About

Holly Moeller is a theoretical ecologist who employs both mathematical and empirical methods to study acquired metabolism. She originally trained as a photophysiologist and phytoplankton ecologist and developed her mathematical skills during her master's studies focused on marine reserve bioeconomics. For her PhD, she worked with Dr. Tadashi Fukami and was co-advised by Dr. Peter Vitousek, investigating the ancient and diverse metabolic mutualism between trees and ectomycorrhizal fungi. Holly's postdoctoral work was primarily conducted as an NSF Postdoctoral Research Fellow at the Woods Hole Oceanographic Institution, where she studied acquired metabolism in plankton alongside Drs. Michael Neubert and Matthew Johnson. She also held a brief Biodiversity Research Centre Postdoctoral Fellowship at the University of British Columbia before joining UCSB. Beyond her scientific research, Holly is an advocate for the importance of mathematics in biology, often promoting its vital role to those she meets.

Research topics

• Biology
• Ecology
• Computer Science
• Fishery
• Political Science
• Environmental science
• Business
• Geology
• Environmental resource management
• Economics
• Oceanography
• Natural resource economics
• Botany
• Environmental planning
• Geography

Selected publications

• Increased prey choice is associated with higher kleptoplastidic reliance in <i>Mesodinium</i> ciliates

  Journal of Phycology · 2026-03-31

  articleOpen accessSenior author

  Kleptoplastidic organisms display varying levels of reliance on stolen plastids, with some lineages evolving complex strategies for plastid (and other organelle) integration into metabolism. More complex methods of plastid integration typically coincide with greater prey specialization, but it remains unclear whether or how kleptoplastidic lineages preferentially obtain organelles from compatible prey types. Here, we used the Mesodinium genus of ciliates, which span a gradient of reliance on kleptoplasty, to test for prey specialization during ingestion. We used two Mesodinum species: a highly kleptoplastidic species, M. rubrum, and a more mixotrophic species, M. chamaeleon. We conducted a series of experiments offering Mesodinium two different cryptophyte prey species simultaneously. Mesodinium and cryptophyte prey populations were measured across six different prey combinations. We observed that M. rubrum showed greater prey selectivity than M. chamaeleon at the time of ingestion. Despite this greater selectivity, M. rubrum was still unable to completely select for compatible prey types during feeding. Growth of M. rubrum was not affected by prey type over the course of this study, while limited effects on the growth of M. chamaeleon were seen. Preferential feeding by M. rubrum suggests the presence of a prey identification system that is not present in M. chamaeleon, consistent with our hypothesis that prey selectivity increases with increased reliance on kleptoplasty.

  PublisherDOI

• Epigenetic Intelligence: How Organisms Track Their Environment Through Molecular Memory

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-01-09

  articleOpen access1st authorCorresponding

  Abstract The regulation of gene expression by epigenetic markers is a growing area of focus for researchers who seek to explain rapid phenotypic acclimatization to environmental change. Yet even as empirical datasets accumulate exponentially, the mechanistic underpinnings of epigenetic changes and their role in connecting environmental variation with the regulation of gene function remain unclear. Here, we use a stochastic model of epigenetic change to generate three testable predictions: (1) that organisms require environmental feedback to track their environments through epigenetic responses, (2) that this tracking requires coordination between the addition and removal of epigenetic markers, and (3) that epigenetically driven tracking is only effective under specific subsets of environmental variability. Despite the intuitiveness of these postulates, few to no experimental studies directly test them. We review correlational evidence consistent with the model’s predictions, describe hypothetical mechanisms by which epigenetic strategies could evolve, and clearly identify knowledge gaps and urgent experimental needs in the field. Overall, the field of environmental epigenetics is poised for major advances, which can be enhanced through the continued synthesis of mathematical frameworks and empirical data.

  PublisherOA PDFDOI

• A model for heat and light stress in photosynthesis

  Ecological Modelling · 2026-05-21

  articleOpen access
  PublisherDOI

• Adapting species risk assessments to a changing climate: the underestimated vulnerability of foundational trees

  DRYAD · 2026-03-26

  datasetOpen access

  This dataset supports a systematic review and risk assessment of 27 endemic and near-endemic California tree species under projected climate change. It comprises two supplementary tables. Table S1 contains 52 records of species distribution model (SDM) outputs drawn from the published literature, organized by species and source study. For each record, the table includes the species' Latin and common names, the citation, climate models and emissions scenarios used, the type of distribution data (presence-absence), baseline period and year, and projected percent contraction in climatically suitable habitat at mid-century (~2055), end-of-century (~2100), and ~2125 time horizons, reported as low and high estimates. Projected values are standardized to common reference years to enable cross-study comparison. Table S2 provides species-level summary data for all 27 focal species, including total range area (km²), the proportion of range occurring within California, mean projected habitat loss and area of persistence across time horizons and estimate ranges, a demographic change score synthesizing field-observed responses to climate change, and climate risk scores corresponding to IUCN Red List Criteria A3 and B1. Risk scores are reported both across all studies and separately for a focal subset (Rose et al. 2023).

  PublisherDOI

• Adapting Species Risk Assessments to a Changing Climate: The Underestimated Vulnerability of Foundational Trees

  Global Change Biology · 2026-04-01

  articleOpen access

  Climate change is one of the top threats to biodiversity. However, many species risk assessment frameworks, including the globally authoritative International Union for Conservation of Nature Red List, do not consistently and comprehensively incorporate loss of climatically suitable habitat into listing or threat categorization decisions. Using California's foundational, endemic and near-endemic trees as an exemplary set of high biodiversity and cultural value species (N = 27), we reviewed and synthesized the literature on species' model-projected changes in suitable habitat, and on field-observed spatial and temporal demographic responses to climate change. We demonstrate multiple approaches to using this existing literature to integrate climate threats into species risk assessments, with a focus on the Red List criteria. Over the next century, our focal species are projected to lose between half and three-quarters of their existing suitable habitat, which would lead to substantial impacts on ecosystem structure and function in forests, woodlands and savannas. Overall, species are more vulnerable than is reflected by their current Red List status. Even under conservative estimates of climate change impacts, two-thirds of our focal species could now meet the Red List A3 Criterion for Endangered or Critically Endangered status, because of projected loss of climatically suitable habitat (a six-fold increase). We also found a positive relationship between species' model-projected risk and observed demographic responses to climate change, indicating that in many cases, projected responses are already evident on the ground. To inform conservation prioritization, we visualized the geographic patterns of species' suitable habitat loss using heatmaps. Our results illustrate the need to revise species risk assessments in light of climate change to better align research and conservation priorities with species' vulnerability. They also highlight the conservation needs of currently widespread but high climate-risk species, and the regional threats to ecosystem structure and function from foundational species loss.

  PublisherDOI

• Effects of mixotrophic metabolism on predation risk

  Marine Ecology Progress Series · 2026-04-13

  articleSenior author
  PublisherDOI

• Seeking service: How client behavior determines cleaning station clustering

  Journal of Theoretical Biology · 2026-02-04

  articleOpen accessSenior author

  Cleaner shrimp engage in a mutualistic relationship with reef fish, providing cleaning services in exchange for nutritional benefits. These shrimp inhabit stationary sea anemones, forming "cleaning stations" that rely on mobile fish clients to locate and revisit them. To investigate how fish movement behaviors influence the spatial distribution of cleaning stations, we developed an individual-based model that explicitly incorporates both stochastic fish movement and two forms of directed fish movement strategies: taxis (i.e. gradient-following) and memory-based movement. Our results reveal that directed movement, whether through taxis or memory, promotes the formation of spatially clustered cleaning stations, but only when the range of directed movement outweighs the homogenizing effects of random dispersal. Specifically, memory-based clustering requires the memory range to exceed dispersal distance, while taxis-based clustering emerges even with taxis-based movement ranges exceeded by dispersal distance. By parameterizing the model with empirical data on client fish visitation frequencies, we further show that reefs dominated by "Choosy" fish (those willing to travel farther for preferred stations) exhibit stronger station clustering compared to reefs with "Resident" fish (territorial species with limited movement). These findings highlight how client behavior shapes the spatial ecology of cleaning mutualisms, with implications for understanding partner encounter dynamics in other species interactions.

  PublisherDOI

• Eco-evo conflicts in a stage-structured mutualism: modeling the consequences of ontogenetic variation in host quality

  Ecological Modelling · 2026-03-18

  articleOpen accessSenior author
  PublisherDOI

• Author response for "A Busse Balloon in the Lagoon: Herbivore Behaviour Generates Spatial Patterns in Coral Reef Ecosystems"

  2025-02-10

  peer-reviewSenior author
  PublisherDOI

• Author response for "A Busse Balloon in the Lagoon: Herbivore Behaviour Generates Spatial Patterns in Coral Reef Ecosystems"

  2025-02-20

  peer-reviewSenior author
  PublisherDOI

Recent grants

• NSF Postdoctoral Fellowship in Biology FY 2014

  NSF · $138k · 2015–2016

• BEE: Testing the evolutionary responses of mixotrophs to future ocean conditions

  NSF · $536k · 2019–2023

• COLLABORATIVE RESEARCH: URoL : Epigenetics 2: Predicting phenotypic and eco-evolutionary consequences of environmental-energetic-epigenetic linkages

  NSF · $599k · 2019–2025

Frequent coauthors

• Matthew D. Johnson

  Woods Hole Oceanographic Institution

  19 shared

• Michael G. Neubert

  11 shared

• Michelle Lepori‐Bui

  University of Washington

  11 shared

• Kevin M. Archibald

  University of California, Santa Barbara

  10 shared

• Ferdinand Pfab

  University of California, Santa Barbara

  8 shared

• Ian A. Dickie

  Economics for the Environment Consultancy (United Kingdom)

  8 shared

• Charlotte Laufkötter

  University of Bern

  8 shared

• Adrian C. Stier

  University of California, Santa Barbara

  6 shared

Labs

• The Moeller LabPI