Study

The effects of winter burning and grazing on resources and survival of Texas horned lizards in a thornscrub ecosystem

  • Published source details Hellgren E.C., Burrow A.L., Kazmaier R.T. & Ruthven D.C. (2010) The effects of winter burning and grazing on resources and survival of Texas horned lizards in a thornscrub ecosystem. Journal of Wildlife Management, 74, 300-309.

Actions

This study is summarised as evidence for the following.

Action Category

Modify grazing regime: Grassland & shrubland

Action Link
Reptile Conservation

Use prescribed burning: Forest, open woodland & savanna

Action Link
Reptile Conservation
  1. Modify grazing regime: Grassland & shrubland

    A site comparison study in 1998–2001 in an area of thornscrub in southern Texas, USA (Hellgren et al. 2010) found Texas horned lizard Phrynosoma cornutum survival was higher under moderate grazing than heavy grazing, but highest in ungrazed sites. Survival of Texas horned lizards over four-months periods was higher in moderately-grazed sites (54%) than in heavily-grazed sites (33%) but lower than in ungrazed sites (77%). Lizard survival was monitored in a wildlife management area (6,500 ha) in three sites (50–60 ha), each with a different grazing regime: the ungrazed site had not been grazed since 1976, the moderately-grazed site was stocked at 30–50 steers/ha/day and the heavily-grazed site had 75–100 steers/ha/day. Lizards were captured by searching roads, chance encounters and drift fences with pitfall traps. Lizards were marked with a PIT tag and toe clips and fitted with a radio transmitter (ungrazed: 20 lizards, moderately grazed: 43 lizards, heavily grazed: 44 lizards). Lizards were located at least once every 24 hours for four months from mid-April to mid-August in 1998–2001.

    (Summarised by: Guy Rotem, Katie Sainsbury)

  2. Use prescribed burning: Forest, open woodland & savanna

    A site comparison study in 1998–2001 in thornscrub in southern Texas, USA (Hellgren et al. 2010) found Texas horned lizard Phrynosoma cornutum survival was similar in prescribed burned and unburned sites. Four-month survival rates of Texas horned lizards were similar between burned and unburned sites that were also subject to livestock grazing (burned: 47%, unburned: 35%). Lizard survival rates were initially higher in the May–June in the second year after burning than in the first year after burning, but overall annual survival rates were similar between the two years (second year after burning: 49%, first year: 32%). Lizard survival was monitored in burned and unburned sites (50–60 ha each) in a wildlife management area (6,500 ha). Lizards were captured by searching roads, chance encounters and drift fences with pitfall traps. Lizards were marked with a PIT tag and toe clips, and fitted with a radio transmitter. Lizards were located at least once every 24 hours for four months from mid-April to mid-August in 1998–2001 (burned sites: 48 lizards, unburned sites: 39 lizards).

    (Summarised by: Guy Rotem, Katie Sainsbury)

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