Extreme climatic events change the dynamics and invasibility of semi-arid annual plant communities

TLDR

Extreme climatic events are disturbances that alter resource availability in ecosystems. The study investigates how extreme climatic events influence annual plant assemblages in a semi‑arid Chilean ecosystem and the implications of climate change and biological invasions for future community dynamics. Researchers analyzed 130 years of precipitation using a generalized extreme‑value distribution to identify extreme events and applied multivariate techniques to 20 years of plant cover data from 34 native and 11 exotic species. Extreme drought resets community dynamics and increases susceptibility to invasion, whereas moderately wet events favor native annuals and enhance resilience, and the probability of extreme drought has doubled over the last 50 years.

Abstract

Ecology Letters (2011) 14: 1227–1235 Abstract Extreme climatic events represent disturbances that change the availability of resources. We studied their effects on annual plant assemblages in a semi-arid ecosystem in north-central Chile. We analysed 130 years of precipitation data using generalised extreme-value distribution to determine extreme events, and multivariate techniques to analyse 20 years of plant cover data of 34 native and 11 exotic species. Extreme drought resets the dynamics of the system and renders it susceptible to invasion. On the other hand, by favouring native annuals, moderately wet events change species composition and allow the community to be resilient to extreme drought. The probability of extreme drought has doubled over the last 50 years. Therefore, investigations on the interaction of climate change and biological invasions are relevant to determine the potential for future effects on the dynamics of semi-arid annual plant communities.