2011 Small-scale Cattail Harvesting Experiment
After learning that the accumulation of old leaf litter plays a large role in Typha × glauca’s detrimental impact, we designed a field experiment that explores the restoration implications of removing litter. With funding from the EPA and the GLRI, we used aquatic weed-wackers to clear 4 x 4 meter sections of Typha marsh. The plots were put in “old” portions of the Typha stand that had been invaded for more than 30 years, and “young” portions of the Typha stand that had been invaded for less than 30 years. We removed the cut stems and litter to simulate harvesting, and in a subset of plots we also removed belowground Typha rhizomes. Implementing this project was a lot of work, and we couldn’t have done it without a dedicated field team of undergraduate and graduate students.
After one year, the plant species richness and diversity (H’) in the rhizome-removal plots was significantly higher than in the controls, and after two years the species richness and diversity was significantly higher in both the “harvest” and “rhizome removal” treatments. Many plant species that were otherwise rare in the marsh appeared in the plots, indicating that a viable seedbank is left buried in the sediment below accumulated cattail leaf litter. There didn’t seem to be different responses that related to time since Typha invasion, which suggests that even wetlands that have been dominated by Typha for a long time can still have viable native seedbanks.