IUCN is working closely with a range of partner organisations to undertake species assessments, and to extend the range of species represented on the IUCN Red List. One such group is freshwater crabs, which have been assessed through the Sampled Red List Index project coordinated by the Zoological Society of London (ZSL) and are contributing to the Pan Africa assessment project.

Almost one fifth of the world’s crabs are restricted to freshwater, a total of 1,281 species. Overlooked in comparison to their more speciose marine counterparts, they are distributed throughout almost all freshwater habitats in tropical regions.

The comprehensive global IUCN Red List assessment revealed unexpectedly high threat levels. The assessment shows that about one-sixth of all freshwater crab species have an elevated risk of extinction, only one-third are not at-risk, and although none are actually extinct, almost half are too poorly known to assess. The majority of threatened species are restricted-range semi-terrestrial endemics living in habitats subjected to deforestation, alteration of drainage patterns, and pollution.

These results underline the need to prioritize and develop conservation measures before species decline to levels from which they cannot recover and represent a baseline that can be used to design strategies to save the World’s threatened freshwater crab species.

Download the article Cumberlidge, N., et al (2009) Freshwater crabs and the biodiversity crisis: Importance, threats, status, and conservation chal- lenges. Biol. Conserv, HERE.