The projections of the analysis, in which two Portuguese researchers participated, “show that, in the middle of the 21st century, climate change could become the main responsible for the decline of biodiversity”, according to a statement from the German Center for Integrative Biodiversity Research (iDiv).

On the other hand, a global meta-analysis of 186 studies reveals that conservation actions – especially those targeting species and ecosystems – have significant positive impacts on biodiversity, says a statement from the American Association for the Advancement of Science (AAAS).

In the case of the first study, the “largest of its kind”, researchers from iDiv and the University of Halle-Wittenberg (MLU) compared 13 models to assess the impact of changes in land use and climate change, taking into account four metrics of biodiversity, as well as nine ecosystem services.

“By including all regions of the world (…), we were able to fill in many blind spots and respond to criticisms of other approaches based on fragmented and potentially biased data”, says Portuguese Henrique Pereira, conservation biologist and leader of the group of scientists who participated in the study, who is the first author of the article.

“All approaches have advantages and disadvantages. We believe our approach (…) provides the most comprehensive estimate of biodiversity trends around the world,” he added, quoted in the statement.

The researchers calculated the impact of changes in land use on ecosystem services, that is, “the benefits that nature provides to human beings”, and analyzed how these and biodiversity could evolve, taking into account the growing importance of climate change.

In the three scenarios evaluated – from sustainable development to high greenhouse gas emissions – “the combined impacts of changes in land use and climate change result in the loss of biodiversity in all regions of the world”, although there are “considerable variations” between the zones.

“The objective of long-term scenarios is not to predict what will happen”, but “to understand the alternatives and, therefore, avoid trajectories that may be less desirable and choose those that have positive results. The trajectories depend on the measures chosen and these decisions are made day by day”, explained Portuguese biologist Inês Martins, from the University of York and co-author of the article published in Science.

In this context, the discovery, made through the meta-analysis published by AAAS, that “in two-thirds of cases, conservation actions had a positive effect, improving the state of biodiversity or at least slowing its decline” becomes relevant.

The team of researchers led by Penny Langhammer, associate professor of biology at Arizona State University and executive vice president of the non-governmental organization Re:Wild (which advocates for the recovery and protection of biodiversity around the world), revealed that interventions are the most effective and most effective are those “directed at species and ecosystems, such as controlling invasive species, recovering habitats, protected areas and sustainable management”.

Although billions of dollars are spent every year on conservation actions aimed at “halting and/or reversing the loss of biodiversity and degradation of ecosystems (…) many international conservation objectives, including those established by the Convention on Biological Diversity, remain to be achieved.”

The study argues that to determine future measures, an in-depth assessment of policy objectives and an analysis of the results of current conservation interventions in terms of biodiversity are necessary.

And, to reverse the global diversity crisis, conservation actions must increase and be applied more broadly, which “will require significant additional investment in many sectors of society”, say Penny Langhammer and her colleagues.