The long-term impact of initial resource availability and seed bank on woody vegetation during early succession in the New Jersey Piedmont.

摘要

This study revisited old field succession plots established in 1989 at Hutcheson Memorial Forest in Somerset County, New Jersey, to look at the impact of initial resource availability and seed bank on old field succession. A combination of two different types of treatments were used: an abiotic treatment to alter available resources, and a seed treatment to change the starting seed bank. The abiotic treatments used were a light reduction, mulch application, and an elemental sulfur application to reduce nutrient availability. Seed treatments were additions of species characteristic of early, mid, or late succession.;Soils from the plots was analyzed for pH and nutrient availability to determine whether any residual effects of the initial treatments still existed after 19 years. The species, density, and diameter at breast height (DBH) of all woody vegetation >2m tall was taken, and the density and species of seedlings <50cm in height were also taken.;Due to loss of data through destruction of 18 out of 48 original plots, Bayesian analysis in WinBUGS was used as the primary form of statistical analysis. Unpublished data from 1997 was used in order to determine how the Bayesian analysis results correlated with the two-way ANOVA used in past analysis of the site, and to ensure that results using full and partial datasets were similar. Relative importance values for species present on the plot were also calculated.;Sulfur treatments had a significant impact on the soil, resulting in lower pH and differences in nutrient availability. No difference in soil organic matter was found. The mature woody vegetation was shown to have lasting differences associated with initial abiotic treatments. Light reduction yielded smaller trees at lower density; mulch treatments had larger trees at high density, and sulfur-treated plots had large trees at very low densities. Little difference was found associated with the seed treatments. No differences were found in the seedling populations. Juniperus virginiana was the dominant species in most plots, with the exception of sulfur-treated plots. Comparison of 1997 data and 2008 data suggests that differences in woody species composition are determined by differences in seedling survival.