Patterns of specific diversity and population size in small mammals from arboreal and ground-dwelling guilds of a forest area in southern Nigeria

Abstract

The small mammal fauna of a forest area in southern Nigeria is studied in order to understand the general patterns regulating the community composition. A set of different methods of trapping was used in order to evaluate the composition of the species at the level of both the ground-dwelling and the arboreal guilds. For the Insectivora, six shrew species were trapped, but only two (Crocidura nigeriae and C. poensis) appeared abundant and widespread in the various habitat types. No arboreal species were found. For the rodents, 17 species were captured, which were arranged by a Principal Component Analysis into four groups: (1) Rattus rattus and Anomalurus derbianus; (2) Xerus erythropus and Grammomys rutilans; (3) Graphiurus cf. murinus and Hylomyscus stella; (4) the remaining, more generalist species. For the ground-dwelling rodents, 14 species were found, which were arranged in three groups: (1) Malacomys edwardsi and Grammomys sp.; (2) Mylomys dybowskii and Rattus norvegicus; (3) all the other species, with stronger similarities between Praomys tullbergi, Mus musculoides, Aethomys sp. (unknown), and Lemniscomys striatus. Although an approximately equal number of species constituted the arboreal and ground-dwelling rodent fauna, the number of trapped animals was much higher on the ground than at the level of the arboreal guild (ratio 8.7: 1; total n=2322). The general implications of the patterns observed are discussed.