Population dynamics can be more important than physiological limits for determining range shifts under climate change

Abstract

Evidence is accumulating that species' responses to climate changes are best predicted by modelling the interaction of physiological limits, biotic processes and the effects of dispersal-limitation. Using commercially harvested blacklip (Haliotis rubra) and greenlip abalone (Haliotis laevigata) as case studies, we determine the relative importance of accounting for interactions among physiology, metapopulation dynamics and exploitation in predictions of range (geographical occupancy) and abundance (spatially explicit density) under various climate change scenarios. Traditional correlative ecological niche models (ENM) predict that climate change will benefit the commercial exploitation of abalone by promoting increased abundances without any reduction in range size. However, models that account simultaneously for demographic processes and physiological responses to climate-related factors result in future (and present) estimates of area of occupancy (AOO) and abundance that differ from those generated by ENMs alone. Range expansion and population growth are unlikely for blacklip abalone because of important interactions between climate-dependent mortality and metapopulation processes; in contrast, greenlip abalone should increase in abundance despite a contraction in AOO. The strongly non-linear relationship between abalone population size and AOO has important ramifications for the use of ENM predictions that rely on metrics describing change in habitat area as proxies for extinction risk. These results show that predicting species' responses to climate change often require physiological information to understand climatic range determinants, and a metapopulation model that can make full use of this data to more realistically account for processes such as local extirpation, demographic rescue, source-sink dynamics and dispersal-limitation.

Macroevolutionary consequences of profound climate change on niche evolution in marine molluscs over the past three million years

“…In particular, our results may somewhat alleviate concerns over inaccurate forecasts due to changing niches [1,3]. Problems still remain, however, in that ENM and SDM methods typically do not account for dispersal limitations or altered biotic interactions [87] (though see [85]); nor do they consider that species can alter their behaviour or microhabitat preferences to buffer against environmental changes [2,88]. We show that large-scale parameters of species' niches, in this case temperature and salinity, do not change for a phylogenetically and ecologically diverse set of marine molluscs.…”

Thermal Characterization of European Ant Communities Along Thermal Gradients and Its Implications for Community Resilience to Temperature Variability

“…First, we used species occurrence data, but perhaps abundance data would have been better, especially if the values of the community thermal indices are heavily influenced by the presence of rare species. The latter may go extinct in response to climate change simply because they are already in sink habitats (Fordham et al, 2013). However, there was no indication that this was a problem in our study; the patterns we found in the community thermal indices along the thermal gradients were strong and significant.…”

Beyond long-term averages: making biological sense of a rapidly changing world

“…In other words, we can now focus on communities and populations rather than species [30,74]. While such an approach is likely not appropriate for all applications, it may be particularly relevant for examination of particular species of interest such as threatened and/or endangered species [75], commercially important species [76,77], disease-causing organisms [78], and keystone or structuring species that have cascading effects on ecosystems [79].…”