Cary Institute of Ecosystem Studies, Inc.

NSF Awards · FY 2026 · 2026-06

Lyme disease is one of the most frequently reported infectious diseases in the United States. The bacteria that cause Lyme disease are transmitted by ticks to people, causing serious illness. The goal of this project is to synthesize 35 years of research to address both scientific theory of infectious diseases and to improve prediction and management of this disease. Lyme disease has become a model for understanding emerging diseases in the USA and worldwide. However, Lyme disease is a complex illness that involves interactions between ticks, bacteria, wildlife, forests, weather, suburbia, and people. Preventing this and related diseases requires improved understanding of where and when people are at greatest risk. Many ticks are infected with several pathogens, increasing human exposure to other infectious diseases. This project advances NSF’s priorities in biotechnology by providing a framework for decision making on modeling, prevention, and management of a complex and critical disease impacting human health and wildlife. A 35-year study of Lyme disease ecology has revealed surprising results inconsistent either with population theory and with expectations from shorter-term studies. For example, (1) despite deer being considered the main reproductive host for blacklegged ticks, long-term data show no effect of deer on densities of ticks, whereas the effect of rodents is considerably stronger. (2) Although white-footed mice are the most efficient host in transmitting zoonotic infections to ticks, the effect of mouse density on infection prevalence for any pathogen is not detectable. (3) Life history theory predicts demographic forcing between consecutive life stages. Yet, contrary to expectations, the abundance of larval ticks in one year does not predict the number of nymphs the following year. (4) The body burden of larval and nymphal ticks on rodents declines as the population density of those hosts increases. (5) Weak effects of summer or winter temperature extremes on tick abundance contradict the prediction that cold or hot extremes cause excess mortality and regulate tick populations in nature. (6) The observed stability in tick infection prevalence is inconsistent with theory suggesting that this system should show a positive feedback loop between infection of ticks and infection of hosts. A review of long-term studies will explore each of the surprises in light of paradigms that arose in the 20th century. Replacement of these paradigms is central to prediction and management of Lyme disease risk. The review will facilitate further research into the ecological systems that support growing incidence of zoonotic diseases. Improved power to predict ecological causes of variable human disease risk expands both the realized and perceived utility of ecology for human health. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-09

Many headwater streams have mosses present, yet these plants are rarely included in current conceptual models of stream ecology. Bryophytes, including mosses, liverworts, and hornworts, are common in small streams where they can provide critical habitat for other aquatic organisms, and store large quantities of carbon, nitrogen, and phosphorus. This project will study the role of stream bryophytes as hotspots of freshwater biodiversity and nutrient cycling, with a particular focus on how bryophyte presence in small streams may have large impacts on water quality downstream. The project supports fifteen or more early career researchers across all career stages and multiple institutions. The research team will disseminate findings to broader audiences at conferences, local homeowners’ meetings, and field trips, and is partnering with the Hubbard Brook Research Foundation and a local school to develop environmental science curricula (5th-12th grades) that enable young students to examine and study mosses in nature. The research uses three complementary approaches to evaluate how and where aquatic bryophytes contribute to the structure and function of headwater stream ecosystems. First, researchers will experimentally remove bryophytes from two stream segments within the Hubbard Brook Experimental Forest (New Hampshire) to directly measure the impact of bryophytes on nutrient uptake, organic matter storage, and in-stream biodiversity. Second, the research team will conduct a regional survey of moss abundance and freshwater biodiversity across 50 headwater streams across the White Mountains National Forest that vary widely in stream pH. Results from both experimental and survey efforts will be used to parameterize a stream network model to estimate the effects of bryophytes on nutrient dynamics at river network scales and to predict the impact of bryophyte loss on river nutrient cycling. The project will inform our understanding of how bryophytes support freshwater biodiversity by providing flow and drought refugia and enhance stream nutrient cycling through their high surface area and capacity to trap and sequester materials. By initiating new, long-term records of moss cover at Hubbard Brook, this effort will inform our understanding of how droughts, extreme floods, and river ice affect moss cover over time. In addition to training of postdoctoral researchers and undergraduate students, and outreach to grade school students, this project will enhance understanding of processes that maintain clean freshwater streams, an essential and limited resource for U.S. citizens. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-04

Lyme disease is one of the most frequently reported infectious diseases in the United States, with roughly 500,000 new cases each year. Risk of exposure to Lyme disease and associated tick-borne diseases varies dramatically from place to place and from year to year. Research that determines what causes this variation is critical in preventing and managing these diseases. The ticks that transmit these diseases to people feed on many different animal species, but rodents like white-footed mice and chipmunks are the most important in boosting tick numbers and tick infection. Numbers of these rodents, in turn, depend on the supply of acorns and other tree seeds. Weather and climate affect the trees, the rodents, and the ticks directly. This research is designed to improve the ability to predict Lyme disease risk, which can have major implications for human health. It asks how each stage in the complex life cycle of the tick responds to rodent numbers and to climate, how the rodents are affected by their predators, and how long-term changes in the forest, including the species and ages of the trees, affect the food supply for rodents and deer. The research will collect new data on numbers and survival of both on-host and off-host ticks in the larval, nymphal, and adult stages and integrate these into full models of tick population changes through time. It will ask how temperature and humidity on the forest floor affects survival of these life stages. It will continue adding to a 30-year data set asking how the production of seeds by forest trees changes as the climate and relative abundances of tree species change over time. The occurrence of predators such as bobcats, foxes, and coyotes will be monitored using camera traps to investigate possible impacts on rodents, ticks, pathogen prevalence, and Lyme disease risk. The data will be used to develop and evaluate forecasts for Lyme disease risk from the component parts. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2025 · 2025-03

The science of ecology is deeply concerned with how “patchiness” – the spatial patterns of plants, animals, microbes, and larger ecosystems – controls the composition, functioning, and sustainability of many ecological systems on which society depends. Individual research projects often use the concept of spatial patchiness as a jumping off point for data collection and modeling. However, it is important to discover how the ideas and data about spatial patchiness develop to help guide future research, shape the growth of ecological science, and facilitate the practical use of the resulting ecological information. This project integrates ecological theories and concepts into a broad synthesis. This is important because it provides an understanding of how synthesis has helped translate ecological knowledge for the public good. Additional broader impacts of the products focus on: 1) The relevance of applying science to urban design, urban planning, and conservation; 2) An improved ability to assess disturbance in social-ecological-technological systems given changing environments and changing human vulnerability; and 3) Support of ecological education and mentoring efforts and programs. Products will be broadly useful for public communication and education, and will include a multi-media collection of resources that will make the results of the synthesis as widely accessible as possible. This project aims to study how such a fundamental ecological concept as patchiness has progressed by synthesizing insights from an exemplary scientific career. The research will focus on how key concepts from community ecology, ecosystem ecology, and urban ecology can be integrated using the theory of patchiness, or heterogeneity, into a cross-disciplinary science of societal importance. The approach is journalistic and interview-based, where the Lead PI will be interviewed by the Co-PI. The synthesis is organized around five thematic modules extracted from the PI’s published record, with each module building on the previous ones while highlighting how new insights and understanding have emerged. This multi-decadal and multi-thematic exploration of the career accomplishments of the Lead PI will reveal cross-cutting approaches and strategies that are not apparent in the collection of individual products. In short, this project will demonstrate the deep intellectual value of emergent synthesis. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2024 · 2024-11

Wetlands are a critical habitat for carbon storage, as well as a potential source of greenhouse gas (carbon dioxide and methane) emissions. Little is known about how wetlands function, especially in the tropics. With changing climate, it is expected that tropical wetlands, especially seasonal ones, may shift between carbon consumption and release of carbon. Methane, which is a more powerful greenhouse gas than carbon dioxide, is typically produced under flooded conditions, although some evidence suggests that shifts between wet and dry conditions also lead to its release. Savannas (Cerrado) in Brazil have a range of grassland types including ever-wet peatlands, seasonally wet grasslands, and dry grasslands that are never flooded, with the seasonal wetlands shifting in water levels between dry and wet seasons. It is expected that these ecosystems will become hotter and drier in the future. Brazilian savannas have been understudied and under protected; they are also at risk of conversion for example to agribusiness and urban development. They are the source of the headwaters for river systems such as the Amazon, meaning they are important for providing clean water and other resources to the people and other organisms dependent on them. Understanding Brazilian savanna carbon dynamics now and under future environmental conditions is critical for the region. They can also be used as models to understand tropical savannas around the globe. This proposal makes use of the natural gradient, from ever-wet peatlands to dry grasslands, and seasonal shifts through time to collect data on the amount and frequency of greenhouse gases emitted today and the changing extents of wetlands seasonally. Researchers will use these data to predict how savannas may store and release carbon under future warming and drying climates. As part of this project, student biologists will be trained, including in classes on savanna field ecology and workshops on using field data to predict changes in greenhouse gas release in the future. Biologists and indigenous artists will also collaborate on artwork to demonstrate the importance of savanna systems for and to public audiences. This proposal will answer three questions: Q1. What are the drivers of spatial and temporal heterogeneity in carbon storage and flux across saturation gradients? Q2. How do saturation extents (areas and perimeters) in tropical grasslands change over seasonal and decadal scales? Q3. How will rates and forms of carbon emissions from tropical grasslands change under future climates? To test Q1, spatially distributed measurements will be coupled with high-temporal resolution measurements to understand greenhouse gas, soil, and vegetation carbon dynamics across the saturation gradient. Greenhouse gas variability will be measured spatially and temporally with chambers. Site changes through time will be determined by initial soil characterization, combined with seasonal measurements of plant phenology, stomatal conductance, porewater chemistry, environmental and groundwater measures. To test Q2, high resolution remote sensing and field reference data will be combined to map wetland extent seasonally. Carbon and lead isotope dating will be used to understand wetlands extent changes at decadal scales. To test Q3, data from Q1 and Q2 will be utilized in Earth system models. Estimates of carbon sequestration patterns and greenhouse gas emissions will be spatially simulated with projections of carbon balance changes and greenhouse gas with expected shifts in regional climate and hydrology. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2024 · 2024-08

Global changes are causing significant shifts in ecosystems worldwide by increasing environmental stress. Species that can withstand these changes are likely to thrive, while those less adaptable may decline. However, it is challenging to link strategies of individual species to community-level responses to global changes. This project explores the vertical layers of forests to test the role of competition and tolerance in community assembly. Abiotic stressors including temperature (3-6°C higher in the canopy), dryness, and microclimate variability increase from the forest floor to the canopy, all within just 20-30 meters of height. This project evaluates how differences in life history strategies, such as tolerance to stress, interactions with other species, and the capacity to colonize new habitats, play a role in community assembly and responses to environmental change. Additionally, this project will develop a curriculum module for secondary school students that aims to foster student involvement in science including the development of educational materials about the value of microbial diversity in nature. The project will develop a novel molecular tool and database for characterizing microbial taxa and traits across the life history strategies, which will be made widely accessible to scientists and practitioners. Finally, the project will support early career scientists by providing professional development and mentorship opportunities for a doctoral student, a research technician, and three seasonal field research assistants. This research will develop a model system – the vertical dimension of forests – to systematically test community assembly and life history tradeoffs of microbial communities across the vertical gradient in a Panamanian tropical rainforest. This will include (1) a multi-omic characterization of the functional and taxonomic diversity of soil communities along the vertical gradient, (2) an assessment of the communities dispersing via air, water, and detritus across the gradient, (3) a reciprocal transplant experiment to test abiotic and biotic controls of community assembly, and (4) a lab-based incubation to specifically evaluate the roles of heat and water stress in shaping community assembly. Finally, the project will (5) synthesize the results using a causal inference modeling approach to explicitly test the role of the competitiveness-to-tolerance tradeoff in shaping community assembly in response to abiotic stress. This project will make significant advances in our understanding of how abiotic stress influences community assembly. Most importantly, this work will test whether a tradeoff between tolerance and competitiveness determines the outcomes of community assembly across a gradient of abiotic stress. Beyond tolerance and competitiveness, the results from this work will provide the first detailed information about trends in dispersal along the vertical gradient and how they vary among different pathways of dispersal. This study will characterize the vertical dimension of microbial diversity in forest soils for the first time, providing insight into this major understudied dimension of global diversity and establishing a model system for testing principles of community assembly. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2024 · 2024-08

In the United States, blacklegged ticks are the main vectors of Lyme disease and several other diseases that afflict roughly 500,000 people each year. The abundance of these ticks is a major risk factor for human populations. Research that identifies the factors that regulate tick abundance is critical for predicting and managing human disease risk. Ticks are susceptible to high temperatures and low humidity at ground level, where they spend 95% of their lives. Spongy moth outbreaks occur roughly every ten years, can extend over large regions, and at high abundance can strip millions of (particularly oak) trees of their leaves, affecting conditions on the forest floor by removing shade, increasing temperatures, and decreasing humidity. This project is designed to ask whether defoliation by spongy moths causes changes in ground conditions that decrease survival and therefore population size of blacklegged ticks. The proposed research will evaluate the influence of humidity and temperature on tick survival and population growth at locations experiencing a range of spongy moth defoliation. The project will allow researchers to predict the impacts of current and future spongy moth outbreaks on risk of tick-borne diseases in nearby communities, facilitating interventions to protect public health. Post-baccalaureate Project Assistants will receive immersive training experiences that provide excellent preparation for research careers. The research involves the experimental deployment of all six stages in the life cycle of the blacklegged tick (i.e. engorged and unfed larvae, nymphs, and adults), in heavily defoliated, lightly defoliated, and experimentally shaded locations on each of six forest plots on the grounds of the Cary Institute of Ecosystem Studies. Known numbers of ticks will be placed in small soil-core enclosures and then enclosures will be removed at regular intervals to quantify mortality. Deploying all stages together with temperature and humidity data loggers inside soil-core enclosures, will allow the investigators to model the hazard of tick mortality as a function of abiotic conditions. Hazard of mortality for each life stage will then be integrated across life stages and abiotic conditions to inform a tick population matrix model and forecast tick-borne disease risk. Because other forest pests, disturbances, and climate change can have similar effects on conditions on the forest floor, the research will lead to a general understanding of what controls tick populations. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

NSF Awards · FY 2024 · 2024-07

This project seeks to understand how water and chemical elements move through ecosystems, and how these processes respond to environmental change. It continues a globally unique 60-year record of precipitation and stream chemistry for ten streams in the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire. This record shows the impacts of air pollution, climate change, and pests on forests, soils, and streams. It has been essential for recording the effects of pollution control laws and for developing and testing theories about how forested ecosystems work. The project will examine how these ecosystems are recovering from acid deposition, as well as how they are responding to new impacts, such as a changing climate. Data from the project are publicly available, and additional broader impacts include the training of undergraduate students through a summer REU. The project measures the chemistry of weekly precipitation and streamwater samples. Some of these watersheds have been subjected to whole-watershed manipulations such as experimental tree harvest, and all of the watersheds are experiencing long-term changes in acid deposition and climate. Chemical analyses include pH, conductivity, dissolved organic and inorganic carbon, major anions and cations, dissolved silica, and trace elements, among other measurements. Input and export fluxes of chemical elements are calculated for nine of the watersheds using precipitation and stream discharge data. The study design uses long-term observation of chemical fluxes through these ecosystems to test and refine theory about ecosystem processes and their responses to change. Key questions to be tested include, among others: 1) The effects of forest disturbance on nutrient losses from soils, and how this interacts with recovery from acidification; 2) How climate change and long-term decreases in stream solute concentrations will interact to control the timing, magnitude, and form of watershed exports; and 3) The long-term effects of forest disturbance on stream pH and the export of dissolved organic carbon and weathering products. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.