THE fossils they are like an open window onto the past: studying them allows us to understand theevolution and the succession of different animal species, to reconstruct the landscapes that characterized our planet millions and millions of years ago. Not only. Looking to the past is also useful in some way foresee the future, and more particularly the possible future of the species currently existing. With a study published in ScienceIn fact, a group of researchers analyzed more than 290 thousand fossils of marine invertebrates – such as sea urchins, snails and molluscs – to try to better understand which factors make animals more vulnerable to the risk of extinction linked in particular to climate change. One aspect that seems to particularly expose them to the risk of extinction is the fact of live in very narrow geographic regions.
I study
The authors of the research, led by Cooper Malanoski and Erin Saupe, respectively researcher and professor of paleobiology at the University of Oxford (UK), examined more than 290 thousand fossils of marine invertebrates, altogether belonging to over 9 thousand genera different and dating back to the latest 485 million years. Starting from this enormous amount of documentation, extracted from the Paleobiology Database, the researchers attempted to determine the set of key traits that may have an influence on the resilience of different species toextinction. Furthermore, through computational simulations, the research group reconstructed the type of climate in which the animals examined lived, and any climate changes to which they were exposed.
The results
The study revealed that the fact of occupying a very narrow geographic region it is one of the factors that in the past has exposed the analyzed species more to the risk of extinction. On the contrary, animals that live in relatively large geographical areas are likely to have a greater chance of surviving climate changes that affect a specific area among all those occupied. The same goes for living in areas characterized by extreme climates, such as the polar regions, and also for the ability to survive more or less wide temperature ranges. Animals can live in environments characterized by a temperature variability below 15 degrees centigrade were found to be much more vulnerable to the risk of extinction. The size of the species taken into consideration was also found to be correlated with the ability to resist extinction: in general, animals of bigger size they were found to be more resilient than smaller ones.
Naturally, beyond the specific characteristics of each individual species, also theextent of climate change to which the different groups of animals have been exposed over time had its weight in determining whether or not they became extinct: “Our study revealed that Geographic range is the strongest predictor of extinction risk for marine invertebratesbut that the extent of climate change is also an important predictor of extinction, which has implications today for biodiversity in the face of climate change”, explains Malanoski. In particular, species exposed to temperature variations above 7 degrees centigrade during the various geological phases they were found to have faced a greater risk of extinction.
Species at risk
All this information, the researchers explain, is useful for identify which of today’s species may be more at risk than others. Especially in view of ongoing climate changes: “Evidence from the geological past suggests that global biodiversity faces a turbulent future, given estimates of projected climate change. In particular, our model suggests that species with thermal ranges limited to less than 15°Cwhich live at the poles or in the tropics, are probably those exposed to a greater risk of extinction”, concludes Saupe: “However, if localized climate change is large enough, it could lead to significant extinction globally, potentially bringing us closer to a sixth mass extinction”.
And one potential sixth mass extinction, the first attributable to anthropic activity, has been talked about for some time now. There are in fact many species at risk and some experts are even starting to talk about the possible disappearance of entire genera.
