Finn Callahan | University of California, Berkeley

About Me

I am a Computational Biology Ph.D. student at UC Berkeley working with Dr. Rasmus Nielsen. I got my BA in Mathematical and Computational Biology from Scripps College in 2021. I work on a variety of statistical and computational models to investigate questions about how ecological communities form, and how and why they change over time. My recent work has focused on simulation studies using network models for community ecology and methods development for analysis of ancient environmental DNA. I am also dedicated to promoting diversity in the sciences through equity-oriented mentorship and teaching!

Research Interests

Community ecology: species interactions, responses to climate change, species distribution modeling
Ecological network theory: co-occurrence networks, interaction networks, dynamical systems
Environmental DNA: sedimentary ancient DNA, time series data, modeling change in communities over time

Publications

*Some publications appear under Fiona Margaret Callahan

Reproducibility and normalization in ancient environmental DNA

Callahan, F. M., Kjær, K. H., Ramsøe, A. D., Willerslev, E., & Nielsen, R.

in preparation

Environmental DNA reveals Reykjavík's human and ecological history

Kjær, K. H.†, Ruter, A. H.†, Menendez-Serra, M.†, Vogel, N. A.†, Ramsøe, A. D.†, Farnsworth, W. R.†, Siggaard-Andersen, M.-L.†, Huang, Z.†, Callahan, F.†, Mesny, F.†, … Willerslev, E. (in review).

Nature.

in review. †co-first authors.

Co-occurrence networks can preserve emergent properties of ecological communities

Callahan, F. M.†, & Evensen, C.†.

bioRxiv, 2026-04. DOI:10.64898/2026.04.15.718781.

PDF In review. †co-first authors.

STEM-LM: Spatio-Temporal Ecological Modeling via Masked Language Model for Joint Species Distribution

Li, J. K., Lim, W., Callahan, F. M., Raskin, L. Y., Lemmon-Kishi, M., & Nielsen, R.

bioRxiv, 2026-05.

PDF in review.

Challenges in detecting ecological interactions using sedimentary ancient DNA data

Callahan, F. M., Li, J. K., & Nielsen, R.

Environmental DNA. DOI:10.1002/edn3.70067.

PDF

Teaching & Mentorship

Graduate Student Instructor, UC Berkeley

Led discussion sections for Human Biological Variation (~80 students, Spring 2026)
Taught Berkeley Connect in Computational Biology (40 students, Fall 2023 & Spring 2024)
Designed original syllabi, lesson plans, and coordinated accessibility accommodations

Math Instructor, Mount Tamalpais College, San Quentin Rehabilitation Center

Volunteer math instructor for college preparatory courses at San Quentin Rehabilitation Center (Summer 2024 - Present)
Designed lessons, assignments, and exams for adult students preparing for college-level mathematics

Research Mentorship

Mentored 6 undergraduate research assistants in computational biology projects (2022 - Present)
Designed independent research projects and provided weekly mentorship meetings

Mentorship & Outreach

Computational Biology Mentorship Committee (2023 - Present): coordinating professional development workshops and one-on-one peer mentorship for early-career PhD students
Workshop leader, Expanding Your Horizons conference (2023 - 2026): introducing middle school girls and gender-diverse youth to STEM careers
Volunteer mentor, Be A Scientist program: guided 7th grade students in designing and conducting independent experiments

Pedagogical Training

Certificate in Teaching and Learning in Higher Education (UC Berkeley, in progress)
Completed workshops in inclusive classroom design, accessibility, and evidence-based teaching practices
Completed pedagogy and mentorship courses at UC Berkeley