Bare GroundTwo Years Later No plant competition for light, space, nutrients or water. Soil mobile and liable to erosion and loss. A more extreme surface microclimate because the bare soil both absorbs and reflects heat more than soil covered in vegetation. A drier environment because there is no plant cover to hold moisture above ground and little humus to hold it in the soil. Lower nutrient levels in the soil. Intense plant competition for space and other resources. Soil bound by roots and plant cover. The plant cover provides a certain amount of ground insulation from extremes of temperature. There are now also a variety of microclimates within the vegetation. Plant cover and increasing humus levels help to retain water. The nutrient levels in the soil will have increased.

 pioneer species: simple and hardy plants that first invade or colonize barren ground and change the environment to support more complex life forms  Eg. Pioneer species—ferns, lichens, mosses, and some bacteria, etc

 These pave the way for more complex organisms as their life processes change the original habitat.  Ex. Bacteria and lichens produce acids that break down the rock.  Minerals are released to provide areas that trap water.  Mosses can then grow in the sparse soil made by lichens and they trap dust and water against the rock. The dead bodies of lichens and mosses add material to the soil when they decay and become the organic component of soil called humus.

 climax community: the stable community that results from the process of succession