Farmland habitats under threat

People have shaped our landscape for millennia, with farming being one of the biggest influences on our environment. Although some areas, such as forest clearings, may have been grazed naturally, our arable land, hedges and orchards are solely a result of human activity. Indeed, many of the semi-natural habitats that are associated with farmland have been managed for resources over time and are now inextricably linked to the way we continue to work the land.

In the Chilterns, the short turf of the chalk grassland that allows orchids to thrive is a result of grazing the steep, chalk slopes. The hedgerows that are filled with blossom, berries and birds were planted and maintained to manage livestock or identify boundaries. The towering beech and coppiced woodlands are a result of a furniture industry that thrived in the Victorian era. The purple-and-yellow heathlands of our commons are a result of forest clearance for grazing. So many of the Chilterns’ special qualities are down to the way we enhance and manage the landscape around us.

Wildlife has made the most of the habitats we humans have provided, moving in and finding abundant food and shelter. Yet, there has also been much loss within the agricultural environment. After the Second World War, traditional methods of farming began to decline, replaced by a more mechanised and modern system. Farmers were able to farm larger swathes of land much quicker, and increased their productivity by removing hedgerows, trees, ponds and ‘untidy’ field corners. Pesticides and fertilisers were developed to help increase yields and reduce loss, and wildlife was eventually pushed out. Now, around 60% of farmland species are in decline.

During the mid-late 20^th century, the outlook for farmland wildlife and habitats seemed bleak. Pesticides and run-off polluted rivers and streams, harming sensitive wildlife like otters, and the physical loss of habitats caused a decline in many traditional species, such as skylarks and turtle doves. But, with the banning of harmful pesticides, and the recognition of the ecosystem services (the benefits that we get from nature) that healthy farmland provides, we began to turn the story around.

Today, many farmers, landowners and land managers care deeply about the way they work their land and the biodiversity it shelters. Wildlife-friendly and sustainable farming methods are not only popular with landowners, but are also a selling point with consumers, and are at the forefront of much of the support that farmers can receive.

Climate change

We are in a climate emergency. Global warming – where the global average temperature rises – is happening at a scary rate, and experts agree that an increase of nearly 3-4^oC could be possible by 2100. The biggest culprit of this change is the greenhouse gas, carbon dioxide, emitted into the atmosphere through human activity like burning fossil fuels and cutting down trees.

Climate change not only affects our wildlife and habitats (our natural capital), but also affects many of our ecosystem services (the benefits we get from natural capital). Thus, it impacts every aspect of society, from disaster risk to food security, economy to health and well-being. In the Chilterns, it will have a major, but unpredictable, influence on the natural beauty and natural capital of the AONB; for example, shifts in the timing of seasonal events, will change how plants and animals live and thrive in our grasslands and heaths.

Initiatives that are carbon-friendly can sometimes have a negative impact on other aspects of wildlife and habitats. For instance, tree-planting in the wrong place, such as on species-rich grasslands, can inadvertently cause damage to these fragile ecosystems. Ecosystems, such as grasslands, not only store carbon themselves, but can also provide a buffer against some of the impacts of climate change, such as increased flooding, extreme weather, soil erosion and decreases in pollinator species.

Habitat loss

Farmland habitats can be impacted by changes in farming methods, as well as other pressures like development, transport infrastructure and changes in land. This can mean that hedgerows are severed, farmland monocultured, and ancient meadows and downland lost, damaged or reduced. Wildlife habitats need to be big enough and well connected for wildlife to thrive. Species need corridors to move through the landscape in response to a changing environment.

A recent report highlighted that England’s wildlife sites are generally too small and too isolated, leading to a devastating loss of some of our most loved or iconic species. To combat this, we need better and more resilient ecological networks for plants and animals; we need more, bigger, better and joined habitats.

Inappropriate management

Our landscape was once a patchwork of farmland, woodland, flower-rich grasslands and purple-studded heaths, knitted together by hedges, streams and ponds, and defined by topography, soils, ancient rights and management. Yet, over many years, there has been a decline in traditional land management, such as grazing, coppicing, the keeping of orchards, the exercise of common rights, and hedge-laying. Coupled with increased development, this has led to the degradation of many of our farmland habitats; during the 20^th century alone, 90% of our grasslands were lost. Wildlife has suffered as a result. Turtle doves, skylarks and corn buntings are on the brink of extinction; plants like pheasant’s-eye and shepherd’s-needle are now classified as Endangered on the Vascular Plant Red List for England; and even the once-common hedgehog is now threatened.

Farmland management is important to create the conditions in which the specialist wildlife that lives there can thrive. Actively managing its habitats to encourage the growth of wildflowers and keep vigorous weeds at bay, and to create networks of habitats through connecting hedges, ponds and floodplains, helps to ensure resilience to climate change, pests and disease.

Invasive species and diseases

There are plants and animals in our countryside that have either been introduced from other countries, or spread from one area to another. Sometimes these species don’t cause too much trouble, but at other times, they can have terrible impacts on native wildlife. Examples include signal crayfish and grey squirrels, but there are many more.

In many wildlife habitats, scrub can become invasive if grazing is not used to keep vigorous plants under control. On grasslands, common ragwort can be invasive and is dangerous for grazing animals, while plants like thistles and docks can take hold quickly and shade out delicate flowers. Non-native plants can also cause devastation; Himalayan balsam escapes from gardens and takes over ditches and wet habitats, and Japanese knotweed invades grassy roadside verges and railway cuttings, crowding out native wildflowers.

Diseases are also a growing problem for our trees and shrubs, especially as climate change affects the resilience of our native wildlife to new threats. Phytophtora diseases are soil diseases that affect trees and shrubs like larch and juniper, now a rare plant in the Chilterns. Box blight is another fungal disease that can be spread from one plant to another on contact. The Chilterns has some important box woods, so it is vital to keep these sites free of infection.

Pollution

Fertilisers, insecticides and herbicides, if over or incorrectly used can become pollutants to our environment. These leach into the ground, changing soil and water composition, kill our much-needed pollinators, and accidentally target native, wild plants as well as those that are an agricultural pest.

Air pollution is mainly nitrogen from transport and power stations, and ammonia from agriculture, particularly, livestock though the effects of ammonia from agriculture can be temporary and reversible. As well as ravaging wild plants, woodlands and meadows, air pollution can have a detrimental and direct effect on our health.

Nitrogen levels in the UK countryside are leading to an increase in nitrogen-tolerant plant species, which out-compete many characteristic native species. This can have a knock-on effect for other species like butterflies. Trees can also directly suffer as they are stripped of their protective lichens, and plants may be more susceptible to damage from drought, frost and diseases.

Lichens are powerful indicators of air pollution. They are sensitive and respond to pollution in short timeframes. Many lichens evolved in naturally low levels of atmospheric nitrogen, so will disappear when faced with polluted air. Assessing the lichen communities in a habitat can provide an indication of its overall health.