PARENT SESSION
Poster Session 3: Aquatic Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 210 D, Level 2, Palais des congrès de Montréal
Stream ecology of an urbanizing watershed in the New Jersey Pine Barrens.
Cromartie, William*,1, Akers, Julie1, Cummings, Denis1, Cook, Justine1, Leckenbush, Jordan1, Millar, Graeme1, 1 Environmental Studies Program, Pomona, NJ, USA
ABSTRACT- In the NJ Pine Barrens, landuse, water chemistry and aquatic biota are changing as urban development encroaches. The watershed of Babcock Creek, in Atlantic County, presents an opportunity to study four tributaries, each of which has been affected in different ways by changing landuse. Viewed counter-clockwise, from east to west: Adams Branch is highly urbanized. It has the highest pH of any tributary, and the channelized streambed carries a heavy load of sand. Jack Pudding Branch has the most agricultural land and the second highest pH. Its upper section is impounded and channelized as well. Babcock Creek, which forms the central stem, is the least disturbed. Much of its watershed is hardwood swamp or Atlantic white cedar forest. Mankiller Branch shows chemical alteration (its specific conductance is as much as four times higher than Babcock Creek) possibly from highway runoff. The macroinvertebrate fauna of woody debris (submerged sticks 3-35 mm in diameter) provides a readily sampled assemblage for biological monitoring in low-gradient, blackwater streams. We collected replicated stick samples at up to nine sites, both upstream, near disturbed areas, and downstream at confluences, to test whether disturbance effects persisted. We sampled during three seasons over three years, including detailed water chemistry data. We analyzed results using multivariate statistics and GIS. Adams branch is generally the most impoverished; flash flooding and shifting sediments may be responsible. Mankiller branch also showed very low invertebrate numbers. Both these streams had few or no Trichoptera, Plecoptera and Ephemeroptera and had elevated numbers of Oligochaeta, compared to Babcock Creek. Jack Pudding Branch had low numbers of all taxa studied, especially at the upstream site. Our results indicate that the macro-invertebrate assemblage on woody debris responds differently to each of the suspected impacts. These differences were seen both at upstream sites and near the confluences, although the land surrounding the confluences was relatively undisturbed. We therefore suspect that chemical changes, as well as inreased sediment and physical alteration are responsible.
Key words: blackwater, macroinvertebrate, disturbance, biomonitoring