Scientia Discipulorum vol. 3 (2008)
Composition and Abundance of Stream Macroinvertebrates as a Determinant of Water Quality Up and Down Stream of the Imperial Dam, Saranac River, New YorkThe removal of the Imperial Dam in Plattsburgh, New York is a subject being currently discussed by parties including city officials, Trout Unlimited and the New York Department of Environmental Conservation. One concern is the impact on water quality and stream benthos below the impoundment which may impact the fishery. This project investigated the hypothesis that the composition and abundance of aquatic stream invertebrates do not differ as a result of the change in water quality above and below the Imperial Dam on the Saranac River. Using a Hess sampler, stream invertebrates were collected, as well as associated physical characteristics (water depth, velocity, substrate size) from two different sites located up and down stream of the Imperial Dam. Aquatic stream invertebrates were identified to Genus or Family and the data were analyzed using various community diversity indices. Results show distinct community differences between the two sites with increased filter feeder abundance at the impounded reach and higher mayfly diversity and abundance at the open river reach. While impoundment has impacted aquatic biota in the Saranac River at Imperial Dam, recovery of the benthos to open river conditions is likely to occur rapidly from upstream colonization sources upon restoration of open river conditions at Imperial Dam.
Nitrogen Cycling and Dynamics in Upland Managed and Preserved Watersheds of the Adirondack Mountains, New YorkThis study investigated nitrogen cycling differences between management systems in the Adirondacks. The definition of managed site was that there had been active logging within the past twenty-five years and the sites fit into the preserve category because they had no active logging within the past eighty-five years. The soil nitrogen cycle is complex and can be disturbed in many ways, including timber harvesting management practices. These disturbances were investigated over the summer of 2005 when logged and preserve forested watershed soil nitrogen was examined. Five soil cores were taken from each of two managed and two preserved watersheds over a two-day period. These four adjacent watersheds have identical temperature, precipitation, and climate so this eliminates outside influence. Chemical and physical parameters including organic matter content, nitrate, ammonium and total Kjeldahl nitrogen (TKN) were compared between watershed management practices. No significant differences were found between organic matter, nitrates, or ammonium, but there was a significant difference in TKN. Managed sites contained higher concentrations of TKN. These differences are most likely not due to direct influences by the timber harvesting that has taken place in the last twenty-five years. The explanation possibly lies in the composition of the forest since the site with less deciduous trees had a higher nitrogen concentration in the soil. This could be due to a lower carbon to nitrogen (C:N) ratio in the forest litter resulting in litter that is broken down more easily.
Leaf Litter Quality in Adirondack Upland Streams: Managed vs. PreserveLeaf litter quality has an important nutritional role in headwater streams. Since upland streams are relatively small (1st order and 2nd order streams) with a dense forest canopy, primary productivity from stream macrophytes and microphytes is hindered (Fisher and Likens 1973). This creates a dependence on the adjacent riparian zone as a primary productivity input, making upland stream ecosystems detrital based and dependent on allochthonous organic matter (Fisher and Likens 1973, Cummins and Klug 1979). Differing riparian vegetation allocate varying nutritional value which in turn reflects the stream macro and microscopic fauna. Riparian vegetation composition can be influenced by disturbances such as logging or natural disasters. This study focused on the effects of logging on leaf litter composition. To determine if logging had an effect on riparian leaf litter food quality indicators, four managed (logged) sites were compared to three Forest Preserve sites within the Adirondack Park. Food quality indicators, protein, ash free dry mass and hydrolysis resistant organic matter, were compared across sites. Managed sites had a slightly higher contribution by volume of all food quality indicators. Differences for individual indicators largely reflected changes in litter species composition.