Plant+diversity

INTRODUCTION Plants are essential to life, as we know it. As well as providing us with everyday things we need to survive, they help regulate our climate and atmosphere, our soils and our water. All living things depend on the huge diversity of plants for their food and other requirements, directly or indirectly. Plant biodiversity* is increasingly threatened by human activities resulting in habitat loss* and extinction of species*. This is causing widespread concern. Faced with the needs and increased expectations of a growing human population, we have to make moral and social judgements about how we are going to use our natural resources today and in the future - in a sustainable manner. Action on biodiversity is now being taken seriously at regional and national levels. In 1992, over 170 countries gathered together in Rio de Janeiro for the United Nations Earth Summit. At this summit, global actions for biodiversity and sustainability were discussed and the United Nations Convention on Biological Diversity (CBD) was signed. Additional agreements have been made at other international conventions. Further information on factors affecting biodiversity and the main environmental agreements can be found in the Information Section. Factors affecting current levels of biodiversity (based on McNeely et al. 1995) Immediate causes: • Exploitation of wild living resources, including hunting and wildlife trading • Expansion of agriculture, forestry and aquaculture • Expansion of transport systems and building • Habitat loss; especially coral reefs, wetlands, primary forests, and coastlines – all vulnerable and with great biodiversity. • Species introductions • Pollution of soil, water and atmosphere • Global climate change Underlying causes • Changes in social organisation, including loss of indigenous cultures • Growth of human population • Patterns of natural resource and energy consumption – often involving the pressures of tourism, now the world’s biggest industry • Global trade • Economic systems that fail to value the environment and it’s resources • Inequality in ownership, management and flow of benefits from the use and conservation of biological resources.

There are an estimated 300,000 to 500,000 plant species* in the world. About 30,000 can be eaten and approximately 7000 of these have been used for food by humans at some point in time. In Java, Indonesia, farmers may plant more than 600 crop species in a single home garden. Farming communities in the Andes, S. America, may use up to 3000 different varieties of potatoes! For many thousands of years plants have traveled around the world, transported by wind and waves, caught in animal fur or carried by people. Tomatoes first grew in S. America. Explorers brought them to Europe in the 1500s. Bananas originally came from SE Asia. They were probably the first fruit to be farmed. Carrots grew in the area of Afghanistan around 3000 years ago and slowly spread to the Mediterranean. The Greeks and Romans used carrot juice to cure stomach problems. The first carrots were white, purple and yellow. From Geneflow Junior, by IPGRI (International Plant Genetic Resources Institute) 2001. ISBN 92 90 43-498-8 TASK 1 Identify the main useful plants that are grown in your area. Describe their main uses and why these plants are important to your community. Are they native to your country or do they originate from elsewhere? If so, can you identify their origins? Do these plants grow naturally or are they planted as a crop? Are they sold and used inside your country, or exported? You may find answers to these questions by looking around you as you travel to school or elsewhere in your local area, visits to local markets and shops would also be helpful. Record the information in a table under the following headings: NAME OF PLANT MAIN USES NATIVE OR FROM WHERE? GROWS NATURALLY, OR PLANTED AS A CROP?