Demography and management of Willamette daisy (Erigeron decumbens)
Executive Summary Over the course of this study 6 populations of Willamette daisy were created (Big Spires, Kirk East, Applegate), or augmented (Atlantic Pacific, Finley Field 29, Finley Field 8N).
Over the course of this study 6 populations of Willamette daisy were created (Big Spires, Kirk East, Applegate), or augmented (Atlantic Pacific, Finley Field 29, Finley Field 8N). A total of 3,416 were outplanted over the course of the study. As of the spring of 2015 1,308 are surviving and an additional 502 new recruits were noted in 2014 and 2015 collectively. For details on survivorship by site and recovery zone, see Table 1, Table 3, Table 4, and Table 5. In each year (2011 and 2013), two plots were outplanted in both the Eugene and Corvallis West Recovery Zones. Survivorship was measured for each population and plots then received a variety of management treatments to evaluate the response of both the daisy and the surrounding plant community to management treatments. Measurements of plant vigor, as well as the plant community were taken annually, and are reported here.
Willamette Daisy Response to Treatment:
Results indicate that treatments for plants outplanted in 2011 had no significant effect on survivorship; indicating that well timed (and even aggressive) management treatments may be an effective tool for managing Willamette daisy. There were however, significant effects on plant size, reproduction and recruitment which indicate that Burn + Glyphosate increased both plant size and reproductive effort. Additionally, the highest number of recruits were found in the Burn + Glyphosate plots at Field 29 (Finley, Corvallis West Recovery Zone.)
Plant Community Response to Treatment:
While the response of plant community varied by site (and starting condition), the most successful treatments for decreasing invasive forb, invasive graminoid and woody/shrubby species cover was the Burn + Glyphosate treatment (followed by mowing, glyphosate only and carbon addition). Carbon addition compared favorably to several herbicide treatment(s) for decreasing invasive forb cover and provides a potential non-chemical method for managers to consider.