Structure et dynamique d’une population d’Agama impalearis (Sauria : Agamidae) dans les Jbilets centrales, Maroc

Abstract

A population study of Agama impaleari was conducted during two consecutive years (1993-1994) in a Jujube bush site located in an arid area at the Jbilet Mountains (Western Morocco). Lizards of both sexes required approximatively one year to reach sexual maturity. One to two clutches were produced per breeding season (May-August) and clutch size was significantly correlated with maternal body size. The annual reproductive output was in average of 20 eggs per female per year and did not exhibit a significant difference between the two years of study. Population size showed important seasonal changes throughout the study period and absolute spring density estimates were of 15 and 11 ind/ha, respectively in 1993 and 1994. In the post-reproductive period (September) the population density (excluding hatchlings) markedly declined and was only of 4-5 ind/ha. After the completion of hatching period (July to early November), the densities of hatchlings were 11 and 13 ind/ha respectively in 1993 and 1994 compensing for the population losses. The annual turnover rate of the population did not exhibit a significant yearly change and was of 77 %. Adult survivorship after the reproductive activity varied between years and juvenile survival during the first year was estimated to be 35 %. Maximum longevity assessed by means of squelettochro-nology was 5 years.