How does environmental variation both maintain and erode the composition, structure, and functioning of biological communities?

We are interested in developing a mechanistic understanding of how populations and communities respond to environmental variation. Given the ongoing and predicted future impacts of global change on environmental conditions– including the mean, variance, and higher moment measures– a predictive framework is needed to understand how such changes will impact life on Earth. As such, we seek to test hypotheses that will further the development and synthesis of ecological theory as well as enhance ecological predictions associated with a warming climate and altered patterns of nutrient cycling. Below are the main themes of our research group:

 1) Uncovering the ecological consequences of phenotypic plasticity

Phenotypic plasticity is an environmentally driven change in phenotype (physiology, morphology, development, life-history, or behavior) exhibited by organisms with the same genotype. It is a widespread feature of life, occurring in a vast range of taxa and prompted by diverse environmental factors.  Yet, the ecological consequences of plasticity are poorly understood. We particularly interested in this topic because most predictions of how ecological systems will respond to environmental change currently ignore many important aspects of plasticity. We are currently developing and testing a framework linking phenotypic plasticity to ecological processes. This work focuses specifically on investigating thermal acclimation in phytoplankton, a globally important group of organisms often inhabiting thermally variable environments.

In collaboration with Colin Kremer and David Vasseur, we are interested in using theory and experiments to i) characterize the features of acclimation in response to environmental fluctuations, ii) understand how acclimation can structure population dynamics, and iii) elucidate how acclimation alters the invasion success, competition, and coexistence of species, as well as the maintenance of biodiversity more broadly.

2) The ecology of thermal refugia: species interactions in variable environments

The mosaic of species interactions (e.g., competition, predation, parasitism) in nature is one reason that communities exhibit varied and seemingly unpredictable responses to changes in environmental conditions. Our group is interested in understanding how temperature and other environmental factors affect species interactions and consequently the dynamics of interacting species. This is complicated by the fact that organisms both experience variation in their surrounding conditions through time, and can access different environmental conditions that exists in space.

How does this variability alter species interactions, the structure of food webs, and the resulting community dynamics? Currently, we are exploring how increases in temperature may alter competitive interactions between zooplankton populations, how the presence of cold thermal refuges can alter such interactions, how the timing of favorable versus unfavorable conditions can alter the dynamics of interacting populations, and how the quality and timing of incoming terrestrial subsidies terrestrial ecosystems can impact aquatic communities.

Collaborators: Lauren Culler, Dan Weiczynski, Cristina Herren

3) Ecological consequences of rare demographic and environmental events

Mass mortality events (MMEs) are infrequent, but rapidly occurring, large-magnitude population losses. These events may be increasing in frequency and magnitude worldwide and disproportionately impact aquatic ecosystems. MMEs involving top-level trophic levels can greatly weaken, or even completely remove top-down predator impacts, and simultaneously increase bottom-up nutrient enrichment via the nutrient pulse from dead biomass. What are the immediate and long-term consequences of such a rapid and drastic re-shuffling on ecological dynamics? Addressing this question has historically been challenging because they are by definition rare events, MMEs can be intractable or unethical to experimentally investigate, and existing observational data are not well suited to understand their ecological consequences. 

Collaborators: Simon TyeStephanie CarlsonJean Philippe Gibert, Andrew Rypel, Adam Siepielski



Samuel Fey
Biology Department
Reed College
3203 SE Woodstock Blvd.
Portland, OR 97202-8199


Phone: 860-573-8838

CV (Feb 2024, as pdf)

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