A comparison between diversity, similarity: The Skelim and Karsang Rivers (Lafour hunting prohibitedarea, Northern Iran) with conservation perspective.

ABSTRACT: This study aimed at comparing the results obtained by processing a series of data according to several diversityIndices (Simpson, Brillouin, Shannon, Smith & Wilson, modified Nee, Camargo) and one similarity index (Jaccard coefficient). The conclusions are the following. There is clearly a certain connection between theabioticmaterials in the habitat, the abundance of individuals and the decrease in the diversity value along the altitude Rivers gradient. The species abundance distribution is a very simple and powerful Tool for describing and comparing the species diversity from different sampling stations. Any type of monitoring(e.g., similarity, diversity indices) is useful in comparing non-polluted and heavily polluted environments.Conversely, small differences between species associations are better highlighted if diversity indices with highdiscriminant ability or species abundance distribution are used rather than biotic indices. Our study indicates that the modified Nee index was reliable value to describe evenness of aquatic system in contrast with other indices.