Reduce numbers of large herbivores

How is the evidence assessed?
  • Effectiveness
    70%
  • Certainty
    30%
  • Harms
    0%

Study locations

Key messages

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A before-and-after trial from 1980 to 2012 in coastal shrubland on Santa Cruz island, USA (Beltran et al. 2014) found that reducing grazing pressure by removing feral sheep, cattle, and horses increased shrub cover and reduced grass cover. After 20 years, cover of woody species was higher after the removal of sheep, cattle, and horses (24%) than before removal (1%), but cover of herbaceous plants did not differ significantly (after: 66%, before: 60%). Cover of bare ground was lower after the removal of sheep, cattle, and horses (9%) than before removal (39%). Sheep, cattle, and horses were removed from the island between 1981 and 1989. In 1980 and 2012 twenty 30 m transects were used to survey vegetation. Every 1 m along the transects the vegetation type was identified and cover was estimated.

    Study and other actions tested
  2. A replicated study in 1991–2001 in two moorland sites in the Cairngorms, UK (Welch et al. 2006) found that reducing grazing pressure by red deer Cervus elaphus increased the cover and height of heather Calluna vulgaris. Nine years after the reduction of grazing pressure by deer, the cover of heather had increased by 6% in one site and by 2% in the other. Additionally, mean height of heather increased from 17 cm to 19 cm in one site and from 25 cm to 29 cm in the other. Deer numbers were reduced by culling and, in one site, grazing pressure was also reduced by localized winter feeding. As a result, between 1992 and 2001, the mean number of deer pellet groups on 60 m2 plots felt from 26.3 to 22.9 in one site and from 17.2 to 5.7 in the other. Sampling plots of 15 m x 4 m (90 in one site and 96 in the other) were visited annually and, at each plot, 25 measures of heather height were taken. Additionally, heather cover was measured at each plot using a sampling stick with four 8 cm diameter circles at 10 positions and by counting the circles containing heather.

    Study and other actions tested
Please cite as:

Martin, P.A., Rocha, R., Smith, R.K. & Sutherland, W.J. (2020) Shrubland and Heathland Conservation. Pages 483-525 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Shrubland and Heathland Conservation

This Action forms part of the Action Synopsis:

Shrubland and Heathland Conservation
Shrubland and Heathland Conservation

Shrubland and Heathland Conservation - Published 2017

Shrubland and Heathland synopsis

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 18

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust