Species Extinction’s Domino Effect Also Destructs Biodiversity

Global climate change is threatening biodiversity. For predicting the fate of species, ecologists use climate models that consider individual species in isolation. This kind of model, however, overlooks the fact that species are part of a giant network of mutual dependencies: for example, plants need insects to disperse their pollen and, in turn, insects depend on plants for your food.

Seven pollination networks in Europe are investigated.

These types of mutually beneficial interactions have been very important in generating the diversity of life on Earth. But the interaction also has a negative blow effect when the extinction of a species causes other species that depend on it to also become extinct, an effect that is called co-extinction. Evolutionary biologists from the University of Zurich, together with ecologists from Spain, Great Britain and Chile, have now quantified the impact of climate change on biodiversity when these mutual dependencies between species are taken into account. To this end, the team of researchers analyzed the networks between flowering plants and their insect pollinators in seven different regions of Europe.

The extinction of the rose rock means that the myrtle is also under threat

The first author, Jordi Bascompte, gives a specific example to illustrate the results of the study: "In one of the networks located in the south of Spain, the rosehip of sage leaf has a 52 percent probability of extinction predicted by the climate change in 2080. Indeed, one of its pollinators, the small carpenter bee, would run a risk of co-extinction as a result of losing one of the resources on which it depends, since the carpenter bee also pollinates the myrtle, The last one is also under the threat of extinction. " Thus, while the expected extinction risk of myrtle considered in isolation is 38 percent, the risk increases to around 62 percent when taking into account the network of interactions.

"If the interactions of individual species are also taken into account, the total number of species threatened with extinction increases," summarizes Bascompte. "Some species with a very low probability of extinction related to climate according to the traditional model have a high risk of extinction due to their dependencies."

Particular threat to biodiversity in the Mediterranean regions

The authors also observed that the role of coexistences in increasing the group of eradicated species could be particularly high in Mediterranean communities. As an example, in a community in Greece, the total number of plant species that are predicted to disappear locally by 2080 could be as high as two to three times the expected amount when the properties are considered related. The researchers point to two reasons for this: first, the Mediterranean regions have seen more that have been improved by climate change than central and northern Europe. Second, the southern regions of Europe harbor species with narrower distribution ranges, which makes them more susceptible to extinction than those widely distributed. With such a high relation of species and their extinct interactions, the rest of the network is more fragile and, therefore, prone to cascades of coexistence.

By: Preeti Narula

Content: https://www.sciencedaily.com/releases/2019/05/190528120337.htm