The consequences of bird extinction are much more serious than previously thought. The loss of hundreds of species caused by humans since their appearance on Earth erases the often irreplaceable roles that each bird represents for ecosystems: pollinator, seed disperser and pest control are just a few of them. them, according to a study conducted by researchers at the Environmental Research Institute. The University of Birmingham and CREAF published this Thursday in the magazine Science.
The book says humanity has so far caused the extinction of some 600 species of birds and that, in the next two centuries, human activities could wipe out another 1,300, what it calls “a devastation massive biodiversity. IMEDEA (CSIC-UIB), for the Science Media Center Spain.
Traveset explains that what has already disappeared “has caused a significant loss of functional space – the set of ecological roles that species play in an ecosystem – and 3,000 million years of unique evolutionary history. The latter implies that not only have many species been lost, but also entire branches of the tree of life.
Birds that control pests by feeding on insects, scavenger birds that recycle dead matter, others that eat fruits and disperse seeds allowing more plants and trees to grow… When a species disappears, its role in the ecosystem dies with it. The more species with different roles disappear, the more functional diversity is lost. In this sense, the study warns that 20% of functional diversity has already been lost worldwide and predicts that in the next 200 years an additional 7% could be added.
A key and vulnerable species case in Catalonia is the bearded vulture (Gypaetus barbatus), a vulture that feeds on bone remains and helps recycle nutrients.
“We have observed a trend towards extinction of species that play a unique role in the ecosystem. For example, the iconic Dodo (Raphus cucullatus) scattered seeds of large fruits on Mauritius and few birds replace this function,” explains Ferran Sanyol, researcher at CREAF and one of the main authors of the publication. A key and vulnerable species case in Catalonia is the bearded vulture (Gypaetus barbatus), a vulture that feeds on bone remains and participates in nutrient recycling: “This species is not threatened on a global scale, but it is in this region,” continues Sanyol.
The authors, after carrying out this “titanic” research, warn that entire lineages of birds have already disappeared, different species, but which share a common ancestor in their genes. The most affected places are islands, where up to 1,000 species could disappear and cause “ecological collapses”, because “their ecosystems are more simplified and therefore more vulnerable to disturbance than mainland areas”, says Traveset.
Borja Milá, researcher at the National Museum of Natural Sciences of the CSIC, highlighted that “this work represents the best estimate to date of the impact that man has had and will have on the extinction rate of a main group taxonomic such as birds, and what these extinctions mean in terms of loss of ecosystem functionality and phylogenetic diversity.
5% of lineages have been eroded. This is the equivalent of erasing 3 billion years of evolutionary history in a few years.
Ferran Sanyol
— CREAF researcher and one of the main authors of the publication
Research indicates that 5% of lineages have already been eroded. Some examples of these extinct lineages are the elephant birds (Aepyornithiformes), which could measure almost three meters and lived in Madagascar or in the moas (Dinornithiformes), large herbivores that inhabited New Zealand. “If the predictions come true in the future, an additional 3% of lineages could disappear,” Sanyol adds. One of them is the species of the subfamily Drepanidinae either honey birds endemic to Hawaii, which have already lost half of their species and “are essential for the pollination of flowers”, warns the researcher.
The Spanish archipelagos, in danger
Data shows that most extinctions are concentrated on islands. Concretely, among all the extinct species, 80% were island and, therefore, 31% of the functional diversity has already been lost in these ecosystems. “The future is not very encouraging, because we see that if we do not act, a thousand more island species could disappear by 2224,” warns Sanyol. Among the reasons they give is the fact that they cannot escape new exotic species or domestic animals like cats, which hunt them or introduce new diseases.
Some close cases of species playing a key role are found in the Canary Islands, where the rabiche pigeon (Columba junoniae) and the turquoise dove (Columba bollii) contribute to the regeneration of laurel forests, since they feed on their fruits and, in return, disperse their seeds. “Both are beginning to be threatened in Spain and with their disappearance we would lose this role,” warns the scientist. For its part, the Balearic shearwater (Puffin mauretanicus)a seabird, contributes to the nutrient cycles of coastal waters thanks to its waste, “it is an endemic species that breeds only in the Balearic Islands and is in danger of extinction”, he adds.
To collect the oldest data, the authors visited museums in various countries where stuffed birds, skeletons and fossils of extinct specimens are kept.
Improve conservation strategies
To carry out the research, the team analyzed the loss of bird diversity over three key periods: since 130,000 years ago; since 1500, when the IUCN began recording extinct and threatened species; and the next 200 years.
To collect the oldest data, the authors visited museums in various countries where stuffed birds, skeletons and fossils of extinct specimens are kept. For each of these species, certain traits such as wing size, beak or height were measured and, thanks to this information, they were able to deduce their role, “for example, if they have a long beak, they are probably pollinators,” says Sayol. With all this information, current data and thanks to mathematical models, they were able to discover the past and future of bird extinction.
“This scientific work reminds us that the current extinction crisis is not limited to the number of species, but that functional and lineage diversity is also reduced,” explains Tom Matthews, researcher at the University of Birmingham and first author of the study. “Understanding the impact of past extinctions will help us better assess future consequences on ecosystems and, therefore, improve global conservation and restoration strategies,” he concludes.
Nicolás López-Jiménez, member of the Society and Territory Unit and SEO/BirdLife delegate in Asturias, emphasized to the SCM that “this type of publications and the data they provide must be taken into account when developing the Species protection catalogs. that one of the criteria for the conservation of a species and its inclusion in one or another category of threats would be based on its functional role within an ecosystem and, even more, on the value of the ecosystem services that it provides. ‘it provides and the negative consequences. this would come from the loss of functions associated with the role it plays in the ecosystem where it lives.
