Why conserve wild plants?

Conserving wild plants in their natural habitats is about more than plants, wildlife and ecosystems – it is about people and our need for food, medicines, fresh air and water, shelter, and a clean and healthy environment in which to live. Two thirds of the ‘services’ provided by nature to mankind are now in decline worldwide, and the ability of the planet’s ecosystems to sustain future generations can no longer be taken for granted.

Wild plants and climate change

• Carbon sinks: with global concern about climate change (caused by increasing levels of carbon dioxide (CO₂) in the atmosphere) the importance of peat bogs in absorbing CO₂ through photosynthesis and locking it up in what is known as a carbon sink, is becoming ever clearer. It is estimated that pristine bogs accumulate CO₂ at a rate of 0.27 tonnes per hectare per year (the UK has approx 1.5 million hectares of peatland). A Government study found that Scotland’s peat bogs contain an astonishing three-quarters of all the carbon locked up in organic matter in British soils and vegetation. By comparison, damaged peat bogs emit 8 tonnes of CO₂ per hectare per year. The world peatland carbon resource is estimated at 329-528 billion tonnes.

• Floodwater management: wetland areas provide an important economic function by holding and releasing floodwaters over an extended period of time. This reduces the likelihood of flooding and is of particular importance if there is a settlement downstream.

• Coastal erosion: in the UK, no one lives more than 75 miles from the sea. The UK Climate Change Impacts Programme predicts that sea levels around the UK will have risen 26-86 centimetres by 2080. In addition, extreme high tides and severe storms will occur more frequently, so threatening many people’s homes and livelihoods. Natural England, the Environment Agency and the National Trust are all looking at restoring natural habitats such as marshes, tidal inlets, and sand dunes around the UK to act as natural coastal defences. Mangroves (tree formations found along tropical and sub tropical coastlines) also act as natural shock absorbers, soaking up destructive wave energy and buffering against erosion.

• Reducing urban ‘heat island effect’ and air pollution
  Living roofs and walls offer ways of mitigating the effects of climate change – plants growing on roofs and walls will help us cope better with hotter summers (a study in Chicago estimated that $100,000,000 in energy costs could be saved if all roofs were green because the need for air conditioning would be so reduced) and wetter winters (a German study showed how during a 200 litres of rainwater fell on an 18m 2 green roof and only 15 litres actually passed from the roof to the ground). Planners in Brighton have insisted that a multi-storey car park must have green walls as part of a larger scheme to create cooler strips of vegetation within large areas of glass and concrete. Plant roofs also have the added benefit of removing heavy metals, airborne particles and volatile organic compounds. The absorbed pollutants do not enter the water system through surface run-off.

Wild plants, food and agriculture

• Healthier food: it has recently been shown that the nutrient content of food has decreased in recent years due to the lack of biodiversity on the majority of farmland today. For example, livestock that feed on flower-rich pastures produce meat and milk with a higher nutrient content than those that graze on a basic commercial mix of grasses.

• Natural pest control: wild plants provide an economic service in modern agriculture by providing habitat for predatory invertebrates, which then provide natural pest control for crops. Set-aside strips, flower-rich margins and allowing some wild plants to survive within the crop have been proven to encourage predatory insects, particularly beetles, which then reduce the number of grain aphids and other pests.

• Genetic diversity: all commercial crops have been developed from what were once wild plants. The genetic diversity needed to sustain healthy food crops in the future is contained today in the wild relatives of our cereals, pulses, fruit and vegetables. It goes without saying that the diary, meat and fish industries could not function without plants to sustain their livestock.

Wild plants, medicine and quality of life

• Herbal medicine: more than 80% of the world’s population depends on herbal medicine for their primary health care. Most material used in herbal medicine and vitamin supplements is taken from wild plants and the rapidly growing demand for medicinal plants is putting pressure on many species. In Europe alone, some 1300 medicinal plants are used commercially with up to 90% collected from the wild. Most raw material in international trade comes from Europe, North America, India and China, where wild collection is often an important part of rural economies. Unsurprisingly, herbalism is big business: in 1994, for instance, £88 million of herbal medicines and health foods were imported into Britain alone.

• Western medicine: one quarter of western medicine's prescribed drugs, and as many as half of the 25 top-selling drugs, derive from compounds discovered first in plants. Every year, new and often life-saving extracts are discovered in wild plants. For instance, Taxol, also known as Tamoxifen, is a modern anti-cancer drug which comes from the leaves of Yew trees and the world’s only weapon against Bird Flu is the star anise, from which the drug Tamiflu is made.

• Wellbeing: Medical evidence shows that access to the natural environment improves health and wellbeing, prevents disease and helps people recover from illness. Experiencing nature in the wider countryside can help tackle stress and mental health problems, as well as provide a way to tackle childhood obesity and coronary heart disease.

Wild plants and water quality

The treatment of various types of pollution has been carried out naturally for a considerable number of years by differing types of plant life. Most of the UK’s larger Water Companies have now successfully installed Reed Bed Sewage Treatment systems e.g. Severn Trent Water is using this system at over 130 sites. It works very simply: Common Reed transfers oxygen from its leaves and out via its root system, so creating ideal conditions for the development of huge numbers of micro-organisms. These are then able to break down soluble material, so effectively and cheaply returning solid matter to the soil and recycling liquids in the form of purified water.

Wild plants, soil erosion and desertification

Soil loss, and its associated impacts, is one of the most important yet one of the least publicised of today's environmental problems. Soil is naturally removed by the action of wind or water and in general this occurs roughly at the same rate as soil is formed. However, without a covering of plants or trees and their root systems, the soil structure becomes weakened and is vulnerable to being blown or washed away leading to desertification. Decaying leaf matter adds to the quality of the soil by decaying into rich humus, which helps to bind soil particles, acts as a natural sponge to store water and nourishes plants and sub-soil life.