Aubry Lab Population Ecology in a Changing World

Quantitative Ecology


Using a 30-year data set, PhD student Jarod Raithel is examining the degree to which black bear behavior and sport harvest have affected their recruitment, survival, abundance and human-bear conflicts over space and time. Jarod's work is based in the state of New Jersey, home to the highest density of black bears and humans in the country, which offers an ideal setting for understanding and predicting human-bear conflicts while quantifying bear population dynamics along an anthropogenic gradient.

PhD Dissertation: Jarod Raithel

With Melissa Reynolds-Hogland, New Jersey Fish & Wildlife

Funded by Bear Trust International, USU Presidential Doctoral Fellowship




We are measuring changes in life history traits in response to climate change over a 50-year period by comparing the historical phenology and demography of three Uinta ground squirrel ‘UGS’ populations to current-day observations along an elevation gradient. We are further investigating trade-offs between immunocompetence, growth, reproduction and survival and how such life history decisions vary across elevation/climate niches within the context of climate change. Ultimately, we hope to predict the ability of hibernators to respond to climate change in the Western US by estimating heritable and plastic variance in life history traits through the establishment of a detailed pedigree.

Master Thesis: Caylee Falvo

In collaboration with Susannah French, Scott Bernhardt, Carsten Meier

Project funded by the National Geographic Society, USU Research Catalyst, USU Agricultural Experiment Station, Colorado State university


Individuals are heterogeneous in many ways and can respond differently to both progressive and rapid changes to their environment, even when belonging to the same population. They may for example differ in their ontogeny, experience, physiology, and behavior. Beyond such observable heterogeneity, demographic stochasticity and unobserved sources of heterogeneity can further affect vital rates, life history outcomes, and the thus the evolution of life histories. 

With efforts led by Stephanie Jenouvrier (Woods Hole Oceanographic Institute) and Hal Caswell (University of Amsterdam), we are interested in i) estimating different sources of individual heterogeneity in species with contrasted life histories; ii) understanding the impact of the different sources of heterogeneity on population dynamics, fitness, and life history evolution; assessing how i & ii operate in light of climate change, where changes in the mean, variance and frequency of extreme climate events can act as selective agents. for more information see Stephanie Jenouvrier's website!

I used a 30-year study of long-lived seabirds (black-legged Kittiwakes) to study the evolution of trade-offs between early-life breeding decisions, future reproduction, and survival. Recruitment age  influenced breeding success and survival trajectories. Sources of unobserved heterogeneity (frailty) further explained substantial amounts of variability in breeding success and survival. Ignoring such individual heterogeneity led to biased inference, with implications for the study of senescence in the wild.

Funded by the Max Planck Institute for Demographic Research

I still collaborate on questions that pertain to the evolution of life histories with Emmanuelle Cam, Matthieu Authier and Jean-Yves Monnat


If rates of human exploitation exceed natural mortality, harvest can “add” to overall mortality and imperil sustainable management. Using ≥ 16 years of data for heavily harvested and semi-protected cougar populations in Utah, we found that uncertainty in estimates of cause-specific mortality led to biased conclusions regarding additive and compensatory mortality hypotheses. Our research reveals that carnivore studies up to now have ignored uncertainty and have likely provided management agencies with flawed managements recommendation in setting their harvest quotas. 

With Mike Wolfe, Dave Koons, Eric Gese, David Stoner, Pat Terletzky

Funded by the Utah Division of  Wildlife Resources


Using a 40-yr study of a rapidly growing population of lesser snow geese, an over-abundant herbivore that is causing extensive damage to Arctic and sub-Arctic ecosystems, we have quantified the impact of population density during early-life development. We are currently working on assessing the effect of spatio-temporal patterns in age-specific survival on population dynamics, and locate where the goose population is likely to expand and inflict more damage to their breeding, staging, and wintering grounds. 

With David KoonsRocky RockwellRemi Choquet and Olivier Gimenez

Funded by NSF-DEB & the Berryman Institute