PARENT SESSION
Poster Session #22: Fish, Lakes, Streams and Wetlands.
Tuesday, August 6. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Fine root biomass in forested wetlands with contrasting hydrologic regimes.

Neatrour, Matthew^*,1, Jones, Robert¹, Golladay, Stephen², Kelley, M², ¹ Department of Biology, Blacksburg, Virginia² Jones Ecological Research Center, Newton, Georgia

ABSTRACT- Proportions of carbon allocated to fine root biomass can vary dramatically with soil fertility. In fertile ecosystems, trees apportion relatively little of their total carbon resources to root production, whereas trees in infertile ecosystems allocate a substantial portion of their carbon resources to roots, presumably to increase nutrient uptake. We measured fine root standing crop in two major types (riparian and depressional) of seasonally-inundated forested wetlands in the Gulf Coastal Plain. Riparian wetlands periodically receive flood-pulses from river-flooding and are generally nutrient-rich. In contrast, depressional wetlands receive most of their water and nutrients from precipitation and are nutrient-poor. All wetlands used in this study were mature forests. We predicted that fine root standing crop (< 2 mm diameter) would be greater in depressional wetlands than in riparian wetlands. However, preliminary data indicate that fine root biomass was greater in riparian wetlands (167 g/m²) than in depressional wetlands (127 g/m²), although the difference was not significant (T-test, p=0.19). Furthermore, using basal area as surrogate for aboveground biomass, fine root to basal area ratios were not significantly different between the two wetland types ( p=0.75). These data suggest that other factors, such as frequency and duration of the annual hydroperiod, may be more important determinants of carbon allocation in these wetlands than overall wetland fertility. Studies are currently in progress to examine the relationship of hydrology and/or soil nutrient availability to fine root production in these wetland types.

KEY WORDS: wetland, fine root, carbon allocation