Forests, grasslands and wetland protect landscapes against erosion floods and landslides through the binding action of plant roots. The root systems of plants hold soils in place, preventing erosion and mudslides. Plants also hold moisture in soils and thereby help reduce the effects of drought. Lands that have been deforested and cleared, have little ability to hold water. These natural drought and flood control services are particularly important to people living along rivers and coastlines and for people in arid regions. Ecosystems bordering regularly flooding rivers (e.g. wetlands) absorb excess waters and thus reduce the damage caused. Certain coastal ecosystems (salt marshes, mangrove forests) prevent the erosion of coastlines.