Edaphic control of vegetation

Ecologists refer to the influence of soils on living things as "edaphology." This photo shows how, within a very small area, different soils support entirely different plant communities. In the left and foreground, the geology is a sandstone layer which weathers to a sand soil, which is good for water retention and produces a lush grassland plant community. In the background and right, the geology is saline shale, which weathers to a salty clay soil; this clay soil contains almost no water for plants, and the land is nearly barren of plants. This distance is far too small to reflect differences in rainfall, temperatures, sunlight, etc.