Evolutionary processes, not environmental drivers, determine the resilience of natural populations

Abstract

Escalating climatic and anthropogenic pressures expose ecosystems worldwide to increasingly frequent disturbances. Yet, our ability to forecast the responses of natural populations to these disturbances is impeded by a limited understanding for how exposure to stochastic environments shapes population resilience. Instead, the resilience, and vulnerability, of natural populations to ongoing global change is often presumed based on their contemporary exposure to environmental stochasticity. To test the validity of this assumption, we investigated the association between the resilience attributes (e.g., resistance and recovery) of natural animal and plant populations, and measures of local environmental stochasticity (e.g., spectral frequency and abiotic range); collating data from 2,242 populations across 369 animal, plant, and algal species. Unexpectedly, recent abiotic stochasticity regimes from the past 50 years do not predict the inherent ability of populations to resist or recover from disturbances. Instead, population resilience is strongly affected by phylogenetic relationships among species, with survival and developmental investments shaping their responses to stochastic regimes. Contrary to the classical assumption that exposure to recent environmental shifts confers a greater ability to cope with current and future global change, our findings suggest that population resilience is a consequence of evolutionary processes and/or deep-time environmental regimes. Significance statementPopulations that currently endure more variable abiotic conditions are often expected to be less vulnerable to future increases in climatic variability. However, without defining the link between abiotic variability and the capacity for populations to resist and recover following disturbances (i.e., their resilience), we cannot predict the consequences of ongoing community reassembly. Evaluating the association between measures of abiotic variability and the resilience attributes of 2,242 animal, plant, and algae populations, we discredit the assumption that contemporary exposure to more frequent environmental shifts confers a greater ability to cope with future global change. Instead, the resilience attributes of natural populations appear to have been moulded over longer-term evolutionary timeframes and are thus not a response to more recent experiences.