Headwater Habitat Streams in Central Massachusetts
HF095 Overview Data EML Archive- Investigators: J. Choiniere, Elizabeth Colburn, Cindy Dunn, H. Jensen-Herrin, D. Williams
- Contact: Elizabeth Colburn
- Start date: 2002-08-01
- End date: ongoing
- Location: Prospect Hill Tract (Harvard Forest) and Mt. Wachusett (Princeton MA)
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- Taxa: Coleoptera, Diptera, Megaloptera, Odonata, Plecoptera, Trichoptera, Desmognathus fuscus, Eurycea bislineata, Gyrinophilus porphyriticus, Plethodon cinereus
- Keywords: conservation, intermittent streams, salamanders, temporary streams, temporary waters, volunteer monitoring
- Abstract:
Headwater streams, particularly those that flow only during part of the year, are understudied and underprotected in Massachusetts. Research being conducted elsewhere suggests that these "Headwater Habitat Streams" are important both for aquatic biodiversity and for ecological function of lower stream reaches. We are carrying out baseline research, involving research scientists and volunteers, on hydrology, habitat characteristics, and biological community composition and structure in headwater streams in northern Worcester County, MA.
We hypothesized that headwater streams exhibit a longitudinal gradient of hydrology, from (1) ephemeral channels that flow only in response to storms, through (2) intermittent sections that flow seasonally until the groundwater table falls below the channel and are dry the rest of the year, to (3) interstitial reaches that flow seasonally and retain pools connected by subsurface flow during the summer, to (4) the perennial stream. We further hypothesized that these different hydrologic units would differ in the biological communities they support, in both species composition and trophic structure. Results to date show a high degree of longitudinal heterogeneity in the study streams, with interspersion of perennially flowing reaches among low-gradient sections of vegetated wetland, high-gradient boulder piles, and braided channels. Perennial flow is found high up in some watersheds. Differences in the macroinvertebrate fauna of intermittent and perennial sections may provide useful indicators of hydrologic regime for use by volunteers.
We expect our methods and results will have implications throughout the Commonwealth for local conservation commissions and other municipal officials responsible for land-use planning and regulation, state agencies responsible for land management and the protection of wildlife, regulators reviewing projects affecting streams, watershed managers, teachers and their students, private land trusts, conservation advocates, and citizen-naturalists.
- Methods:
Starting in late summer of 2002, we have carried out habitat surveys in headwater tributaries of 15 perennial streams in central Massachusetts. Each of 36 headwaters was flagged at 20-m intervals. Using a modification of the field procedures established by Ohio EPA (2002) for assessment of headwater streams, we recorded habitat characteristics such as flow, gradient, substrate (percent boulder, cobble, sand, leaf dams, etc.), channel conditions (pool, riffle, cascade, etc.), riparian vegetation, and adjacent land use for each 20-m reach of each tributary. In a subset of the study streams, we randomly established quadrats for macroinvertebrate sampling and transects for intensive visual searches for salamanders in 50-m stream reaches. Habitat characteristics of the quadrats and transects are quantified using the same procedures followed for reach-level habitat assessments. Each salamander transect is 1 m wide and with a length of 4x the mean stream width at the reach. Where the channel is more than 1 m wide, the side of stream to be followed is determined randomly. In reaches without standing water, leaf-dams, woody debris, and rocks are carefully searched and bank vegetation and refugia are examined for the presence of stream salamanders. Where water is present, potential refugia are lifted and the water swept with a D-frame aquatic net. All salamanders are identified and released back into the stream. We sample macroinvertebrates in separate, randomly located, 1 m2 quadrats in each 50-m reach by repeatedly stirring the substrate and sweeping dislodged organisms into a D-frame aquatic net. The samples are decanted into a white pan filled with water and picked live in the field. With the exception of very small Chironomidae, which are subsampled, and amphibians, which are identified and released, all macroscopic organisms captured in the quadrats are preserved in 70 percent ethanol and returned to the laboratory for identification to the lowest possible taxonomic level. Trophic classifications of identified organisms are based on data in Merritt and Cummins (1996).
- Related datasets: HF099