Spatial and temporal patterns of nutrient concentrations in foliage of riparian species

Foliage of the dominant riparian canopy species of a blackwater stream floodplain was collected from three sites and analyzed for C, cell walls, N, P, S, K, Ca, Mg, Al, Fe, Mn, Zn, Cu and B. Foliage was collected three times to compare nutrient concentrations after leaf-out (April), in midsummer (August) and before abscission (October). Several species occurred at two sites and Acer rubrum occurred at all three sites. Decreases in foliage C, N, S, P, K and Cu were noted for most species as the growing season progressed. Increases in foliage cell walls, Ca, Fe, Mn and B were also observed. The concentrations of foliage Mg, Al and Zn increased or decreased depending on species. Riparian species exhibit a wide range of foliage nutrient concentrations, particularly for K Ca, Al, Mn and Zn. Separation of species based on gradients of foliage nutrient concentrations, especially Ilex opaca and Quercus spp., was clearly demonstrated by principal components analysis. Principal components were also used to examine the temporal separation of Acer rubrum at three sites. Separation of A. rubrum was most distinct in October although there were no significant differences in foliage nutrient concentrations of cell walls, Ca, Al, Mn, Zn and B.