Brazil has More Threatened Bird Species than the Current Red List

Researchers have found a new way to assess the bird population in the Amazon. Their study shows that currently, there are many bird species that have severe habitat loss but aren't yet listed as threatened species.

The study was led by researchers from The New Jersey Institute of Technology. Previously, researchers had shown that a metric called meta-population capacity has the right criteria to measure the impact of habitat fragmentation on the survivability of a particular species. Meta-population capacity provides information about the population's survival after considering the extent of the fragmented habitat.

"Our goal was to assess the extinction risk for bird species in the Atlantic Forest of Brazil, a global 'hotspot' of bird diversity," said Gareth Russell from The New Jersey Institute of Technology. "Based on elevation restrictions and forest type requirements, as well as ongoing tropical deforestation, we already knew that most species have access to far less habitat than typically assumed.  But what habitat remains is also highly fragmented. Looking at area alone is not enough."  

In the present study, researchers used meta-population capacity to assess the effect of habitat loss to 127 passerine birds from the Atlantic Forest of Brazil. Just 10 percent of the region now has forest cover.

The study found that habitat loss resulted in some populations declining severely, while it had a very mild effect on a few others.

Researchers also found that 28 out of 58 bird species that have suffered from severe habitat fragmentation haven't been listed as threatened species by the International Union for the Conservation of Nature.

"Assessing extinction risk is enormously challenging, and the dedicated teams that do this work are faced with many unknowns," Russell said in a news release. "The most endangered species are often the most rare, and therefore also the hardest to find and study.  Our approach requires only basic knowledge about a species, but optimizes that information by linking it to the recent flood of data about the environment."

The study was published in the journal PLOS One.