Robbie Emmet Presents at Graduate Student Seminar

QERM graduate student, Robbie Emmet (advisor: Beth Gardner) will be presenting today at the Graduate Student Seminar (GSS). The title of his presentation is, “Developing a monitoring framework for wolverines in the Cascades.” Details are below.


Wolverines (Gulo gulo) are recolonizing Washington’s Cascade Mountains, but changes in snowpack driven by climate change may limit or reverse this process. It is therefore crucial that managers be able to detect changes in wolverine abundance in order to manage potential population declines. Remote cameras offer a relatively safe, non-invasive method of detecting wolverines and monitoring trends in wolverine populations over time. However, it is difficult to estimate wolverine abundance using remote cameras if individuals cannot be identified by unique marks or with supplemental DNA sampling. Thus, we developed a model and monitoring framework capable of relating changes in occupancy to changes in abundance more efficiently than traditional occupancy-based monitoring. We tested models estimating independent occupancy in each year (“implicit dynamic”) and models estimating colonization and extinction rates (“explicit dynamic”),  and compared occupancy and short-term occurrence (“snapshot occupancy”) as metrics of abundance.We also tested which survey design aspects were most important for increasing power to detect trends in abundance using occupancy-based metrics. When we used an explicit dynamic occupancy model, occupancy outperformed snapshot occupancy in terms of power to detect changes in abundance. However, snapshot occupancy outperformed occupancy when we used an implicit dynamic occupancy model. In general, increasing the number of survey years and researcher ability to detect wolverines most improved power to detect changes in abundance. We conclude that model additions, such as multi-scale parameters or colonization and extinction rates, can increase power to detect trends in abundance when survey effort cannot be increased, but that the power of these methods varies based on the type of information available.

Date/Time: April 16, 5-6pm

Location: Atmospheric Sciences and Geophysics Building (ATG) 610