Cornell Botanic Gardens

Todd Bittner, Cornell Botanic Gardens

Cornell Botanic Gardens has been working to conserve American Globeflower (Trollius laxus ssp. laxus) ex situ through seed banking efforts across multiple populations and in situ within two Garden-owned natural areas. The in situ conservation work has primarily focused on habitat protection and invasive species, deer, and nuisance beaver control. A population viability analysis (PVA) conducted for Eames Fen indicated a high likelihood of local extirpation, prompting a population augmentation effort. The seven- year augmentation, with a donor site 200-250 meters from the original population, has been successful with over 340 plants successfully outplanted and a 95% or higher survival rate.

Despite active management in the original Eames population, the globeflower numbers declined 62% (down to 63 plants) by 2018. Recent research has identified partial shade between 20 – 40% available light to be preferred habitat conditions for plants. To quantify the existing light conditions and inform potential canopy cover manipulation at Eames, we deployed an array of HOBO light sensors during the peak of the growing season in the fen and a nearby control full sun site. The average available light was 12.56% (SE +/- 1.4; range 6.8 to 39.5%), placing it well below the favored light range. Given the strong correlation, we embarked on a canopy thinning study with the goal of increasing available light to 30-40%. In the winter of 2018-2019, we removed 45 northern hemlock trees (Tsuga canadensis) from the eastern, southern, and western perimeter of the fen, with a basal area totaling 14.1 ft2. In 2019, we intend to replicate the environmental monitoring and corresponding response of the individual globeflower plants and population to inform future management actions.

Contributing Author(s): 
Date Recorded: 
Thursday, May 2, 2019

Christopher Dunn, Todd Bittner and Robert Wesley, Cornell Botanic Gardens

In situ conservation efforts for American globeflower (Trollius laxus) are ongoing within two Cornell Botanic Garden Natural Areas. A reintroduction program was initiated to augment the globeflower population and a total of 344 propagated plants have been successfully introduced with a 90-95% survival rate. The introduced population now surpasses the original population at the site, which has declined by during the same period 50%. Excessive shading is suspected as the causal factor for this population decline. Data collection on light intensity is underway to quantify the level of shading across the population, and will be used to inform future experimental canopy thinning to obtain 30-50% light availability.

Contributing Author(s): 
Date Recorded: 
Friday, May 4, 2018