A tradeoff between robustness to environmental fluctuations and speed of evolution

Abstract

Organisms must cope with both short-and long-term environmental changes to persist. In this study we investigated theoretically if life histories trade off between their robustness to short-term environmental perturbations and their ability to evolve directional trait changes. By the use of mathematical models and stochastic individual-based simulations we could confirm the tradeoff, at least for comparisons between standardized life histories. Offspring dormancy and high adult survival allowed to maintain large population sizes when confronted with interannual environmental fluctuations while depressing the speed of evolution with ongoing environmental change. Instead, precocious offspring maturation and short-living adults promoted evolvability while lowering robustness. This tradeoff had immediate consequences for extinction dynamics in variable environments. High evolvability allowed to cope best with long-lasting gradual environmental change, but came at the expense of more pronounced population declines from environmental variability and during the initial phase of environmental change.

Plasticity’s role in adaptive evolution depends on environmental change components

“…Such impacts of population size depend on life history strategies; for example, long-lived species can persist longer at small population sizes than short-lived species, whose populations can collapse quickly [54,55]. Furthermore, these strategies can determine the rate of trait evolution [8]. It is therefore vital to consider the impact of different environmental components on population dynamics and life history to understand the impact of the type of environmental change on the interplay between plasticity and adaptive evolution.…”

“…In the face of unprecedented environmental change (see Glossary), natural populations, especially those with limited mobility/dispersal, can avoid extinction via phenotypic plasticity and/or adaptive evolution [4]. However, our understanding of the interplay between adaptive evolution and plasticity in changing environments remains limited [1,[5][6][7][8]. This limitation is not trivial, for plasticity can itself evolve [9], be adaptive, or nonadaptive [10], and have differing effects on adaptive evolution [11,12].…”