Effects of logging on stream macroinvertebrate communities and vertebrate populations in New England headwater streams

W. Lowe¹, K.H. Nislow², and D. Bolger³. ¹Institute of Ecosystem Studies, Millbrook, NY 12545, ²USDA Forest Service Northeastern Research Station, Amherst, MA 01003, ³Environmental Studies Program, Dartmouth College, Hanover, NH 03755

Logging can strongly affect stream communities, but the direction and magnitude of these effects varies among regions and is difficult to predict. We sampled macroinvertebrate communities and vertebrate populations (spring salamanders and brook trout) in 23 1st-order streams in northern New England representing a chronosequence of logging history (< 10 to > 30 years since logging), and also measured physical habitat and riparian forest structure. Logging history was significantly associated with several important aspects of stream community structure. Streams that had not been recently logged had a higher proportional representation of invertebrates in the shredder functional feeding group, lower substrate embeddedness, low brook trout abundance and greater abundances of spring salamanders. Streams that had been recently logged had greater total macroinvertebrate abundance, a higher proportional representation of invertebrates in the collector-gatherer and grazer-scraper functional feeding groups (including several taxa important in trout diets), and higher abundance of brook trout. These results suggest that headwater stream community response to logging in the New England region is mediated by a combination of direct and indirect effects, and may result in alternative community states (salamander/shredder dominated vs. brook trout/grazer dominated).