Disturbance Effects on forested ecosystems in the Great Lakes Region
Winter Ecology
Regional climate change models for the Great Lakes Region predict that winter precipitation patterns may change dramatically. In northeast Ohio, there is likely to be an increase in lake effect precipitation during autumn and winter, and the lake effect snow season may be extended due to delayed ice coverage on Lake Erie. Smemo and Mahaney recently initiated a field experiment at The Holden Arboretum to examine how the timing, amount, and form (rain versus snow) of winter precipitation affects soil C and N cycling, microbial activity, and the performance of sugar maple (Acer saccharum) seedlings. Changes in winter precipitation may alter the synchrony between nutrient uptake and nutrient availability in forested ecosystems, which may affect sugar maple growth. We focus on sugar maple because it is a dominant species in our forests and is economically important, but also because it may be particularly sensitive to changes in winter conditions. Smemo, Mahaney, & Burke have also submitted a grant proposal to NSF to examine similar questions regarding how changes in winter precipitation will affect sugar maple-beech dominated forests on a larger scale.
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Sugar Maple seedling experiment usiing enclosed mesocosms to manipulate winter precipitation |
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Are native forest understory herb communities declining?
Invasive species, deer herbivory, acid deposition, and forest fragmentation have all been blamed for reducing the abundance and diversity of forest understory communities. This fall, Burke and I started a seed-bank study to evaluate whether these factors are affecting the distribution and abundance of native species in the forest understory. This initial seed-bank analysis will determine whether seed limitation is a factor controlling understory herb community composition, and whether the ingestion of soil and seeds by invasive earthworms affects the viability of seeds in the soil seed-bank. We will follow up on this initial study by performing field manipulations to address specific mechanisms and test specific hypotheses (i.e., perform seed additions to examine dispersal limitation, seedling transplants or soil condition manipulations to examine environmental constraints on species survival).
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Low and high density forest herbaceous understory |
The role of forest understory herbs in determining litter decomposition rates
Studies of litter decomposition often show that litter mixtures decompose differently than what is predictable when considering each species separately. I am performing a litter-bag decomposition experiment to determine whether the presence of an understory herbaceous community affects the decomposition rates of dominant canopy trees in sugar maple-Beech-dominated forests. Litter-bags filled with sugar maple, beech, and a 50/50 mix of both, were placed in forested areas with and without an herbaceous understory and will be collected over two years to determine whether the labile tissue of those herbs increase decomposition rates.
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Liiterbag study to look at the effect of herbaceous understory plants on decomposition and microbial communities |
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