Even in metropolises humans depend on natural, healthy ecosystems for goods such as high-protein food and services such as soil nutrient recycling and water filtration.
Ecosystem Goods and Services
Without realizing it, even
in big cities humans depend on natural ecosystems for goods and
services. Examples of tropical goods range from fruits and fish to
timber. Ecosystem services are less well known and are usually
unacknowledged and not valued economically. These services, given to us
free of cost from ecosystems, include pollination of crops, provision of clean
filtered water and recycled soil nutrients...
even the production of the oxygen
we breathe. As one concrete example in the tropics shows, these services are costly to lose: agro-ecologists, ecologists who study agricultural ecosystems, now know that the presence of a nearby patch of tropical forest increases the pollination and therefore bean production of coffee groves. The forest harbors the pollinators.
One of the services that the original tropical rainforest provided was protection of soils from erosion, the topic of our studies. High up, an intact forest canopy intercepts the force of storms, softening the blows of pounding rain on the forest floor below. Down below, tree roots are associated with underground networks of fungal tendrils that form a mat binding the soil together, resisting erosion. For more information scroll to 'Ecological Notes' at http://www.marietta.edu/~biol/biomes/troprain.htm.
When the forest and its fungal-root mat are removed and soil is washed down slope, the sediment silts up rivers, lakes, and eventually, coastal mangroves and coral reefs, ultimately smothering many of their creatures. Both upstream and down, fish, mollusks, and other aquatic animals that once served as protein sources for local people cannot get oxygen and die.
Beyond the local scale, the damage is regional, even global. The mangrove-reef ecosystem is thought to provide 1/3 of the world’s commercial fish production by acting as large fish nurseries, another example of an unacknowledged ecosystem service. Reduction of marine fisheries in the tropics has been linked by several scientific studies to deforestation upriver.
We are witnesses to a global tragedy.