing, global climate, and land use databases to improve understanding of the resilience and resistance of this ecologically vulnerable and societally-critical land use. To characterize the effect of climate on pastureland productivity, we analyze the relationship between satellite-derived vegetation index and gridded precipitation datasets at 1 to 6-month time lags. To account for the effects of different production systems, we stratify our analysis by agroecological zone and by rangeland-based versus mixed crop-livestock system. Results show that 14.5% of global pasturelands experienced statistically significant greening or browning trends over the 15-year study period, with the majority of these locations showing greening. In arid ecosystems, precipitation and lagged vegetation index anomalies explain up to 69% of variation in vegetation productivity in both crop-livestock and rangeland-based production systems. Livestock production systems in Australia are least resistant to contemporaneous and short-term precipitation anomalies, while arid livestock production systems in Latin America are least resilient to short-term vegetation greenness anomalies. More generally, large swaths of semi-arid global pasturelands show substantial sensitivity to variation in precipitation, and hence, are vulnerable to climate change. Because many arid regions of the world are projected to experience decreased total precipitation and increased precipitation variability in the coming decades, improved understanding regarding the sensitivity of pasturelands to the joint effects of climate change and production system is required to support sustainable land management in global pasturelands.