Emma Rice defends her thesis assessing control methods of invasive Baby's Breath
On July 10, 2018, graduate student Emma Rice successfully defended her Master’s thesis, titled “Assessment of invasive Gypsophila paniculata control methods in the northwest Michigan dunes”. Her thesis committee members include Dr. James N. McNair, Dr. Charlyn Partridge, Dr. Daniel Frobish, and Dr. Timothy Evans.
Emma conducted her research at Sleeping Bear Dunes National Lakeshore where a large infestation of baby’s breath is present. This project aimed to assist The Nature Conservancy and the National Park Service by assessing and improving current treatment methods of controlling invasive baby’s breath in northwest Michigan. Baby’s breath (Gypsophila paniculata) is an invasive species in Michigan’s northern lower peninsula and a problem invasive in much of the northern United States and Canada. On the dunes, baby’s breath readily outcompetes native plants in sandy, well-drained soils due to its deep taproot, which allows access to scarce resources. Baby’s breath is of particular concern in lakeshore dunes because the areas where it is most dense are also populated by several endemic and threatened species. Despite many years of intensive management, high densities of baby’s breath persist in previously treated areas. To determine why this occurs, her research assessed current removal methods (foliar application of glyphosate and manual removal) by (1) measuring baby’s breath density and frequency over a large area using a point-intercept grid before and after treatment from 2016-2018, (2) investigating how timing of treatment affects baby’s breath density, (3) determining the resprout frequency of treated plants, (4) characterizing the local seed-maturation phenology and (5) investigating how timing of treatment affects resprouting and seed germination. Her results confirm that treatment for one or two years reduced the density of baby’s breathbut did not extirpate it, overall treatment is most effective from late June through early July, and a small percentage of manually removed plants and herbicide-treated plants resprout following treatment. Seed germinability increased quickly at the end of July and reached a maximum of 90% or higher by early August in both 2016 and 2017. The germinability of seeds from plants sprayed with glyphosate in early, mid, and late July 2016 was higher the later treatment was administered, highlighting the need to treat early in the growing season. To effectively control baby’s breath, managers should treat for consecutive years to remove regrowth and missed plants and focus treatment from late June to early July for best control. Ultimately, this information will contribute to an adaptive management plan specific to baby’s breath that can be used in infested areas throughout northern North America.
Emma hopes to continue a career in applied ecology focusing on aquatic ecological restoration.