Effects of Habitat Fragmentation and Management Practices on Desert Lizards
Investigators (most current known information)
Our previous study (IALC project 97R-15) pointed at some effects of the JNF plantations in the Sayeret Shaked Park. We found a different composition of species in the planted plots. A critically endangered species (A. beershebensis) clearly avoided the planted plots in the Park. In the current study we aimed to expand the understanding of two management practices used in the same area: planting trees and livestock grazing. Using a combination of observations and manipulations we found that plantations affect community structure and the relative abundance of species not only in the planted plots, but also in their vicinity. The composition of lizards differs in the Park, compared with that of natural areas, due to species replacement. We found support to the hypothesis that these effects are caused by an increase in predation risk in the plantations. As a test to this hypothesis we "planted" metal trees, in the habitat of the lizard A. beershebensis, simulating the effect of planting trees. As expected, we witnessed an increase in avian predator activity. The following parameters were modified as a result of the manipulation: frequency of missing tails, population density, body size and condition, infestation by external parasites, morphological asymmetry, and running speed of juveniles. Unlike some other lizards, A. beershebensis seems rigid in its typical risky foraging behavior, and this may be the reason for its vulnerability to predation, and its absence from the planted plots.
Livestock grazing was found to have negative effects on A. beershebensis. However, at low levels, grazing ameliorates the habitat and prevents the modification of the habitat to densely vegetated habitat, poorly suited for this endangered lizard. We propose management practices that are aimed at preserving the sensitive community in the loess plains.
Articles in Journals
Hawlena, D. and A. Bouskila. 2006. “Land management practices for combating desertification cause species replacement of desert lizards.” Journal of Applied Ecology 43:701-709.
Hawlena, D., R. Boochnik, Z. Abramsky, and A. Bouskila. 2006. “Blue tail and striped body: why do lizards change their infant costume when growing up?” Behavioral Ecology http://dx.doi.org/10.1093/beheco/arl023 Advance Access publication 13 July 2006.
Hawlena, D. A, Bouskila and Z. Abramsky. 2005. Bird's predation or ectoparasite infestation: Manipulative field experiment assessing increased predation effects on parasite infestation. (in press).
Hawlena, D. A, Bouskila and Z. Abramsky. To be eaten or to be parasitised- possible relationship between predation and infestation. (in review).
Hawlena, D. & A. Bouskila. Effects of large scale land management practices on the lizard assemblage in an arid landscape. (in review).
Bouskila, A. and R. Boochnick. 2005. The risk associated with foraging modes: a comparison between Lacertid foragers. Proc. of the Fifth World Congress of Herpetology June 2005. Stellenbosch, Republic of South Africa.
Hawlena, D., A. Bouskila, and Z. Abramsky. 2005. Foraging mode may indicate why growing-up lizards lose their infant costume of blue tail and striped body. Proc. of the Fifth World Congress of Herpetology June 2005. Stellenbosch, Republic of South Africa.
Boochnik, R. and A. Bouskila. 2000. "Resource partitioning between adults and juveniles of the desert lizard Acanthodactylus boskianus" In Proceedings of the joint herpetological meeting of ASIH, HL and SSAR, July. La Paz, Mexico.
Hawlena, D. and A. Bouskila. 2000. "Effect of habitat fragmentation and patch alteration on the northern Negev lizards assemblage" In Proceedings of the joint herpetological meeting of ASIH, HL and SSAR, July. La Paz, Mexico.
Annual meeting of the Zoological Society of Israel. 2000. Effect of anthropogenic patch alteration on the lizard assemblage in arid landscape, December. Ben-Gurion University of the Negev, Beer-Sheva, Israel.
80th annual meeting American Society of Ichthyologists and Herpetologists. 2000. Effects of large scale land management practices on the lizard assemblage in an arid landscape, June. Universidad Autonoms de Baja California Sur, La Paz, Mexico.
Biological Society of Ethiopia and the Linnean Society of London, Ethiopia: A biodiversity challenge. 2000. "Effect of habitat alteration on the lizard assemblage in arid landscape," February. Addis Ababa University, Ethiopia.
Hawlena, D. and A. Bouskila. 2000. "Estimation of the importance of the Hirbet Hasif area for the conservation of the endangered lizard, Acanthodactylus beershebensis." Report prepared for the Forestry Department of the Jewish National Fund, Southern District. Israel. (in Hebrew).
Boochnik, R. 2001. Title? M.S. Thesis. Ben-Gurion University of the Negev. Sede Boker, Israel.
Hawlena, D. 2000. Title? M. S. Thesis. Ben-Gurion University of the Negev. Sede Boker, Israel.
Projects of Third-year Undergraduate Students
Adout, A. 2001. Ben-Gurion University of the Negev. Sede Boker, Israel.
Hawlena, D. 1998. Ben-Gurion University of the Negev. Sede Boker, Israel.
Gil, P. 2000. Ben-Gurion University of the Negev. Sede Boker, Israel.
Salomon, M. 2000. Ben-Gurion University of the Negev. Sede Boker, Israel.
Hawlena, D. 1998. Yoav Livne Award, for the Best Research Project, Department of Life Sciences, Ben-Gurion University of the Negev, June. Israel.