Impacts of Soil Nitrogen and Carbon Additions on Forest Understory Communities with a Long Nitrogen Deposition History

摘要: Rates of nitrogen (N) deposition have been historically high throughout much the northeastern United States; thus, understanding legacy these N loads is important for maintaining forest productivity and resilience. Though many studies documented plant invasions due to associated impacts on ecosystems, less known about whether invasive plants will continue increase in dominance with further shifting nutrient regimes. Using soil carbon additions, we examined impact both increasing decreasing native understory dynamics over 4 years a deciduous long history deposition. Despite applying large quantities N, found no difference nitrate (NO3 )o r ammonium (NH4 + ) pools addition plots course study. Indicative potential saturation soils, resin-available NO3 - NH4 showed evidence that added was rapidly moving out plots. Accordingly, also adding altered neither nor abundance, though temporally increased richness. Carbon additions decreased availability seasonally, but did not alter total percent cover or plants. Rather than being suppressed by excess availability, species this ecosystem are primarily inhibited species, which now dominate site. In conclusion, communities potentially N-saturated may be buffered future alterations availability.