Effects Of Habitat Fragmentation And Patch Alteration On Desert Lizards

Amos Bouskila, Mark Anderson (NMSU), Dror Hawlena and Rami Boochnik

Habitat alterations by anthropogenic disturbances, and especially the effects of habitat fragmentation on animals, are often studied in forests. Nevertheless, patchiness and the scale of patches seem to be very important in desert ecosystems. Therefore, the effects of human modification of natural patterns of patchiness in drylands need to be addressed. The goal of this study is to examine the influence of fragmentation and patch alteration on communities of lizards in arid ecosystems. Lizards are important contributors to ecosystems, especially in arid zones: lizards may occur in very high densities and they are predators of arthropods, prey for larger vertebrates and burrow diggers. The study is performed in the Negev Desert, in the Sayeret Shaked Park.We concentrate on a medium-scale patch alteration, utilizing a project of "Savannization" which is conducted in order to restore desertified areas. High productivity patches are added to the natural slopes as part of the project, and we examine the effects of this addition on the lizard species inhabiting this region. We look at habitat selection, relative abundance, survival and reproductive success of each species. In addition, by direct observation and food abundance analysis, we will find the mechanisms that contribute to the patterns that will be detected. We will examine what inthe ecology of the lizards is affected by the habitat alterations and which of the species benefit from them. The study includes also an investigation in New Mexico, where the effects of fragmentation by human dwelling and development is assessedon a community of lizards.

This study covers both community and population level processes, as well as the level of the individual lizard, leading to a better understanding of the effects of human management on an important component of arid ecosystems. It will allow to evaluate the costs and the benefits of the current management practices in terms of the effects on the fauna, and will help in maintaining sustainable management of arid lands.

 

The endangered species Acanthodactylus beershebensis	(photo: A. Bouskila)