Journal of Tropical Ecology



Microhabitat separation among diurnal saxicolous lizards in Zimbabwe


Karen E.  Howard a1 and Adrian  Hailey a1c1
a1 Department of Biological Sciences, University of Zimbabwe, P.O. Box MP167, Mount Pleasant, Harare, Zimbabwe

Abstract

Studies of niche overlap within communities of lizards have shown that separation may be along the three major dimensions of space, time and food. Space is usually the most important dimension where a range of habitats are involved; there is less information on the importance of microhabitat separation within a single habitat type. This study investigated microhabitat relationships of small diurnal lizard species occupying granitic rock habitat in Zimbabwe. There was statistically significant niche separation among all species in both the type of rock occupied (size, shape, number of cracks, closeness to other rocks, and vegetation cover) and the position of the lizard in the microhabitat (height on rock, slope angle, and distance to cover). Overlap of microhabitat was lowest between the generalist terrestrial skink Mabuya varia and all other species. The arboreal skink Mabuya striata was found on rocks at one site where the more saxicolous Mabuya quinquetaeniata was absent, due to competitor release. Overlap of microhabitat among rock specialists was lowest between the sit-and-wait foragers Agama kirkii and Platysaurus intermedius, as in other tropical lizard communities. The high degree of microhabitat separation was attributed to the high structural complexity of the granitic rock habitat.

(Accepted December 26 1998)


Key Words: Agama; community; habitat; lizards; Mabuya; microhabitat; niche; Platysaurus; rocks; Zimbabwe.

Correspondence:
c1 52 Mascotts Close, London NW2 6NS, UK. Email: ah2@ahailey.force9.co.uk