You are here:
HOW MUCH OF STREAM HABITAT IS PREDETERMINED BY NATURAL GEOMORPHIC CONTROLS?
Citation:
Kaufmann, P R. AND A. T. Herlihy. HOW MUCH OF STREAM HABITAT IS PREDETERMINED BY NATURAL GEOMORPHIC CONTROLS? Presented at Annual meeting Oregon Chapter, American Fisheries Society, Sunriver, OR, February 26-March 1, 2002.
Description:
Detailed pre- and post-disturbance research has demonstrated the ability of human activities to alter stream channel characteristics, including the amounts of deep pool habitat and fine substrate. However, it is often difficult to demonstrate consistent associations between these same channel features and human activities on large regional scales. In such research, it is important to quantitatively determine the amount of regional habitat variation that is reliably determined by "natural" topographic, geomorphic, and climatic factors. Using data from the USEPA's EMAP regional surveys, we show that within a geoclimatic region, most of the variation in residual pool volume and substrate size appears to be predetermined by drainage area, channel slope, and basin lithology. In many dynamic landscapes, a substantial amount of variability derives from stream response and recovery from episodic natural disturbances. Furthermore, the relative roles of deterministic geomorphic control and disturbance change with the spatial scale of analysis. After consistent geomorphic controls are factored out, the effects of human activities and natural temporal variability are clarified.