Aboveground production in southeastern floodplain forests: A test of the subsidy-stress hypothesis
- Duke Univ., Durham, NC (United States)
- Baruch Forest Science Inst., Georgetown, SC (United States)
- and others
Periodically flooded forests may have higher rates of aboveground net primary production than upland forests and near-continuously flooded forests, but the benefits of periodic inputs of nutrients and water may be diminished by stresses associated with anaerobic soils or drought. Groundwater table depths were measured and aboveground productivity in floodplain forests of South Carolina and Louisiana. Paired plots on locally dry, intermediate, and wet topographic positions across three hydrologic transects encompassed upland hardwood, bottomland hardwood, and cypress swamp forests. Aboveground net primary production (NPP) on wet plots was significantly lower than on intermediate and dry plots (P {le} 0.02). There was no significant difference between intermediate and dry plots. In addition, aboveground NPP on intermediate plots was not significantly different from 22 temperate upland forests in the literature. Combining data with data from the literature, aboveground NPP on wet plots was negatively related to MWD. On sites with evidence of hydrologic disturbance the slope of this line was 5 times greater. Conditions of periodic flooding and flowing water do not often lead to high rates of productivity compared with upland forests. However, extensive flooding is nearly always a significant stress on forest productivity, particularly when the flooding regime has been recently perturbed through levee construction or impoundment. The data support a more complex interaction between subsidy and stress factors. 79 refs., 4 figs., 2 tabs.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC09-76SR00819
- OSTI ID:
- 478383
- Journal Information:
- Ecology, Vol. 78, Issue 2; Other Information: PBD: Mar 1997
- Country of Publication:
- United States
- Language:
- English
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