Predation by rodents and the distribution and abundance of the snail Trochoidea seetzenii in the Central Negev Desert of Israel

The desert snail Trochoidea seetzenii exhibits a regular pattern of spatial distribution in the Central Negev drainage basin : high density at the wadi bottom, gradually decreased density toward the top, and very low density at the hill tops. This pattern might be the result of increasing predation pressure by rodent species along the slope (...) To test the hypothesis that predators limit the distribution of rodents along the slopes, we constructed artificial shelters along an entire slope (...) We also collected data from a long term manipulation of shelters (27 yr) and found that the snail density is significantly and drastically reduced relative to a control plot. Snail density along the hillside is also correlated with the number of shrubs and the availability of egg laying sites. Predation, shrubs, and laying sites determine the basic distribution pattern of the snails in the area