Thanks to runaway climate change on our planet, Earth is experiencing a global mass extinction event unprecedented in human history. But this global extinction crisis encompasses more than the widespread loss of species, it is an exceptional loss of species with unique physical shapes and structures, a process called “taxonomic homogenization” or “morphological homogenization.” This is the conclusion of a recent paper published in the journal Current Biology.
new risk
“As species go extinct, you expect that the traits they represent will also be lost. But what we found was that with morphological diversity, traits were lost at a much, much higher rate than species loss would predict. This is really important because it can lead to a significant loss of ecological strategies and functions,” says Emma Hughes, an avian researcher at the University of Sheffield, who has spent her career examining broad morphological traits in birds.
According to the expert, the loss of diversity is more likely to affect birds with extreme characteristics. The size and shape of birds vary greatly in the class, from the flightless giant ostrich to the tiny buzzing hummingbird. “That’s the kind of species that you would expect to be most at risk of extinction,” says Hughes. “We found strong evidence to support the hypothesis that larger and smaller species are likely to be most at risk of extinction.”
“The article shows that there will be a greater risk of extinction for more specialized birds that live in rarer habitats, either because of their restricted distribution or because of their more specific ecological requirements. While the most generalist, cosmopolitan and adaptable species will be the ones that survive”, Nicolás López-Jiménez, head of the SEO/BirdLife Species Conservation Program and SEO/BirdLife delegate in Asturias, explains to the Science Media Centre .
“The work presented by Dr. Emma Hughes and her team provides information to understand that the disappearance of key bird species in the functioning of ecosystems, such as pollinating birds or seed dispersers, could have disastrous consequences for the survival of the plants that those birds pollinate or whose seeds they help disperse. It also states that these loss of functions in ecosystems could mean that some of the ecosystem services that birds offer us would disappear , with human populations also being affected. In addition, the article reflects a harsh reality, which is that the loss of morphological and phylogenetic diversity in birds will mean that thousands of years of evolution and adaptation to ecosystems will have disappeared in a few years, losing this irreplaceable genetic heritage forever. This is the most exhaustive and up-to-date review on how the current global crisis of biological diversity loss could cause the disappearance of ecosystem services facilitated by birds and generate the homogenization of bird fauna diversity worldwide, analyzing the situation in a large variety of ecosystems throughout the entire planet and evaluating the possible losses of morphological and phylogenetic diversity with the study of characters of more than 8,400 species of birds”, concludes the expert.
Birds with distinctive physical traits are vitally important to their livelihoods by relying on specialized or rare ecological strategies, such as pollinating flowers, spreading seeds, controlling pests, or creating burrows or holes in trees that other animals can use, all so that birds ecosystems function in a balanced way.
What impacts will this have on habitats and people?
Referencia: Emma C. Hughes, David P. Edwards, Gavin H. Thomas. The homogenization of avian morphological and phylogenetic diversity under the global extinction crisis. Current Biology, 2022; DOI: 10.1016/j.cub.2022.06.018
