Why do we have to prevent desertification?
When desertification takes place in one certain area, the land will not have the nutrients that the other living organisms need.
Especially a lot of plants will die, since water is necessary for the plants in order for them to carry out photosynthesis. Dying plants cause less food for certain insects, because a lot of them are fed on plants. Slowly the land becomes 'desertified' and shows little livingness of it.
Desertification causes
- 100 damaged nation are in danger.
- Famine One Billion(1,000,000,000)
- Environment Refugee : 50 million(50,000,000)
- Main cause of disasters, extreme weather, and global warming
Consequences of desertification
- Conversion, particularly to cropland. Large-scale transformation to cropland in drylands is dependent on availability of freshwater, either as surface waters (lakes, rivers, reservoirs) or in aquifers. In many areas, conversion is followed by abandonment as soil becomes degraded, often through salinisation or waterlogging.
- Changing fire regimes. Many dryland ecosystems are naturally adapted to some degree to fire. However, in many areas fires caused by humans (often as deliberate burning to produce new growth for livestock) are far more frequent and extensive than natural fires, and have very different impact on ecosystems and their biodiversity.
- Impact of introduced herbivores, particularly livestock, through trampling, removal of plant biomass, introduction of pathogens and alteration of plant species composition through selective grazing and competition with native species.
- Introduction of non-native plants. Grassland ecosystems have been routinely modified by deliberate introduction of non-native species, particularly other grasses and leguminous plants.
- Water. By definition, water is a limiting resource in dryland ecosystems. Human use of existing water resources in these systems therefore has often a disproportionately extreme impact. Abstraction of water for irrigation from freshwater systems such as lakes and rivers has an often extreme impact on the biodiversity of these ecosystems. Depletion of groundwater resources may have a less obvious direct impact but is likely to affect natural ground-fed springs and deep-rooted vegetation where the aquifer is relatively near the surface. Creation of artificial water-sources for livestock leads to the creation of virtually barren “sacrifice zones” around the water source as a result of extremely heavy trampling by livestock.
- One of the most significant human impacts in natural or semi-natural dryland and savannah ecosystems in developing countries is through harvest of wood for fuel. Quantifying this, and assessing its long-term impact on ecosystems, has proved problematic, although in some areas the impact is undoubtedly severe.
- Overharvest of wild species. Excess hunting of wildlife and collection of plants, whether for subsistence use or national or international trade, can have severe impacts, in some cases driving species to extinction. Because dryland species tend to have relatively low population growth rates, and in the case of plants, individual growth rates, they may be particularly sensitive to overharvest.
- Chemical inputs. In many grassland ecosystems, highest biological diversity seems to be associated with poorer soils. Artificial enrichment of grasslands, particularly through application of nitrogenous fertiliser, generally leads to a very marked decrease in plant species diversity.
- Long-term impacts of climate change. The potential impacts on dryland ecosystems of human-induced climate change remain to be quantified but are likely to be significant.
