Ecological limits to evolutionary rescue

Abstract

Environments change, for both natural and anthropogenic reasons, which can threaten species persistence. Evolutionary adaptation is a potentially powerful mechanism to allow species to persist in these changing environments. To determine the conditions under which adaptation will prevent extinction (evolutionary rescue), classic quantitative genetics models have assumed a constantly changing environment. They predict that species traits will track a moving environmental optimum with a lag that approaches a constant. If fitness is negative at this lag, the species will go extinct. There have been many elaborations of these models incorporating increased genetic realism. Here, we review and explore the consequences of four ecological complications: non-quadratic fitness functions, interacting density- and trait-dependence, species interactions and fundamental limits to adaptation. We show that non-quadratic fitness functions can result in evolutionary tipping points and existential crises, as can the interaction between density- and trait-dependent mortality. We then review the literature on how interspecific interactions affect adaptation and persistence. Finally, we suggest an alternative theoretical framework that considers bounded environmental change and fundamental limits to adaptation. A research programme that combines theory and experiments and integrates across organizational scales will be needed to predict whether adaptation will prevent species extinction in changing environments. This article is part of the theme issue ‘Integrative research perspectives on marine conservation’.

Integrative research perspectives on marine conservation

“…More generally, Bernhardt et al [59] conceptualize the ability of organisms to cope with such variability, and complement the feedback strategies, where organisms respond to changes in conditions by feed-forward mechanisms, where they adjust to anticipated future changes in conditions via sensing the environment. Klausmeier et al [60] then ask how evolutionary adaptation to changing conditions can occur and whether it can be fast enough to prevent extinction. They review different approaches to modelling evolutionary rescue, and finally propose a new approach that explicitly includes bounded environmental changes and limits to adaptation.…”

Evolution reverses the effect of network structure on metapopulation persistence

“…In general, trait‐based eco‐evolutionary models typically assume that maximum growth is a unimodal function of trait, which is satisfied by both Gaussian and quadratic functions. We note that while the exact shapes of fitness functions remain largely unknown (Klausmeier et al 2020 , Osmond and Klausmeier 2017 ), both types explored here can locally approximate any smooth, general fitness function (Shaw and Geyer 2010 ).…”

Evolutionary rescue in one dimensional stepping stone models

“…We do not expect our model to be predictive for organisms reproducing with low recombination rates if multiple rescue mutations are required for restoring positive growth rates, as we neglected competition between beneficial mutations [Gerrish and Lenski, 1998] or competition in other ecological contexts (e.g. Osmond and de Mazancourt [2013], Klausmeier et al [2020]). It has also been shown that the shape of the distribution of fitness effects as well as the recombination rate between loci harbouring rescue mutations can play an important role [Uecker and Hermisson, 2016, Anciaux et al, 2018.…”