Wetlands are critically important habitats that provide many ecosystem services but loss and degradation of wetland habitat and functions has led to the growing need to create and restore functionally sound wetlands. In temperate climates, Typha spp. are an invasive plant genus that is problematic for mitigation efforts as it spreads quickly and aggressively into disturbed habitats and creates monotypic stands with dense rhizomes that are difficult to eradicate. Control is most often attempted through mechanical cutting or application of herbicide. In this study I surveyed four mitigation wetland vegetation communities in two years to determine species distribution and change at HANA, locate areas invaded by four emergent wetland species (Typha spp., P. arundinacea, P. australis, L. salicaria), and monitor manual and chemical control efforts. P. arundinacea cover was reduced 81% by herbicide application and Typha spp. cover was reduced 38% overall, with greater reduction through mechanical cutting than herbicide. I conducted experimental manipulations following control and found that leaving floating Typha debris in deep water ponds after cutting did not negatively impact ecosystem recovery, and that the addition of organic carbon (sugar) limited Typha growth by 80% after herbicide, though I found no correlation between carbon addition and soil nitrogen to suggest nitrogen immobilization was the mechanism. Overall I found that there are many factors, including type of control, the post-control methods employed and the nutrient availability of the system, which significantly impact the recovery of aquatic and emergent wetland systems following control implementation. My investigations help to provide a better understanding of Typha invasion and potential improvements to control efforts
