Are caecilians rare? An East African perspective

Abstract

Despite increasing reports to the contrary, caecilians are often considered to be unusual components of tropical ecosystems, where they predate largely on soil ecosystem engineers. The status of two East African Boulengerula species is assessed using a quantitative randomised survey method and timed searches, in low-intensity agriculture and natural forested settings. Mean density of B. boulengeri was found to be greater in forest than agriculture (0.43 and 0.11 m^-2, respectively), but not significantly. B. taitanus were significantly more dense in agriculture (0.21 m^-2) than in forest (0.02 m^-2). Forest B. taitanus were found to be significantly longer (x 285.9 mm) than those found in agricultural settings ( x 219.3 mm), and possible causes of this size bimodality is discussed. Results from quantitative surveys are found to be remarkably consistent, and significantly correlated with timed searches in the same habitats. Possible causes of over- and under-representation are identified. It is concluded that not all members of the order Gymnophiona in East Africa are rare, although more field studies are needed to redress herpetology's subterranean blind spot.

Journal of East African Natural History Vol. 93 (1&2) 2004: pp. 1-21