This article concerns the threat on freshwater ecosystems, which harbor a disproportionate amount of the world's biodiversity. In many parts of the world, freshwater ecosystems are already degraded from a range of human activities, including water extraction, pollution and physical alteration. The data that showed a biodiversity crisis in ecosystems included species loss and breakdown of the ecological processes and resources. Furthermore, several case studies were cited to illustrate the status of freshwater diversity. Numerous reasons for freshwater biodiversity loss were mentioned, which included pollution from pesticides and agricultural and mine run-off, and physical alteration through channelization and impoundments that affected the hydrology and benthic habitat. Despite the successful establishment of institutions to conserve water birds and wetland habitats, there was a lower priority for conservation of freshwater biodiversity in terms of species and habitats. This bias has had important and serious implications for allocation of resources to increase the knowledge and understanding of freshwater ecosystems, as well as for the adequacy of impact assessments for development projects affecting them.