Current Recipients of the Graduate Student Fellowship

The Philomathia Graduate Fellowship in the Environmental Sciences provides fellowships for graduate students studying issues related to the environment at UC Berkeley. Students are nominated to receive the award on the basis of their high level of academic distinction and exceptional promise.

2020 - 2021 Recipients

Nicolas AlexandreNicolas Alexandre
Integrative Biology
Ph.D. Candidate

Nicolas' research focuses on linking phenotypic variation with genotypic variation and fitness within species for complex, quantitative traits. Through fine-mapping of natural genome-wide variation, he is localizing putatively causal loci segregating as polymorphisms that underlie phenotypic variation for bill shape which can be subsequently tested for signals of selection. The bills of hummingbirds represent an excellent model for studying adaptive evolution in quantitative traits given their widespread distribution, feasible collection, and recently available genomic resources. To understand how genomic architecture of complex traits evolves in nature, he is implementing a combination of genome-wide association studies, niche modelling, pollen metabarcoding, functional experiments, and phylogenetic analyses to understand the link between evolution of complex traits within and between species.

 


Mallory BallingerMallory Ballinger
Integrative Biology & Museum of Vertebrate Zoology
Ph.D. Candidate

Understanding how organisms adapt to their environment is a major goal in evolutionary biology. Mallory’s research aims to identify the factors underlying environmental adaptation by integrating evolutionary analyses of DNA sequence variation with experimental studies of whole-animal physiology. Currently, she is studying small mammal populations that inhabit temperate and tropical environments across North and South America. Through the integration of population and comparative genomics, functional genomics, and whole-animal physiology, Mallory’s research ultimately aims to determine how small mammals colonize new environments and the signatures of subsequent adaptation to those new environments. For more information about Mallory’s research, visit her website here.

 


Stephano Cestellos-BlancoStefano Cestellos-Blanco
Material Science Engineering
Ph.D. Candidate

Modern society is entirely reliant on accessible sources of ammonia (NH 3 ) as a fertilizer to meet agricultural needs for an expanding world population. However, industrial production of ammonia relies on fossil fuels consuming up to 3% of global yearly energy and contributing to local environmental pollution. Stefano strives to combine biological N 2 -to-NH 3 enzymatic pathways within bacteria with light-active nanomaterials. The goal of his research is to power N 2 -fixing bacteria with energy harvested from sunlight by semiconducting nanostructured materials. Stefano employs a variety of electroactive bacteria in his research while fabricating and synthesizing biocompatible nanomaterials.

 


Jackie ChildersJACKIE CHILDERS
Museum of Vertebrate Zoology
Ph.D. Candidate

Jackie’s research focuses on understanding the processes that underlie species diversification and phenotypic evolution by integrating analysis of character trait data with phylogenetic approaches. For her dissertation she is studying the Weavers (family Ploceidae), an Old World radiation of sparrow-like birds distributed throughout sub-Saharan Africa and Southeast Asia. The 117 species that comprise the family exhibit marked variation in plumage color, bill morphology, sociality and mating systems, and are best known for their elaborately designed nests. The primary goals of her research are to characterize the nest diversity across species, identify the selective forces that have influenced nest design throughout the family, and investigate molecular patterns of evolution using whole genomes. As part of this work Jackie has collected morphological data from museum specimens and their nests by working in natural history collections in both the U.S. and Europe. On campus, with the help of her undergraduate research assistants, she combines this data with DNA sequence data in order to address the broader goals of her research.  

 


Natalie GrahamNatalie Graham
Environmental Sciences, Policy and Management
Ph.D. Candidate

Understanding how biodiversity might accommodate, resist, or collapse in response to pressures of global change is critical for the future health of the planet. What properties make a biological community more resilient or more susceptible to sudden change? Are changes integrated or rejected in predictable ways? Natalie’s research aim is to simplify the complexity of biodiversity dynamics by assessing metrics of stability in arthropod communities across the Hawaiian archipelago, using the age of the volcano, from about 50 years to 5 million years old, as a proxy for community complexity. Advances in next-generation sequencing allow her to rapidly asses species richness and abundance, incorporating tens of thousands of individual insects, spiders and other Arthropoda. Natalie then reconstructs ecological networks from biological interactions among herbivore-plant, predator-prey, parasitoid-host, using natural history information from the literature and associations of organisms in the field. Metrics based on the network structure, and how it changes over time, assist in forecasting how communities are adapting and responding to change.

 


Clarke KnightCLARKE KNIGHT
Environmental Sciences, Policy and Management
Ph.D. Candidate

Clarke’s doctoral research links basic tenets of forest carbon ecology to some of California’s most pressing environmental legislative goals. California is leading the international debate about the best way to manage forests to store carbon and mitigate climate change. Sustaining the State’s forests as reliable carbon sinks requires an understanding of the baseline carbon carrying capacity. The overarching goal of Clarke’s research is to understand the impacts of disturbance on forest carbon cycling and to develop a baseline of forest conditions for a high-priority landscape – Six Rivers National Forest in the Klamath Mountains. As a historical ecologist, she uses paleo-ecological data from fossil pollen records in lake sediments, witness tree data from public land surveys (conducted in the 1880s), and spatial interpolations from contemporary forest inventories to document long-term biomass trends in California. Clarke’s goal is to inform our understanding of the structure and function of forests before fire suppression and provide an opportunity to reassess assumptions about long-term forest carbon storage.

 


Ella VisherELLA VISHER
Integrative Biology
Ph.D. Candidate

Why specialists exist in the face of broad-niched generalists remains a central question for the biological sciences. At a fundamental level, this question underpins most of our theories for why there is so much genetic, phenotypic, and species diversity in nature. Elisa Visher’s work focuses on the nature of trade-offs to resistance and infectivity breadth in host-parasite systems and on the environmental factors that bias systems towards selecting for specialists or generalists. They primarily use experimental evolution techniques in the Plodia interpunctella (Indian meal moth) and baculovirus model system to explore the geometry of trade-offs with host resistance, the effects of spatial structure and host genetic diversity on parasite niche breadth evolution, and the factors driving the coevolution of diversification. For more information about Elisa's research, see their website.

 


Wenjing XuWENJING XU
Environmental Sciences, Policy and Management
Ph.D. Candidate

Wildlife migration carries important ecological functions and social values in many ecosystems, especially in arid and semi-arid rangeland. However, linear infrastructures such as fencing have proliferated around the world. Wenjing's search focuses on ecological responses and consequences of migratory pronghorn and mule deer to landscape fragmentation caused by fencing in the rangeland of the American West. Using GPS tracking data and remote sensing imagery, Wenjing quantifies animals' behavioral responses to linear barriers and examines the ecological consequences of such changes in animal movement and habitat use. Her study adds empirical insights to the emerging subdiscipline of fence ecology and offers direct guidance to conservation decisions that aim to maintain and improve landscape connectivity.