Gaylord Donnelley Postdoctoral Associates

Natasha Picciani, Ph.D.

Research description: Natasha is an evolutionary biologist interested in understanding how organismal diversity evolves and the mechanisms that can constrain or facilitate complex evolutionary outcomes across species. At Yale she will focus on understanding the mechanisms that drive the evolution of complex life cycles using the polyp and jellyfish life stages of cnidarians. The goal of her work is to better understand the relationship between jellyfish reduction and polyp specialization and investigate whether disruption of cell differentiation can serve as a developmental mechanism underlying the loss of complexity. The loss of complexity in one phase of a life cycle is often associated with an increase in another phase of the life cycle. Overall, her work investigates the dynamics of evolutionary constraints, how these shape changes in organismal complexity, and the developmental basis of those changes.

Fellowship dates: December 2020 – February 2023


Erynn Johnson

Erynn Johnson, Ph.D.

Research description: Erynn uses interdisciplinary approaches and biomechanical experimentation to understand how predation pressures shaped the evolution of mollusk shells over deep time. She utilizes mathematical modeling, 3D printing, and computer-automated design to test the form and function of modern, extinct, and theoretical morphologies. These tests are used to isolate and analyze how different aspects of mollusk shell morphology contribute to shell strength. Studying key intervals of ecological change in the fossil record allows us to understand how predators have influenced their prey over long periods of time, providing potential insights to the long-term impacts of human activities on marine ecosystems.

Fellowship dates: July 2021 – June 2023


Maya Stokes, Ph.D.

Research description: Maya works at the intersection of Life and Earth sciences to understand how changes to Earth’s surface over geologic timescales influence the distribution and evolution of life. Maya uses computational models as well as geologic and genomic datasets to integrate disparate disciplines. Her graduate training was in geomorphology with a focus on “river capture”, an abrupt change in flow direction when one river segment forges a new connection with a channel in another basin. Geomorphic processes, like river capture, are hypothesized to influence the evolution of aquatic organisms, yet testing such hypotheses requires the integration of geologic and genomic data. At Yale, she will be investigating how river incision has shaped the landscape of the Appalachian Mountains as well as the evolution of the aquatic taxa in the region. She is broadly interested in understanding the ways in which tectonic, climatic and geomorphic processes influence the evolution of life.

Fellowship dates: August 2021 – July 2023

Catherine Hernandez

Catherine Hernandez, Ph.D.

Research description: Catherine Hernandez is generally interested in how environmental change will alter microbial interactions. Just like in macroorganisms, microorganismal physiology and fitness are impacted by abiotic factors, and their ecology and evolution will be shaped by global change. At Yale, Catherine will be particularly focused on how temperature impacts the interactions between environmental bacteria and the bacteriophage (phage) viruses that infect them. Catherine will be using observational and experimental evolution approaches to study geographic patterns of thermal responses, the relationship between viral host range and thermal performance, and how virus populations adapt to changing temperatures. These results will provide insight into how temperature can alter microbial community composition, trait evolution, and the structure of microbial networks. Given the important role of phages in structuring microbial communities, this work has implications for predictions of climate change impacts on microbially-mediated ecosystem processes like nutrient cycling.

Fellowship dates: September 2021 – August 2023

Karen Chen

Karen Chen, Ph.D.

Research description: Karen Chen is a quantitative geographer studying how urban land cover and form change over time and their impacts on human well-being. Working with Prof. Karen Seto, she will use the synergy of deep learning, remote sensing, and Geographic Information Systems to characterize the 3-D built environment and urbanization in the Global South.

Fellowship dates: September 2021 – August 2023

Armita Manafzadeh

Armita Manafzadeh, Ph.D.

Research description: Armita is interested in the evolution and development of vertebrate animal form and function. She integrates approaches from biomechanics, paleontology, computer animation, and experimental biology to better understand how synovial joints (like hips and knees) work. At Yale, Armita will be exploring how her research can interface with ecology by studying ecomorphological diversification through a joint-focused lens.

Fellowship dates: July 2022 – June 2024

Nohemi Huanca-Nunez

Nohemi Huanca-Nuñez, Ph.D.

Research description: Nohemi’s research focuses on plant ecology, plant-animal interactions, and the understanding of mechanisms driving species diversity, distribution, and forest regeneration after natural and human disturbances. At Yale, Nohemi will be focused on the interaction between above-ground and below-ground functionality and the role of root traits in shaping composition in tree communities recovering from human disturbance.

Fellowship dates: August 2022 – July 2024

Cesar Martinez-Alvarez

Cesar Martinez-Alvarez, Ph.D.

Research description: Cesar is an environmental social scientist interested in combining quantitative methods and qualitative sources to understand the political economy of deforestation. His doctoral research employs satellite imagery, administrative data, archival sources, and quasi-experimental empirical designs to study the drivers of community-based ecosystems stewardship in Mexico. He also studies the politics of governmental climate action in a comparative perspective, particularly surrounding fossil fuels subsidies.

Fellowship dates: August 2022 – July 2024

Sina Rometsch

Sina Rometsch, Ph.D.

Research description: Sina is interested in understanding the dynamics of reproductive isolation in adaptive radiations. At YIBS, her research will focus on elucidating the environmental drivers of speciation in a radiation of anole lizards from the island of Hispaniola. Connecting species’ ecology with population genomic, behavioral and developmental approaches, she aims at determining how environmental gradients affect population divergence and the progression towards complete reproductive isolation.

Fellowship dates: November 2022 – October 2024