A Fine-Scale Examination of Larix laricina and Picea mariana Abundances along Abiotic Gradients in an Adirondack Peatland

Abstract Wetland research has described changes in plant communities along environmental gradients, however, little is known about the relationship between fine-scale hydrologic and abiotic factors and the relative abundances of individual, co-occurring species. Larix laricina (Eastern Larch) and Picea mariana (Black Spruce) are the 2 dominant tree species in open boreal peatlands in the northeastern US. In order to describe abiotic gradients that correlate with species abundances at local spatial scales, we collected data on Eastern Larch and Black Spruce stem abundances, groundwater pH, conductivity, depth to water table, water temperature, dissolved oxygen, and canopy closure from 42 plots along 6 transects in an Adirondack wetland. We correlated stem abundances with each of the abiotic variables and then used regression to explain variation in stem abundances of the 2 species along those abiotic gradients. Percent canopy closure explained 56% of the variability in Eastern Larch stem abundance, and dep...