Habitat use by the arid-dwelling land snail Iberus g. gualtieranus

Iberus gualtieranus gualtieranus is an arid-dwelling land snail that needs to use karstic fissures as refuge in order to survive in arid environments. Karstic fissures are primarily on vertical rocky walls. Because displacement is costly to terrestrial gastropods, it is predictable that this snail will move on vertical substrates near its refuges. However, this species eats primarily phanerogam plants, which are placed on bare soil in horizontal surfaces. Thus, it is also predictable that this snail will move on horizontal substrates far of its refuges. In the present study, this contradiction is examined. Results show that this snail moves far of its refuges to forage on horizontal substrates, while is sheltered in fissures on vertical and rocky surfaces. This suggests that the need of a refuge for survive imposes on this species a habitat use based in the alternation of two microhabitats: vertical and rocky substratum when inactive, and horizontal and bare soil when active. r 2006 Elsevier Ltd. All rights reserved.