Evidence of Land-Use Effects in High-Resolution Overbank Deposition Rates in the Pacific NW
Abstract
A palynological technique was employed to calculate high-resolution overbank deposition rates on a river floodplain in a Pacific NW drainage. The floodplain is located at the terminus of a low-order basin that experienced three logging and two intervening forest recovery periods. In sharp contrast to the prior 600 years, the logging era has experienced rapid sediment pulses with over an order of magnitude more deposition. During recovery periods, Seqouia has not returned to its pre-disturbance conditions, having been partly replaced by disturbance-tolerant species. It is clear that overbank deposition rates observed during modern times at the study site are much greater than any rate observed over the nearly thousand year record, suggesting that over hundreds of years, anthropogenic disturbance may be so severe that it becomes the dominant control on floodplain evolution and perhaps on denudative processes. Results suggest that in order to protect habitat quality, land-management strategies need to be focussed on curtailing rapid land-use change in the most sensitive, low-order drainages.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AGUFM.H21C0832C
- Keywords:
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- 1803 Anthropogenic effects;
- 1815 Erosion and sedimentation;
- 1871 Surface water quality;
- 1890 Wetlands;
- 1894 Instruments and techniques