Friday, August 8, 2008: 10:30 AM
101 A , Midwest Airlines Center
Background/Question/Methods Revegetation of littoral zones is crucial to the overall success of a lakeshore restoration. Efforts to improve fish habitat and reverse shoreline erosion both depend upon the re-establishment of emergent macrophyte beds. Despite their central role in lakeshore restoration, most littoral plantings fail. The reasons for this are poorly understood, in part due to limited information on the effects of planting time, water depth, and root/rhizome development on the survival of emergent macrophyte plantings. To address this, we planted 3.8 liter pots and 28 x 28 cm prevegetated mats of S. validus at two different water depths (0-30 cm and 31-60 cm of water depth) in fives lakes each month between May and September 2006, to evaluate the effect of planting month, water depth, rootstock type and plant condition on the survival of transplanted softstem bulrush (Scirpus validus Vahl). Survival of plantings was assessed three times after planting.
Results/Conclusions Overall survival decreased from 73% at 30 days after planting to 15% one year later. The results of our study indicate that the robustness of the stock used for the restoration effort, as well as planting date, are critical factors influencing bulrush survival. Our evaluation of the two different bulrush rootstocks indicates that pots generally outperform mats when planted early- to mid-summer. Water depth is only important immediately after planting, after which time its influence on successful establishment diminishes. Survival of bulrush planted later in summer is poor, regardless of the rootstock type used, and should be avoided. Overall, our research indicated that key choices made by the restoration practitioner can improve the likelihood that transplants establish. That said, lake environment effects, such as herbivory and wave impacts, also contributed to transplant mortality. Research into these lake effects could further increase the success of littoral revegetation efforts. Keywords: emergent aquatic macrophytes, littoral wetlands, revegetation, transplant,Minnesota
Results/Conclusions Overall survival decreased from 73% at 30 days after planting to 15% one year later. The results of our study indicate that the robustness of the stock used for the restoration effort, as well as planting date, are critical factors influencing bulrush survival. Our evaluation of the two different bulrush rootstocks indicates that pots generally outperform mats when planted early- to mid-summer. Water depth is only important immediately after planting, after which time its influence on successful establishment diminishes. Survival of bulrush planted later in summer is poor, regardless of the rootstock type used, and should be avoided. Overall, our research indicated that key choices made by the restoration practitioner can improve the likelihood that transplants establish. That said, lake environment effects, such as herbivory and wave impacts, also contributed to transplant mortality. Research into these lake effects could further increase the success of littoral revegetation efforts. Keywords: emergent aquatic macrophytes, littoral wetlands, revegetation, transplant,