The Azores’ native forest continues to be a symbol of biodiversity resilience, according to an international study conducted over more than 20 years and developed by researchers from CE3C (Center for Ecology, Evolution and Environmental Changes) of the Faculty of Sciences of the University of Lisbon and by the University of the Azores.
The study shows that arthropod communities (a group of small animals that includes insects or even crustaceans) in the Azorean native forests withstood better than expected—while still highlighting the need to continue and strengthen the conservation of soil species in pristine forests.
“Stability in the Face of Global Decline: A 20-Year Study of Arthropods in an Oceanic Archipelago” is the name of the study published in the scientific journal Scientific Reports, of the Nature Portfolio group, which is based on data from the BALA project (Biodiversity of Arthropods from the Laurisilva of the Azores). The conclusions reached are the result of samples and information collected between 1999 and 2023 at 30 standardized sites, distributed across 15 fragments of native forest on seven Azorean islands.
For this study, 30,000 observations belonging to 405 arthropod species were considered, of which 91 are Azorean endemics. The analysis covered both the soil arthropod communities—sampled through pitfall traps—and the communities whose habitat is above the soil, in the trees (sampled by beating the canopies of the respective trees).
In a global context in which the decline of insects and other arthropods has generated strong scientific and public concern, the results obtained in the Azores add an important perspective: not all insect communities follow a uniform trajectory of collapse, especially when native habitats are still protected. The study shows strong temporal variability, with about 28% of species showing significant declines, 17% increasing, and more than half (55%) remaining stable.
Despite this sign of hope, the authors warn that the situation should not be interpreted as an absence of risk. Some species of great conservation importance continue to show worrying signs, and seven rare endemic species were not re-found over more than 20 years of sampling, being considered probably extinct – in other words, there remain important threats to island biodiversity.
This broad and ambitious study was led by the University of the Azores in collaboration with other international institutions. Among the authors is Paulo Borges, a CE3C researcher based at the University of the Azores and coordinator of the BALA project, which underpins this work. “This study synthesizes more than 25 years of field work, laboratory work, taxonomic identification and international scientific collaboration. The main message is that protecting the native forest works, but it is not enough: long-term monitoring must be maintained and action must be directed at the most vulnerable species and habitats,” explains the researcher Paulo Borges.
The stability observed in the Azorean native forests may be linked to the legal protection and conservation efforts developed in recent decades – which is good news. But the final message is clear: the Azores’ native forest remains an essential refuge for the archipelago’s unique biodiversity, but its future depends on active protection, continuous monitoring and long-term scientific investment.
