Major threats to savanna ecosystems
Savannas are amongst the oldest ecosystems used by people. Homo sapiens evolved in a savanna environment in East Africa about one million years ago. Anthropologists believe that these human populations existed by hunting wildlife and gathering plant materials. The Australian Aborigines are one of the traditional savanna hunter-gatherer cultures that still exist (Solbrig 1993).
Savannas land use currently includes fully nomadic pastoralism, semi-nomadic pastoralism, subsistence cultivation with no cash crop, and cash crop cultivation (including ranch, estate and plantation farming). In addition to food, fibre and wood production, savannas are also used for mining, national parks, tourism and urban developments.
Human usage of the savanna biome is increasing, which can lead to degradation of vegetation and soil resources, resulting in nutrient losses and shifts in water balance and availability. Brazilian cerradão contains over 800 species of trees and shrubs alone; approximately 40% of the cerradão and llanos has now been cleared or altered for agricultural uses with crops such as coffee, soybeans, rice, corn and beans.
Read the section Threats to long-term sustainability in Hutley L.B. and Setterfield S.A. (2007, in press) Savannas. In S.E. Jørgensen (ed.) Encyclopedia of Ecology, Elsevier, Amsterdam.
What are the major threats to savanna ecosystems and their ecosystem services?
Your list would include:
- Land clearing
- Firewood collection
- Poor fire management
- Conversion to cropping
- Climate change
- Invasive species