Population monitoring for Lupinus oreganus (Kincaid’s lupine) at Eagle’s Rest
This report documents the tenth year of monitoring for the Lupinus oreganus (Kincaid’s lupine) population located at Eagle’s Rest, managed by the Eugene District of the Bureau of Land Management
This report documents the tenth year of monitoring for the Lupinus oreganus (Kincaid’s lupine) population located at Eagle’s Rest, managed by the Eugene District of the Bureau of Land Management (BLM). Monitoring will provide the BLM with information on population status and long-term trends and supply baseline data to help understand and predict the response of the population to habitat changes caused by natural forces, human-induced threats, and prescribed management actions.
The objectives of this project are to:
1) Evaluate the effectiveness of using cover as a surrogate for counting leaves to determine lupine abundance.
2) Document population trends of Kincaid’s lupine at Eagle’s Rest.
3) Assess impacts of ORV use, and any other anthropogenic impacts.
Our results showed that he number of leaves and cover were highly correlated across all sites where we monitor L. oreganus. The cover of L. oreganus has steadily increased since monitoring began in 2003. The dramatic increase in cover between 2011 and 2012 could be an artifact of sampling bias, future monitoring will elucidate the long-term trends of the foliar cover of this lupine population. Overall, the number of racemes present has also increased, however raceme totals for 2011 and 2012 may also be due to sampling bias, as sampling took place earlier in the season and, therefore, may have included racemes which would have been aborted later on.
While the increase in total Lupinus oreganus cover between 2005 and 2012 suggests a stable population and even increasing lupine population, the relatively small size of this site and the population make it susceptible to damage.
Monitoring at Eagle’s Rest in 2003 noted off-road vehicle use that damaged some Lupinus oreganus. The threat of continued ORV use led to the placement of boulders at the foot of the slope to discourage easy access to the site. No additional evidence of ORV traffic or damage to L. oreganus has been observed.
The data also suggests that climate affects growth and development of L. oreganus at Eagle’s Rest. Wet and moderate conditions during development seem to play an important role in this species developing mature inflorescences. Our models only test for effects of climatic factors on the growth and development of L. oreganus at Eagle’s Rest; additional environmental factors could also affect development and growth of this species.
We suggest that population monitoring continue on a semi-annual basis in order to detect any population declines. Continued monitoring will also be valuable for gaining sufficient data to determine the role of climate in driving variability in reproduction. We also suggest that future monitoring efforts include surveying for Fender’s blue butterfly. Plant community surveys should also be conducted to observe invasive species encroachment, as well changes in species diversity, and abundance.