Original article Niche separation and comparative abundance of Boulengerula boulengeri and Scolecomorphus vittatus (Amphibia: Gymnophiona) in an East Usambara forest, Tanzania DAVID J. GOWER 1 , SIMON P. LOADER 1,2,3 , CLIVE B. MONCRIEFF 1 AND MARK WILKINSON 1 1 Department of Zoology, The Natural History Museum, London, SW7 5BD, UK, d.gower@nhm.ac.uk 2 Institute of Biomedical and Life Sciences, Division of Molecular Genetics, University of Glasgow, Pontecorvo Building, 56 Dumbarton Road, Glasgow G11 6NU, UK 3 Society for Environmental Exploration / Frontier, 50-52 Rivington Street, London EC2A3QP, U.K. Abstract.—The ecology of the sympatric caecilians Boulengerula boulengeri and Scolecomorphus vit- tatus was studied in Nilo Forest Reserve in the East Usambara Mountains, Tanzania. Three sampling methods (timed digging, pitfall trapping and casual visual encounter surveys of the forest floor) yielded 85 B. boulengeri, found only by digging soil, and 23 S. vittatus, mostly collected above ground. The dif- ference between these taxa in the proportions of captures above and below ground is statistically signif- icant and is taken to indicate different ecologies. B. boulengeri is interpreted as predominantly a bur- rower in soil, and S. vittatus as an animal spending more time than B. boulengeri above ground. Niche separation appears to be correlated with some morphological differences. The vast majority of all verte- brate specimens dug from the top 300 mm of soil were B. boulengeri, and this species appears to be more abundant than S. vittatus in East Usambara forest soils. As an abundant endogeic animal, B. boulengeri may play an important role in the ecology of forest soils. Key words.—caecilians, Eastern Arc, ecology, Caeciliidae, Scolecomorphidae, soil. 183 African Journal of Herpetology, 2004 53(2): 183-190. C aecilians are elongate, limbless, snake-like amphibians found mainly in the wet trop- ics. Little is known about caecilian ecology (Himstedt 2000). Most ecological information that has been published has been gleaned from examination of preserved specimens, and from piecemeal natural history observations made during the often opportunistic collection of caecilians. Recently, however, several largely field-based studies have made encouraging breakthroughs. These include quantitative esti- mates of abundance through surveys (Oommen et al. 2000; Measey et al. 2003a; Measey & Di- Bernardo 2003; Measey in press), testing and implementation of marking methods in recap- ture experiments (Measey et al. 2001, 2003b), investigations of diet and condition based on randomised sampling (Measey et al. 2004, Measey & Gower in press; Gaborieau & Measey 2004), growth (Kupfer et al. 2004a), and reproductive ecology (Kupfer et al. 2004b). The majority of these studies have focussed upon autecology in agricultural or otherwise disturbed habitats. In this paper, we present a