Comparative Study of Rodents and Insectivores in Natural and Coffee Forest Habitats of Afalo Area, Gera District, Southwestern Ethiopia

Abstract

A comparative study of the diversity, distribution and abundance of small mammals (rodents and insectivores) in natural and coffee forest habitats of Afalo area of Gera district was conducted from August, 2014 to March, 2015. Two sites, one with coffee forest and the other natural forest, were selected for the study. Grids were established and randomly selected in each of the habitats, and representative sample sites were taken from each habitat type. Mammals were sampled by setting traps on randomly selected grids. Sherman traps and snap traps were used to trap small mammals and animals were identified to the species level in the field. Skin and skull of some representative specimens were mounted and used for identification of animals that were difficult to identify in the field. A total of 110 individuals were trapped during the present study. Seven species of rodents and three species of shrews were identified and recorded from Afalo area. Of the total trapped species, Lophuromys flavopunctatus had the highest relative abundance 35(49.3%), followed by Grammomys dolichuros, and Lophuromys chrysopus with 23(47.5) % and 16(29.7) % respectively. Rattus rattus, Mus musculus, Crocidura flavescens, Crocidura fumosa and Crocidura bicolor had 22.2%, 20.7%, 13.3%, 10.7% and 1.4% respectively. Hystrix cristata and Paraxerus ochraceus had the lowest relative abundance (1.4%) each. Hystrix cristata and Paraxerus ochraceus were recorded only from NF habitat. The abundance of species varied among habitats and between seasons. There was significance variation in the rodent and insectivore abundance among the seasons (x2= 2.11, df =1, P<0.05). Diversity and abundance of small mammals affected by increased habitat heterogeneity, open habitat, habitat disturbance, vegetation structure and composition and seasonal availability of food and water. The highest and insectivore species diversity was recorded in NF habitat (H’ =1.634). Vegetation cover, rainfall and human interference were the major factors affecting the diversity, abundance and distribution of small mammals in the study area. To gain detailed account of the forest fauna of the area and to evaluate the impacts of forest management on the diversity and abundance of small mammals several sites from each habitat has to be assessed.