An international conservation group says many freshwater fish, crabs, dragonflies, mollusks and aquatic plants are at risk of extinction in southern Africa.

The International Union for Conservation of Nature said a study conducted with the South African Institute for Aquatic Biodiversity shows 7 percent of species are known to be regionally threatened or extinct and that figure is expected to rapidly increase unless conservation is considered in development planning.

The U.S. organization's study shows that while 77 percent of species aren't threatened with extinction, there isn't enough information for the remaining 16 percent to determine their threat status.

The ICUN said its assessment of 1,279 freshwater species in southern Africa show the more developed a country is, the more species are threatened with extinction. Of the 94 species threatened in southern Africa, 78 of these are found in South Africa, the most developed country in the region.

"We are in a unique position in Africa to avoid an extinction disaster," said IUCN Director General Julia Marton-Lefevre. "Most developers have not taken freshwater species into consideration because they simply don't have the information they need. We hope this study will change that."

An executive summary of the report is available at http://cmsdata.iucn.org/downloads/the_status_and_distribution_of_freshwater_biodiversity_in_southern_africa_es.pdf.