Around 40% of the species of small mammals analyzed worldwide are associated with a specific climate zone, according to a new study based on more than 4,200 species. Published in Nature Communications, the work involves the participation of Neftalí Sillero, a researcher at the Faculty of Sciences of the University of Porto (FCUP), and Iván Rey-Rodríguez, a researcher from the University of Vigo, who spent a year integrated into the FCUP Spatial Biology Lab.
The idea for this investigation emerged from a frequent observation in small mammals: they are animals closely tied to climatic and environmental conditions and, therefore, potentially sensitive to their changes.
“We wanted to test this idea at a global level: to check to what extent small mammals are really climate specialists and to see whether this specialization is related to their evolutionary history and diversification patterns,” explains Neftalí Sillero, a researcher in the Spatial Biology Lab specializing in the modeling and distribution of species.
In total, the scientists analyzed 4,231 species belonging to four groups: Chiroptera (bats), Eulipotyphla (moles, hedgehogs), Lagomorpha (rabbits and hares) and Rodentia (rats). Among the most common examples found in Portugal are, for example, the mole, the hare, the rabbit and the field mouse.
The authors of the study verified that four in ten of these species are climate specialists, i.e., they are restricted to one of the five main climate zones (tropical, dry, temperate, continental and polar). They also concluded that half of these are climate super-specialists, restricted to one of the 30 subclimatic zones.
Climate specialization occurs in all four groups studied, but is particularly frequent among rodents and is mainly associated with tropical, temperate and arid climates.
However, greater climatic specialization could, nevertheless, represent greater vulnerability to rapid changes in environmental conditions, a hypothesis that the team, which includes seven additional researchers from the University of Vigo, now intends to test.
“A climatically specialized species occupies a narrower range of climatic conditions than a generalist and, therefore, may have a reduced capacity to respond to rapid changes in those conditions,” reinforces Iván Rey-Rodríguez, the lead author of the study.
The results also show that climate specialization is strongly associated with the diversification of some lineages of small mammals. However, lineages with greater climatic specialization are not necessarily those with greater species richness. The age of the families proved an important factor: the older families tend to accumulate more species over time.
As next steps, the researchers’ aim is to determine whether vulnerability to climate change in these species also varies among groups or regions.
In this investigation, the scientists look not only to the future but also to the past of these species. “Small mammals have been used for decades to reconstruct past environments and climates, so we can study how their climate specialization and the composition of their communities responded to the major climatic changes of the Quaternary,” notes Neftalí Sillero.
By linking past, present and future, the study contributes to a better understanding of how climate has conditioned the diversity of small mammals throughout their evolutionary history and how changes in climatic conditions may influence these species in the coming decades.
