Abstract:
Measuring diet breadth from gut content by Levins or Smith does not give true range of diet of an organism in comparison to available food resources in the environment. These measures consider proportions of food content in the gut to total food content in the gut for analysis. However, the credibility of food organisms available in the environment to exhibit and supply food to the prey feeding on it has been totally ignored. To overcome such limitations a new and simple non parametric diet breadth i.e., DB(χ2) has been proposed. A theoretical data set with gut content from six fish species as F1, F2, F3, F4, F5 and F6 have been considered to explain the DB(χ2). All these gut content data have variations within the gut content data set as well as between two guts and also with resource state as R. The computation and analysis of DB(χ2) not only explain a realistic picture of diet breadth of guts considered, but also provide an information on possible of diet overlap between two or more guts through ‘clumping’ of guts. The ‘clumping’ of guts based on DB(χ2) clearly explains diet overlapping or competition among different species or individuals of a species for available resources. While comparing the DB(χ2) to niche measures of Levins, Hulbert and Smith, the DB(χ2) showed clearer representation guts exploiting food organisms around R. DB(χ2) also shows sensitivity to variation of food abundances within gut content as well as to resource state that other measures failed to express.
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