Sunday, December 5

The loss of threatened species will have dramatic effects on ecosystems

The loss of threatened vertebrates is not just an ethical tragedy but it can have dramatic effects on the functioning of ecosystems. Data compiled from 50,000 vertebrates in six biogeographic kingdoms has revealed that the loss of threatened species would cause a decrease of up to 30% of diversity functional, mainly in Europe and Asia.

The results, published in the journal ‘Nature Communications’, can be applied to establish conservation priorities for species that provide unique ecological functions in the particular region.

The number of vertebrate species that inhabit the different regions of the world is highly variable, as is the proportion of threatened species. Some regions, such as the tropics, have more threatened species than expected given the total number of species. However, the vulnerability of ecosystems to the continued loss of species depends not only on the number of species, but also on their ecological role.

These roles depend on the characteristics of the species, their size, weight, shape, reproductive capacity or the food resource they use. If the threatened species have similar characteristics to the non-threatened species, the loss of functions due to the extinction of the threatened species could be compensated by other species. Conversely, if threatened species have unique characteristics, their loss can have a dramatic effect in the functioning of ecosystems and in the services they provide to human well-being.

To understand how different regions of the world could be functionally affected by the loss of threatened vertebrates, a research group from the University of Tartu and the Paul-Sabatier University, in France, collected data on the characteristics of 50,000 species of vertebrates (around 70% of all vertebrates) and their spatial presence in the six major biogeographic realms.

They then compared whether the loss of threatened species will have similar consequences on functional diversity in each biogeographic kingdom for each group of vertebrates.

For the five groups of vertebrates (birds, mammals, reptiles, amphibians and freshwater fish) the loss of species currently identified as threatened with extinction by the International Union for Conservation of Nature (IUCN) would cause very different effects ranging from almost zero decline to a loss of up to 30% of the functional diversity of kingdoms.

The Indo-Malay kingdom would be the most affected due to the loss of threatened species for mammals and birds (up to 20% decrease in functional diversity), while the Palearctic kingdom would be the most affected for reptiles, amphibians and freshwater fish (up to 30%). % decrease).

Lead author Dr. Aurele Toussaint notes that the study “will have important consequences in terms of conservation planning. The Indo-Malay kingdom is not only home to the highest proportion of threatened vertebrates on Earth, but also threatened species with functional traits. unique, ” he adds. Their loss would seriously endanger these fragile ecosystems. This highlights the need for action to conserve biodiversity in Asia. ”

To understand the current and future threat to functional diversity, we first have to understand the distribution of functional diversity in kingdoms. Due to the long evolutionary legacy of the different taxonomic groups, species have evolved differently in each biogeographic kingdom and, therefore, they could have explored different ecological strategies.

The researchers found that, in the case of birds and mammals, which are less affected by geographic barriers across great distances, most of the world’s ecological strategies are represented in each kingdom. Thus, the functional diversity of each kingdom is comparable to the global functional diversity, and the loss of threatened species will have similar consequences throughout the world, but with different intensity.

In the case of mammals, the loss of functional diversity is mainly related to the loss of the most charismatic primate species, such as chimpanzees (‘Pan troglodytes’), bonobos (‘Pan paniscus’) and gorillas (‘Gorilla spp.’) in Africa, or orangutans (‘Pongo spp.’) in the Indo-Malay kingdom, together with some spider monkeys (‘Ateles spp.’) and capuchin monkeys (‘Cebus spp.’) in the South American tropics.

In the case of birds, the loss of functional diversity in the Indo-Malay kingdom is mainly due to the loss of large birds such as the white-shouldered ibis (‘Pseudibis davisoni’) or the Indian vulture (‘Gyps indicus’), what are very close to extinction, mainly due to habitat loss and degradation.

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