2 October 2023

Climate change puts 40 percent of biodiversity in eastern Brazil at risk

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In the Catinga forest rising temperatures threaten to destroy nearly half the biodiversity by 2060, a Brazilian study says. Ecosystem services are under threat

by Matteo Cavallito

 

Climate change could wipe out up to 40 percent of the biodiversity in the semi-arid portion of northeastern Brazil by 2060. This is claimed in a study published in the Journal of Ecology, a publication of the British Ecological Society. The survey, which involved several Brazilian universities, looked at plant collections, herbaria and scientific literature to compile a database of about 3,000 plant species in the biome.

Combining this information with data on geographic distribution, growth form, climate and soils, notes FApesp in an article by Julia Moióli, the scientists looked at a number of models validated with different types of statistical and artificial intelligence algorithms to hypothesize more than a million projections of the possible responses of plant species to future climate variations.

Climate change will promote biodiversity loss

The study, conducted by researchers from the universities of Campinas (UNICAMP), Paraíba (UFPB), Pernambuco (UFPE) and Viçosa (UFV) and the Federal Institute of Goiás (IFG), focused on the Caatinga forest in eastern Brazil. Characterized by semi-arid biomes, the area is one of the richest in the world in terms of biodiversity.

Because of climate change, the agency writes, the area will experience species loss, replacement of rare plants by more generalist vegetation, biotic homogenization (in which previously distinct plant communities become increasingly similar), increased aridity and even desertification in some areas.

Shrubs and grasses will replace trees

“Climate emergency is a significant threat to biodiversity in the 21st century, but species will not be equally affected,” the study says. In the end, “More than 99% of plant assemblages were projected to lose species by 2060, with biotic homogenisation—the decrease in spatial beta diversity—forecasted in 40% of the Caatinga.”

Moreover, “The replacement of narrow-range woody species by wide-range non-woody ones should impact at least 90% of Caatinga plant assemblages.”

The reduction in vegetation diversity and complexity will obviously have particular consequences in terms of the function performed by the environment. “The projected biotic changes in dryland plant assemblages indicate the erosion of ecosystem services linked to biomass productivity and carbon storage,” the study continues. Therefore, the authors “highlight the importance of long-term conservation planning for maintaining tropical dry forests.”

Mitigation actions needed

In short, the researchers call on central and local governments to develop long-term conservation plans to mitigate the negative effects of climate change and the impact of environmentally damaging human activities such as deforestation, habitat destruction, land degradation and exposure. Otherwise, the risk is to accelerate those processes that underlie the so-called twin crises: climate emergency and biodiversity loss.

Without action, the research explains, the reduction in plant diversity will be most visible in the mountainous areas of Brazil’s eastern forest, such as Chapada Diamantina and Chapada do Araripe. Indeed, rising temperatures will favor the development at higher altitudes of some lowland plants. Meanwhile, high-altitude species will become extinct.