Background/Question/Methods Invasive species remain a grave threat to native habitats, fundamentally altering patterns of biodiversity and the function of ecosystems. In particular, northeastern broadleaf forest habitats are facing increasing threats to regeneration from invasive shrubs. Understanding the fundamentals of these invasions from a traits based perspective may shed light on the particular mechanisms allowing invasion, as well as predicting potential changes in the functional composition of vegetation stands and their likely ecosystem properties. These understandings may also be of value in prevention, remediation, and restoration. This research uses the distribution of leaf functional traits of native and invasive woody plants in three forests in southeast Michigan to address questions of changing community functional distributions. By working with forests of varying degrees of invasion but of similar native community structure. Traits associated with the leaf economics spectrum – specific leaf area, leaf dry matter content, leaf nitrogen content, leaf laminar area and delta 15N – were analyzed. We utilized the Mouillot et al (2005) kernel estimator and overlap index as a means of comparing native and invasive woody plant communities. Both occurrence and abundance weighted measures were used. Results/Conclusions Results suggest an increasing divergence between native and invasive communities as the both number of invasive species and the abundance of those species increase relative to the native community. This pattern holds true for specific leaf area, leaf nitrogen content, delta 15N, and leaf dry matter content, but was not true of leaf laminar area. These patterns are consistent with the expectation for increased changes in ecosystem properties as invasive species become more common. In particular, from changes in nitrogen related properties suggest a potentially profound change in nitrogen availability in more heavily invaded communities. It appears these increases are to a large extent driven by Elaeagnus umbellata, a species known to have associated nitrogen fixing microbes.
