Action: Use electric fencing to exclude large native herbivores
- One controlled study in South Africa found that using electric fencing to exclude elephants and nyalas increased tree density.
Activity of large herbivores can result in physical damage and degraded understory species diversity. Excluding large herbivores from forest areas by creating exclosures using electric fences can increase species diversity.
Supporting evidence from individual studies
A controlled study in 2005-2007 in Sand Forest in South Africa (Lagendijk et al. 2011) found that exclusion of elephant Loxodonta africana and nyala Tragelaphus angasii increased tree density. The density of all trees was higher when both species were excluded than unfenced plots (unfenced: ~8,000/ha; elephant excluded: ~10,000; nyala and elephant excluded: ~14,000). The density of seedlings was higher when both species were excluded than unfenced plots (unfenced: ~5,000; elephant excluded: ~6,000; nyala and elephant excluded: ~8,500). There were no differences between treatments for the density of saplings (unfenced: ~2,000; elephant excluded: ~2,500; nyala and elephant excluded: ~3,200) and grown trees (unfenced: ~1,000; elephant excluded: ~1,500; nyala and elephant excluded: ~2,300). Data was collected in 2007 in 12 plots (20 ×20 m) of each treatment: unfenced (accessible to elephants and nyalas), elephant excluded (inside elephant-excluded area of 3.1 km2 surrounded by electrified-wire) and nyala and elephant excluded (wire-fence exclosures to exclude nyalas inside the elephant-free area) treatments. Treatments were applied in 2005 in a 5.2 km2 Sand Forest patch.