The Fredston Lab is part of the Department of Ocean Sciences at the University of California, Santa Cruz. Our team of quantitative ecologists uses data science, modeling, and synthetic approaches to solve interdisciplinary environmental problems, particularly in the sea. Across many geographies, systems, and scales, we study marine biogeographic patterns and ecological processes; how human influences are reshaping them; and how well their dynamics can be predicted with models. Most of these projects are co-developed with ocean managers and stakeholders, advancing biodiversity conservation and human well-being while also contributing to foundational science.
We study ecological processes and biogeographical patterns, in the context of human impacts. While we focus on oceans, we often test concepts developed on land in marine systems; working across realms helps to understand the universality of ecological theories and conservation approaches.
Species around the globe are shifting their ranges in response to climate change, reshuffling ecosystems and challenging paradigms of natural management. Yet species’ range shifts are highly variable, perhaps because many ecological and environmental processes besides climate also influence species distributions. Without understanding these other processes and how they interact with one another and with climate, it’s difficult to predict range shifts and make management recommendations. We work to advance our mechanistic understanding of processes that govern species distributions in the Anthropocene, and consequently, our ability to forecast those distributions. Recent and ongoing work in the lab on this topic has:
Climate change may transform ecosystems through not only the “press” of gradual warming but also the “pulse” of extreme events like heatwaves. Further, sustainable oceans require managing other human impacts, including runoff and fishing. Runoff—the direct influx of sediments, nutrients, and other forms of pollution carried to coastal oceans from rivers—directly threatens sensitive habitats that are crucial to biodiversity conservation, like coral reefs and seagrass beds. Well-managed fisheries could provide protein with a low greenhouse gas footprint to billions of people and support livelihoods in countless coastal communities. Unfortunately, many fisheries in the world are associated with problematic social or ecological outcomes—or both. We engage with these issues both through primary research and through collaboration and outreach with stakeholders. Past work on this topic includes:
We are enthusiastic about open science. To meet planetary challenges, we need to—as Dr. Julia Stewart Lowndes and friends put it—do “better science in less time”. We strive to implement best practices for open and reproducible science. Beyond the lab, Dr. Fredston has contributed extensively to collaborations aimed at making it easier for the field to do impactful science, from demystifying climate scenarios for marine ecology audiences (Burgess et al. 2023) to building a data infrastructure that standardized dozens of publicly-available bottom trawl surveys from around the world (Maureaud et al. 2024) and created an international community of practice around trawl data (Maureaud et al. 2025). She has also written about the challenges and opportunities that the open science movement presents to the marine sciences, especially for early-career scientists (Fredston and Lowndes 2024).
Dr. Alexa Fredston is a quantitative ecologist and Assistant Professor in the Department of Ocean Sciences at the University of California, Santa Cruz. She earned her Ph.D. from the Bren School of Environmental Science and Management at the University of California, Santa Barbara and graduated summa cum laude from Princeton University with a B.A. in Ecology and Evolutionary Biology and a certificate in Environmental Studies. Dr. Fredston’s publications are listed on her Google Scholar and ResearchGate pages. You can contact her for PDFs of any publications, and download her CV here.
Dr. Fredston is committed to translating science into action. As a postdoc, she collaborated with managers and fishermen through the Mid-Atlantic Fisheries Management Council. Previously, she worked at the Environmental Defense Fund as a High Meadows Fellow. She has served on CESAB and SNAPP working groups, aimed at synthesizing ecological information to advance biodiversity conservation and human well-being. Dr. Fredston is on the Steering Committee for FISHGLOB and is Treasurer of the Society for Open, Reliable, and Transparent Ecology and Evolutionary Biology (and was on the Board of Directors from 2022 – 2024). All of the code for her published research, as well as numerous coding tutorials she developed, can be viewed on GitHub. A number of her recorded talks can be found on this site.
Dr. Emma Walker is a postdoctoral scholar in the Fredston Lab working on both developing and applying theory that better resolves the nonlinear dynamics present in ecological systems. The aim of her research is to further understanding of the interplay of fundamental processes and address their consequences for ensuring the sustainability of populations. One of the main projects she is currently working on is using empirical dynamical modelling to discover whether marine heatwaves have had nonlinear consequences on fish species abundances in the bottom trawl surveys of the North Eastern United States. She is also interested in and working on how spatiotemporal variability impacts the size and rates of change of species’ populations and ranges. Read more about Emma and her research on her personal website or her Google Scholar page.
Jordana Sevigny joined the Fredston Lab in 2023 as a PhD student in Ocean Sciences. Prior to moving to Santa Cruz, Jordana worked in Seattle in several labs researching transmissible cancer in bivalves, evolution and ecology of microbes, and alpine wildflower ecology and citizen science. Jordana holds a B.S. in Biology with an emphasis in Ecology from University of Washington. In the Fredston Lab, Jordana’s research centers on mechanistic modeling of marine invertebrate species’ dispersion and range edge dynamics. Outside of lab, Jordana enjoys many hobbies including kayaking, camping, reading, and crafting. Read more of her research on Jordana’s Google Scholar page.
Theodore Tran is a PhD student and a National Science Foundation Graduate Research Fellow interested in investigating questions of ecology among sharks and other large, mobile marine predators. He earned in BS in Marine Biology at San Jose University. He aims to integrate and synthesize interdisciplinary methods to establish factors and trends in migratory patterns and habitat use in light of anthropogenic impacts and climate change.
Thank you for your interest in joining the lab! UCSC is on the cutting edge of environmental and marine research. Strong support exists for interdisciplinary work and partnerships, via the Institute for Marine Sciences, NOAA’s Southwest Fishery Science Center, and more. Prospective graduate students are encouraged to explore the Ocean Sciences prospective student page, including the program prerequisites listed here.
The Fredston Lab is a computational group that develops and tests hypotheses about fundamental dynamics of marine ecosystems using theoretical models and Bayesian and frequentist statistics. Successful Fredston Lab members are likely to have experience and/or substantial interest in these methods. In other words, there is a lot of math, probability, and code involved, and most people in the group will not be collecting primary (field or lab) data. That said, we am open to a broad array of approaches to answering these questions, and committed to training early career researchers in quantitative methods. Regardless of technical background or research topic, everyone in the lab is committed about open science principles and practices.
Dr. Fredston is always open to co-developing proposals for fellowships and other externally funded positions, such as the Smith Fellowship (due annually in September), and NSF Ocean Sciences and Biology postdoctoral fellowships (due annually in November). PhD students in the lab are expected to apply to competitive fellowships for which they are eligible, including the NSF GRFP, NDSEG, the NOAA Population and Ecosystem Dynamics Fellowship.
Many lists exist of national fellowships; you may find some relevant graduate fellowships on this University of Miami page, some postdoc fellowships on this University of Minnesota page, and both on Dr. Jurgens’ page. Johns Hopkins University also maintains lists of graduate and postdoctoral fellowships for all research fields.
Dr. Fredston sometimes has additional funding for students and postdocs to join the lab. All prospective lab members should email her directly, unless you are applying for an advertised postdoc, in which case please use the UCSC job application website instead. You should include the following in your email:
This great guide to emailing prospective PhD advisers by Dr. Hart at UNSW is worth reading, too (and if it’s paywalled for you just let Dr. Fredston know and she will send you a copy).