Study Number: 

4017

Project Title:

The role of floods in particulate organic matter dynamics of a southern Appalachian river/floodplain ecosystem.

Investigator(s):

J.R. Webster E-Mail | Tel. 540.231.8941 | Biographical Sketch
E.F. Benfield E-Mail | Tel. 540.231.5802 | Biographical Sketch
 Matt Neatrour E-Mail
Affiliated Institution(s): Virginia Polytechnic Institute and State University 
Address: Department of Biology
Virginia Polytechnic Institute and State University 
Blacksburg, Virginia 24061  USA
Study Category: Regional
Project Type: Type 1
Study Period: 09/1997 - 09/1998
Notes:

 
Funding Source(s):

National Science Foundation, Grants DEB-9632854 and DEB-0218001 to Coweeta LTER.
Abstract: We investigated the role of a flood in particulate organic matter (POM) dynamics of the Little Tennessee river/floodplain ecosystem in western North Carolina, USA. We measured litterfall, leaf breakdown, and floodplain litter at 12 sites. Annual litterfall (274-625 g m-2 y-1) was typical of a temperate deciduous forest but lower than lowland floodplain forests in the eastern United States. Leaf breakdown rates of 4 tree species ranged from 0.001-0.010 d-1. Following a flood on 8 January 1998, the 12 sites were separated into 3 classes of inundation: inundated, partially-inundated, and non-inundated. Sites inundated by the flood had significantly less floodplain leaf litter and large woody material after the flood. There was no significant change at the partially-inundated or non-inundated sites. In addition, there was no significant difference in herbaceous litter between pre- and post-flood collections at any site. The flood also increased leaf breakdown rates of red maple (Acer rubrum) and black walnut (Juglans nigra) but had no effect on American hornbeam (Carpinus caroliniana) or sycamore (Platanus occidentalis). Our measurements of litterfall, leaf breakdown, and floodplain litter suggest that flood entrainment of POM from the floodplain of Little Tennessee River is a source of POM to the active channel. However, floodplain POM inputs were a small annual source of POM for the river compared to direct litterfall.
Location(s), Described: Sites along the Little Tennessee River in Macon and Swain counties:

Site Location Site code River km
Saw Mill rt 441 south of Riverside Rd. U1 1.2
Riverside Riffle Riverside Rd. U2 1.7
Franklin Mini Storage Rt 441 north of Riverside Rd. U3 3.5
Worthys Skeenah Creek U4 6.1
Macon County Coon Club Wide Horizon Rd. U5 9.1
Subway Behind Subway in Franklin L1 18
NPL Property Rt. 28 at Iotla Bridge L2 28.8
Porter Farm Hall Rd. off Rose Cr. Road L3 33.3
Bill McLarneys Meadows Rd. off Rt. 28 L4 38.4
NPL Property HP McCoy Rd. L5 40.4
Cecil Dorseys Off Needmore Rd. near Rattlesnake Cr. L6 51.5
Tomato Patch Lower Needmore Rd. L7 53.3
Location(s), Download GPS: ArcView Shape Files (shp.):  UTM, NAD83, Zone 17  |  Lat/Lon
Location(s), Online Map(s): USGS Topographic-based Maps of Research Sites (Printable for fieldwork)
Methods/Experimental Design: Litter inputs to the floodplain
Ten litter traps were placed at each of the 12 sites at 2-m intervals along a transect parallel to the river channel located approximately 2 m from the river bank. Litter traps consisted of a 0.25-m2 frame fitted with 1-mm mesh fiberglass screen and supported by three wooden stakes. Litter was removed from the traps twice monthly during times of peak leaffall (October-November) and monthly at other times from September 1997 until September 1998. Litter was dried (50°C, 2 d) and separated into leaves, wood, and miscellaneous litter (e.g., flowers, seeds). Leaves were sorted to species, weighed, recombined, ground, and subsampled. Wood and miscellaneous litter were separately weighed, ground, and subsampled. Subsamples were weighed, ashed (550°C, 45 min), and reweighed to determine ash free dry mass (AFDM).

Leaf breakdown
Fifteen leaf bags of the 2 most common floodplain species, sycamore and American hornbeam, were placed on the floodplain at 8 of the 12 sites, and 15 leaf bags of 2 other common floodplain species, red maple and black walnut, were placed at 3 sites. Leaf bags of a given species were placed at sites where that species was common. Each leaf bag initially contained 8 g of leaf material. Three bags of American hornbeam, black walnut, and red maple were retrieved after 1, 2, 4, 6, and 7 mo at each site, and 3 leaf bags of sycamore were collected after 1, 2, 4, 7, and 9 mo at each site. All leaves were washed, dried, weighed, ground, and subsampled. Subsamples were weighed, ashed, and reweighed to determine AFDM. Species-specific exponential rates of breakdown were determined from the negative slope of the log percentage AFDM remaining (y-axis) vs. the days of exposure (x-axis) (e.g. Benfield 1996).

Floodplain litter standing crop
Floodplain litter standing crop (FPL) was measured by removing all coarse litter from 20 0.05-m2 plots at each site (240 total plots) in December 1997 (pre-flood) and January 1998 (post-flood). Litter was dried and separated into leaves, wood, and herbaceous material. Sorted materials were then weighed, ground, and subsampled to determine AFDM.

Sampling Frequency: See Methods/Experimental Design above.
Data Columns: Not Applicable, publication serves as data.
Publications:

Neatrour, M.A. 1999. The role of floods in particulate organic matter dynamics of a southern Appalachian river/floodplain ecosystem. Masters thesis. Virginia Polytechnic Institute and State University, Blacksburg, Virginia.

Neatrour, M.A., J.R. Webster, and E.F. Benfield. 2004. The role of floods in particulate organic matter dynamics of a southern Appalachian river-floodplain ecosystem. Journal of the North American Benthological Society.  23(2): 198-213.

Data Restrictions: Users must adhere to the Coweeta LTER Data Policy.
Metadata: EML Format (XML Schema) | Information about EML
Data Downloads: Download publication (Serves as data for this project)