Stewart Ecology

Research Interests:

Reforestation and Forest Management- Increased high severity fires and drought are leaving vast areas devoid of natural conifer regeneration. Where are forests regenerating on their own and where are they not? When managers opt for reforestation, where should seeds be sourced from to ensure they have the best chance of growing into healthy, resilient, and climate-adapted forests? Where can strategic fuel reduction lead to the largest gains in conserving forest habitat, resources, and natural heritage?
Conservation Biogeography – Environmental changes are driving shifts in the geographic distribution of species. What management actions can we take to save disappearing wildlife?

Decision Support Tools:

Climate Adapted Seed Tool (CAST) – Rapid climate change has caused a mismatch between the climate that tree populations have adapted to and the climate they currently grow in. This tool helps ecosystem managers identify seed sources that are pre-adapted to local climate conditions at their planting sites. CAST currently serves CA, OR, WA, ID, & NV, though some features are limited to California.
Postfire Spatial Conifer Reforestation Planning Tool (PostCRPT) – Large and severe wildfires are leaving vast areas devoid of natural conifer regeneration. This tool aids managers in prioritizing areas for reforestation by providing maps of predicted natural conifer regeneration. It includes taxon-specific regeneration predictions and a range of postfire climate and seed production scenarios. This is a supplement to our paper on postfire conifer regeneration. PostCRPT currently serves low-moderate-elevation forests of California and Southern Oregon.
Pika Extirpation Predicter – This is an interactive supplement to our paper on pika extirpations in California. Adjust the slider to see where American pika populations are predicted to become extinct as temperatures warm.

Peer-Reviewed Papers:

Technical Reports and Book Chapters:

Our research on the American pika was featured on the National Geographic Channel.

Selected Media Coverage:

Invited Seminars:

van Mantgem P.J., Stewart J.A.E., Wright M.C. (2021) Rebuilding Forests After Fire. Southwest Climate Adaptation Science Center Webinar Series. University of Arizona, Tucson, AZ.
Stewart J.A.E. (2018) Conserving wildlife in a changing world. Sierra Science Lecture Series, Sierra College, Grass Valley, CA.
Stewart J.A.E. (2016) Methods for assessing vulnerability of species to climate change. National Institute of Ecology, Seocheon, South Korea.
Stewart J.A.E. (2014) On the distribution and abundance of pikas in Yosemite. Yosemite Forum, Yosemite Valley, CA.

Selected Presentations:

Stewart J.A.E. Thirty-year trends in postfire conifer regeneration in California and western Oregon. 10th International Fire Ecology and Management Congress. Monterey, CA.
Stewart J.A.E., Wright J.W., Godfrey J.M., O’Neill G.A., Ostoja S.M., Thorne J.H., Boynton R.M. 2023. Climate Adapted Seed Tool (CAST): An evidence-based tool to improve reforestation outcomes. LA Moran Reforestation Center Open House. Davis, CA.
Stewart J.A.E. 2022. The Climate-Adapted Seed Tool: Using Provenance Tests to Inform Oak Seed Transfer in a Changing Climate. 8th California Oak Symposium. San Luis Obispo, CA.
Stewart J.A.E. 2022. Adapting Forests to Climate Change via Climate-Adapted Seed Transfer. The 10th Biennial UCSC Plant Science Symposium. Santa Cruz, CA.
Stewart J.A.E. (2021) Optimizing Assisted Gene Flow for Forests. Introduction, Breeding, Propagation and Deployment of Pacific Northwest Conifers Around the World: 70 years of Progress, Opportunities, and Challenges. Virtual.
Stewart J.A.E. (2019) Climate and seed availability drive postfire conifer regeneration: scenario planning for the 21st century. Climate Change and the Ecology of Sierra Nevada Forests, Merced, CA.
Stewart J.A.E. & D.H. Wright. (2017) Invited Presentation. Geographically representative surveys of whitebark pine occurrence and stand characteristics in the northern Sierra with implications for vulnerability to climate change. Field-based Studies on Whitebark Pine in California – A Data Sharing Session, Parsons Lodge, Yosemite National Park, CA.
Stewart J.A.E. & H.S. Butterfield. (2017) Invited Presentation. Habitat restoration opportunities for endangered species of the San Joaquin Desert. San Joaquin Desert Strategic Fallowing Workshop, National Center for Ecological Analysis and Synthesis, Santa Barbara, CA.
Stewart J.A.E. (2016) Invited Presentation. Descent to the underworld: climate change opens gap in distribution of American pika in the Sierra Nevada, USA. Mathias Symposium, Bodega Bay, CA.
Stewart J.A.E. (2016) On the vulnerability of biodiversity to climate change. Science on Tap, a monthly lecture organized by UCSC Women in Science and Engineering, Santa Cruz, CA.
Stewart J.A.E., B. Sinervo, M.F. Westphal, H.S. Butterfield, & E. Tennant. (2015) Interaction of exotic grasses and climate drives contraction of blunt-nosed leopard lizard range at the northern range margin. Thirteenth Annual Species Interaction Workshop, Stanford University, Stanford, CA.
Stewart J.A.E., M. Gogol-Prokurat, J.H. Thorne, E. Tennant, B. Sinervo, M.F. Westphal, H.S. Butterfield, & D.H. Wright. (2015) Assessing climate change vulnerability of California species. California Dept. of Fish and Wildlife Science Symposium, Davis, CA.
Stewart J.A.E., B. Sinervo, M.F. Westphal, & H.S. Butterfield. (2015) Temporal and spatial relationships between vegetation productivity and type and the endangered blunt-nosed leopard lizard. California Native Plant Society Conservation Conference, San Jose, CA.
Stewart J.A.E. (2013) Interactions between climate, vegetation, prey, and the federally endangered blunt-nosed leopard lizard (Gambelia sila). Eleventh Annual Species Interaction Workshop, Stanford University, Stanford, CA.
Stewart J.A.E., R.D. Cooper, M. Westphal, S. Butterfield, & B. Sinervo. (2013) The potential impacts of climate change on local extinction of blunt-nosed leopard lizards. Blunt-Nosed Leopard Lizard Workshop, California State University Bakersfield, CA.
Stewart J.A.E. (2013) Using historic revisit data to model climate change impacts on pikas. Annual Conference the Western Section of The Wildlife Society, Sacramento, CA.
Stewart J.A.E. (2013) Pikas in Yosemite: patterns of occurrence at two spatial scales. George Wright Society Conference on Parks, Protected Areas, and Cultural Sites, Denver, CO.
Stewart J.A.E. (2012) Moving beyond resurveys of historic pika record locations: using relict feces to test the hypothesis of climate-mediated range retreat in California, Ecological Society of American Meeting, Portland, OR.
Stewart J.A.E., J.D. Perrine, D.H. Wright, & C.P. Massing. (2012) Resurvey of historical pika locations in California: analysis and critique, North American Congress for Conservation Biology, Oakland, CA.
Stewart J.A.E., & D.H. Wright. (2011) Persistence and apparent extirpation of American pika (Ochotona princeps) at historical California localities. Annual Conference the Western Section of The Wildlife Society, Riverside, CA. *Received award for best student presentation.
Stewart J.A.E., & D.H. Wright. (2010) Investigating the status of American pika (Ochotona princeps) at historical northern Sierra sites. Annual Bay Area Conservation Biology Symposium, San Francisco State University, CA.

Citizen Science:

Places mammal species haven’t been documented for decades – have you seen any of these species in areas where confirmation of their continued existence has been lacking? Document your observations on iNaturalist!
Pika Citizen Science Survey – adventurers and citizen scientists are invited to help collect baseline data on pika occupancy in areas where climate change may cause local extinction over the coming decades. Here’s a clip of Junior High students doing just that:

Crowdfunding:

How much does global warming threaten the American pika? -Mycroryza-crowdfunding for science