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Presented at the NABS Annual meeting, Vancouver, British Columbia, 2004
in Community Ecology
Seasonal changes in organic matter, periphyton and macroinvertebrates in a small stream flowing through conifer and deciduous forests and an abandoned farm field.
R.L. Fuller, M. Anastasi, J. Molina, H. Salcedo, S. Ward, M. Behum, and E. Zacheim. Biology Department, Colgate University, Hamilton, NY 13346
Bucks Brook is a second order stream that flows through a conifer forest, into a deciduous forest and then out onto an open floodplain. Light levels are low throughout the year in the conifer forest section, high throughout the year in the open canopy section and vary considerably from summer to autumn in the deciduous section. Periphyton abundance reflected differences in light levels except in winter when ice and snow decreased light and periphyton abundance at all sites. Benthic coarse particulate organic matter was high in all seasons in the conifer forest section, seasonally highest in autumn in deciduous forest reaches and lowest in the open canopy section. These differences in energy resources strongly influenced macroinvertebrate community composition. Grazing mayflies and caddisflies dominated the open canopy section except in June when a filamentous algal bloom resulted in a dramatic increase in Orthocladiinae chironomids. Shredding stoneflies dominated the forested sections; capniids were abundant in autumn and winter whereas leuctrids were abundant in spring and summer. Collectors (chironomids and leptophlebiid mayflies) were most abundant in forested sections from autumn to spring. Total macroinvertebrate density was lowest in summer at the forested sites but very high at the open site; densities were similar and high at all sites in autumn and declined throughout the winter and spring.
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