What Have Plants Done For Us

On 25th June ODGC was delighted to welcome back Timothy Walker, former Director of Oxford Botanic Garden and lecturer at Somerville College, Oxford.

What have plants done for us?  Everything.  Plants contain chlorophyll which harnesses solar energy by photosynthesis to create protein.  Algae appeared 1.2 billion years ago and 470 million years ago plants started to colonise dry land, first as mosses then eventually trees.  The energy stored in dead trees became coal.  The complex ecosystem of plants is the green glue which holds life on earth.

A quarter of a million years ago man domesticated fire enabling us to eat different food and leading to the emergence of agriculture.  Unpromising grasses were hybridised to create food crops, wheat and rye, increasing the food capacity of the planet.  Potatoes were discovered 8000 years ago in South America.  Cotton was discovered 6000 years ago and slightly more recently sorghum, coffee and sugar.

Many painkillers and medicines are plant derived.  The Shropshire Romanies used foxgloves in medicine and this led to the development of digoxin for heart problems.  Vincristine is derived from the Madagascar periwinkle, Catharanthus, which has had wonderful results in the treatment of childhood leukaemia.

And yet, Timothy warned, two in five plants are threatened with extinction.  So, what can we do for plants?  There is no technical reason why any plant should be threatened with extinction.  Habitats can be recreated, seed banks have been created.  Horticulture and gardening are at the heart of this.  Politicians have the power to aid conservation but the local population must be involved.  Land must be managed and there must be compromise between food production and biodiversity.  In 1999 the Global Strategy for Plant Conservation was established to slow the pace of plant extinction worldwide.

Timothy has helped to create wildflower meadows from previously farmed land outside Oxford and told us that gardeners have a big part to play in conservation and habitat creation.  They create ecosystems and feed birds which in turn aid seed dispersal.  For example it was thought that mistletoe would decline with the decline in orchard cultivation.  This has not been the case. It has been discovered that Blackcaps overwintering from Germany, attracted by British bird tables, aid seed dispersal by rubbing sticky beaks along branches after eating mistletoe berries.

This was an upbeat and thought provoking talk which engendered hope for the future and the knowledge that gardeners have an important role to play.

                                                                                                         Ghislaine Arundale

Recommended reading:

The Biodiversity Gardener  –  Paul Sterry

 Resilient Garden  –  Tom Massey