Assessing the resilience of natural and anthropogenic vegetation to droughts in Argentina through remote sensing data

Human-induced climate change has increased climate system instability, making droughts more frequent and intense. Vegetation response to drought is commonly assessed through the lens of ecosystem resilience, quantified by resistance and recovery. This study addresses the lack of long-term, high-resolution assessments of ecosystem resilience to drought and dry events at a country-level scale. The general objective of this study is to evaluate long-term variations of aboveground net primary productivity (ANPP; using enhanced vegetation index (EVI) as a proxy) through ecosystem resilience measurements across diverse natural and anthropogenic vegetation covers in Argentina, in response to droughts during the 2001–2024 period. While all the analyzed vegetations were sensitive to water deficits, the anthropogenic covers exhibited notably more variable resistance than their natural counterparts. Among natural classes, shrubs and herbaceous cover exhibited the highest drought resistance, while grasslands and flooded grasslands manifested the lowest resistance, highest variability, and shortest recovery. Conversely, among anthropogenic classes, temporary crops and pastures recorded the lowest resistance, and pastures presented the longer recovery. Natural cover drought resistance exhibited a similar distribution of drought intensities across classes, whereas anthropogenic covers showed a more dissimilar distribution, manifesting larger variations in EVI drops as drought intensity increased. In contrast to drought resistance, resistance during dry events was less variable across all covers, with consistently higher EVI values that occasionally reached positive levels, particularly for flooded grasslands. Regarding recovery time, forest plantations recovered faster but were more sensitive to more intense droughts than natural covers. Natural woody ecosystems exhibited the highest resistance and variable recovery. Spatial distribution of resistances and recoveries showed no clear pattern. This research demonstrates that, as climate instability increases, maintaining the structural complexity of natural vegetation is a critical requirement to avoid irreversible losses of key ecological processes and sustain the provision of ecosystem services.