Habitat fragmentation threatens Brazilian tapir in the Atlantic Forest, study finds

Por: Gabriela Andrietta

The article "Habitat fragmentation explains the occupancy probability of the largest herbivore in the Neotropical forests," published in the journal Biological Conservation and led by researchers from Unesp, with the participation of Prof. Dr. Mauro Galetti, Dr. André Luis Regolin, and collaborators from several Brazilian and international institutions, reveals that forest fragmentation is one of the main factors reducing the probability of the Brazilian tapir (Tapirus terrestris) occurring in the Atlantic Forest.

Between 2014 and 2019, the researchers monitored 42 landscapes in the state of São Paulo using camera traps. They also analyzed land use and land cover maps and satellite imagery to examine landscape structure, including forest cover and fragment size.

The results showed that it is not only the amount of forest that determines the occurrence of the tapir. The landscape configuration, such as the number of fragments and the density of edges, was crucial, as the more fragmented and isolated the forest, the lower the likelihood of the species' presence.

Tapirs are essential to the balance of tropical ecosystems. Known as the gardeners of the forests, these animals act as dispersers of large seeds, contributing to the regeneration of vegetation and the maintenance of carbon stocks in forests. However, the destruction of the Atlantic Forest has limited the species' presence.

According to André Regolin, "this species is distributed across several biomes in Brazil, occurring in the Caatinga, Amazon, Atlantic Forest, Pantanal, and Cerrado. However, the study focuses on the interior areas of the Atlantic Forest, where the vegetation is drier. These regions have been deforested since the colonial period, so few fragments remain today. What we show in this study is that the arrangement of these fragments is very important. If the fragments are close together or if there is a suitable minimum size, the chances of finding the species increase. As the landscape fragments, the species disappears."

Another important point is that fragmentation has other effects. "The increase in highways cutting through natural areas increases the number of roadkills. Hunting also poses a significant threat. The more fragmented the landscape, the easier access to the areas and, consequently, the hunting rate increases. Even when there is not a complete division of the forest, areas with very irregular shapes, full of edges, make the interior of the forest more vulnerable," explains André. Restoring and reconnecting forest fragments is essential.

A conservation strategy would be to bring fragments closer together and restore the degraded areas between them. Connections between fragments are essential because they enable the so-called rescue effect, which occurs when a healthy, growing population can sustain a declining one. Work like this is crucial for identifying areas that need protection, highlighting the importance of connecting areas, and estimating species extinction risk. It allows us to understand population distribution, estimate their size, and, based on this information, analyze extinction risk in different regions.