Effects of livestock removal and perennial grass recovery on the lizards of a desertified arid grassland

Published source details Castellano M.J. & Valone T.J. (2006) Effects of livestock removal and perennial grass recovery on the lizards of a desertified arid grassland. Journal of Arid Environments, 66, 87-95.
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This study is summarised as evidence for the following.

	Action	Category
	Cease livestock grazing: Grassland & shrubland Action Link

Cease livestock grazing: Grassland & shrubland

A paired sites, controlled study in 2002–2003 of semi-desert shrub and grassland, south-eastern Arizona, USA (Castellano & Valone 2006) found that lizard species richness was similar in ungrazed and grazed sites, but that some species abundances were higher in ungrazed sites, depending on the vegetation type. Species richness was the same in ungrazed and grazed sites (both 7–8 species). In tarbrush-dominated vegetation, two species were more abundant in ungrazed (eastern fence lizards Sceloporus undulatus: 17 individuals; common side-blotched lizards Uta stansburiana: 21) than grazed land (eastern fence: 2; side-blotched: 1), one species was less abundant (round-tailed horned lizards Phrynosoma modestum ungrazed: 3, grazed: 13) and one species had similar abundances (western whiptail Cnemidophorus tigris: 31, 37). For three species sample sizes were too small for analysis (desert spiny Sceloporus magister: 0, 1; ornate tree Urosaurus ornatus: 2, 1; grassland whiptail lizards Cnemidophorus uniparens: 7, 3). In creosote-dominated vegetation, four of eight lizard species abundances were similar in ungrazed and grazed land (eastern fence 26, 17; side-blotched 34, 29; round-tailed horned: 10, 11; western whiptail: 85, 82). For four species, sample sizes were too small for analysis (desert spiny lizard: 2, 3; ornate tree lizard: 3, 4; western banded gecko Coleonyx variegatus: 1, 1; grassland whiptail: 8, 2). A 9 ha area was fenced (post and barbed wire) to exclude livestock in 1958. Grazing continued outside of the enclosure. Lizards were monitored using pitfall traps along 12–13 transects (3–5 traps/transect) that extended from outside to inside the enclosure (60–100 m each side of the enclosure, 20–250 m apart) in August 2002 (728 trap nights) and May–August 2003 (4,620 trap nights). Transects included two vegetation types: tarbrush (1,428 trap nights) and creosote (3,920 trap nights). All lizards, other than western banded geckos, were individually marked with toe clips. Only adults were included in the analysis.

(Summarised by: Guy Rotem, Katie Sainsbury)