I am broadly interested in understanding factors (natural and anthropogenic) impacting wildlife populations and how this knowledge can lead to better species management and conservation. I study a variety of systems and questions, all unified by the use of population demographic models to allow for better resolution of the underlying ecological processes at work. My research includes trying to determine what stressors set species ranges limits, how habitat fragmentation shapes the composition of species communities, and available management actions and their implications for the removal of invasive species.
I am currently a postdoctoral researcher with Dr. Sarah Converse at the University of Washington.
Check out my current and previous research links to read more!
Developing methods for estimating brown treesnake density in Guam
How can we collect data to estimate densities of species in a cost effective yet informative way?
In collaboration with Drs. Sarah Converse, Beth Gardner and Amy Yackel-Adams, I am developing capture-mark-recapture models to estimate the density of invasive brown treesnakes on the island of Guam in order to better understand the effects of removal efforts. Management of this species aims to mitigate the ecological impacts of brown treesnakes on the island’s native avifauna and eventually facilitate the reintroduction of locally extirpated species. A first step in this process is identifying modeling approaches that lead to accurate density estimates of unmarked animals using camera trapping photos at bait stations. The second step will be optimizing combinations of sampling methods used for monitoring brown treesnakes to find what results in the most robust abundance estimate given sampling limitations and costs.
How does the response of breeding of wood frogs to annual variation in weather variables vary across their range?
Using egg mass count data for wood frogs (Lithobates sylvaticus) from across their broad range, I investigated how count data and trends in abundance vary in respect to climatic conditions to better understand patterns and variation across the species range. Using dynamic state space models to incorporate annual and regional climate, I tested hypotheses concerning breeding conditions, water availability, and overwintering survival across the range.
How does interspecific competition help shape species ranges?
Shenandoah salamanders are a range-restricted, federally-listed species, occurring only on the tops of certain mountains in Shenandoah National Park, Virginia. The range boundary of this species is currently not well-defined, and the factors setting these limits need to be better elucidated to assist in conservation efforts. Temperature and humidity likely play a large role in establishing the lower limits of the Shenandoah salamander's range, but competition with another native salamander, the red-back salamander, may also be important.
By surveying for both species along the range boundary, I modeled and compared the current distribution of each species along these mountain tops using single and two species occupancy models. In addition, I measured individual physical traits and behavioral use of habitat to understand if and how competitive interactions between these two species influence physical and demographic traits where they overlap.
How do small vertebrate communities change in response to fragmentation?
In collaboration with the Western Ecological Research Station, I analyzed species community data using multispecies occupancy models to better understand patterns in species richness. This will allow managers to better understand species richness-fragment size relationships when determining land parcels in which to invest.
I also explored the if range position or life history traits can help explain species responses to changes in fragment size. I plan on continuing this work by understanding alpha, beta, and gamma diversity across fragments in the Southern California landscape. This work allows managers to better understand individual species risk to altered landscapes in addition to understanding biotic homogenization in a fragmented landscape.
What trends exist in amphibian occupancy across North America and what factors are responsible?
I worked under the John Wesley Powell Center as a data technician and then graduate fellow in the Amphibian Decline working group. Collaborators from across the United States, Canada, and Europe were involved in this broad-scale, collaborative project. We were interested in large scale patterns in amphibian occupancy and understanding declines at continental scales using occupancy models. This involved analysis of amphibian monitoring data from long time series and from broad spatial scales. Our focus was on understanding the role of water availability and other climate-related factors in explaining patterns of amphibian occupancy.
What factors influence the demography and persistence of high elevation pond breeding amphibians?
In collaboration with the USGS Fort Collins Science Center, we hoped to better understand the dynamics of high elevation amphibians. Using long time series of capture-mark-recapture data in high elevation populations of Boreal chorus frogs (Pseudacris maculata), we increased our basic ecological and demographic knowledge of this species. In addition, this pond-breeding amphibian is a useful system in which to understand the importance of climate, hydroperiod, and the impacts of climate change on high elevation, montane amphibian species. We approached this through continued data collection of marked populations, analysis of current monitoring data, and data reclamation efforts from studies conducted in the 1960s and 1970s.
Knowing your limits: estimating range boundaries and co-occurrence zones for two competing plethodontid salamanders
Quantifying climate sensitivity and climate-driven change in North American amphibian communities
D.A.W. Miller, E.H.C. Grant, E. Muths, S.M. Amburgey, M.J. Adams, M.B. Joseph, J.H. Waddle, P.T.J. Johnson, M.E. Ryan, B.R. Schmidt, D.L. Calhoun, C.L. Davis, R.N. Fisher, D.M. Green, B.R. Hossack, T.A.G. Rittenhouse, S.C. Walls, L.L. Bailey, S.S. Cruickshank, G.M. Fellers, T.A. Gorman, C.A. Haas, W. Hughson, D.S. Pilliod, S.J. Price, A.M. Ray, W. Sadinski, D. Saenz, W.J. Barichivich, A. Brand, C.S. Brehme, R. Dagit, K.S. Delaney, B.M. Glorioso, L.B. Kats, P.M. Kleeman, C.A. Pearl, C.J. Rochester, S.P.D. Riley, M. Roth, B.H. Sigafus. Nature Communications, 2018
Staci M. Amburgey, David A. W. Miller, Evan H. Campbell Grant, Tracy A. G. Rittenhouse, Michael F. Benard, Jonathan L. Richardson, Mark C. Urban, Ward Hughson, Adrianne B. Brand, Christopher J. Davis, Carmen R. Hardin, Peter W. C. Paton, Christopher J. Raithel, Rick A. Relyea, A. Floyd Scott, David K. Skelly, Dennis E. Skidds, Charles K. Smith, and Earl E. Werner. Global Change Biology, 2018
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Quantitative evidence for the effects of multiple drivers on continental-scale amphibian declines
E. H. C. Grant, D. A. W. Miller, B. R. Schmidt, M. J. Adams, S. M. Amburgey, T. Chambert, S. S. Cruickshank, R. N. Fisher, D. M. Green, B. R. Hossack, P. T. J. Johnson, M. B. Joseph, T. Rittenhouse, M. Ryan, J. H. Waddle, S. C. Walls, L. L. Bailey, G. M. Fellers, T. A. Gorman, A. M. Ray, D. S. Pilliod, S. J. Price,
D. Saenz, W. Sadinski, and E. Muths. Scientific Reports, 2016
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By getting involved with the community scientists can show how cool nature can be and highlight the importance of conservation to the public. From national initiatives such as Save the Frogs Day, Skype a Scientist, and Letters to a Pre-scientist to local programs such as 4H Extension activities, Bioblitzes, or nature centers and museums, these opportunities allowed me to talk about ecology and science with children, parents, and the general public and get excited about my own research. In addition, I have helped organize and present science talks to the general public through the Science Cafe series.