What-do 'wet' and 'dry' really mean to vegetation?
Stephenson NL. 1992. What-do 'wet' and 'dry' really mean to vegetation?. Bulletin of the Ecological Society of America. 73(2):355-356
The different effects of evaporative demand and water supply are often confused by investigators interpreting local moisture gradients. For example, both sunward slopes and soils with low water-holding capacities are usually considered to be "dry," but the former are dry because of increased evaporative demand, the latter because of decreased water availability. The two forms of "dry" are not equivalent, and should not be combined (as they often are) in a single moisture index. In contrast, local water balances inherently address the different and interacting effects of water supply and water demand. Consideration of the water balance leads to specific predictions about the distribution of vegetation types in mountains; for example, vegetation on sunward slopes should most closely resemble vegetation on level ground at lower elevation, whereas vegetation on shallow soils should most closely resemble vegetation on deep soils in rainshadows. I present data from the Sierra Nevada of California that support these predictions, and contrast my results with those of other North American studies. The distribution of vegetation types in mountains is more easily understood in terms of local water balances than in terms of some of the more familiar moisture indices.
- Type
- Journal Article
- Authors
- Stephenson, Nathan
- Units
- SEKI
- Keywords
- CA, Plant Moisture, Plant Studies, Sequoia and Kings Canyon National Parks, Sierra Nevada, Vegetation