Woody Species Regeneration in the Albany Pine Bush Following the Invasion of the Nitrogen-Fixing Black Locust (Robinia Pseudoacacia)

The soils of the Albany Pine Bush are affected by a legacy of invasion by the nitrogen-fixing black locust (Robinia pseudoacacia). The invasion disrupted the Pine Bush's natural fire regime and has caused abnormally high levels of nitrogen in the soil, which presents issues to land managers. Because invasive species that alter their environments often have an impact on a system even after their removal, we set out to investigate the regeneration of post-invasion communities in the Pine Bush, quantifying three key woody stems, scrub oaks (Quercus ilicifolia, Q. prinoides), pitch pines (Pinus rigida), and blueberries (V. angustifolium, V. pallidum). In our experiment, we established 38 transects in management plots and counted the number of juvenile oaks, pines, and blueberries to track the progress of the recovery of restored plots. We define recovery in terms of the similarity of the community composition of restored plots to native plots, i.e. in a "recovered" restored plot, we would find that the abundance of each woody species is statistically similar to that of species found in native plots. Factoring for whether or not a plot has burned (and when that last was), how long it has been since the plot was restored, distance to seed source in meters, percent total cover, and percent grass cover, we generated several models to investigate which factors affect woody regeneration in restored Pine Bush plots. The models suggest the following: 1) Pitch pine abundances in restored plots were statistically similar to native abundances, 2) Scrub oak abundances in restored plots were statistically lower than in native plots, although there are indications that current management tactics were positively influencing the abundance of oaks, and 3) Blueberries were statistically lower in restored plots than in native plots by a large margin, with no indication that management tactics had any effect on their abundance. We conclude that pitch pine communities in the Pine Bush have recovered, that scrub oak communities are not recovered but that current management techniques are having a positive effect to that end, and that blueberries in the Pine Bush are not recovering, and as such new management techniques and strategies may need to be adopted to increase their abundance in restored plots.