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Providing evidence to improve practice

Individual study: Increasing crop diversity, reducing chemical inputs and providing set aside increase farmland bird populations in Bedfordshire, England

Published source details

Henderson I.G., Ravenscroft N., Smith G. & Holloway S. (2009) Effects of crop diversification and low pesticide inputs on bird populations on arable land. Agriculture, Ecosystems & Environment, 129, 149-156


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Sow crops in spring rather than autumn Bird Conservation

A before-and-after site comparison study in 2000-2005 in Bedfordshire, England (Henderson et al. 2009), found that fields sown with wheat in spring held significantly more skylarks Alauda arvensis, seed-eating songbirds and insect-eating birds than winter-sown wheat. In addition, 20 bird species showed significant population increases on a 61 ha site where the area of spring-sown wheat and naturally regenerated set-aside was increased over the study period. Increases were lower or absent on an 80 ha area of farmland adjacent to the experimental area and without the land use change. Five species were recorded breeding for the first time after management started. Ten species showed no significant increase on the study site, whilst none decreased significantly. The biggest increases occurred in the first three years of management and were higher for farmland birds than for woodland birds. This study also investigated the impact of reducing pesticide and fertiliser inputs (see ‘Reduce pesticide or herbicide use generally’) and of set-aside (see ‘Provide or maintain set-aside’).

 

Plant crops in spring rather than autumn Farmland Conservation

A before-and-after site-comparison study in 2000-2005 in Bedfordshire, England (Henderson et al. 2009), found that fields sown with wheat in spring held significantly more Eurasian skylark Alauda arvensis, seed-eating songbirds and insect-eating birds than winter-sown wheat. In addition, 20 bird species showed significant population increases on a 61 ha site where the area of spring-sown wheat and naturally regenerated set-aside was increased over the study period. Increases were lower or absent on an 80 ha area of farmland adjacent to the experimental area and without the land use change. Five species were recorded breeding for the first time after management started. Ten species showed no significant increase on the study site, whilst none decreased significantly. The biggest increases occurred in the first three years of management and were higher for farmland birds than for woodland birds.

Reduce pesticide or herbicide use generally Bird Conservation

A controlled study in 2000-5 on 61 ha of farmland in Bedfordshire, England (Henderson et al. 2009), found that both winter and summer densities of most farmland bird species studied were higher on areas with no pesticide input, compared to areas with conventional levels of pesticides (higher summer densities with no pesticides for 10 of 14 species, although only Eurasian skylark Alauda arvensis, yellow wagtail Motacilla flava and linnet Carduelis cannabina showed a significant increase; all songbirds and 16 of 19 species recorded in winter were at higher densities on zero-fertiliser fields). Skylarks were also found in significantly higher numbers on areas with zero fertiliser inputs, but no other species were affected by fertiliser reduction. This study also investigated the impact of set-aside provision (see ‘Provide or maintain set-aside’) and spring sowing wheat (see ‘Sow crops in spring, not autumn’).

 

Provide or retain set-aside areas in farmland Bird Conservation

A before-and-after site comparison study in 2000-2005 in Bedfordshire, England (Henderson et al. 2009), found that set-aside fields sprayed in May or June supported higher densities of grey partridge, seed-eating songbirds and skylarks Alauda arvensis, compared to set-aside sprayed in April or crop fields (although seed-eating passerines were equally numerous on oilseed rape Brassica napus fields). Early-sprayed set-aside had consistently lower densities of all species, compared to all land uses except winter-sown wheat. The site-level effects of set-aside and sowing crops in spring are discussed in ‘Sow crops in spring, not autumn’. This study also investigated the impact of reducing pesticide and fertiliser inputs.

Reduce fertilizer, pesticide or herbicide use generally Farmland Conservation

A controlled study in 2000-2005 on 61 ha of farmland in Bedfordshire, England (Henderson et al. 2009) found that both winter and summer densities of most farmland bird species and ground beetles (Carabidae) were higher on areas with no pesticide input, compared to areas with conventional levels of pesticides (higher summer densities with no pesticides for 10 of 14 species, although only Eurasian skylark Alauda arvensis, yellow wagtail Motacilla flava and linnet Carduelis cannabina showed a significant increase; all songbirds and 16 of 19 species recorded in winter were at higher densities on zero-pesticide fields). Skylarks were also significantly higher on areas with no fertilizer inputs, but no other species were affected by fertilizer reduction.

 

Provide or retain set-aside areas in farmland Farmland Conservation

A before-and-after site comparison study in 2000-2005 in Bedfordshire, England (Henderson et al. 2009) found that set-aside fields sprayed in May or June supported higher densities of grey partridge Perdix perdix, seed-eating songbirds and skylark Alauda arvensis, compared to set-aside sprayed in April or crop fields (although seed-eating songbirds were equally numerous on oilseed rape Brassica napus fields). Early-sprayed set-aside had consistently lower densities of all species, compared to all land uses except winter-sown wheat.