Action: Use fences to exclude large herbivores
Key messagesRead our guidance on Key messages before continuing
- One controlled study in the USA found that using fences to exclude deer increased the height of shrubs, but not shrub cover.
High densities of large herbivores such as deer or non-native feral livestock have been shown to reduce species diversity and limit the regeneration of shrublands in some parts of the world (Perea et al. 2014). Using fences to exclude these species from shrublands may help plants to increase in height and cover.
Perea, R., Girardello, M. & San Miguel, A. (2014) Big game or big loss? High deer densities are threatening woody plant diversity and vegetation dynamics. Biodiversity and Conservation, 23, 1303-1318.
Supporting evidence from individual studies
A controlled study in 2001–2006 in chaparral shrubland that had been cut to reduce wildfires in California, USA (Potts et al. 2010) found that using fences to exclude deer from shrubland increased the height of shrubs, but not shrub cover after three years. In plots that were fenced to exclude deer, shrubs were taller in one of two years (67 cm) than in plots that were not fenced (55 cm). However, shrub cover in plots that were fenced was not significantly different to that in plots that were not fenced (data not presented). Fuel reduction treatments to reduce wildfire risk were carried out in all plots in 2001–2003. In 2003 mesh fences 1.5 m tall were built around five 2.5 m2 quadrats and five quadrats were left unfenced. The height and cover of vegetation in all quadrats was assessed by eye in 2005 and 2006.