Mangroves are trees and shrubs that have adapted to life in a saltwater environment. There are about 80 different species of mangrove trees. All of these trees grow in areas with low-oxygen soil, where slow-moving waters allow fine sediments to accumulate. Mangrove forests only grow at tropical and subtropical latitudes near the equator because they cannot withstand freezing temperatures. The main contribution of mangroves to the larger ecosystem comes from litter fall from the trees, which is then decomposed by primary consumers.