Susceptibility of lizards to predation under two levels of vegetative cover

The risk of increased predation is a potential cost for habitat specialists, when dispersing through non-habitat matrix. We hypothesized that dispersal success of lizards is limited by the loss of vegetative cover, as occurs with overgrazing, due to increased susceptibility to predation. We analyzed the movement behavior of the saxicolous lizards (Liolaemus elongatus and Phymaturus patagonicus) in the Patagonian steppe using a habitat generalist (Liolaemus bibroni) as a control species. We compared the proportion of stops on bare ground during movement in two experimental enclosures with different levels of vegetative cover. Both specialists and generalists stopped more frequently on bare ground when there was less vegetative cover, and specialists stopped more frequently than generalists on bare ground. We found no significant difference in the time it took specialists to reach the end of the enclosure in the two different levels of vegetative cover. Additionally we compared the time to capture by a human predator under the two levels of vegetative cover. All species were captured more quickly when there was less vegetative cover and we found a tendency towards shorter capture times in specialists than in generalists. Our results suggest that saxicolous lizards are more susceptible to predation with less vegetative cover.