Habitat Carrying Capacity Index: A Formalized Assessment Of Habitat Importance To Maintain Diversity Of The Littoral Fish Assemblage


V.I. Maltsev, M.A. Beletskaya

To assess the significance of the habitat for maintaining biodiversity, for example habitats of coastal fish assemblages the following carrying capacity index for habitats was developed (A): where N is the total number of specimens, S – the number of species, ni – the number of specimens of each species, Q – coefficient, which makes possible to obtain A index values more convenient for perception. In our case, the most convenient is Q=100, so the equation is as following: The minimum value of the index as 0 is reached when S=1 for any value of N, regardless of the evenness of the system. A larger index value corresponds to larger species number and total number of specimens considering equable distribution of the elements in community. If S and N tend to infinity, the index tends to 1. Evaluation of the effectiveness of the index applying to an analysis of the carrying capacity concerning fishes of the littoral habitats according to visual counts showed the suitability of the index for these purposes. There is every reason to believe that the proposed index is suitable for assessing the carrying capacity of the habitats for other groups of aquatic organisms also, however, a comparison of the habitats using this index is possible only if the way of presenting the results of quantitative estimates of abundance is identical.

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