What Are Ecosystems?
		Agricultural | Forests | Coastal | Grasslands | Freshwater | Urban The Value of Ecosystems Ecosystems are communities of interacting organisms and the physical environment in which they live. They are the combination and interaction of the plants, animals, minerals, and people in any given area of the Earth. A small bog, a single sand dune, or a tiny patch of forest is an ecosystem. But ecosystems are also forests covering thousands of kilometers, a major river system, a desert. Every centimeter of the planet is part of an ecosystem. Maybe the most familiar natural ecosystems are our backyards or parks near our home. Below are the six ecosystems on which life on Earth most heavily depends: Agroecosystems - the farms where we grow our food and the livestock production systems-ranches and hog farms, for example-where we produce meat products. Forest ecosystems - the woodlands where we hike, cut timber, and hunt. Freshwater ecosystems - the lakes, streams, and rivers we fish in, boat on, transport our goods over, and rely on for drinking water. Grassland ecosystems - meadows, prairies, pampas, savannas, and steppes where we graze our cattle. Coastal ecosystems - the beaches where we play, the marine waters we trawl, the reefs and atolls that line coasts in tropical waters and buffer our coastlines. Urban ecosystems - Even cities and suburbs are ecosystems, where a greater concentration of economic and educational opportunities are offered and where nearly half of the world's populations live. The goods and services that ecosystems provide us with form the foundation of our economies. Agriculture, forestry, and fishing are responsible for 50% of all jobs worldwide and 70% of the jobs in sub-Saharan Africa, East Asia, and the Pacific. In 25% of the world's nations, crops, timber, and fish still contribute more to the economy than do industrial goods. Ecosystems also purify our air and water, help to control our climate, and produce soil-services that can't be replaced at any reasonable cost. In our heavily industrialized societies, work, religious expression, and recreation often take place in urban areas. But natural ecosystems also provide places for religious expression, aesthetic enjoyment, and recreation. Every year, millions of people make pilgrimages to outdoor holy places, vacation in scenic regions, or simply pause in a park or a garden to reflect or relax. It is our very reliance on ecosystems that is threatening them. As our populations grow and consumption of food, water, and other materials increases, the ecosystems that provide for these needs are being stressed and in some cases destroyed. For comprehensive data about the world's ecosystems, visit EarthTrends at www.earthtrends.wri.org/. Take our Interactive Quiz to see how much you know about ecosystems, then check out our Get Involved section to learn about ways you can make a positive difference in your home, your community, and your world.
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