Évolution de la densité de population de l’iguane des petites Antilles (iguana delicatissima) dans la réserve naturelle des îles de la petite terre (Guadeloupe) entre 1995 et 2002

Abstract

The ecosystem of the two Petite Terre Islands (a natural reserve of 148,6 ha since 1998, Guadeloupe, French West Indies) is original because it is dominated by a large size vegetarian reptile, the Lesser Antillean Iguana (Iguana delicatissima), a IUCN vulnerable species. A survey of the Lesser Antillean Iguana population was carried on by the AEVA Natural History Society at the request of the authority in charge of the management of this protected area. The main goals of this study were to gather data on the interannual evolution of the population density and to identify possible threats. A line-transect census, based on a method accounting for the perpendicular distance between the animal and the line transect, was conducted annually from 1995 to 2002 (except in 1997). Correlations were established between large declines of the population and two major climatic events, i.e. two hurricanes in 1995 and a long drought in 2001. With an estimated size of 10,000 adults outside the breakdown periods, the Lesser Antillean Iguana population of the Petite Terre Islands appears as one of three largest ones in the world, with those in Dominica and Désirade Islands. These protected islands are thus a quite important place for this threatened species. The size of the population and its location on two protected islands should favour studies on the biology and the ecology of the species. Hypotheses about the origin of the present population and on the factors that might limit its perpetuity are discussed.