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Harvard Forest Data Archive
Stream Subsurface Flowpaths and Macroinvertebrate Communities at Harvard Forest 2004Related Publications
- Lead: Bridget Collins, William Sobczak, Elizabeth Colburn
- Contact: William Sobczak
- Start date: 2004
- End date: 2004
- Status: completed
- Location: Prospect Hill Tract (Harvard Forest)
- Latitude: +42.53 to +42.55
- Longitude: -72.20 to -72.17
- Elevation: 280 to 420 meter
- Taxa: Hydracarina, Oligochaeta, Aeshnidae, Ceratopogonidae, Chironomidae, Dytiscidae, Elmidae, Ephemerellidae, Gerridae, Gomphidae, Hydrophilidae, Leuctridae, Nemouridae, Perlodidae, Philopotamidae, Polycentropodidae, Sialidae, Simulidae, Tabanidae, Tipulidae, Veliidae, Homoplectra sp., Lepidostoma sp., Lype sp., Molanna sp., Oligostomis sp., Parapsyche sp., Potamyia sp., Psilotreta sp., Rhyacophila sp., Theliopsyche sp.
- Release date: 2009
- EML file: knb-lter-hfr.64.12
- DOI: digital object identifier
- Related links:
- Headwater Habitat Streams in Central Massachusetts 2002-2005
- Longitudinal Streamflow in Headwater Streams on Prospect Hill Tract at Harvard Forest 2003
- Study type: short-term measurement
- Research topic: watershed ecology
- LTER core area: populations
- Keywords: hyporheic zone, macroinvertebrates, stream ecology, streams
Headwater streams and wetlands with a combination of surface and subsurface flows are common features of many upland-forested watersheds. Unlike headwater stream reaches with continuous surface flow, the hydrology and ecology of subsurface stream reaches are poorly studied and not factored into existing wetland legislation. We assessed subsurface habitats and associated biota in a 435-m reach of a first-order, intermittent stream draining a riparian zone dominated by eastern hemlock (Tsuga canadensis) in north central Massachusetts. Stream flow was found only in subsurface flowpaths beneath large boulders and surface root mats over approximately 70% of the total stream length at summer base flow. Temperature, specific conductivity, dissolved oxygen, and dissolved organic carbon concentrations of subsurface water were similar to surface water. Macroinvertebrates were found in subsurface habitats but at a lower abundance and richness per unit area compared to surface habitats. Collectors such as Chironomidae, Polycentropodidae, and Ephemerellidae were generally the most abundant families in both surface and subsurface habitats. Our findings indicate that in some glaciated watersheds, intermittent streams with no visual evidence of surface flow may contain subsurface flowpaths with water chemistry and biota comparable to coupled perennial surface flow reaches. The prevalence and importance of subsurface habitats in some headwater streams may warrant review or revision of existing state and local regulatory definitions of intermittent and headwater streams.
Stream Hydrology and Chemistry
We installed 16 shallow wells in four transects perpendicular to the stream channel in July 2004 to investigate the hydrology and chemistry of the subsurface flow reach. Wells were constructed using 6-cm diameter polyvinylchloride pipes with the bottommost 10 cm perforated and screened. Transects were placed at 148, 224, 305, and 373 m upstream from the beaver wetland in reaches without discernible stream channels or surface flow. Numerous wells were installed using a post-hole digger, but wells were only left in locations hydrologically connected to the stream (i.e., where wells quickly recharged after bailing with a bilge pump). Dowels were used to measure water depth in wells in July, August, and September 2004. Data loggers (Thermochron i-buttons, Dallas Semiconductor Company, Dallas, Texas) were used to collect temperature of well water, surface flow, and ambient air temperature every 30 minutes from August 14 to September 14, 2004. Mean daily water temperature was compared between surface flow and wells using a one-way ANOVA. Water chemistry (pH, specific conductivity, and dissolved oxygen) was sampled four times in July 2004 at randomly selected sites in upstream surface flow, and at 20 subsurface flow sites. Specific conductivity and pH were measured using a YSI Model 63 pH, conductivity, and temperature meter, and dissolved oxygen (DO) was monitored using a YSI Model 57 dissolved oxygen meter. Dissolved organic carbon (DOC) concentrations were measured via high-temperature combustion using a Shimadzu 5000 TIC/TOC analyzer for samples from upstream and downstream surface water and from well water samples collected in July 2004. Measurements for each parameter (conductivity, pH, DO, and DOC) were compared among reaches with a one-way ANOVA.
We sampled randomly selected locations (to the closest riffle) in upstream and downstream surface flow twice, once each in summer (June–July) and fall (October) 2004 for a total of 12 samples. Samples were collected in surface flow locations by kick netting a 0.5 m2 quadrate and holding a D-net downstream from the riffle to collect macroinvertebrates and substrate. We sampled macroinvertebrates in the subsurface reach in summer (July) and fall (October) 2004 from 0.5-m2 pits. Pits were dug in three of the four well transects at the nearest accessible subsurface flowpath, and separate pits were dug for each summer and fall sampling to yield a total of six samples. Once the appropriate sized pit was dug, we collected the thin layer of silt and sand substrate within the exposed flowpath for our sample. We were unable to dig pits at the fourth well transect due to an abundance of boulders. Both surface and subsurface samples were placed in bags in the field and returned to the lab for preservation in 70% ethanol and sorting. Samples were sorted in their entirety, and subsurface samples were screened through an 860-mm mesh to remove silt. Invertebrates were identified to at least family (with the exception of mites and oligochaetes) using Merritt and Cummins (1996). Macroinvertebrate samples from the upstream surface, subsurface, and downstream surface reaches were compared in regards to total abundance, total taxa, Shannon index of diversity, and evenness. Over and under-represented taxa in the three reaches were identified according to binomial probabilities, where the observed frequency of a taxon in a given sample is compared with the taxon’s overall frequency out of all pooled samples.
This dataset is released to the public under Creative Commons license CC BY (Attribution). Please keep the designated contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement.
Collins B, Sobczak W, Colburn E. 2009. Stream Subsurface Flowpaths and Macroinvertebrate Communities at Harvard Forest 2004. Harvard Forest Data Archive: HF064.
hf064-01: macroinvertebrate abundance
- order: order
- family: family
- genus: genus
- upstream.summer: upstream abundance in summer (unit: number / missing value: NA)
- upstream.fall: upstream abundance in fall (unit: number / missing value: NA)
- subsurface.summer: subsurface abundance in summer (unit: number / missing value: NA)
- subsurface.fall: subsurface abundance in fall (unit: number / missing value: NA)
- downstream.summer: downstream abundance in summer (unit: number / missing value: NA)
- downstream.fall: downstream abundance in fall (unit: number / missing value: NA)
- total: total abundance (unit: number / missing value: NA)