One fifth of all invertebrates are now considered threatened by extinction according to a report published by the Zoological Society of London last week. As a category invertebrates are of great significance – ranging from insects to jellyfish, they make up approximately 98% of all animal species.
The study looked at over 12,000 species, and was completed in conjunction with the IUCN. The accuracy of the findings have been questioned by some due to the small sample size used; about 1 million invertebrate species are currently known, and studies suggest only 14% of species have been discovered.
As the first study of its kind, however, the report helps to give an overall idea of the status of a group that comprises almost all of Earths animals. Freshwater species were found to be particularly vulnerable, as were less mobile species. The trends revealed by these disparities will assist scientists in targeting species and areas of particular concern. Habitat loss, pollution and invasive species were listed as the top threats to species survival. Although these factors have been the subject of much concern already, clarifying their level of threat helps to form a scientific basis for future action. The results are similar to those of studies on vertebrates and plants, which also found a fifth of species to be at risk.