African Dwarf Crocodiles in the Likouala Swamp Forests of the Congo Basin: Habitat, Density, and Nesting

Abstract

Strip-transect methods were used to assess distribution and density of the dwarf crocodile, Osteolaemus tetraspis osborni, in a pristine region of the Likouala swamp forest, east of the Batanga River, northern Congo Republic, during the 1995 and 1996 dry seasons. Surveys by day were undertaken to locate the presumably solitary animals that occupied the few remaining pools. The cumulative percentage of inhabited pools (n = 34) was a function of the perpendicular distance of the center of the pool from the transect line. The effective distance was 19.5 m (strip width = 39 m). Strip surveys covered a linear distance of 28.36 km and yielded a total of 57 permanent pools, subjectively deemed suitable for crocodiles. Eight pools were associated with nests guarded by an attendant female. Crocodiles were not found in the interior of swamp forests but were limited to a peripheral zone, approximately 2.5 km wide, adjacent to terra firma forest. Within this zone minimum population density was calculated at one per 3.62 ha (0.28 crocodiles per ha).