Relative impacts of cattle grazing and feral animals on an Australian arid zone reptile and small mammal assemblage

Published source details Read J.L. & Cunningham R. (2010) Relative impacts of cattle grazing and feral animals on an Australian arid zone reptile and small mammal assemblage. Austral Ecology, 35, 314-324.
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This study is summarised as evidence for the following.

	Action	Category
	Modify grazing regime: Grassland & shrubland Action Link
	Use fencing to exclude predators or other problematic species Action Link
	Remove or control predators using fencing and/or aerial nets Action Link
	Remove or control invasive or problematic herbivores and seed eaters Action Link
	Exclude livestock from semi-natural habitat (including woodland) Action Link
	Cease livestock grazing: Grassland & shrubland Action Link

Modify grazing regime: Grassland & shrubland

A replicated, paired sites, site comparison study in 1993–1996 and 2007 in chenopod scrubland in South Australia, Australia (Read & Cunningham 2010) found overall reptile species richness and abundances did not show a clear response to different grazing intensities. Overall reptile species richness was 9 species/site in light and medium grazing sites and 10 species/site in heavy grazing sites (numbers taken from figure 6). Of 38 species recorded, no individual species or species group (agamid lizards, skinks, geckos) abundances changed in response to different grazing intensities alone (results reported as model outputs, see paper for other factors affecting individual abundances). However, gecko capture rates may have been lower in light grazing sites (8 individuals/site) compared to medium grazing (13 individuals/site), but similar to heavy grazing (8 individuals/site; number taken from figure 6). Four paired sites of differing grazing pressure were set out in 1993 (low intensity grazing: <12 cattle dung/ha; medium: 12–100; high: >120). Reptiles were sampled for 10 days in summer from 1993–1996 and again in 2007 using 300 mm long flymesh drift fences with 13 unbaited pitfall traps (500 mm deep x 150 mm wide, 8 m apart).

(Summarised by: Maggie Watson, Guy Rotem, Katie Sainsbury)
Use fencing to exclude predators or other problematic species

A site comparison study in 1993–2007 on a shrubland site in South Australia (Read & Cunningham 2010) found that using fencing to exclude feral mammals (cats Felis catus, foxes Vulpes vulpes and rabbits Oryctolagus cuniculus) increased the abundance and species richness of small mammals. Small mammal abundance in the absence of feral mammals (10.3 individuals/sample) was higher than where feral mammals were present (3.6 individuals/sample). Species richness followed a similar pattern (feral mammals absent: 3.0 species/sample; feral mammals present: 1.7 species/sample). An area of approximately 5 × 5 km was fenced to exclude feral mammals and cattle in 1999. An adjacent area, approximately 9× 9 km, was fenced in 1986 to exclude cattle, but not feral mammals. Small mammals were sampled using pitfall traps for a 10-day period in either December or January. Three points in the feral mammal and cattle exclosure were sampled in 2007. Five points in the cattle-only exclosure were sampled in 1993–1996 and again in 2007.

(Summarised by: Nick Littlewood)
Remove or control predators using fencing and/or aerial nets

A paired sites, controlled, before-and-after study in 1993–1996 and 2007 in chenopod scrubland in South Australia, Australia (Read & Cunningham 2010) found that fencing to exclude predators and herbivores had mixed effects on different reptile species and species groups. One gecko species increased and two geckos decreased in abundance after exclusion fencing was added, compared to before when the same plots were grazed (knob-tailed gecko Nephrurus levis after fencing: 3.3 individuals/plot vs. grazed: 0.3–0.5 individuals/plot; tessellated gecko Diplodactylus tessellatus 0.0 vs. 1.3–1.8; variable fat-tailed gecko Diplodactylus conspicullatus 0.4 vs. 1.5–1.9). See paper for details of other species responses. Five grazed sites and four paired sites of differing grazing pressure were set out in 1993 (low intensity grazing: <12 cattle dung/ha; medium: 12–100; high: >120). Following the initial four years of the study, three of the eight grazing pressure sites were fenced to exclude cattle and predators. Reptiles were sampled for 10 days in summer from 1993–1996 and 2007 using 300 mm long flymesh drift fences with 13 unbaited pitfall traps (500 mm deep x 150 mm wide, 8 m apart). Lizards were marked by toe clips.

(Summarised by: Maggie Watson, Katie Sainsbury)
Remove or control invasive or problematic herbivores and seed eaters

A paired sites, controlled, before-and-after study in 1993–1996 and 2007 in chenopod scrubland in South Australia, Australia (Read & Cunningham 2010) found that fencing to exclude herbivores and predators had mixed effects on different reptile species and species groups. One gecko species increased and two geckos decreased in abundance after exclusion fencing was added, compared to before when the same plots were grazed (knob-tailed gecko Nephrurus levis after fencing: 3.3 individuals/plot vs. grazed: 0.3–0.5 individuals/plot; tessellated gecko Diplodactylus tessellatus 0.0 vs. 1.3–1.8; variable fat-tailed gecko Diplodactylus conspicullatus 0.4 vs. 1.5–1.9). See paper for details of other species responses. Five grazed sites and four paired sites of differing grazing pressure were set out in 1993 (low intensity grazing: <12 cattle dung/ha; medium: 12–100; high: >120). Following the initial four years of the study, three of the eight grazing pressure sites were fenced to exclude cattle and predators. Reptiles were sampled for 10 days in summer from 1993–1996 and 2007 using 300 mm long flymesh drift fences with 13 unbaited pitfall traps (500 mm deep x 150 mm wide, 8 m apart). Lizards were marked by toe clips.

(Summarised by: Maggie Watson, Katie Sainsbury)
Exclude livestock from semi-natural habitat (including woodland)

A site comparison study in 1993–2007 on a shrubland site in South Australia, Australia (Read & Cunningham 2010) found that excluding cattle increased abundances of small mammals compared to high intensity cattle grazing but not to medium or low grazing intensities. The average number of small mammals/sample at ungrazed points (3.6 individuals) was higher than with intensive cattle grazing (1.7 individuals) but not higher than the numbers with medium- (5.0) or low-intensity cattle grazing (7.7). Species richness followed a similar pattern (ungrazed: 1.7 species; intensive grazing: 1.2 species; medium grazing: 1.7, low intensity grazing: 2.2 species). Livestock were fenced out from an approximately 9 × 9-km area in 1986. Small mammals were sampled using pitfall traps for a 10-day period in either December or January 1993–1996 and again in 2007. Five points were sampled inside the enclosure (ungrazed) with 13 outside (grazed). Cattle grazing intensity was determined by dung counts. Low intensity grazing was <12 dung/ha, medium grazing was 12–100 dung/ha and intensive grazing was >120 dung/ha.

(Summarised by: Nick Littlewood)
Cease livestock grazing: Grassland & shrubland

A paired sites, controlled, before-and-after study in 1993–1996 and 2007 in chenopod scrubland in South Australia, Australia (Read & Cunningham 2010) found that the effect of ceasing grazing on abundance varied depending on the species. After fencing to exclude livestock, one gecko species increased (knob-tailed gecko Nephrurus levis after fencing: 3.3 individuals/plot; before fencing: 0.3–0.5 individuals/plot) and two geckos decreased (tessellated gecko Diplodactylus tessellatus after fencing: 0.0; before fencing: 1.2–1.7; variable fat-tailed gecko Diplodactylus conspicullatus after fencing: 0.4; before fencing: 1.5–1.9) in abundance compared to beforehand when the same plots were grazed. The abundance of five other species remained similar after grazers were excluded (see paper for details). Four paired sites of differing grazing pressure were set out in 1993 (low intensity grazing: <12 cattle dung/ha; medium: 12–100; high: >120). After four years, three of the eight grazing pressure sites were fenced to exclude cattle and predators. Reptiles were sampled for 10 days in summer from 1993–1996 and 2007 using 300 mm long flymesh drift fences with 13 unbaited pitfall traps (500 mm deep x 150 mm wide, 8 m apart).

(Summarised by: Maggie Watson, Guy Rotem)