Examining The Seed Bank And Restoration Potential In Great Lakes Coastal Wetlands Invaded By Phragmites Australis Electronic Resource PDF Download

Anthropogenic forces create pathways for the spread of invasive species potentially causing economic and environmental change. Invasion by exotic species frequently results in altered ecosystem states, but the mechanisms that influence invasion are incompletely understood. Cryptic invasions pose a significant challenge as these invaders often remain undetected for long periods of time. One such cryptic invader, Phragmites australis, is a common invader of North American wetlands. While the exotic genotype has been studied extensively, notably less work has been dedicated to the native genotype. Comparing the ecology of both genotypes provides an opportunity to better understand the mechanisms by which the exotic Phragmites genotype successfully invades and alters recipient ecosystems. This knowledge will directly improve Phragmites management and wetland restoration efforts. The first objective of my research was to improve mechanistic linkages between dominant plant traits and ecosystem properties by assessing differences between genotype and recipient ecosystems. Aboveground biomass was greater in exotic than native Phragmites australis stands, and these differences appeared to be driven by differing soil conditions. Litter accumulation, in situ decomposition, and plant biodiversity appeared higher in exotic Phragmites stands but this may have resulted from distinct site conditions rather than genotypic driven differences. In general, seed addition increased plant richness but there was no significant effect of litter removal, or the interaction between the two treatments. These results suggest that differences in standlevel plant traits between native and exotic Phragmites are strongly driven by differences in site conditions. This manuscript will be submitted for publication to journal Biological Invasions. The second objective of my research was to determine the effectiveness of in-field Phragmites australis genotype identification using a suite of six quantitative and qualitative morphological characters. Results from in-field identification were compared to results from genetic analyses using trnT-trnL intergenic spacer in the chloroplast DNA. Identification via morphological characters proved just as successful as genetic analyses and, as such, I suggest the use of a suite of morphological characters to reliably identify the genotypic lineage of Phragmites populations in Upper Lake Michigan. This manuscript will be submitted for publication as a "Short Communication" to the journal Restoration Ecology. Altogether, this research identifies the need for site evaluation when designing Phragmites australis management or wetland restoration plan. My results also provide a simple and effective method for proper Phragmites genotype identification. Furthermore, my results present possible alternatives to contemporary exotic Phragmites management.