The Herpetological Journal

DOI: https://doi.org/10.33256/36.3.209223

pp. 209-223

Authors: Florian Desigaux, Killian Martin, Bernard Thierry & Damien Chevallier

Abstract: We investigated the geographical areas inhabited by the Critically Endangered Lesser Antillean iguana Iguana delicatissima and the invasive common green iguana Iguana iguana in Martinique. Invasive iguanas pose a significant threat to endemic iguanas when they co-occur. Our objective was to examine how landscapes influence the coexistence of these species by focusing on landscape composition, configuration, altitude and the proximity to watercourses. We analysed data collected on 4,085 individuals (I. delicatissima n = 942; I. iguana n = 3,143) between 1998 and 2022. The methodology involved a 'landscape-centred' approach, which entailed categorising the landscape to assess patterns of habitat utilisation and distribution. Our results showed that the two species used different landscape types, with invasive iguanas occupying more urbanised and mixed landscapes. This indicates that they had a broader habitat range compared to the more specialised endemic iguanas. The latter were more frequently associated with unfragmented landscape types, forest areas, higher elevations and areas near to watercourses. Habitat characteristics in Martinique did not significantly influence encounters between the two species, suggesting that the threats posed by the invasive iguanas are not directly linked to landscape use. However, there are potential pathways for the spread of the invasive iguana across the island, particularly along the urbanised coast, which could lead to encounters between the two species. The study highlights the need for effective management of landscape configurations to conserve biodiversity and mitigate the impacts of invasive species in a context of increasing urbanisation and habitat fragmentation on French islands.

Keywords: reptile, iguana, landscape, conservation, invasive species