Ecology and Biogeography of a Northern Caddisfly (Cape Cod MA)

• Investigators: Elizabeth Colburn, Frances Garretson
• Contact: Elizabeth Colburn
• Start date: 1996-01-01
• End date: 2002-12-31
• Location: Cape Cod MA
• Latitude: +43.85
• Longitude: -69.96
• Elevation: 0 to 6 meters
• Taxa: Phanocelia canadensis
• Keywords: biogeography, caddisfly, conservation, habitat, life history
• Abstract:

  We have documented a large population of a rarely collected northern caddisfly, Phanocelia canadensis (Banks) (Trichoptera: Limnephilidae), on Cape Cod, Massachusetts. This species' range is generally considered to be centered in northern Canada, although there are individual records of adults from eastern Maine and New Hampshire, and a single adult was collected from Sherborn, Massachusetts, in the 1920s. The scarcity of this species in collections may reflect true rarity, with populations sparsely but widely distributed across the northern part of the continent. Alternately, it may reflect a sampling bias, in that the larvae of this species were unknown until the late 1980s, adults are diurnal and fly late in the fall, and larvae occur in wetlands and are closely associated with Sphagnum, from which they make their cases. We have carried out an in-depth habitat comparison of sites in which we found or did not find larvae on Cape Cod in seven years of intensive sampling. Habitat characteristics distinguishing wetlands with and without Phanocelia include dominance by Sphagnum sp., shrub cover, and low pH. We are currently searching in similar habitats across the state for additional populations.

• Methods:

  We sampled 17 flooded, kettle-hole wetlands in the Cape Cod National Seashore from 1996-2002. Sites were stratified by depth and vegetation and sampling locations were established randomly within each stratum. For each sample, we made a standard, 1 m x 33 cm sweep of water column, vegetation, and substrate with a D-frame aquatic net (Ward's Natural History Establishment, Rochester, NY). Net contents were decanted into a white pan filled with water and invertebrates were picked live in the field, preserved in 70 percent ethanol, and returned to the laboratory for identification. Water depth, substrate, and vegetation were recorded for each sample. Water samples were collected from all pools in spring, 1986 and 1998, by National Park Service staff. Chemical analysis was carried out by the Cape Cod National Seashore's North Atlantic Coastal Research Laboratory following standard methods for pH, alkalinity, color, dissolved oxygen, calcium, magnesium, sodium, potassium, nitrate-N, ammonium-N, and phosphate-P (American Public Health Association et al. 1985; Clesceri et al. 1998). A posteriori analysis of habitat characteristics of wetlands with and without Phanocelia canadensis involved analysis of variance of surface area, depth, water chemistry, and dominant vegetation.

• Related datasets: