Action

Provide 'sacrificial' grasslands to reduce the impact of wild geese on crops

How is the evidence assessed?
  • Effectiveness
    20%
  • Certainty
    5%
  • Harms
    not assessed

Study locations

Key messages

  • All six studies from the UK (including four replicated, controlled trials) found that managing grasslands for geese increased the number grazing there. Two replicated, controlled studies found that fertilized and cut areas were grazed by more white-fronted geese or brent geese than control areas. A replicated, controlled trial found that re-seeded and fertilized wet pasture fields were used by more barnacle geese than control fields, and that fertilized areas were used less than re-seeded ones. A replicated, controlled study found that spring fertilizer application increased the use of grassland fields by pink-footed geese. A replicated study found that plots sown with white clover were preferred by dark-bellied brent geese compared to plots sown with grasses.
  • However, four of the studies found that the birds were moving within a relatively small area (i.e. within the study site) and therefore the grasslands may not reduce conflict with farmers.

 

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 replicated, controlled trial in the winter of 1972-1973 at a 6 ha pasture (periodically flooded by saltwater) in Gloucestershire, UK (Owen 1975), found that significantly more greater white-fronted geese Anser albifrons fed on fertilized and cut areas, compared to control areas (overall average of 30-35% of geese on cut, fertilized areas vs 17-20% on control areas, maximum of 65% use of cut, fertilized areas vs 20% for controls). Preferences decreased over time as preferred areas lost vegetation and became more crowded. Vegetation from experimental areas had a higher nitrogen content than that from control areas. Fertilization consisted of 125 kg/ha of ‘nitro-chalk’ - 25% nitrogen - applied in mid October. In mid-October, the grass was also cut to approximately 8 cm.

    Study and other actions tested
  2. A before-and-after study in Gloucestershire, England (Owen 1977) found that up to 87% of geese on a grassland site used a 130 ha area managed for them in 1975-1976. The main management practice was to change the stocking regime of the site.

    Study and other actions tested
  3. A replicated, controlled trial in 1984-1987 on a reserve on the island of Islay, west Scotland (Percival 1993) found more barnacle geese Branta leucopsis used wet pasture fields if they were re-seeded or fertilized than if they were unmanaged. However, fewer geese used fertilized fields than re-seeded ones. Fertilizers were either 34.5% nitrogen in pellet form (at 125 kg/ha), or ‘nitrochalk’ – 25% nitrogen in granular form – (at 175 kg/ha) and spread in October (wet and dry fields) and March (dry fields only). However, increases in barnacle geese were due to a redistribution of local birds, rather than new birds visiting the reserve. The author therefore suggests that improving the reserve grasslands will only minimally reduce conflict with farmers elsewhere on the island.

    Study and other actions tested
  4. A series of replicated controlled trials on grassland sites at two reserves in Essex, England, between 1990 and 1992 (Vickery et al. 1994) found that brent geese Branta bernicla grazed at significantly higher densities on fertilized and cut areas, compared to unfertilized areas, but only at high levels of fertilizer application (50 kg N/ha used: 28-30 droppings/m2 for fertilized areas vs 23-28 droppings/m2 for controls, 18 kg N/ha used: 30-35 droppings/m2 for fertilized areas vs 25-35 droppings/m2 for control areas). There were no differences between trials using organic and inorganic fertilizer.

    Study and other actions tested
  5. A replicated study in the winters of 1992-1993 and 1993-1994 on an arable field on Thorney Island, West Sussex, England (McKay et al. 2001) found that dark-bellied brent geese Branta bernicla bernicla preferentially foraged on plots sown with white clover Trifolium repens, compared to three grass species (10-13 droppings/m2 for 12 clover plots vs 0-5 droppings/m2 for 36 grass plots). There were no differences between grass species (perennial rye grass Lolium perenne, red fescue Festuca rubra or timothy Phleum pratense). Plots were established in spring 1991 and preferences were found in both years, although more geese used grass plots in 1993-1994.

    Study and other actions tested
  6. A replicated, controlled study in 1990-1993 at a reserve in Aberdeenshire, Scotland (Patterson & Fuchs 2001), found that spring fertilizer application in 1990-1991 significantly increased the use of grassland fields by pink-footed geese Anser brachyrynchus, until applications of approximately 80 kg N/ha (1990: average of 13-14 goose droppings/m2 with no application vs 18-22 droppings/m2 with 40 kg N/ha, 28 droppings/m2 with 80 kg/m2 and 27-31 droppings/m2 with 120-160 kg N/ha; patterns in 1991 were similar but with fewer droppings). However, two slow-release fertilizers did not affect foraging densities in winter 1990-1992 (average of 24.5-26.7 droppings/m2 for fertilized vs 24 droppings/m2 for control grasslands). Split fertilizer application did not increase field use, compared to a single application (average of 11 droppings/m2 for fields with split applications vs 10 droppings/m2 for single applications), although the authors note it may reduce nitrogen leaching.

    Study and other actions tested
Please cite as:

Dicks, L.V., Ashpole, J.E., Dänhardt, J., James, K., Jönsson, A., Randall, N., Showler, D.A., Smith, R.K., Turpie, S., Williams, D.R. & Sutherland, W.J. (2020) Farmland Conservation. Pages 283-321 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

Farmland Conservation

This Action forms part of the Action Synopsis:

Farmland Conservation
What Works 2021 cover

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, mammals, 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