Freshwater Biodiversity Crisis in Brazil

7/7/2010

Three quarters of Brazil’s most important freshwater habitats are inadequately protected and 40 per cent are in an advanced state of degradation, threatening a “gigantic disaster” for the planet’s biological powerhouse, an important new report reveals today.

The report Restricted-range Fishes and the Conservation of Brazilian Freshwaters, which was released this week in the scientific journal PLoS ONE, is the most comprehensive look at the freshwater habitats of Brazil – which has the largest diversity of freshwater life on Earth – ever to have been undertaken.

A group of 6 scientists from Conservation International Brazil, the Federal University of Rio de Janeiro and the University of Sao Paulo compiled data from more than a decade of research to identify 540 key freshwater biodiversity areas in Brazil and 819 species of rare fish – many of which exist only in tiny areas.

But only 26 per cent of these sites have “reasonable” protection, and more than 40 per cent are in an advanced state of degradation – threatening the survival of 344 endemic species of fish.

Many of the restricted range fishes are annual fishes, belonging to the Rivulidae family (genera Simpsonichthys, Cynolebias, Austrolebias, among others). These share unusual adaptations to survive in seasonally dry environments in marshlands and temporary lagoons. They depend on very well regulated rainfall regimes, and the entire adult population dies during the dry season. The new generation survives as fertilized eggs that hatch with the beggining of the wet season.

Author of the study Paulo Buckup from the Federal University of Rio de Janeiro and president of Brazilian Society of Ichthyology said: “These results show that the conservation of Brazil’s aquatic biodiversity and the maintenance of these ecosystems has been neglected throughout the years.”

The primary problems are the impacts of hydro electric power generation on the flow of rivers and streams and the loss of both terrestrial and aquatic habitats because of inadequate protection.

Fabio Scarano, Executive Director of Conservation International Brazil said: “If the current rate of degradation of these areas continues Brazil runs the risk of losing an important share of its unique biological heritage - which would be a gigantic disaster for the planet’s biological power house.”

Several of the narrow endemic Brazilian fishes (including Corydoras spp., Hyphessobrycon spp.) are also explored as aquarium fish due to their beautiful colors and unusual behavior, and illegal captures may further threaten these already rare species.

Report coauthor Naércio Menezes from the University of Sao Paulo said: “This mapping represents an important step that will allow Brazilian society to see that our rivers are home to an important part of our country’s unique biodiversity.”

Cristiano Nogueira, who is based at the University of Brasilia was part of the Conservation International involved in the the study added: “Without healthy freshwater ecosystems, people will face drought, water shortages and will lose vital economic resources. Some of the areas in our study are within densely populated regions where water resources are already critically depleted, posing threats not only to biodiversity but also to sustainable development and to human health.”

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A selection of images of some of the threatened fish is available here:

http://bit.ly/dp8Xy3

Some details about the Simpsonichthys species featured in the images:

The two Simpsonichthys species are found only at restricted veredas (palm swamps) close to Brasilia, the capital of Brazil, constructed in the middle of the Cerrado region. The S. boitonei species is even called pirá-brasília, as it was discovered and described during the construction of the new capital in early 1960s. These and many other fishes with restricted distribution are threatened due to habitat loss and lack of formal protection.

These two Simpsonichthys species are iconic because they inhabit pristine areas close to a large urban center, where water resources are critical. The entire population of Brasilia depends on drinking water from pristine, undisturbed Cerrado areas, like those that harbor the last populations of Simpsonichthys boitonei and S. santanae.