There are around 400,000 plants species recorded in the world and many more waiting to be discovered and named. Yet although the threat to the existence of many wild animals is now widely recognized, not many people are aware that plants are also in danger. In February 2015, the Center for Biological Diversity stated "Of the more than 300,000 known species of plants, the IUCN has evaluated only 12,914 species, finding that about 68% of evaluated plant species are threatened with extinction."
Large areas of desert around the world bear testimony to people’s destruction of vegetation. Most of the Middle East is now desert or is being rehabilitated at great expense. Many bare and eroded lands around the Mediterranean once supported forests. In many parts of Africa and India cattle and goats wander the stony plains eating up any scrap of green that manages to appear on what were once good pastures. Overgrazing by domestic and feral stock is, in fact, the greatest menace to plants, although ‘raids’ by botanists and other enthusiasts on some beautiful plants have sometimes exacted a serious toll on rare species.
Perhaps people forget that all our domestic crops and garden flowers spring from wild stock. Just as important is the fact that plants provide a high proportion of medicines in modern use. Who knows what secrets of value to mankind are still locked away among plants awaiting discovery. Tropical rainforests are where a quarter of the active ingredients in modern medicines were first discovered. Yet they are the most threatened habitat in the world containing 63% of the world’s threatened plant species.
One of the greatest threats to plant species is the conversion of natural habitats to land for agricultural and livestock use, for example where rainforests are destroyed in order to graze cattle or grow soya, an animal feed or palm oil. Britain’s ancient woodlands are also under threat, many areas having already been planted with coninfer trees instead. Ancient woodlands are special because they must have been there for at least 400 years and are a niche of biodiversity supporting plentiful wildlife, specialist eco-systems which have been operating for hundreds of years.
When it comes to food, people have worked through the centuries developing the strains of wheat, rice, barley and other crops from wild varieties. Having used the primitive stocks, the wild varieties have been neglected with the result today that many are being lost as natural vegetation is cleared for cultivation. Does it matter? Yes! The experts are already sounding warnings that new varieties which are helping to feed our growing numbers are often less resistant to disease, and that it may be only reaching back to genes in the wild stocks that diseases can be fought.
A large proportion of our diet is supplied by four cereals – wheat, rice, maize and sorghum. Imagine, if you can, the scope of the disaster if one of these should fail or if some new virulent disease should appear with which we are unable to cope in time.
In Britain alone there are over sixty-one plants that have become so rare that they are protected by law. Some of these are:
Alpine gentian
Killarney fern
Spiked speedwell
Oblong woodsia
Ghost orchid
Snowdon Lily
Blue heath
Diapensia
Wild gladiolus
Red helleborine
Alpine woodsia
Mezereon
Monkey orchid
Tufted saxifrage
Alpine sow-thistle
Drooping saxifrage
Spring gentian
Kew Garden’s Millenium Seed Bank Partnership is an ambitious project with a mission - to collect and store the seeds from a quarter of the world’s plant species by 2020. They’ve made a good start and already have 10% of the world’s rarest and most useful plants and eventually hope to have over 1 billion seeds in their bank!