Not all terrestrial mammals are resisting the climate crisis in the same way

A study, conducted by Spanish scientists, shows that the relationship between evolution and climate change depends on the ecological specialization of animals. The most generalists are more resistant to alterations, while the specialists are very affected. It is the first work to include all species of terrestrial mammals, more than 5,000.

The ability to inhabit many environments – generalist – or low – specialist species – is the most important factor in the adaptation of the different families of terrestrial mammals and their evolution in the face of the effects of climate change, according to international research carried out by the Complutense University of Madrid (UCM).

The study, published in the journal Story Biology, part of paleontologist Elisabeth S. Vrba’s 1980s hypothesis of the environmental specialization of species as crucial to understanding species evolution and diversification.

We have already analyzed some groups in previous work, but this is the first time that we have included information on all terrestrial mammal species, over 5,000 in 153 families, to examine this question.», points out Manuel Hernández Fernández, researcher at the Department of Geodynamics, Stratigraphy and Palaeontology of the UCM and the IGEO.

Species, such as generalists, capable of occupying different biomes, i.e. large ecological units defined by their environmental conditions, experience less alterations due to climate change, since they are able to take advantage of resources of different origins, and may remain unchanged for long periods of time.

For their part, species, such as specialists, which can only live in a single biome are strongly affected by climate change, which can fragment their populations and will further diversify.

If this fragmentation is maintained long enough for gene flow to be interrupted between them, it can result in the differentiation of a different species in each of these population fragments. This results in an overabundance of specialized species compared to generalists.», explains Hernández Fernández.

However, he adds, this greater capacity for diversification comes at the cost of greater vulnerability to climate change.


Extreme biomes, more conducive to diversification

To carry out the study, distribution data was collected for each species, taking into account the biomes they inhabit. This made it possible, in addition to corroborating the hypothesis, to establish that certain biomes represent places that are particularly favorable to the diversification of specialist species.

These would be the biomes located in the climatic extremes of our planet, which undergo the greatest alterations due to variations in the Earth’s climate.“, indicates the paleontologist of the UCM, which lists them: “equatorial rainforests (extremely hot-humid), subtropical deserts (hot-dry), steppes (cold-dry) and tundra (cold-humid)”.

A large variability was also observed between the different families and biomes, associated with their environmental heterogeneity, as well as the evolutionary history and physiological differences of each family, which condition the ability of their species to survive or colonize a new biome.

Indeed, besides ecological specialization, the diversification processes associated with climate change must also be affected by other factors, which we are still far from fully understanding.adds Emilia Galli, co-author of the book and also a researcher at UCM.


Hernandez Fernandez, M., et al. (2022) “Macroevolution and Climate Change: A Global Multifamily Test Supports the Terrestrial Mammal Resource Utilization Hypothesis”. Historical biology: DOI 10.1080/08912963.2022.2042807.


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