Primeros datos sobre la población de lagarto negro (Gallotia simonyi simonyi STEIND.) de la Isla de Hierro1

Abstract

AbstractThis paper presents the first data on the ecology of the Giant Hierro Lizard (Gallotia simonyi simonyi) from Canary Islands; this animal was believed to be extinct until its recent finding, in 1975. The biotope, a very steep rocky cliff, almost inaccessible in many places, is described; the climate of the area is subdesertic and the plant cover, very sparse, is xerophytic; the vertebrate fauna is poor, but insects are abundant and diverse. The colour of this lizard is almost black, with large dull grey patches at the sides in the adults, while in the youngs the colour is earthly brown with whitish dorsal stripes. The largest specimen we measured was near 70 cm from snout to tail's end. Daily activity begins in young specimens when the sun reaches the area, while in the adult ones activity begins somewhat later, even at noon for the oldest animals. The diet consists entirely of plants, and includes lignified stems and other non-nourishing parts from several species (Kleinia neriifolia, Lavandula abrotanoides, etc.). Obviously there exists a strong intraspecific competition for food. The number of animals was very low in September 1975, about 200 specimens, half of them or more being young. This number might have been increased by now through protective measures recently adopted. Nevertheless, the status of the population is still critical and the danger of its extinction is strong. Some recent plans to modify the area, building industrial facilities nearby, may have, of course, very bad effects on this lizard.