Avian species diversity in different habitat types in and around North Nandi Forest, Kenya

摘要

Forest fragmentation and degradation leads to formation of modified habitats whose ability to support existing avifaunal diversity is still largely unknown. Bird diversity in indigenous forest, disturbed forest, plantation forest and farmlands adjacent to North Nandi Forest reserve was studied between January 2015 and June 2015. The distribution of bird feeding guilds in these habitat patches was also evaluated. Birds were surveyed using point counts, timed species counts and line transects and classified into six feeding guilds. A total of 3,232 individual birds of 151 species were recorded in the four habitats. Significant difference on bird abundance across the four habitats (F = 15.141, P = 0.05, df = 3, 1121) was noted. Shannon-Weiner diversity index H' for bird community ranged from 3.06 for plantation forest to 4.05 for disturbed forest showing a relatively diverse bird community. Insectivores (F = 3.090, P = 0.05, df = 3, 297) dominated the foraging species assemblage in all the habitats significantly. Linear regression analysis revealed a strong linear relationship on bird species richness and abundance with vegetation variables (P 0.01 in all cases). The results indicate that disturbed forest and indigenous forest support high bird species richness than plantation forest and farmlands. However, high bird abundance was observed in farmlands and plantation forest as opposed to indigenous forest and disturbed forest as they provide dispersal routes over a short distance and are important for creating corridors between primary forests.