Research

As the effects of anthropogenic stressors (fragmentation, habitat degradation, climate change, etc.) on natural populations increase, it is essential that we understand the factors governing population persistence and resilience. The overarching research goal of my lab group is to link genetic and genomic factors with other aspects of an organism’s biology, life history, and demography to help predict population persistence. More specifically, we conduct research that aims to understand: 1) spatial patterns of an organism’s genetic diversity, 2) effective population size as a predictor of persistence probability, 3) whether translocation is an effective practice to enhance persistence probabilities ("genetic rescue"), and 4) adaptive dynamics and mechanisms. We also develop and test general tools that will help advance the field and be used to help conserve a wide variety of taxa.

Genetic Rescue

Genetic RescueOne possible solution to alleviate small-population “extinction vortex” dynamics is to introduce a small number of individuals into an isolated population, known as genetic rescue. Successful reproduction by translocated individuals can elevate fitness and ultimately lead to increased abundance and population growth rates. Genetic rescue has been implemented for single populations of high-profile species such as Florida panthers, prairie chickens and Swedish adders. However, there are few examples of replicated and controlled experimental implementations of genetic rescue. Extensive fragmentation in stream networks makes genetic rescue an appealing conservation approach that would be feasible for situations where barrier removal is not possible. We have ongoing replicated and controlled genetic rescue experiments underway in brook trout populations in Virginia and in westslope cutthroat trout populations in Montana, in close collaboration with Montana Fish, Wildlife and Parks. This work was funded in 2017 through an NSF CAREER award.

Hybridization Between Species

Hybridization Between SpeciesHybridization with rainbow trout (Oncorhynchus mykiss) threatens westslope cutthroat trout (Oncorhynchus clarkii lewisi) with genomic extinction. In partnership with the Montana Conservation Genetics Lab, we test many Montana westslope cutthroat trout populations for hybridization. We are also involved in long-term analyses of hybridization dynamics in Montana, simulations to understand hybridization dynamics in rivers, and testing questions related to admixture, partial migration, and survival and individual growth early in the life cycle. The latter is a new project in the Jocko River in collaboration between UM and the Confederated Salish and Kootenai Tribes. 

Long-term Pedigree Studies

Long-term Pedigree StudiesWe collaborate with researchers from the U.S. Geological Survey and the U.S. Forest Service on several long-term, individual-based studies of brook trout in New England. Our goal is to understand the link between adaptive dynamics and population persistence in greater depth. We have developed models to understand the influence of environmental factors, like stream flow and temperature, on demographic vital rates. We have reconstructed pedigrees to examine movement and dispersal, and we are now working to develop genomic resources to build longer pedigrees to comprehensively examine fitness in natural metapopulations.

Effective Population Size

Effective Population Size Genetic monitoring offers a promising complement to traditional population monitoring approaches. Within-population genetic metrics that can be monitored over time include aspects of genetic variation (heterozygosity and allelic richness) and effective populations size (Ne and Nb). We are particularly interested in understanding Nb. Our working hypothesis is that single-cohort estimates of Nb reflect variation in spawning habitat quantity and quality. We have been exploring this hypothesis through empirical work on brook trout (Salvelinus fontinalis) and have ongoing simulation projects underway. We have also collaborated with Montana Fish, Wildlife and Parks to examine Nb in Arctic grayling (Thymallus arcticus).

Introduced Species

Introduced SpeciesThe rapid decline of native species in fragmented aquatic ecosystems is highly influenced by the introduction of non-native species. We are working with Seattle City Light to examine non-native brook trout genetic structure and life history variation in tributaries to the Lower Pend Oreille River in northeastern Washington. We are collaborating with SCL, Washington Department of Fish and Wildlife and Idaho Fish and Game to examine the efficacy of releasing YY male brook trout in this region using simulations and proposed empirical work.