Influence of habitat types on the diversity and relative abundance of Belete forest bird guilds in shebe-sombo district South-west Oromia, Ethiopia

Abstract

Birds are important bio-indicators and provide various ecosystem services including pollination, seed dispersal, and pest control. However, habitat deterioration, fragmentation, and loss pose a threat to them. This study was conducted to assess the influence of habitat types on the diversity and relative abundance of forest birds in the Belete Forest, South West Ethiopia. The research was conducted between January 2023 to August 2023. Based on the vegetation type the study area was classified in to three habitat types ( shade coffee, natural forest, and farmland). Line transects and point count methods were used to collect data . Shannon-Weiner indices were used to estimate the avian guilds diversity during both seasons and habitats. One-way ANOVA was performed to determine influence of land cover type on bird avian relative abundance by comparing means of bird between the groups and within the groups across the three land use types. A total of 1361 individual birds distributed in 103 species belonging to 16 orders and 40 families were recorded across all point counts during wet and dry seasons. The greatest relative abundance of bird in shade coffee with (RA= 79.66%) during wet and the lowest in farmland( RA=21.3% ) dry sessions was recorded. The results also indicated the highest diversity and evenness of birds in shade coffee with (H'= 3.651, E = 0.597) while, lower in farmland (H'= 2.676, E =0.461) was recorded in both seasons. Between wet and dry highest ( SI= 0.58 ) of overall bird species was recorded in shade coffee while, less similarity index with (SI= 0.48) were at farmland. In the wet season, there was the greatest relative abundance of bird populations (SI=0.92) between the habitats of shade coffee and natural forests, and the lowest (SI=0.16) between farmland and natural forests during the dry season. Compared in the guild level, the significant difference between natural forest and farmland, shade coffee had higher bird abundance and species richness of carnivores, nectarivores and frugivores whereas insectivores was higher in natural forest (p < 0.05) respectively. The abundance and species richness of forest specialists ( p = 0.028 were higher in natural forest than in other habitats, whereas forest forest generalists ( p = 0.03) and visitors ( p = 0.022) status were high in shade coffee than other habitats. However, omnivores in the three habitats and granivores in the natural and shade coffee did not differ substantially (p > 0.05). The findings investigated the highest overall bird relative abundance and diversity was recorded in shade coffee during study period. This is because, large and widely spaced shade trees can provide excellent feeding opportunities for many groups of birds especially if the trees were indigenes. Conserving native trees in coffee and occasionally in farmland in the forms of shade, can conserve all groups of birds and even conserving multiple biodiversity. At the same time farmers around Belete forest should be encouraged to plant indigenous tree species in the farms to attract ecological services provided by birds (e.g. pest control, pollination and seed dispersal) additionally, raise national and individual coffee incomes