Gardens: Arks of triumph

But while Araucaria araucana might thrive in gardens, its fate in the wild is less certain. In parts of Chile and Argentina, the monkey puzzle tree's natural habitat, it is in decline because of logging, fire and other pressures on the natural environment. A lost cause? No - thanks to the work of botanic gardens. The International Conifer Conservation Programme was established at the Royal Botanic Garden Edinburgh in 1991, and part of its work includes field surveys, habitat protection, conservation and restoration of wild populations. Approximately one third of the 630 conifer species are threatened with extinction in the wild, and the monkey puzzle tree is one of the conifers which botanists from Edinburgh are working to save, in partnership with local institutions.

This story, and many others like it, feature in a new book by Sara Oldfield, secretary general of the charity Botanic Gardens Conservation International (BGCI). In Botanic Gardens: Modern-Day Arks (24.99, New Holland) she highlights the crisis currently being faced by the world's plant populations and the work being done to address it. "How many people would know that the monkey puzzle tree is endangered in the wild?" she says. "You see them in every suburban housing area in the UK. Animal conservation and threatened species are very much in the public consciousness, but I think plants are relatively invisible when we talk about extinctions."

Even for the knowledgeable gardener with an interest in conservation, the statistics concerning endangered plants are shocking: scientists estimate that at least one third of all flowering plant species are threatened with extinction. Oldfield points out that with experienced scientists and horticulturalists, as well as collections of both living plants and reference materials, botanic gardens are in a strong position to help tackle the crisis. It's serious stuff, and a topic that might pass by the many of us who use our local botanic garden as a place to relax. "Botanic gardens are places people see as a place to go for a walk or a picnic and to get inspiration for their own gardens," says Oldfield. "That's an important role for them, but the scientific work that's going on behind the scenes, and the conservation work isn't always so generally appreciated."

Oldfield explains that around 2,500 botanic gardens collectively grow about one third of all known flowering plants. In this way, they can be thought of as modern-day arks. And despite the scale of the problem, there are many examples of plant species that have been rescued from extinction. The toromiro tree (Sophora toromiro) was traditionally very important as the only native tree species and source of wood on Easter Island. It became extinct in the wild because of grazing and removal of bark by domestic sheep and cattle introduced by European settlers. Seeds of the last tree were collected by Norwegian explorer Thor Heyerdahl in the mid-1950s, and the few remaining trees are descended from those seeds. Today 18 botanic gardens grow the species and there are hopes of reintroducing the tree to its native habitat. Closer to home, the Royal Botanic Gardens Kew was behind a survival plan for the lady's slipper orchid (Cypripedium calceolus), a native orchid reduced to one flowering individual. Small amounts of seed were collected for micropropagation and in 1987 the first six seedlings were planted back into the wild. Today over 1,500 seedlings have been planted and monitoring and protection of the plants is in place.

"I think there's been a change in emphasis in botanic gardens over the years," says Oldfield. "Many of the botanic gardens started out as places for growing and studying medicinal plants when medicine and botany were basically one science - that was the situation at the Royal Botanic Garden Edinburgh, the Chelsea Physic Garden and so on. Then there was the colonial era where a lot of new gardens were established in the colonies to see where tea would grow and coffee and rubber and so on. Since the 1970s, conservation of plant species has become really important." BGCI operates a PlantSearch database which holds records from over 150,000 taxa, provided by nearly 700 botanic gardens. These plant records are linked to the IUCN Red List of threatened plant species, meaning that botanic gardens can check which of the species they have in their collections are of global conservation concern.

With many botanic gardens being located in urban areas, they have a great opportunity to welcome visitors and educate them about the importance of plants. Singapore Botanic Gardens, for example, contains a remnant patch of rainforest, containing 314 plant species. Two million visitors a year come to the gardens to experience this patch of rainforest. Educational programmes and talks are given to 19,000 children a year. On the other side of the world is Brooklyn Botanic Garden in New York. Established in 1910 on the site of a reclaimed waste dump, it set up a Children's Garden programme in 1914 and since 1989 has run Project Green Reach, encouraging the study of botany and environmental science in low-income urban communities. "BGCI did a global survey recently to see what botanic gardens were doing to support biodiversity conservation in the International Year of Biodiversity," says Oldfield. "The highest response was education, so I think there is a really important role there."

Oldfield says that while it's easy to feel powerless in the face of big, global environmental issues, botanic gardens can inspire us to do our bit. And as individual gardeners, we're well placed to make a difference. "When you've grown some sweet peas or you've got honeysuckle in your garden and you're sitting there surrounded by all the smells and colour of flowers, it does make you feel that plants are pretty special," she says. "I think gardening potentially is the link with caring for our natural world."

This article was first published in the Scotsman, July 31, 2010