Fundação Renova

UNPRECEDENTED STUDY IDENTIFIES THE RISK OF EXTINCTION OF AQUATIC SPECIES IN THE DOCE RIVER BASIN

Published in: 10/01/2021

Renova Foundation

Based on this research, the Renova Foundation prepared the Action Plan for the recovery and conservation of aquatic fauna 

The Red Book of the Doce River Aquatic Biota Threatened with Extinction after the Fundao dam collapse, Mariana | Minas Gerais, released in August 2021, presents an unprecedented list of threatened species from the Doce River Basin.  The result of a technical cooperation agreement between the Biodiversity Foundation and the Renova Foundation, this was the first time that the aquatic biota of the Rio Doce was the object of a study with these characteristics. Based on the results, an Action Plan for the Recovery and Conservation of the Doce River’s Aquatic Fauna was prepared.

In Brazil, until now, a list of threatened species on a hydrographic basin scale had never been generated. The methodology applied was developed by the International Union for Conservation of Nature (IUCN), which is adopted by governments, researchers, non-governmental organizations (NGOs), universities and companies from several countries to prepare red lists of threatened species. 

According to the book, “one of the greatest difficulties encountered was the lack of specific data on species in the region before the collapse of the dam.” The research also highlights that, “despite being one of the most important basins in the Brazilian Southeast, the aquatic biodiversity of the Doce River basin is still unknown”. 

However, for any assessment of the risk of species extinction, at any geographic scale, the report concludes that “it is essential to recognize that you are working with the best data available at that time, albeit incomplete and with a certain degree of uncertainty. After a first categorization of species, more targeted research can be developed to answer questions raised by the assessment”.

Renova Foundation’s Biodiversity coordinator, Renata Stopiglia, states that, even before the collapse, most species were already threatened by a set of anthropic factors (caused by man), which have been negatively affecting the Doce River basin for a long time. “However, until then, the methodology for analyzing the risk of extinction had not been applied to these species, especially at the hydrographic basin level”.

Legacy for conservation

Renata Stopiglia emphasizes that, as mentioned in the study, this assessment does not replace or change the risk of extinction of species at the national or state level and there is no change in the status of the species after the collapse, since there are no lists prior to the event that allow a comparison at the river basin level. “For this reason, the result of the published assessment of the conservation status of the species and the unprecedented gathering of information in a database are a legacy for the conservation of the aquatic biota of the Doce River. As soon as this is documented and information about the degree of threat is known, it is possible to proceed with reparation and conservation actions”, she says.

Of the 515 species of the four target groups with occurrence for the river basin region (fish, crustaceans, odonates and ephemeroptera – the last two being aquatic insects), 123 were selected for extinction risk analysis. Of these 123 evaluated, 23 species were considered to be at some degree of threat in the context of the Doce River Basin. Nine were not considered affected by the dam collapse and are threatened by other sources of degradation. Seven species of mayflies and two species of fish are in this situation. 

Eleven species are also assessed as threatened for other reasons, but the tailings from the collapse impacted their conservation status. In this group, there are nine crustaceans and two fish, all estuarine and dependent on the mangrove. 

The dam failure appears as the main threat for only two species of mayfly. 

For one fish species, it was not possible to establish a correlation between the collapse of the dam and the degree of threat due to the lack of data.

Action plan

Based on the Report on the Assessment of the State of Conservation of Species, coordinated by the Biodiversity Foundation, the Renova Foundation prepared an Action Plan for the Recovery and Conservation of the Aquatic Fauna of the Doce River. It was built in a participatory process, with the contribution of entities and experts. The scope includes actions for the recovery of aquatic environments and Permanent Protection Areas (PPAss), monitoring and research focusing on threatened and data-deficient species, environmental education, effluent treatment, risk and impact analysis of the occurrence of invasive species or that may impact the target species in the Doce basin, among others. 

The final version of the Assessment of the State of Conservation of Aquatic Biota Species Impacted by the Fundao Dam Collapse, in Mariana (MG) was filed with the Technical Board of Conservation and Biodiversity (TB-Bio) this year, by the Biodiversity program of the Renova Foundation.

The study was produced in compliance with clause 164 of the Transaction and Conduct Adjustment Agreement (TTAC). According to the term, it is the responsibility of the Renova Foundation to draw up and implement measures for the recovery and conservation of aquatic fauna in areas where tailings were deposited in the channels and banks of the Gualaxo do Norte, Carmo and Doce rivers.

 

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