Rubio, J. L. & V. Martín

Habitat use by peripheral populations of a lizard with a highly restricted distribution range, the Spanish algyroides, Algyroides marchi. pp. 405-412.

Abstract. Peripheral populations are considered vulnerable but important for conservation. The Spanish algyroides is a small and endangered lacertid lizard, endemic to a small area in the southeastern mountains of the Iberian Peninsula. It is a stenotopic species that will typically inhabit shaded and humid microhabitats in enclosed rocky situations. These habitat preferences relate to a very low thermal inertia and high evaporative water loss consistent with its small body size. Its patchy distribution is delimited by dryer and warmer lowlands. Newly detected localities seemed to expand its known distribution range, providing a contact zone with core populations. We studied the habitat selection and conservation status of populations living in the border zone, produced a species distribution model of the new area, and compared border versus core structural and environmental variables. The results confirmed the predicted occurrence, showing no differences in border vs. core selected habitat characteristics. From the perspective of habitat selection alone, edge effects and local adaptation seem insignificant. This could be related to the ‘hard-type edge’ and ‘two-patch system’ of the small distribution of this species. Detected alterations of the habitat in this border area were mainly road and forest track construction, urbanisation, and livestock grazing. In the longer term, aridification of the area due to the global climate change could potentially gain importance, considering the dependency of the species on humid habitats, and the proximity of the edge of its distribution to the uninhabitable lowlands that determine its range limits. It is of great importance to identify the shape of the whole edge of this species’ range, effect in-depth evaluations, and monitor its conservation status.
Key words. Edge populations, habitat selection, reptile conservation, species distribution model, Spain.