Model of the assessment of the critical risk of extinction and the priorities of protection of endangered aquatic species at the national level

In the period 1995–2006, the biodiversity of the aquatic habitats in the area of Serbia was explored, with the aim to identify the endangered species of macroalgae, macroinvertebratae and fishes. During the work a data base was formed (Aquatic Ecosystems Diversity in Serbia, AEDSer), containing the data from exploring the biodiversity of the aquatic ecosystems of Serbia since 1860. Based on the data base, classification of the aquatic species was made into categories of endangerment based on IUCN criteria. The following was noted: (1) the global IUCN category assigned to the species often is not identical with the national status of endangerment; and (2) the species that are given a category of endangerment at the national level do not have the same realistic risk of extinction in all their habitats. This remark imposed the need for a model for assessing the critical risk of extinction of the endangered species and determining the priorities of their protection at the national level. Two categories of characters were used to develop the model: the characters that determine the degree of ecological specialisation of the species based on the circumstances of habitat; and the characters suggesting the risk factors from the system: “HIPPO” in the spatial and time dimension. The possibility to apply the model was tested on 10 aquatic species belonging to different categories of endangerment at the national level (macroalgae 2, macroinvertebrates 7, and fishes 1 species). The model based on points determined the level of extinction risk and, that way, the species needing urgent conservation from the same or different categories of endangerment were isolated. The model suggested can contribute to a more efficient defining the conservation priorities.