[LUM#12] Diversity as a means of adaptation

[LUM Magazine] - Published on June 25, 2020 in Environmental Issues and Social Responsibility, Science-Society

Genetic diversity reduces the risk of population extinction in the face of global warming. This has been demonstrated by a team of researchers who studied the genome of bats in order to better predict their future as temperatures rise. These findings open up new avenues for better species conservation.

How will different animal species react to climate change? "Some scenarios suggest that animals will simply migrate northward as temperatures rise, in search of more favorable conditions," explains Sébastien Puechmaille. This model is described as "naive" by the chiropterologist fromthe Institute of Evolutionary Sciences in Montpellier (ISEM).

"It's not that simple; many animals actually move very little. This is the case, for example, with the lesser horseshoe bat, a species of bat that has been shown to move less quickly than global warming." As for those that manage to keep up, their destination must still meet their needs , particularly in terms of food. "Many bats are insectivorous, so if the prey they feed on has not followed this new distribution, then the conditions for their survival are not met. This is what we call a mismatch ."

Resist the heat

"If we want to model the future of populations in the face of global warming, we can't just take temperature and humidity into account; there are actually many parameters to consider." One of these, which until now has been the subject of little study, is genetic diversity. "It's about considering the variability of populations within the same species, " explains the chiropterologist. For example, within the same bat population, some individuals are genetically better adapted to withstand heat or cold.

To understand this parameter, Sébastien Puechmaille and his colleagues developed a new approach: they incorporated genetic adaptation potential into models that predict changes in a species' range in response to climate change. To do this, the researchers analyzed genomic data from two species of bats native to the Mediterranean, a region particularly affected by rising temperatures.

Forest corridors

"DNA analysis of 278 bats has made it possible to identify and differentiate individuals that are adapted to thrive in hot, dry habitats from those adapted to colder, wetter habitats," explains the researcher.
This diversity is important to consider because this potential for genetic adaptation gives these individuals a better chance of survival when temperatures rise or droughts occur. Indeed, in the event of rising temperatures, populations of individuals adapted to colder and wetter habitats will decline, unless they receive individuals from populations adapted to hot and dry habitats who will bring with them the genetic diversity necessary for adaptation, thereby reducing the risk of extinction.

However, bats from different habitats must be able to reach each other. "These species live in forests and require forest corridors to move from one area to another," explains Sébastien Puechmaille. If the forest cover is favorable for bat movement, there is good connectivity between populations, which maximizes the arrival of adapted individuals and promotes population survival compared to what is predicted by conventional models that do not include this parameter."

Preserving the habitat

These findings may lead to more accurate predictions of the effects of global warming, but they also encourage us to rethink conservation strategies. "In addition to the fact that there are geographical barriers limiting movement, such as the Pyrenees and the Alps, politicians have so far very rarely taken into account the importance of these forest corridors on a national or even continental scale. The habitat of these species is therefore fragmented overall, which hinders the movement of individuals, " explains the researcher. "It is essential to preserve habitat to ensure the survival of species in the face of climate change, and to do so we need to think on a large scale; it is not just local management that is required, but international management."

This is a key issue for the future of these small flying mammals, whose populations already declined dramatically after World War II, "largely due to the use of pesticides and changes in agricultural practices." There are currently 1,400 species of bats worldwide, and some species are already considered extinct.

Keywords: Climate, Environment, LUM#12, LUM Magazine, Research, Company