Vital GEO Graphics

Impacts on Human Health About one billion people around the world live a subsistence lifestyle and any loss of ecosystem pro- ductivity – through declines in soil fertility, drought or overfishing and other factors – can rapidly lead to malnutrition, stunted childhood growth and increased susceptibility to disease. The conceptual links between broader environmen- tal changes and human health are well under- stood. Changes to ecosystems and their services, especially freshwater sources, food-producing systems and climatic stability, have been respon- sible for significant adverse impacts on human health in the past 20 years, predominantly in poor countries. Changes in land use, invasive alien-species, many forms of intensive animal production and the inter- national wildlife trade can result in an increased risk from infectious diseases. As ecosystems are lost or degraded, their capacity to remove harmful pollutants from the environment is reduced. Local and sometimes global pollutant accumulation is the result. Examples include the accumulation of particles and gases in the air and of microbial contaminants, inorganic chemicals, heavy metals, radioisotopes and persistent organic pollutants in water, soil and food. Such harmful substances have a wide range of negative health impacts. Ecosystems and their associated biodiversity are also the source of many health cures. In 2002- 2003, 80 per cent of new chemicals introduced globally as drugs could be traced to or were inspired by natural products. Traditional medicines mainly derived from plants, are a staple of pri- mary health care for a significant proportion of the population in developing countries. Valuing Is Vital Ecosystems such as forests, grasslands and man- groves provide valuable environmental services. They include provisioning services that furnish food, water, timber and fibre; regulating services that affect climate, floods, disease, wastes and water quality; cultural services that provide recrea-

tional, aesthetic and spiritual benefits; and support- ing services, such as soil formation, photosynthesis and nutrient cycling. The maintenance of healthy ecosystems and sustaining the diversity of goods and ecological services they provide is of vital importance to the lives of millions and for global food security. Losses of biodiversity, such as the erosion of ge- netic variability in a population, are often gradual and not seen or fully recognized until it is too late. The global nature of ecosystems and of many biodiversity values often means the impacts of degradation and loss are often felt across national boundaries: this means that efforts to curtail such losses can be hampered by political and territorial considerations.

Agriculture in a rain forest in Ghana, growing cassava and fruits such as bananas and papayas. Credit: Ron Giling/StillPictures

37 ECOSYST EM MANAGEMENT