Action: Restore or create shrubland
- Only one of the four studies captured investigated the effects of shrubland restoration in isolation. This small before-and-after study from the UK found that one or two pairs of northern lapwing bred on an area of restored moorland, whereas none had previously bred in the area.
- A study from the USA and one from the Azores found that populations of target species (gamebirds and seabirds) increased following shrubland restoration, amongst other interventions.
- A replicated study from the UK which did not distinguish between several interventions performed found a negative relationship between the combined intervention and the ratio of young-to-old grey partridges.
Shrublands are extremely diverse habitats, being found from subantarctic regions, through temperate climates to tropical dry and moist shrublands such as karoo (in South Africa) and restingas (in Brazil). They are also found from sea level up to beyond the tree line in mountains. However, we found relatively few studies describing the effects of shrubland restoration on bird populations, so we have not subdivided the studies further.
Supporting evidence from individual studies
A small 1967 study in Maryland, USA (Burger & Linduska 1967), investigated the impact of planting areas of shrub, as well as other interventions, on northern bobwhites Colinus virginianus and found that the population on the farm increased from five to 38 coveys in eight years. This study is described in detail in ‘Threat: Agriculture – Plant new hedges’.
A small before-and-after study on an area of purple moor grass Molina caerulea dominated moorland in northern England (Smith & Bird 2005) in 2004-5 found that one or two pairs of northern lapwing Vanellus vanellus bred on a an area of restored moorland, whereas none had previously bred in the area. The moorland was mowed and flailed in 2004, which encouraged grass re-growth and subsequent heavy grazing by both livestock and wild red deer Cervus elaphus.
A before-and-after study on Praia Islet (12 ha), off Graciosa, Azores, Portugal (Bried et al. 2009), found that the breeding populations of common terns Sterna hiundo, roseate terns S. dougallii and Madeiran storm petrel Oceanodroma castro increased dramatically after European rabbit Oryctolagus cuniculus eradication and subsequent habitat restoration. Restoration included the planting of native shrubs, the removal of non-native species and the control of soil erosion. This study is also discussed in ‘Provide artificial nesting sites’ for ground-nesting and burrow-nesting seabirds.
A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) investigated the impact of scrub restoration on grey partridge Perdix perdix. However, the study does not distinguish between the impacts of scrub restoration, scrub control, rough grazing and the restoration of various other semi-natural habitats. There was a negative relationship between the combined intervention and the ratio of young to old partridges in 2008.
- Burger G.V. & Linduska J.P. (1967) Habitat Management Related to Bobwhite Populations at Remington Farms. The Journal of Wildlife Management, 31, 1-12
- Smith D. & Bird J. (2005) Restoration of degraded Molinia caerulea dominated moorland in the Peak District National Park Eastern moorlands, Derbyshire, England. Conservation Evidence, 2, 101-102
- Bried J., Magalhaes M.C., Bolton M., Neves V.C., Bell E., Pereira J.C., Aguiar L., Monteiro L.R. & Santos R.S. (2009) Seabird habitat restoration on Praia Islet, Azores Archipelago. Ecological Restoration, 27, 27-36
- Ewald J.A., Aebischer N.J., Richardson S.M., Grice P.V. & Cooke A.I. (2010) The effect of agri-environment schemes on grey partridges at the farm level in England. Agriculture, Ecosystems & Environment, 138, 55-63