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ABSTRACT: Understanding the mechanisms that allow for plant invasions is important for both ecologists and land managers, due to both
the environmental and economic impacts of native biodiversity losses. We conducted an observational field study in 2008 to
examine the relationship between native and non-native forest understory plant species and to investigate the influence of
soil nitrogen (N) on plant community richness and diversity. In 2009, we conducted a companion fertilization experiment to
investigate how various forms of N deposition (inorganic and organic) influenced native and non-native species richness and
diversity. We found that native species richness and diversity were negatively correlated with 1) non-native species richness
and diversity and 2) higher total soil inorganic N. In the deposition experiment, adding organic N fertilizers decreased native
richness and diversity compared to inorganic N fertilizers. Together, these results indicate that increasing soil N can be
detrimental to native species; however, native species richness and diversity may counteract the N-stimulation of non-native
species. Furthermore, the negative effects of organic N deposition on native plants may be just as strong, if not stronger,
than the effects of inorganic N deposition.
KeywordsInvasion–Soil nitrogen–Non-native–Richness–Native–Diversity
Plant and Soil 04/2012; 345(1):257-269. · 2.73 Impact Factor
