Project Title:

Investigator(s):

Virginia Polytechnic Institute and State University
Department of Biology
Blacksburg, Virginia 24061  USA

Department of Forest Resources
College of Natural Resources
115 Green Hall
1530 Cleveland Avenue North
St. Paul, Minnesota 55108-1027  USA

Forestry Sciences Laboratories
P.O. Box 12254
Research Triangle, North Carolina 27709  USA

National Science Foundation Grants DEB-9632854 (Text Version) and DEB-0218001 (Text Version) to Coweeta LTER.

Sediment cores
Sediment core samples were collected at each site using a 60 cm (height) x 25 cm (diameter) stainless steel stovepipe corer. Sediment cores were located haphazardly in three riffles and three pools at each site. The coring device was inserted approximately 10 cm into the streambed. All substrate was removed to a depth of 10 cm. Large substrate (> 64 mm) was removed first and weighed in the field. All remaining substrate was removed, placed in plastic bags and transported to a lab at UGA for processing. Samples were dried in the lab at 105?C for three weeks, or until completely dry. Samples were then sieved into three size fractions: gravel (2 64 mm), sand (0.063 2 mm) and silt-clay (< 0.063 mm). Size fractions were then weighed to the nearest 0.1 gram. Percent fines (< 2 mm) and percent coarse material (> 2 mm) were determined
using sediment core data.

TSS
Total suspended solids (TSS) samples were collected at baseflow at each site. Three 125 ml water samples, to be used for determining water chemistry, were collected from the thalweg of run habitat. Using a hand pump, water samples were filtered in the field onto a pre-ashed, pre-weighed 47 mm, 0.45 m Whatman glass fiber filter. Filters were placed in aluminum envelopes, transported to the lab, dried in a 105 C oven for 24 hours and weighed. Water sample filtrate was placed on ice and transported to lab for water chemistry analysis.

Pebble Count
Pebble counts were conducted to determine the particle size distribution of the bed substrate. One hundred particles were picked up and measured while traversing a zig-zag pattern at each site. Particles were measured in riffle-run habitat, while pool habitat was avoided. This affords direct comparison of similar habitat among sites. Medial axes of particles were measured to the nearest millimeter. Measurements were then converted to phi size (i.e. the negative log, base two), and average phi was determined. Some studies have suggested average phi as a good predictor of fish and macroinvertebrate measures (pers. comm., D. Walters, University of Georgia).

Temperature
Stream temperature data was collected in late summer 2000, from August 3rd to September 15th. Temperature was measured every 2 hours during this period, using a Hobo data logger contained in a waterproof PVC housing. Mean temperature and daily temperature flux were determined for each site.

Algae Standing Stock
Benthic algal biomass samples were collected at each site using a custom made suction apparatus. The apparatus consisted of a 20 cm long plexiglass cylinder with a 4.3 cm diameter. A rubber gasket was fitted to the end of the sampler which was pressed against the substrate to ensure a water tight seal between the sampler and substrate. Inside the sampler was a round scrub-brush, which was used to dislodge the algae from the substrate. Three algae samples were collected haphazardly and composited at each of 10 evenly spaced transects per site. Composite samples were placed on ice and transported to lab for processing. Algae samples were sub-sampled for determination of chlorophyll a concentration, ash-free dry mass and species identification. Chlorophyll a concentration was determined from sub-samples using standard pigment analysis methods (Wetzel and Likens 1991). Pigments were extracted using 90% acetone buffered with ammonium hydroxide. Chlorophyll a was measured using standard fluorometric methods.  Ash-free dry mass (AFDM) was also measured. Sub-samples were filtered through pre-weighed 47 mm, 0.45 ?m Whatman? glass fiber filters. Filters were then dried in a 105 C oven for 24 hours and weighed.

Fish
Fish were collected between April 16th and July 6th 2000 using a backpack electroshocker, seines and dip nets. At each site a quantitative sample was taken during one thorough pass within a representative 50 m reach. To ensure comparable catch per unit effort, an attempt was made to equalize electroshocking time per area sampled. After each quantitative collection, a larger area was randomly searched to determine community species richness. One individual from each species (except the federally threatened Cyprinella (Erimonax monacha) was kept for museum specimens. Remaining fish were identified in the field, counted, and returned to the stream.

Energy Grade Line and Channel Cross Section Surveys
Standard survey techniques were used to survey three channel cross sections along the 100m study reach at each site. Energy grade line was also recorded by measuring water depth in the thalweg and channel elevation along the 100m reach. Pools and riffles were noted to allow calculation of pool to pool and riffle to riffle gradients. Point bar elevations were recorded separately, as were elevations of the flood plain.

Benthic Macroinvertebrates
Benthic macroinvertebrates were collected in riffle habitat by disturbing substrate inside a 0.4-sq. meter frame to a depth of 10 cm for 2 minutes. Material was collected in a net (353 micron mesh) held downstream of the sampling area and fixed in 3% formalin. Samples were rinsed in the laboratory in a 125 micron sieve and preserved in 80% ethanol. Macroinvertebrates were separated from other materials (sand, detritus) and identified to genus.

Gardiner et al. Stream ecosystem and landscape trajectories in the Southern Blue Ridge. In Prep.