The trees of the species pouteria bullatapopularly known as red guapeva, are unique to the Atlantic Forest and produce succulent and sweet fruits.
Its seeds are about two centimeters long and therefore too large to be swallowed by birds and small mammals. In this way, the plant depends exclusively on primates such as the howler monkey (Alouatta howler) and the muriqui (Brachyteles arachnoides) and, eventually, the tapir (tapirus terrestris) to disperse their genetic material and perpetuate the species.
In places where these mammals have disappeared, it is also no longer possible to find the red guapeva, classified as “vulnerable” on the list of endangered species of the International Union for Conservation of Nature (IUCN).
And, according to a study published in the journal Biotropica, precisely these animals that are important for seed dispersal are the first to disappear as a result of the deforestation of the Atlantic Forest.
“The dispersion of seeds is a complex process, which encompasses many types of vertebrates at the same time. The reflex of deforestation is the extinction of both animals, which lose their food, and plants, which can no longer disperse”, says Lisieux Fuzessy, first author of the study, carried out with the support of Fapesp during her postdoctoral work at the Institute of Biosciences of the Universidade Estadual Paulista (IB-Unesp), in Rio Claro.
The work is part of the project “The effect of fragmentation on the ecological functions of primates”, also funded by the Foundation and coordinated by Laurence Culot, professor at IB-Unesp.
Part of the research was carried out during an internship carried out by Fuzessy at Estación Biológica de Doñana (EBD-CSIC), in Spain, with a grant from Fapesp and the collaboration of researcher Pedro Jordano.
“At first, the idea was to verify only the role of primates in seed dispersal, but it became clear that it was necessary to analyze the performance of all vertebrates”, says the researcher.
In addition to primates, data on seed dispersal by birds, bats, carnivores, marsupials, rodents and ungulates (deer, tapirs, wild pigs, etc.) were included in the study. With this, the study provides an unprecedented overview of the role of animal-plant interactions in maintaining biodiversity.
Conserved areas and fragments
To understand the impacts of wildlife loss on the forest, the researchers compared the interactions between animals and plants in two forested areas in the state of São Paulo.
One is known as one of the most conserved of the Atlantic Forest in Brazil, the Serra de Paranapiacaba, with more than 120 thousand hectares spread over protected areas and private properties.
Some of the most endangered large mammals currently live in the area, such as the jaguar (panthera onca), the vinegar dog (Speothos venaticus) and the peccary (tayasu peccary)in addition to tapirs and muriquis).
The Serra de Paranapiacaba is still the most important refuge for the jacutinga (Pipile jacutinga), a large frugivorous bird extinct in most of the Atlantic Forest remnants.
The Santa Geneva forest, in turn, is a 250-hectare fragment surrounded by urban areas and plantations, a reflection of most of the remnants of the biome.
The area was deforested until 1984, when it became protected. As a reflection of this history, most large vertebrates do not exist at the site. Only small birds are found, in addition to medium-sized mammals such as pacas (cuniculus paca), skunks (Didelphis spp.) and Kaxinguleese (Guerlinguetus brasiliensis).
However, there are also a few species of large frugivores, such as howler and jacuguaçu (obscure penelope). Even so, interactions are much smaller than in the conserved area.
In the Serra de Paranapiacaba, 1,588 interactions were recorded between 133 animals and 315 plants. In the Santa Geneva forest, on the other hand, there were 221 interactions between 54 animals and 58 plants.
“It’s a very important difference. Key species like the muriqui or tapir eat a much greater diversity of fruits than a bird, for example. In addition to the high demand for calories, the larger throat allows them to swallow large fruits and disperse plants that , without these animals, they simply disappear, in a cascading effect”, explains Fuzessy.
The work is yet another demonstration of the importance of conserving not only species, but functional diversity, that is, the interactions between animals and plants that make the forest thrive. Therefore, it serves as a basis for conservation and reforestation projects.
