Farmland accounts for 74% of Oxfordshire’s land cover, of which 56% is under cereals farming and 30% under livestock grazing. Farm types vary: drystone walls define the arable land of the Cotswolds; large fields of mixed arable and pasture typify the Midvale Ridge; and hedged livestock farms dominate the Upper Thames Clay Vales.
Farmland can support a wide range of habitats and wildlife. Hedgerows, with their associated banks and ditches, are home to an amazing array of flowers, birds, butterflies, moths and mammals. Farmland ponds attract amphibians, reptiles and dragonflies, while arable weeds like cornflower and common poppy can grow at field edges. However, the intensification of farming has caused a massive decline in farmland biodiversity, particularly in farmland birds. Thus, the biodiversity value of farmland depends on good stewardship. Even less species-rich, agriculturally improved grasslands can be managed in a way that supports wildlife. Indeed, managing farmland sensitively helps to combat habitat fragmentation, provides vital links between protected sites and creates a more resilient landscape.
Since the Second World War, farming policies and practices have rapidly changed and intensified, causing dramatic declines in traditional farmland habitats and species. Changing management methods include decreases in mixed farming, moving from spring to autumn sowing of arable crops, switching from hay to silage production, increases in pesticide and fertiliser use, and removing non-cropped features like hedgerows. Additionally, agricultural pollutants now contribute 50-60% of nitrates, 20-30% of phosphates and 75% of soil, as sediment, to England’s waterways. Agriculture is very vulnerable to extreme weather events, so climate change will impact heavily on farmland nature.
For more information about Oxfordshire’s agriculture download this extract from the State of Nature 2017 report and visit the other wildlife and farming pages on this website. Download the practical handbook from WildCru about how to conserve wildlife on working farms in Britain.
Follow links below to organisations using research, tools and case studies to show how farms can address issues including sustainable management and conservation.
WildCru
Agricology
Linking Environment and Farming
Campaign for the Farmed Environment
The variety of habitats and connectivity provided by arable field margins makes them key areas for conservation in farmed landscapes (Smith, 2015). They buffer hedgerows, ponds and ditches from farming operations. They also provide refuges for small mammals and important habitat for birds and invertebrates, including pollinators. Pollinator numbers and ranges have decreased at national and local levels since the 1950’s, with some species now lost or incredibly rare. Pollinating insects include honey bee, solitary bees, bumblebees, hoverflies and other flies, butterflies, moths and beetles.
Field margins are important breeding areas for several butterfly species, including in the Upper Thames area (Berkshire, Buckinghamshire, Oxfordshire) the small skipper Thymelicus sylvestris and Essex skipper Thymelicus lineola. Both species have declined by approximately 14% over the last twenty years. This reflects the habitat indicators for butterfly populations at farmland sites in England, that show significant decreases in overall abundance both in the long-term (since 1990) and over the past 10 years.
Arable plants are considered the fastest-declining group of plants in the UK. A quarter of these species are threatened including in Oxfordshire spreading hedge parsley Torilis arvensis and broad leaved cudweed Filago pyramidata. Where cultivated margins can naturally regenerate without the use of herbicides they may promote growth of these and other rare and declining arable plants, such as rough poppy Papaver hybridum, fine-leaved fumitory Fumaria parviflora, few-flowered fumitory Fumaria vaillantii, broad-leaved spurge Euphorbia platyphyllos and the glorious annual of chalky soils pheasant’s-eye Adonis annua. Corn cleavers Galium tricornutum, an annual of arable fields, is Critically Endangered and a UK Priority Species which prior to its recent re-introduction in Wytham Woods ‘triangle’ and at College Lake BBOWT reserve, had last been recorded in Oxfordshire in the early 1970s.
For more information and downloads on planting and managing arable field margins for wildlife visit:
Cotswold’s AONB Farmland Birds Project
RSPB Arable Field Margins
Buglife – cereal field margins
LEAF – Guide to pollinating insects for farmers
Many of our hedgerows are ancient and have associated banks and ditches of great archaeological importance. They are the most important wildlife habitat over our farmland and can support an amazing diversity of plants and animal. They are especially important for farmland birds, butterflies, moths, bats and dormice. Hedgerow trees form networks of mature specimens across the landscape between woodland patches. They may facilitate the dispersal of populations of a range of species across the landscape, and their decline has impacts for species such as invertebrates including moths, birds and bats.
At least 47 species of conservation concern use hedgerows as their main habitat, and associated tussocky grass margins and patches of scrub provide food and shelter for many more species. Scrub on farmland can comprise scattered shrubs, young trees or dense thicket and is valuable for many bird and invertebrate species. It can buffer other valuable habitats from farming activities and, like trees, help retain soil, enhance infiltration and reduce run-off by ditches and ditches and rivers.
Neglect or poor management practices has resulted in the historic loss of hedgerows from the countryside, with many of the remaining hedges left in poor condition. The loss of hedgerows, which has been identified as a factor in the decline of many farmland plant and animal species, was quantified by Banbury Ornithological Society’s ‘Domesday Survey’. This recorded a 27% reduction in hedgerow length between the 1980s and 2000s, within the 1200km2 study area centred on Banbury.
Visit the following pages for more advice on:
who has responsibility for hedges in Oxfordshire
hedge-laying
hedge-row species for wildlife
hedge-row grants
If managed sympathetically cropped areas can also provide valuable habitat for arable plants, birds and mammals. Conservation headlands, which have reduced inputs from insecticides, herbicides and fertilisers, benefit farmland bird species that have suffered the most extensive declines, such as grey partridge Perdix perdix, corn bunting Emberiza calandra and turtle dove Streptopelia turtur, with the last showing the greatest decrease of any species, 93% since 1994. Turtle doves have suffered a 93% UK population decline since 1994, and research shows that the number of chicks they are producing has halved since the 1970s.
Banbury Ornithological Society (BOS) conducts what is probably the longest running survey of winter farmland birds anywhere in the country. This is the “Winter Random Square Survey” which started in 1975 and is continuing to this day. It measures the abundance and distribution of around 40 common species. This survey has shown that several resident farmland birds, including yellowhammer and linnet, declined greatly in the 70s and 80s, before stabilising somewhat in the late 90s and 2000s. For a few, the declines are continuing, notably corn bunting Emberiza calandra and tree sparrow Passer montanus.
Small farmland mustelids, such as the weasel Mustela nivalis and stoat Mustela ermine are lacking county data due to difficulties in robustly assessing population size. Both considered declining species in 1998, opportunistic anecdotal evidence suggests that both species are still widespread throughout the county. The harvest mouse Micromys minutus, arguably the most iconic farmland mammal, is also currently lacking data to determine population status and trends but recent surveys by the Oxfordshire Mammal Group should provide a better picture of their status for future reports.
Farmland often includes a range of non-farmed features, such as ponds and ditches, which have significant benefits for wildlife. Good water quality in these features attracts amphibians, reptiles, birds, dragonflies and other important invertebrates. Seasonally flooded and permanent ditches provide habitats for a range of rare plants and invertebrates, if they have good water quality, as well as acting as wildlife corridors.
Feber and Macdonald (2016) found that the flowering plants along wet ditches provide important foraging for bumblebees, especially in late spring. The true fox-sedge Carex vulpine was regarded as rare and declining in 1998, limited to just a few sites along the River Ray. In 2004/2005 it was discovered at eight new sites along the Ray, and since then has been the subject of careful management by BBOWT and others which has stabilised the population in the area. Research by Feber and Macdonald (2013) suggested that up to 50% of recorded ponds had disappeared from farmland in the Upper Thames region area over the last century.
Organisations offering advice and guidance on:
creating and monitoring ponds and ditches
permission to work near watercourses
invasive species that might be in your ponds and ditches
