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Full-Text Articles in Life Sciences
Regional Variation In Recruitment Of Hemlock Seedlings And Saplings In The Upper Great Lakes, Usa, Thomas P. Rooney, Ronald J. Mccormick, Stephen L. Solheim, Donald M. Waller
Regional Variation In Recruitment Of Hemlock Seedlings And Saplings In The Upper Great Lakes, Usa, Thomas P. Rooney, Ronald J. Mccormick, Stephen L. Solheim, Donald M. Waller
Biological Sciences Faculty Publications
Mature eastern hemlock–northern hardwood forest cover decreased drastically in the upper Midwest following European settlement and has yet to rebound substantially. Previous studies show that stands retaining substantial hemlock canopy coverage have low hemlock seedling and sapling densities. Results from various geographically restricted studies suggest several possible mechanisms that could cause low seedling or sapling density. We examined the relative importance of these proposed mechanisms in the Southern Superior Uplands Section of the Laurentian Forest Province. We surveyed 294- m2 plots in 100 hemlock stands in northern Wisconsin and western upper Michigan to assess how these proposed mechanisms affect the …
Periphyton Production On Wood And Sediment: Substratum-Specific Response To Laboratory And Whole-Lake Nutrient Manipulations, Yvonne Vadeboncoeur, David M. Lodge
Periphyton Production On Wood And Sediment: Substratum-Specific Response To Laboratory And Whole-Lake Nutrient Manipulations, Yvonne Vadeboncoeur, David M. Lodge
Biological Sciences Faculty Publications
Substratum heterogeneity is a large source of variability in periphyton production, but the influence of substratum on periphyton response to experimental manipulations is rarely measured. Using laboratory and whole-lake experiments, we compared area-specific primary production of periphyton on wood (epixylon) and sediment (epipelon), and tested whether periphyton on the 2 substrata responded differently to water-column fertilization. In the laboratory, natural periphyton assemblages on wood or sediment were exposed to 1 of 6 treatments in a fully factorial (light [250, 70, or 10 μmol m−2 s−1] × nutrient [control or + N and P]) experiment. We measured 14 …