2017 ESA Annual Meeting (August 6 -- 11)

COS 115-3 - Long-term effects of short-term variation on population viability of monarch butterflies in western North America

Wednesday, August 9, 2017: 2:10 PM
B113, Oregon Convention Center
Cheryl Schultz1, Leone M. Brown2, Emma Pelton3 and Elizabeth Crone2, (1)School of Biological Sciences, Washington State University, Vancouver, WA, (2)Department of Biology, Tufts University, Medford, MA, (3)Xerces Society for Invertebrate Conservation, Portland, OR
Background/Question/Methods

Count-based PVA allows researchers to assess patterns of population change through time and to evaluate future persistence. We combined state-space models and citizen scientist data to evaluate viability of the western population of monarch butterflies over 36 years. A key feature of our analysis was combining irregular sampling from multiple sites to obtain a single estimate of the total population size using state-space models.

Results/Conclusions

The average population growth rate was negative, u = -0.0762 (λ = 0.927), average population size in the 2000’s was less than 5% of average abundance in the 1980’s, and current quasi-extinction risk is 72% within 20 years. To obtain viable populations, managers could target historic abundance and high enough growth rates to avoid near-term extinction. Improved knowledge about environmental drivers of vital rates is likely necessary to achieve these targets