Plant community patterns in a gypsum area of NE Spain. I. Interactions with topographic factors and soil erosion

The aim of this paper is to explain how topographical factors and soil erosion affect plant community patterns in the gypsum hills of the Middle Ebro Basin (NE Spain). Both the altitudinal location on the hill and, secondarily, the aspect determine a regular distribution pattern of the plant communities, which is closely related to soil and erosion features, as well as to some plant attributes. Tall perennial grasses dominate the valley bottoms, and scrub vegetation the hillsides and hilltops. Water availability, soil depth and particle movement down the slope are the main factors that could explain this segregation.