Early warning signals detect critical impacts of experimental warming

Abstract

Earth's surface temperatures are projected to increase by ~1–4°C over the next century, threatening the future of global biodiversity and ecosystem stability. While this has fueled major progress in the field of physiological trait responses to warming, it is currently unclear whether routine population monitoring data can be used to predict temperature‐induced population collapse. Here, we integrate trait performance theory with that of critical tipping points to test whether early warning signals can be reliably used to anticipate thermally induced extinction events. We find that a model parameterized by experimental growth rates exhibits critical slowing down in the vicinity of an experimentally tested critical threshold, suggesting that dynamical early warning signals may be useful in detecting the potentially precipitous onset of population collapse due to global climate change.

Temperature triggers a non‐linear response in resource–consumer interaction strength

“…Indeed, previous laboratory trials suggest that D. magna have a thermal optimum around 20°C (Giebelhausen and Lampert 2001), similar to that for the green algal species used in this study (Jarvis et al 2016). Our theoretical model suggests that this would be expected if the thermal optima for both consumers and resources were similar.…”

“…Our goal was to investigate how temperature might influence interaction strength when the thermal performance curve for the consumer peaks at a lower, identical, or higher temperature than that of its resource, which were determined based on previous publications (Dell et al 2011, Jarvis et al 2016; see also Introduction). Our goal was to investigate how temperature might influence interaction strength when the thermal performance curve for the consumer peaks at a lower, identical, or higher temperature than that of its resource, which were determined based on previous publications (Dell et al 2011, Jarvis et al 2016; see also Introduction).…”

“…This could happen because thermal performance curves, which are determined by metabolic rate, are often a dome-shaped function of ambient temperature , Sibly et al 2012). This domeshaped form has been empirically demonstrated for several key traits that mediate species interactions, including resource growth rates and feeding rates of many consumers in aquatic and terrestrial system , Knies and Kingsolver 2010, Dell et al 2011, Englund et al 2011, Fey and Cottingham 2012, West and Post 2016, Jarvis et al 2016). In addition, the position and shape of such curves vary across species (Dell et al 2011, Schulte et al 2011, and changes in temperature might have different effects for consumers than it does for their resources , Ohlberger 2013, Dell et al 2014.…”

Moving forward: insights and applications of moving‐habitat models for climate change ecology

“…For populations with density‐dependent growth, it is necessary to fit parameters that describe depensation (Berec & Mrkvička ), compensation (Brown, Downing & Leibold ) or overcompensation (Jarvis et al . ) (see Fig. , column 2 for examples).…”

“…For some populations, with little or no density dependence, the growth function is simply the product of a constant net reproductive rate and the number of females. For populations with density-dependent growth, it is necessary to fit parameters that describe depensation (Berec & Mrkvi cka 2013), compensation (Brown, Downing & Leibold 2016) or overcompensation (Jarvis et al 2016) (see Fig. 1, column 2 for examples).…”