Book contents
- Frontmatter
- Dedication
- Contents
- Foreword
- Preface
- Acknowledgements
- 1 Introduction
- 2 Fibres and Fibre Yielding Plants
- 3 Cereal Crops
- 4 Sugars, Starches and Cellulose Products
- 5 Legumes or Pulses
- 6 Vegetable Oils and Fats
- 7 Fruits and Nuts
- 8 Vegetables
- 9 Spices, Condiments and Other Flavourings
- 10 Fumitory and Masticatory Materials
- 11 Beverages
- 12 Wood and its Uses
- 13 Vegetable Tannins and Dyestuffs
- 14 Rubber
- 15 Medicinal Plants
- 16 Insecticides and Herbicides
- 17 Essential Oil Yielding Plants
- 18 Plant Diversity and its Conservation
- 19 Petrocrops: Our Future Fuels
- 20 Ethnobotany: An Integrated Approach
- References
- Index
18 - Plant Diversity and its Conservation
Published online by Cambridge University Press: 08 February 2018
- Frontmatter
- Dedication
- Contents
- Foreword
- Preface
- Acknowledgements
- 1 Introduction
- 2 Fibres and Fibre Yielding Plants
- 3 Cereal Crops
- 4 Sugars, Starches and Cellulose Products
- 5 Legumes or Pulses
- 6 Vegetable Oils and Fats
- 7 Fruits and Nuts
- 8 Vegetables
- 9 Spices, Condiments and Other Flavourings
- 10 Fumitory and Masticatory Materials
- 11 Beverages
- 12 Wood and its Uses
- 13 Vegetable Tannins and Dyestuffs
- 14 Rubber
- 15 Medicinal Plants
- 16 Insecticides and Herbicides
- 17 Essential Oil Yielding Plants
- 18 Plant Diversity and its Conservation
- 19 Petrocrops: Our Future Fuels
- 20 Ethnobotany: An Integrated Approach
- References
- Index
Summary
The earth supports approximately five to ten million species of plants and animals (IUCN, 1980), which have been the result of three billion years of evolution, including mutation, recombination and natural selection. Humans have been in existence for some two million years. Our prehistoric ancestors were a hunter of animals and gatherer of plants. As compared to the history of man, agriculture is a very recent innovation. It was only about 12 000 years ago that women probably started collecting plants from the wild and began cultivating them, leading to the birth of agriculture. For its continued growth, however, we have to protect the basic life support systems consisting of soil, water, flora and fauna and the atmosphere.
Walter G. Rosen coined the term biodiversity (or biological diversity) in 1985, and it refers to the variety of life forms and habitats found in a defined area. The Convention on Biological Diversity (CBD) defines biodiversity as ‘variability among living organisms from all sources, including inter alia, terrestrial, marine and other aquatic ecosystems; this includes diversity within species (intraspecific) as well as among species (interspecific) and ecosystems’.
Plant genetic resources are the most precious but very vulnerable and irreplaceable natural assets of a nation. They have evolved through thousands of years of natural and human selection—both conscious and subconscious. However, certain developments of relatively recent times are posing great threats to the basic life support systems that protect rich plant diversity.
Threats to Biodiversity
The chief causes for the disappearance of plant species are as follows:
• Destruction of habitats through fragmentation; environmental pollution (such as acid rains, discharge of industrial effluents, increased use of agrochemicals, build-up of greenhouse gases, leading to global warming and the destruction of ozone layer by aerosol sprays and refrigerant fluids); sea pollution (through oil spills, etc.); deforestation; soil erosion (the destruction of top soil, encroachment of deserts); agricultural expansion; overgrazing; urbanisation; forest fires; developmental activities, such as dams, reservoirs, roads, railway lines, cropland; industries; mining, etc.
• The introduction of invasive exotic species are known to threaten the survival of many native species, for example, [Chromolaena odorata (L.) King and H.E. Robins (Syn. Eupatorium odoratum L.)], Parthenium hysterophorusL., Eichhornia crassipes (Mast.) Solms., andLantana camara L.-the latter has entered into forests, seriously competing with native species for factors like competition for nutrients, space and habitat.
- Type
- Chapter
- Information
- Economic BotanyA Comprehensive Study, pp. 615 - 626Publisher: Cambridge University PressPrint publication year: 2016