Background information and definitions
Changes in farming practice in northern Europe have included a shift from sowing crops in spring to sowing them the preceding autumn/winter. This change is considered to have adversely affected farmland biodiversity including invertebrates and farmland birds (see for example, Donald & Vickery, 2000).
Donald, P. F. & Vickery, J. A. (2000) The importance of cereal fields to breeding and wintering Skylarks Alauda arvensis in the UK. 140–150 in: N. J. Aebischer, A. D. Evans, P. V. Grice and J. A. Vickery (eds) Ecology and Conservation of Lowland Farmland Birds, British Ornithologists Union, Tring.
Supporting evidence from individual studies
A replicated, controlled study between 1984 and 1994 in Västmanland, Sweden (Berg et al. 2009), found that northern lapwings Vanellus vanellus nested on spring-sown crops more than expected based on their availability, and on autumn-sown crops less than expected. However, hatching success on spring crops was lower than on autumn crops (29-50% for 1,236 nests on spring crops vs. approximately 85% for 27 nests on autumn crops). This study is discussed in more detail in ‘Restore or create traditional water meadows’.Study and other actions tested
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’).Study and other actions tested
A replicated, controlled paired sites study in 2004 in Uppsala, Sweden (Eggers et al. 2011), found that there were significantly greater numbers of ground-foraging breeding birds and more species in spring-sown barley than in autumn-sown wheat (0.8 species/ha in spring-sown vs. 0.5 species/ha in autumn-sown plots). Territory densities of lapwing Vanellus vanellus and wheatear Oenanthe oenanthe were also higher in spring-sown (lapwing: 0.08 territories/ha; wheatear: 0.12) compared to autumn-sown cereal plots (lapwing: 0.02; wheatear: 0.05). There was no effect of sowing time on skylark Alauda arvensis or yellowhammer Emberiza citronella breeding density. In spring-sown plots, numbers of species decreased significantly as the proportion of autumn-sown cereals in the surrounding landscape increased. Forty-one independent pairs of autumn-sown wheat and spring-sown barley plots were selected, each centred on an infield non-crop island. Non-crop islands were surveyed for cover of trees, shrubs and weeds and cereal height was measured on five occasions in each field. All birds were recorded within a radius of 100 m from the centre of each plot during five point counts of seven minutes (mid-May - end of June 2004).Study and other actions tested