Comparison of Shannon-Weinner’s and Simpson’s indices for estimating birds species diversity in Bodel forest of Gashaka Gumti national park, Nigeria

Abstract

The decline in bird’s species population and their diversity posed a great challenge to the conservators and the ornithologist. Shannon-Weinner’s and Simpson Indies were used to evaluate the bird’s species diversity in Bodel forest reserve of Gashaka Gumti National Park. A systematic sampling method was adopted, in which three (3) transects of 1 km in length were laid at an interval of 200 m apart in the study site. Species of birds sighted along the transect were observed and recorded. The species evenness was determined using the evenness equation E = H’/Ln(S). The results on bird’s species distribution revealed a total of 788 birds, belonging to 73 species and 26 families in the study area. Lunchura cucullata has the highest frequency of 82 birds (10.4%), this was followed by Ploceus cuculatus with a frequency of 50 birds (6.3%), while the least frequency of 1(0.1%) was recorded for Eliminilongi cauda. The two diversity indices revealed that bird species in the Bodel forest reserve of Gashaka Gumti National park are highly diverse. Simpson’s index gave a value of 0.97, while Shannon-Weinner’s index gave a value of 3.79 of species diversity in the Bode forest reserve. T-test conducted shows that the two indices are significant in measuring bird’s species diversity, but, Shannon-Weinner’s index is mostly preferred due to its lower mean standard error (0.005). The study has shown that the Bodel Forest reserve of Gashaka Gumti National Park is capable of sustaining a large population of bird species, if human interference is curtailed. Since bird’s are an integral part of the ecosystem that occupy many tropic levels in a food chain ranging from producers to consumers, there occurrence should be protected and conserved as they are of helpful in environmental health indicator, pollinators, seed dispersal and as an agent of pest control.