Environmental variation and population responses to global change

Abstract

Species' responses to environmental changes such as global warming are affected not only by trends in mean conditions, but also by natural and human-induced environmental fluctuations. Methods are needed to predict how such environmental variation affects ecological and evolutionary processes, in order to design effective strategies to conserve biodiversity under global change. Here, we review recent theoretical and empirical studies to assess: (1) how populations respond to changes in environmental variance, and (2) how environmental variance affects population responses to changes in mean conditions. Contrary to frequent claims, empirical studies show that increases in environmental variance can increase as well as decrease long-term population growth rates. Moreover, environmental variance can alter and even reverse the effects of changes in the mean environment, such that even if environmental variance remains constant, omitting it from population models compromises their ability to predict species' responses to changes in mean conditions. Drawing on theory relating these effects of environmental variance to the curvatures of population growth responses to the environment, we outline how species' traits such as phylogenetic history and body mass could be used to predict their responses to global change under future environmental variability.

Predicting population viability of the narrow endemic Mediterranean plant Centaurea corymbosa under climate change

“…Such results are consistent with the GLMs 484 showing negative impacts of warming and drought, and several studies investigating population 485 viability in response to climate change (Andrello et al, 2012;Lawson et al, 2015;Marrero-Gómez 486 et al, 2007;Shryock et al, 2014). More importantly, the warm scenario had more severe 487 consequences on population viability than the dry scenario whatever the initial population size.…”

Identifying the best climatic predictors in ecology and evolution

“…thermal performance curves; Angilletta 2009) and the fact that threshold values are regularly used as an aggregate statistic emphasizes that the responses of traits to weather signals can be nonlinear. Sometimes the shape of the response curve may even be of interest in itself: the effects of environmental variability on population dynamics may depend on the curvature of the response of demographic or population growth rates to weather (Lawson et al 2015).…”

Behavioural, ecological and evolutionary responses to extreme climatic events: challenges and directions

“…Specifically, it has been argued that changes in climatic extremes are having a stronger impact on ecology [10] and evolution [11] than changes in climate means, and a similar discussion exists about the population dynamical impact of changes in climatic means and variability [28,33]. Such issues are important because the bulk of the biological research focuses on changes in climate means, while the effects of extremes and variability are often not studied, but could be crucial for making reliable predictions and an integrative understanding of impacts of climate change [33].…”

“…[57]) and ecological processes (e.g. [28]). Whether a strong context-dependence is a characteristic property of response to ECEs remains to be determined, as responses to other aspects of climate or environmental change are often also highly idiosyncratic [62].…”