Grasslands and heaths under threat

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 that not only store carbon themselves (permanent grasslands and rough grazing pasture are important for their carbon storage, maybe more so than our woodlands), but can also provide a buffer against some of the effects of climate change, such as increased flooding, extreme weather, soil erosion and decreases in pollinator species.

Development, transport infrastructure and changes in land use fragment habitats. For grasslands and heaths, 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.

Flower-rich grasslands and purple-studded heaths were once part of a patchwork of farmland and common land, knitted together by hedges 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 grassland and heathland 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.

Grassland and heathland management is important to create the conditions in which the specialist wildlife that lives there can thrive. Actively managing these places 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.

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 non-native muntjac deer and grey squirrels, but there are many more.

On heathlands, bracken, gorse and scrub can become invasive if grazing is not used to keep them under control, and exotic rhododendrons escaped from gardens can shade and exclude native plants. 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.

Our grasslands and heaths are under threat from pollutants used for farming, such as fertilisers, insecticides and herbicides. 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. Over-fertilised areas promote the growth of vigorous grasses at the expense of other herbs.

Air pollution is mainly nitrogen from transport and power stations, and ammonia from agriculture, particularly, livestock. 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.