2025 SURES Fellowship Projects

Paulo Brand0, Understanding the role of starch reserves in xylogenesis and growth of tropical trees

Description: Wood biomass is the largest long-term carbon sink in tropical forests. Larger carbon allocation to wood increases the duration carbon remains in the biosphere. Thus, wood formation plays a crucial role in climate change mitigation by regulating the time and quantity of carbon stored in the biosphere. Non-structural carbohydrates (NSC) stored in wood provide energy and carbon reserves for wood formation. For some tropical species, growth never ceases, and NSC reserves, primarily in starch form, become essential for maintaining growth functions when photosynthesis is limited by environmental factors.

Nevertheless, the dynamics of starch reserves during xylogenesis remain poorly understood. Before starch can be used to build new tissues, it must first be converted into soluble sugars such as glucose, fructose, or sucrose. These sugars not only provide energy and carbon but also act as osmolytes, increasing turgor pressure, which is fundamental for enlarging wood cells during xylogenesis. Examining starch dynamics during xylogenesis will enhance our ability to predict growth patterns, including cell production, enlargement, and growth duration in tropical trees with diverse wood anatomical traits. This understanding will contribute to modeling the dynamics of wood formation, identifying growth resilience of tropical trees to environmental changes, quantifying carbon sequestration, and providing data-driven tools for improved forest management.
 
This project aims to address this knowledge gap by quantifying growth and starch dynamics in the stem wood of tropical trees from two contrasting ecosystems: a seasonally dry forest in Brazil (Tanguro) and a hyper-humid ever-wet forest in Colombia. The student will develop expertise in histological techniques to quantify xylogenesis, starch, and wood anatomical traits, applying these methods to characterize starch and growth dynamics in mature trees. Existing histological images stained with Lugol’s iodine, taken during wet and dry seasons in the Tanguro forest, will be leveraged for analysis. Additionally, the student will collaborate with researchers to collect samples and create new histological images from the ever-wet forest in Colombia.
 
This work will contribute to ongoing projects in Brazil and Colombia that have investigated carbon allocation processes, providing a rich dataset to integrate into the projects. By joining this interdisciplinary research team, the student will gain insights into tree ecophysiology and forest ecology. They will visit Yale University for two weeks, enhancing their presentation and writing skills while fostering international collaboration.
 

Location: Colombia and New Haven, CT

Indy Burke, Understanding radiation use efficiency along a latitudinal gradient in the Western Great Plains of the U.S.

Description: We are looking for an enthusiastic student to join the Burke/Lauenroth lab for a summer of field work studying dryland ecology in the beautiful western Great Plains of the U.S.
 
Drylands, covering 41% of Earth’s terrestrial surface, are essential for food security, livestock forage, and carbon storage. These fragile ecosystems are highly sensitive to rising temperatures and declining precipitation caused by climate change. This project offers a rare opportunity to contribute to research exploring how plant communities in drylands respond to these challenges. Aboveground net primary production (ANPP), a key measure of ecosystem productivity, drives forage availability, wildlife migration, and carbon cycling. While much is known about ANPP trends, the role of radiation use efficiency (RUE)—how effectively plants convert sunlight into biomass—remains understudied, despite its importance in estimating ANPP. Even less understood is how photosynthetic pathways (C3, C4, CAM) influence RUE. To understand RUE, we must first estimate ANPP.
 
As part of this project, you’ll assist a master’s student with plant biomass collection to estimate ANPP. Biomass will be gathered from sites along a latitudinal gradient in the western Great Plains, spanning from Marfa, Texas, to Malta, Montana. This gradient encompasses diverse climates and plant communities, from C3-dominated northern sites with cool mean annual temperatures (2°C) to C4-dominated southern sites with warm mean annual temperatures (25°C). Meanwhile, precipitation remains relatively constant at about 350mm. This gradient provides a natural experiment to understand how plant composition affects RUE and ANPP—key to improving predictions of grassland productivity as drylands evolve under climate change.
 
This project is a unique opportunity to gain hands-on, real-world experience in ecosystem ecology while exploring beautiful native grasslands. The student will learn techniques in plant ecology such as identifying plant functional groups and collecting biomass, all while experiencing the diversity of these ecosystems and spending long days outside in the picturesque landscapes of the American West. This is an excellent experience for any student looking to build research skills, learn fieldwork techniques, and enhance their understanding of plant ecology, climate science, and data collection. The student will also have an opportunity to design and conduct their own research, relating to the project’s goals. We encourage anyone who is interested in dryland ecology or environmental science, and eager to collaborate with Yale researchers, to apply. Fieldwork will involve long hours in dynamic weather conditions and extended travel between sites. We are excited to read your application!
 

Locations: Central Grasslands of the U.S. from Texas to Montana

Jenn Coughlan, Causes of low seed production in a group of monkeyflowers

Description: Seeds and flowers are key evolutionary innovations in plants. While seeds protect and nurture the embryo, flowers allow the efficient transfer of pollen. Humans, too, have benefited from these two innovations. For millennia, seeds and flowers have been the target of domestication efforts to source food, ornaments, and many other goods. Processes affecting the production of seeds might also hold the keys to the origin and persistence of species. When a flower is pollinated, pollen must embark on a long, complex journey through the floral tissues to deliver their sperm cells to the ovaries and fertilize the eggs. This process might yield few seeds, or no seeds at all, if both the pollen and egg donors have divergent evolutionary histories. In other words, the interaction between pollen and pistils – the floral structure that contains the ovaries – can prevent interbreeding from happening. Since plants have little control over the type of pollen grains that land on their flowers, pollen-pistil interactions are particularly important for gatekeeping reproduction when a species co-occurs with closely related species or genetically-modified cultivars. Despite their crucial role in reproduction, we know little about the mechanisms by which plants discriminate against different pollen donors during fertilization. For instance, pollen grains might fail either to attach to the stigma – the receptive tip of the pistil – or to pull resources to grow a pollen tube. Similarly, pollen tubes might be arrested while growing through the style – the structure that connects stigma and ovaries – or fail to penetrate the ovaries upon reaching them. This proposal seeks to characterize the mechanisms behind low seed production in monkeyflowers. We are tapping into an unprecedented crossing experiment involving 16 species to inform the selection of species pairs that exhibit dramatic differences in seed production. Using in vivo pollen tube imaging techniques, we aim to visualize the journey of the pollen tube throughout the pistil. By contrasting the observations of pollen tubes in crosses that produce normal seed sets and crosses that produce reduced seed sets, we aim to pinpoint the mechanisms behind reproductive failure. The SURES student will work in the greenhouse and laboratory crossing plants, counting seeds, dissecting flowers, and observing pollen tubes in the microscopy. They will also be trained in speciation theory and statistical analysis. The results of this project will shed light into the mechanisms of plant speciation and unveil new targets for plant breeders tackling plant reproduction issues.

Location: New Haven, CT

Marlyse Duguid, Forests under threat: evaluating the impacts and responses of Connecticut’s forests to canopy loss from “invasive species”

Description: The introduction of non-native pests and pathogens has resulted in significant ecological, economic, and cultural impacts across the world. The northeastern United States is a hotspot for invasive species and our forests are projected to continually be impacted by novel invasive organisms. This study examines how canopy loss from two recent novel forest pests in Connecticut is impacting ecosystem structure and function in Connecticut. 

The invasion of North America by Emerald ash borer (EAB, Agrilus planipennis) has caused widespread canopy losses and death of trees across the continent. With close to 100% Ash mortality since first detected in Connecticut in 2012, EAB has fundamentally changed the forests of Connecticut. Beech leaf disease (BLD) is a rapidly spreading, nematode vectored disease, causing progressive canopy decline to beech (Fagus spp.) trees. First detected in 2020 in New Haven, the urban canopy has rapidly declined over the past four years because of this invasion. This loss will have substantial ecological, economic, and social impacts, including changes in forest structure, species composition, and diversity as well as disrupting forest dynamics and successional processes. Significant knowledge gaps regarding how canopy loss from both of these novel pests affects both rural and urban forests in the Northeast. 
 
We have established a network of permanent long-term plots across a rural to urban gradient in collaboration with CAES, CT DEEP, and the City of New Haven to monitor the impacts of these invasions on the present and future forests. These studies track the long-term vegetation response following canopy loss as well as ecosystem function. These data can provide important insights on forest resiliency and can inform management and restoration strategies to natural resource managers to promote diverse and resilient forests following invasion. 
 
Duties: The intern will work on all aspects of data collection including finding plots, vegetation surveys, collecting soil samples, and data entry. There may be opportunities for some soil sample processing and data analysis depending on interest and timing.
 
Note: This internship takes place predominantly outdoors, in urban and rural forests across Connecticut. It is based in New Haven with daily travel to field sites. Candidates should be comfortable walking over uneven terrain and should be comfortable being outdoors for extended periods of time including in adverse weather conditions (heat, rain, etc.). The ideal candidate will be organized, adaptable, and have an interest in forest science and/or ecological fieldwork. 
 

Location: Connecticut

Vanessa Ezenwa, Causes and consequences of within-host pathogen interactions

Description: Most organisms (i.e., hosts) are simultaneously infected with multiple pathogens at the same time. These co-occurring pathogens can interact in ways that affect disease outcomes, including altering the severity of an individual host’s infection or changing the rate of disease spread through an entire host population. One important way that pathogens interact is through the host immune system, where one pathogen can enhance or suppress host immunity to another resulting in a decrease (competition) or increase (facilitation) in the abundance or impact of the second pathogen. However, emerging work in wild animals suggests that immune-mediated interactions between pathogens are highly context dependent. For example, facilitation via immunosuppression may only manifest under stressful environmental conditions (e.g., drought), in particular individuals (e.g., resistant genotypes), or during specific life stages (e.g., pregnancy). This project will investigate the context-dependency of immune-mediated pathogen interactions in a wild African buffalo population where a range of pathogen interactions have been described and examine if this context-dependency can help explain variation in disease outcomes. 

Skills and experience: The project will introduce the student to the literature on ecological immunology and methods used to quantify immune function in non-model species. The student will also gain skills in data management and statistical analysis. 
 
Mentorship: The student will be mentored by Dr. Vanessa Ezenwa and a postdoctoral researcher. The mentoring team will meet weekly with the student.
 

Location: New Haven, CT

William Lauenroth, Understanding the effects of livestock grazing on above-ground primary production in big sagebrush dominated ecosystems

Description: Are you looking for research experience in one of the most beautiful regions of the North American West? Join our team as we investigate how livestock grazing and climate change shape dryland ecosystems in Wyoming’s Upper Green River Basin in the shadow of the Wind River Mountain range. This project focuses on big sagebrush-dominated landscapes, where we aim to understand the complex interactions between grazing pressures, plant communities, and the changing climate. Livestock grazing is one of the most widespread land uses on Earth, covering 54% of the planet’s terrestrial surface, with the majority occurring in drylands. As global demand for meat and animal products continues to rise, the scale and intensity of grazing are expected to grow, putting even more pressure on fragile ecosystems. Drylands, already sensitive to changes in water availability and temperature, face significant challenges from both grazing and climate change. Our research centers on above-ground net primary production (ANPP), which is a critical measure of ecosystem health, forage availability for livestock, and carbon cycling. Despite its ecological and socioeconomic importance, there’s no clear consensus on how grazing affects ANPP and related aspects of plant communities, such as cover, species composition, and abundance. As part of our team, you’ll help collect data across 17 field sites, studying ANPP, plant community composition, soil texture, and grazing intensity. Your work will contribute to understanding how grazing impacts these ecosystems and inform sustainable land management practices. You’ll also have the opportunity to design your own project, addressing a research question related to the study’s goals.

This position is ideal for students eager to gain valuable experience in field-based ecological research. You’ll spend extended periods outdoors exploring some of the most stunning landscapes in the country. Beyond research, this experience will provide a chance to live and work with a diverse team of young scientists, fostering collaboration and learning in a real-world setting. If you’re curious about ecosystem ecology, passionate about environmental science, and ready for an adventure in the field, we encourage you to apply. This is a unique opportunity to build your skills, contribute to important research, and make meaningful connections with Yale scientists.
 

Location: Pinedale, Wyoming 

William Lauenroth, Restoring vital ecosystems in the heart of Wyoming’s sagebrush steppe

Description: Join an exciting research project that tackles one of today’s most pressing environmental challenges: restoring ecosystems impacted by oil and gas development. Our study focuses on the recovery of aboveground net primary production (ANPP) and plant functional type composition on restored oil and gas well pads in the dryland ecosystems of the Upper Green River Basin in Wyoming.

Drylands, comprising 40% of global terrestrial areas, are particularly sensitive to anthropogenic activities such as oil and gas extraction. By examining grasses, forbs, shrubs, and their contributions to ecosystem function, this project will shed light on how restoration efforts can help reclaim the resilience of these landscapes.
Using a combination of fieldwork and remote sensing technology, we will evaluate recovery patterns over time. This work will not only measure how restored well pads compare to areas which have not been affected by oil and gas development, but also explore how factors like precipitation and soil texture influence recovery. The insights gained will have implications for carbon sequestration, soil stability, and ecosystem resilience—key components in combating climate change.
 
Why You Should Join:
●        Engage in Fieldwork: Immerse yourself in the stunning sagebrush steppe while collecting ecological data and gaining important field experience.
●        Learn Remote Sensing Techniques: Gain skills in advanced data analysis to monitor vegetation changes across restored landscapes.
●        Impactful Research: Contribute to understanding the effectiveness of restoration strategies in one of the most iconic dryland ecosystems in the United States.
●        Be Part of the Solution: Your efforts will inform future restoration practices, ensuring the health and productivity of dryland ecosystems.
 
Project Highlights:
●        Location: The Jonah Field in Wyoming’s Upper Green River Basin, with well pads of different construction years
●        Scope: Assess long-term recovery across a chronosequence of restored well pads to provide actionable insights for land management.
●        Skill Development: Build expertise in ecological data collection, analysis, and interpretation while working alongside a dedicated team of researchers.
 
Budget Support:
We’ve got you covered! The research budget includes funding for travel, lodging, field equipment, and lab processing costs to ensure you can focus on the science.
 
Don’t miss this opportunity to explore the wild landscapes of Wyoming, develop hands-on ecological expertise, and make a difference in restoring dryland ecosystems. Apply now to become part of this project and kickstart your journey in environmental research!
 

Location: Pinedale, Wyoming 

Jennifer Marlon, Improving flood mapping in Connecticut using LiDAR data

Description: The Yale Center for Geospatial Solutions (YCGS) invites an enthusiastic undergraduate student to join a summer research project focused on enhancing flood mapping and risk assessment in Connecticut using the state’s newly released high-resolution LiDAR dataset. This project is part of a broader effort to apply cutting-edge geospatial technologies to address pressing environmental challenges such as climate resilience, disaster preparedness, and urban sustainability.

The student will analyze LiDAR data to create detailed maps of flood-prone areas, model water flow pathways, and identify vulnerable infrastructure. By combining LiDAR-derived elevation data with other geospatial datasets—such as satellite imagery, precipitation patterns, and land use information—the student will contribute to developing more accurate and actionable flood risk assessments. This research has direct applications for improving Connecticut’s climate resilience, helping communities prepare for extreme weather events, and guiding the design of flood mitigation strategies. A unique aspect of this project involves fieldwork to validate the LiDAR-based models. The student will conduct ground-truthing surveys in the New Haven area, measuring terrain features, drainage patterns, and flood control infrastructure to ensure the accuracy of their analysis. This hands-on experience will provide invaluable training in integrating remote sensing data with real-world environmental observations.
 
Throughout the 8-week internship, the student will work closely with YCGS faculty, PhD students, and research staff. They will gain hands-on experience using advanced geospatial tools such as QGIS and Google Earth Engine, and Python-based libraries for data processing and analysis. The project also emphasizes skill development in LiDAR data processing, hydrological modeling, and spatial analysis, providing the student with technical expertise highly sought after in environmental science and geospatial research.
 
By the end of the summer, the student will have developed valuable research and technical skills, gained experience in field validation techniques, and contributed to meaningful research addressing real-world environmental challenges. This internship offers a unique opportunity to work in a collaborative research environment, apply geospatial technologies to pressing climate issues, and make a tangible impact on flood resilience in Connecticut.
 

Locations: Connecticut

Martha Muñoz, Discovering the physiological diversity of Caribbean rain frogs

Description: Ongoing climate change presents an existential threat to biodiversity, but these threats are especially pronounced in amphibians (e.g., frogs and salamanders). As wet-skinned ectotherms, amphibians are highly vulnerable to changes in both temperature and moisture. Rain frogs (Genus Eleutherodactylus) are highly diverse, with dozens of endemic species found across the Caribbean. Yet, we know very little about the natural history and ecophysiology of these species, which are critical pieces of information needed for forecasting the vulnerability of these frogs under global change. The YIBS SURES student(s) will participate in an ongoing research project on the ecology and evolution of Eleutherodactylus frogs. First, students will join an expedition to the Dominican Republic where they will participate in field work on these frogs. They will collect ecological, behavioral, and environmental data while working in several natural preserves across the country. They will assist with physiological assays on the frogs, including estimation of water loss rates, metabolic rates, and heat tolerance. Then, they will come back to the lab at Yale, where they will learn how to extract and sequence DNA so that a phylogenetic tree for the Eleutherodactylus frogs can be built. Students will learn how to perform phylogenetic analyses. Through this project, the students will develop field, laboratory, analytical, and programming skills.

Locations: Dominican Republic and New Haven, CT

Lidya Tarhan, Investigating environmental patterns in marine bioturbation

Description: Bioturbating marine animals (animals that inhabit, burrow in and mix seafloor sediments) are powerful ecosystem engineers. Their activities shape the physical and chemical composition of seafloor sediments, the ecology of seafloor communities, and global marine biogeochemical cycling. Despite their importance, however, major questions remain regarding both drivers of modern bioturbation and the factors underlying major changes in bioturbation behaviors and intensities over the last 540 million years of Earth’s history. Untangling relationships between bioturbation and climate, nutrient cycling, community composition, and ocean chemistry in ancient and modern settings is crucial both for reconstructing the evolutionary history of bioturbating animals and for forecasting their responses to anthropogenic climate change. The Tarhan Geobiology Lab seeks a motivated, curious undergraduate student to assist with several bioturbation-related projects ongoing in our lab, including an investigation of Zoophycos, a complex, enigmatic burrow whose appearance in the fossil record may be associated with past changes in ocean chemistry and nutrient cycling; an exploration of spatial, environmental and geologic trends in trace fossil preservation; and assessment of the intensity and variability of bioturbation on the modern deep seafloor (using samples recently collected from an Atlantic Ocean shipboard research expedition). We also anticipate opportunities for the student to pursue additional research questions arising from these projects. As part of this fellowship, the student will develop skills in field geology and paleontology (including stratigraphic logging and recognition of trace fossils and fossilized bioturbated sediments in geologic outcrops), collection and interpretation of geochemical data, database construction, and statistical analysis of paleontological data. The student should be prepared to spend approximately one week working outdoors (and tent camping) during fieldwork in the Hudson Valley for the Zoophycos project, but no prior field or camping experience is required, and all field gear will be provided by the Tarhan Geobiology Lab. The additional seven weeks of the fellowship will take place in New Haven and be based in Yale’s Department of Earth and Planetary Sciences.

Locations: New Haven, CT and Hudson Valley, NY

David Vasseur, How does temperature variability impact extinction risk in ectotherms?

Description: Forecasting the risk of warming and temperature variability on species is of paramount importance. Recent work in my lab has developed a new measure of extinction risk that uses thermal performance curves (relationships between ambient temperature and fitness or a fitness proxy) to determine two key quantities that regulate extinction risk: the mean population growth rate and the variance of population growth rate. For any species that has a documented thermal performance curve, we can use this measure to assess its likelihood of extinction in current, historical, or future environments. Last summer, we piloted an experiment to test these ideas – with great success. This year, we plan to conduct a more detailed and rigorous test of our theory.  

YIBS SURES students will take a central role in two key projects. The first project will use laboratory experiments to assess the utility of this extinction risk measure. Briefly, we will grow replicate populations of aquatic microbes across a range of different temperatures and subject them to different amounts of thermal variation. We will track population dynamics through time by sampling populations (using standard cell counting techniques and using flow cytometry/automated particle counting). We will compare observed extinctions to our forecasted measure of risk to validate its utility. In a second project, we will use thermal performance curves from the literature to construct the Hutchinsonian niche in two dimensions: mean temperature and variance (temporal) of temperature. This second dimension will represent new information and allow us to perform a meta-analysis focusing on how the shape of the Hutchinsonian niche varies at a macro-ecological scale.  
 

Location: New Haven, CT

Michelle Wong, Digging belowground: measuring the quantity and composition of root exudates in northeastern temperate forests

Description: Forests play a critical role in the global carbon cycle by sequestering approximately one-third of anthropogenic carbon emissions from fossil fuels and land-use change annually. However, global change drivers – such as rising atmospheric carbon dioxide levels and warming – may be altering the carbon cycle balance in many northeastern forests. Specifically, indirect evidence suggests that more carbon is moving through plant roots and into soils as root exudates, potentially leading to soil carbon losses through increased microbial activity. The quantity of root exudates released by plants remains the largest unknown carbon flux in forests, and it is unclear what factors control the flux and the composition of root exudates. To address this large knowledge gap, the undergraduate student will have the opportunity to participate in a multi-week field campaign at Hubbard Brook Experimental Forest in New Hampshire with a larger team. This includes identifying trees across the watersheds at Hubbard Brook, tracing plant roots, quantifying fine root biomass, and collecting and measuring root exudates. In summary, the undergraduate fellow will be able to carve out their research question of interest; learn lab, field, and project management skills; conduct data analysis; and collaborate with a larger team consisting of at least two PIs (Michelle Wong and Angela Possinger) and a postgraduate associate. The student will be based at the Hubbard Brook Experimental Forest, a research station administered by the USDA Forest Service. Living and conducting research at Hubbard Brook, located in the beautiful White Mountains, will provide many enriching and fun opportunities to interact with many students and scientists working on different ecological questions. 

Location: Woodstock, NH and New Haven, CT

How to apply

The application process for 2025 is now closed. Applications were due no later than February 13th, 2025 at 11:59 PM (Eastern). For any questions or concerns regarding the application process contact yuji.torikai@yale.edu