Research

Current Projects

Some handy keywords for your enjoyment:

invasion biology, evolutionary ecology, ecological genomics, plant biology, plant-associated microbiomes, population genetics, ancient DNA, ethnobotany, science communication

Adaptive Capacity in Big Sagebrush

Big sagebrush (Artemisia tridentata) is a foundational species of the North American West. Threatened and endangered species rely on it. And yet the range of this iconic species is shrinking, due to pressure on several fronts, including invasive species, encroaching native species, altered fire regimen, and climate change. The Turner Lab is working to understand the evolutionary impact that invasive species and land use change has had on big sagebrush, and how big sagebrush may be able to adapt to and succeed in the face of these pressures. This work has been supported in the past as part of the NSF-funded Idaho EPSCoR GEM3 research program, a large and collaborative network of transdisciplinary scientists and stakeholders across Idaho.

Related projects:

Developing a low-cost genetic toolkit to enable effective Big Sagebrush conservation - VIP Project (ongoing)

Role of genome size, resource co-limitation, and competition on seedling establishment of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) - Treyton Harris (thesis)

Competition between basin big sagebrush seedlings and invasive cheatgrass - Carson Kantack (thesis)

Related publications:

Harris TS, Grinath JB, Rachman R, Forbey JS, Turner KG. 2026. Evaluating Nondestructive Age Estimation Methods for Big Sagebrush, a Long-Lived, Wide-Ranging Shrub. Rangeland Ecology & Management 104: 35–42. doi: 10.1016/j.rama.2025.11.003

Heil J, Simler-Williamson A, Striluk M, Trawick D, Capezza R, DeFehr C, Osorio A, Finney B, Turner KG, Bittleston L. 2025. Weather and leaf age separately contribute to temporal shifts in phyllosphere fungal community structure in sagebrush. Ecosphere 16(6): e70295.

Field of big sagebrush and lupines on the edge of Craters of the Moon National Monument. Image by Kathryn Turner.

Image from California Academy of Sciences Herbarium.

Population structure in an invasive crop weed

Collaborators: Ruth Hufbauer, John McKay, Jesse Lasky

Biological invasions of non-native species present compelling motivation to understand how human-induced changes in the environment and species distributions influence ecological and evolutionary processes. We are investigating population diversity and structure in invasive North America populations of blue mustard (Chorispora tenella, Brassicaceae), a widespread and governmentally listed noxious invasive weed. We also hope to develop a reference genome for this understudied species. See more at a related project website, here.

Related projects:

Genetic variation among invasive Chorispora tenella populations - Rachel Havok (thesis)

Invading hybrid Diffuse Knapweed

Heterosis has been hypothesized to contribute to invasion success. Previous work, including a comparison of transcriptome libraries from the native and invaded ranges (Lai et al., 2012), has shown that Centaurea diffusa individuals of hybrid ancestry (with introgression from C. stoebe ssp. stoebe) are more common in the invaded than the native range, though hybridization occurs in the native range only. Our work assesses the impact of this heterosis on phenotypic and genetic divergence in the invaded range.

Related projects:

Hybridization in invasive and native populations of Centaurea diffusa - Bailee Grisham (ongoing)

Related publications:

Turner KG, Ostevik KL, Grassa CJ, Rieseberg LH. 2021. Genomic analyses of phenotypic differences between native and invasive populations of diffuse knapweed (Centaurea diffusa). Frontiers in Ecology and Evolution, 8. doi: 10.3389/fevo.2020.577635

Diffuse knapweed flower with hybrid traits

Putative hybrid diffuse knapweed, Okanagan Valley, British Columbia 2009. Image by Kathryn Turner.

Black-capped vireo nestlings handled for data collection by permitted field biologist.

Inbreeding in recently de-listed threatened songbird

The Black-capped Vireo (Vireo atricapilla) is a small migratory songbird species native to the south-central United States and northern Mexico. In the 20th century, overgrazing, vegetation succession, brood parasitism by the Brown headed cowbird, and habitat loss has significantly reduced the available breeding range for this species. In 1987, Black-capped Vireo was listed under the U.S. Endangered Species Act. In 2018, the species was assessed to have recovered enough to be de-listed. Yet populations remain fragmented. In collaboration with Dr. Laurel Moulton of the Balcones Canyonlands Preserve (a Habitat Conservation Plan that was created in partnership with the City of Austin and Travis County to protect endangered species habitat within Travis County from development), we aim to use genetic techniques to examine relatedness and genetic diversity among Black-capped Vireos in Travis County, Texas, which is at the eastern range extreme. We also aim to examine hatch year dispersal and site fidelity.

Related projects:

Black-capped Vireo genetic diversity, inbreeding depression, and hatch year dispersal at the Balcones Canyonlands National Wildlife Refuge - Brad Carr (ongoing)

Designing restoration to resist invasion

In collaboration with the Josh Grinath lab and other folks at ISU, we are investigating the lasting effects of ecological disturbance on the post-fire recovery of sagebrush steppe ecosystems. Wildfires are becoming more common as environmental change progresses, destroying entire landscapes and costing the American public billions of dollars annually. Wildfire frequency in many regions is intensified by the invasion of exotic grasses that are highly flammable, and which often replace native plants as burned landscapes regrow. To prevent invasive species from taking over burned landscapes, land managers are increasingly applying seeds of native plants to encourage ecosystem recovery and keep invasive plants at bay. However, there is still much to learn about the factors that determine the success of seed additions in terms of the ability of seeded species to establish, and to suppress flammable invaders. It is also unclear how previous human-caused landscape changes, such as nitrogen pollution or the removal of water-hogging shrubs (a practice common in western USA rangelands), will affect the success of native seed additions and plant recovery from fire. Moreover, it is unclear how different seed mixes repel exotic plants from invading disturbed areas. This research project addresses these issues by building on a long-term experiment investigating the effects of past nitrogen pollution and shrub removal (originally intended to improve rangeland forage) in a highly invaded sagebrush steppe ecosystem. The experimental site was entirely burned in a recent wildfire, providing a unique opportunity to evaluate how a history of nitrogen pollution and shrub removal will influence plant recovery from wildfire. The research team will develop criteria for creating seed mixes that suppress invasive plants, particularly flammable annual grasses, and will determine their effectiveness within the different long term experimental environments present across the study site. The results from this study will aid land managers in choosing native seed mixes that will help to prevent the spread of invasive plants and decrease the risks and costs of future wildfires. This RAPID project was funded by the National Science Foundation. More details here.

Related published datasets:

Grinath, JB, Kerner P, Turner KG, Reinhardt K, Finney BP, Lohse KA. 2024. Ecological memory effects on plants and soils in early post-fire steppe, Barton Ecological Research Area, Pocatello, Idaho, 2021 ver 1. Environmental Data Initiative.

Barton Road Ecological Research Area, post fire, October 2020. Image by Kathryn Turner.

Header image: Centaurea diffusa herbarium specimen, Plant Science Center, University of Texas at Austin. Image by Kathryn Turner.

Page updated

Report abuse