Macroinvertebrate
Data In order to better demonstrate these two calculations, a stepbystep example of each is provided here using biological data collected at Site A in Bear Creek Watershed presented in the below table.
The Shannon Index of Species Diversity measures diversity by the formula ; where H = diversity index, s= number of species (or orders), i = species (or order) number, and p= proportion of individuals of the total sample belonging to the ith species (or order). H = {[(6/6150)*(log 6/6150)] + [(2/6150)*(log 2/6150)] + [(5/6150)*(log 5/6150)] + [(165/6150)*(log 165/6150)] + [(5695/6150)*(log 5695/6150)] + [(5/6150)*(log 5/6150)] + [(272/6150)*(log 272/6150)] H = [(0.002937292) + (0.001134259) + (0.002512118) + (0.042159275) + (0.030911707) + (0.002512118) + (0.059897771)] H = 0.14206454 Remember, the higher the value of H, the greater the probability that the next individual chosen at random from a sample of species containing N individuals will NOT belong to the same species as the previous one (i.e. the greater H, the greater the diversity of species within an area). The EPT Index is calculated as the sum of the number of insects from the orders Ephemeroptera, Plecoptera, and Trichoptera divided by the total number of insects of the species Diptera: Chironomidae: EPT = (Ephemeroptera + Plecoptera + Trichoptera) / Diptera: Chironomidae. EPT = (6 + 2 + 5) / 5695 EPT = 13 / 5695 EPT = 0.002282704 The greater the EPT value, the greater the proportion of pollutionsensitive insects (i.e. the greater the quality of water). Some images © 2004 www.clipart.com Privacy Statement and Copyright © 19972004 by Wheeling Jesuit University/NASAsupported Classroom of the Future. All rights reserved. Center for Educational Technologies, Circuit Board/Apple graphic logo, and COTF Classroom of the Future logo are registered trademarks of Wheeling Jesuit University.
