Heat tolerance highly variable among populations and species

14 01 2020

Many ecological studies have examined the tolerance of terrestrial wildlife to high and low air temperatures over global scales (e.g., 1, 2, 3). This topic has been boosted in the last two decades by ongoing and predicted impacts of climate change on biodiversity (see summary of 2019 United Nation’s report here and here).

However, it is unfortunate that for most species, studies have measured thermal tolerance from a single location or population. Researchers interested in global patterns of thermal stress collect those measurements from the literature for hundreds to thousands of species [recently compiled in the GlobTherm database] (4), and are therefore often restricted to analysing one value of thermal tolerance per species.

CB_FunctionalEcology_jan2020_Photo

Three of the 15 species of Iberian lacertids sampled in our study of thermal tolerance (9), including the populations of Algerian psammodromus (Psammodromus algirus), Geniez’s wall lizard (Podarcis virescens) and Western green lizard (Lacerta bilineata) sampled in Navacerrada (Madrid), Fuertescusa (Cuenca) and Moncayo (Soria), respectively. Photos by S. Herrando-Pérez

Using this approach, ecologists have concluded that cold tolerance is far more variable than heat tolerance across species from the tropics to the boreal zone (5-8). Consequently, tolerance to heat stress might be a species trait with limited potential to change in response to global warming compared to cold tolerance (5). Read the rest of this entry »