Birds of 80 species may have disappeared from areas in SP – 05/22/2023 – Environment

In recent decades, preservation areas in the interior of São Paulo may have lost 80 species of native birds, estimates a new study. The vast majority of the missing birds inhabited fragments of the Atlantic forest and are probably being victimized by the progressive de-characterization of their habitat in São Paulo.

The data obtained from the survey, which has just been published in the journal Revista do Instituto Florestal, cover four areas of strict protection in an arc that runs from east to west in the interior of the state, from São Simão (Ribeirão Preto region) to Marília, also passing through by Paulo de Faria (São José do Rio Preto region) and Andradina (Araçatuba region). All these areas originally housed different types of forests associated with the Atlantic Forest biome, in addition to the predominant presence of cerrado in the reserve located in the municipality of São Simão.

“People always tend to think of the stretches of Atlantic forest in the Serra do Mar and Serra da Mantiqueira, which are more continuous and preserved, and the tiny areas in the interior are forgotten”, says biologist Vagner Cavarzere Junior, a professor at Unesp in Botucatu and one of the authors of the study. “I think the work is a wake-up call. If inside an integral protection unit we see a decreasing species richness, imagine the situation outside them.”

Out of a total of 358 species mapped inside the reserves in older studies, the survey carried out by Cavarzere Junior and his colleagues managed to find 278 birds. Most of the previous surveys in the same areas had taken place between the end of the 1970s and the beginning of the 1980s. “The exception is Andradina, in which this work had been done in 2010, but we can also compare this recent information with a work done in the years 1930-1940 in Valparaíso, which is very close”, says the researcher.

Considering these dates, what can be said, according to the biologist, is that even the forest areas protected by law correspond to forests that have gone through several episodes of degradation. “All of them were cleared in the 1930s because of the coffee plantations”, he explains. “Later, this vegetation grew again, but it has suffered new pressures since then.”

To map the bird species, Cavarzere Junior and his colleagues used direct observation of the animals (with the help of binoculars) as well as singing. In the survey, carried out between September 2021 and January 2022, starting 15 minutes before sunrise, the researchers used the so-called ten-species list method. In it, a certain area of ​​forest undergoes a scan in which observers note the presence of each species until reaching a total of ten birds.

If a member of an already registered species appears again before the set of ten species is completed, he “passes the turn”, and the species is only cited again in the next list of ten. This also generates an estimate of the species frequency at that location by dividing the number of times each species was detected there by the total number of lists compiled.

The loss of bird diversity even within protected areas is clear based not only on the raw numbers of species, but also taking into account what has happened to those that are endemic (exclusive to a given environment) and are considered endangered.

Based on the oldest records, the areas studied would harbor nine endemic birds from the Atlantic Forest, five endemic from the Cerrado and 26 endangered species. Data from recent years, however, indicate the presence of only one endemic bird of the Atlantic Forest and five endangered species (the number of endemic species of the cerrado has not changed).

“What we see is a great predominance of generalist species, which spend a good part of their time at the edge of the forest or in the canopy [a parte mais alta das árvores]. Those who are more specialists, who need mature vegetation inside the forest, are no longer registered, regardless of their eating habits or other factors”, says the researcher.

Large birds of prey have completely disappeared from forest environments, for example. Among the threatened species registered in the studied sites is the blue-and-yellow macaw (macaw macaw) – a couple was seen by the authors of the study flying over the urban area of ​​Andradina. “It is still possible to find it more frequently far to the northwest of the state, near the Paraná River, something that was not imagined until a few years ago.”

The scenario revealed by the data indicates that the only path for a possible recovery of biodiversity in the interior of the state is to promote the reconnection of fragments of Atlantic forest that are now completely isolated. “Waiting for the vegetation in the remaining protected areas to fully regenerate and attract these species is not going to solve the problem. In the case of the Atlantic Forest, we already know that we can’t deforest anything else. It’s past time to connect these fragments to see if , in a few decades, we may have some positive difference”, explains the biologist.