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Team:Imperial College London/Project/Background
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text[3] = "China is one of the largest dryland areas in the world, nearly a quarter of which is at risk of desertification. The problem has been fed by large-scale industrialisation with the over-use of land and water resources, as well as prolonged drought. Since 1978 the Great Green Wall project has been underway in the Kubuqi desert to protect cities from wind erosion carrying dust. The trees (Xinjiang poplars and willow species) are planted as saplings protected with wooden frames so they can take root before being blown away. These plants form fibrous roots that help hold down the sand. Although this project has slowed the desertification process in China, it remains an imminent problem."; | text[3] = "China is one of the largest dryland areas in the world, nearly a quarter of which is at risk of desertification. The problem has been fed by large-scale industrialisation with the over-use of land and water resources, as well as prolonged drought. Since 1978 the Great Green Wall project has been underway in the Kubuqi desert to protect cities from wind erosion carrying dust. The trees (Xinjiang poplars and willow species) are planted as saplings protected with wooden frames so they can take root before being blown away. These plants form fibrous roots that help hold down the sand. Although this project has slowed the desertification process in China, it remains an imminent problem."; | ||
text[4] = "30% of landmass in India is comprised of drylands and desertification is leading to crop losses of up to 41% in eastern Himalayan areas, which are recognised as biodiversity hotspots. Communities living in the Himalayas are heavily dependent on the forest as a resource for fuel wood and for their livestock. Increasing deforestation is leading to soil erosion and interference with water courses which is likely to have a major affect on inhabitants of the Ganges Plain who rely on the forest to slow flash floods. Small scale charities such as the Berkely Reafforestation Trust are working with local organisations to re-establish indigenous tree populations. So far they have funded the locally initiated reforestation of about 1600 hectares of degraded land and provided training programs to promote sustainability."; | text[4] = "30% of landmass in India is comprised of drylands and desertification is leading to crop losses of up to 41% in eastern Himalayan areas, which are recognised as biodiversity hotspots. Communities living in the Himalayas are heavily dependent on the forest as a resource for fuel wood and for their livestock. Increasing deforestation is leading to soil erosion and interference with water courses which is likely to have a major affect on inhabitants of the Ganges Plain who rely on the forest to slow flash floods. Small scale charities such as the Berkely Reafforestation Trust are working with local organisations to re-establish indigenous tree populations. So far they have funded the locally initiated reforestation of about 1600 hectares of degraded land and provided training programs to promote sustainability."; | ||
| - | text[5] = "In Australia, desertification and soil degradation are wide-spread problems in rangelands, particularly in the dry inner parts of the continent. They result from overgrazing of the land but also climate conditions and invasive animal species such as rabbits. Economic factors play a big role as pastoralism is mostly export and profit oriented. Land degradation | + | text[5] = "In Australia, desertification and soil degradation are wide-spread problems in rangelands, particularly in the dry inner parts of the continent. They result from overgrazing of the land but also climate conditions and invasive animal species such as rabbits. Economic factors play a big role as pastoralism is mostly export and profit oriented. Land degradation was triggered by the arrival of European pastoralism and has been an ongoing problem for the last century. Source: Pickup, G. (1998) Desertification and climate change - the Australian perspective. Climate Research 11, pp.51-63."; |
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Revision as of 21:04, 18 September 2011
Desertification
Desertification is the degradation of drylands which include arid, semi-arid and sub-humid areas. Drylands make up roughly 40 percent of the Earth’s land and are home to some two billion people, most of which live in developing countries. Dryland soil sustains a fragile ecosystem adapted to infrequent precipitation and dramatic temperature changes. Over-exploitation of dryland for cultivation and feedstock purposes renders the soil unproductive, forcing migration of communities in search of fertile land, leaving the unproductive land bare and vulnerable to erosive forces. A lack of food supply in many developing countries forces constant cultivation of land for short-term gain as well as deforestation to provide arable land.
Case studies
Downstream Effects
Soil affects the climate and biodiversity and leads to often irreversible desertification (see figure above). Roots increase the stability of soil and prevent erosion (Gyssels & Poesen, 2003). In addition, trees provide cover and protect nearby fauna and flora. In areas prone to soil erosion, this is especially important as rainfall tends to be rare but when it does occur, it is often very intense and easily leads to topsoil being washed away. Roots are also important carbon sinks. Increasing root biomass is therefore very likely to improve the carbon budget of the plants we are seeding (Dr Alexandru Milcu, oral communication).
Image taken from the Millenium Ecosystems Assessment - Desertification synthesis.
