HABITAT RELATIONSHIPS OF THE LIZARD FAUNA IN THE RAMON EROSION CIRQUE, NEGEV HIGHLANDS (ISRAEL)

Lizards were censused in the Ramon erosion cirque (Central Negev, Isra el) in 1994 on 24 one-ha plots. Fifteen quantitative habitat variables , describing soil and vegetation structure, were measured at 25 points of each plot. Data were analysed to examine a classification of habit at types based on lizard species composition and the sets of environme nt variables influencing density of each lizard species. Three hundred and fifty three individuals of 14 lizard species were recorded on the sampling plots. Of these species, only one (Acanthodactylus boskianus ) was abundant, eight (Ptyodactyhus guttatus, Stenodactylus sthenodact ylus, Mesalina guttulata, M. olivieri, Ophisops elegans, Ablepharus ki taibellii, Chalcides ocellatus, Eurnesces schneiderii) were common, an d five (Laudakia stellio, Pseudotrapelus sinaitus, Trapelus pallidus, Hemidaetylus turcicus, tropiocolotes steudneri) were rare. Four main h abitat types and two sub-types were distinguished: wadis among loess h ills (I); rock outcrops among loess hills (II); rock outcrops among gr avel plains (III); wadis among gravel plains (IVa); open gravel plains (IVb), and sand dunes (IVc). Lizard density and biomass were greatest (15-19 ind./ha; about 200 g/ha) in IVb, and IVc, and least(3.7 ind./h a; 38 g/ha) in III. Lizard species richness and diversity were low (th ree species) in IVc and higher and similar (6-10 species) in all other habitat types. Among common and abundant species, densities of three (A. boskianus, O. elagans, A. kitaibellii) were highly (30-60 % of den sity dispersion) affected by habitat variables and densities of six (P . guttatus, S. sthenodactylus M. guttulata, M. olivieri, C. ocellatus, E. schneiderii) were weakly (13-30% of dispersion) affected. Densitie s of S. sthenodactylus, A. boskianus, and M. guttulata were determined mainly by soil structure, of M. olivieri and O. elegans mainly by str ucture of annual vegetation, and of C. ocellatus, A. kitaibellii, and E. schneiderii mainly by the structure of shrub vegetation. Density of P. gutratus was determined by both soil and annual vegetation structu re.