Heading to the National Adaptation Forum this year? We hope you'll check out some of the presentations and trainings organized by the Climate Science Centers (CSCs) and the National Climate Change and Wildlife Science Center (NCCWSC)!
Be sure to also stop by Booth 20 to learn more about the national Climate Science Center network and Booth 20A to learn more about the North Central CSC (booth map). Three new Tribal Climate Liaisons for the CSCs will also be at the BIA Booth 42!
A special congratulations to Olivia LeDee, Northeast CSC Deputy Director, who will be receiving a Minnesota Climate Adaptation Award for her work in integrating and advancing climate adaptation in natural resource management in Minnesota! The award ceremony will be held at NAF on the evening of Monday, May 8, 2017.
NAF is being held in Saint Paul, Minnesota from May 9 to May 11, 2017. We hope to see you there!
Translational ecology for climate adaptation: Old wine in new bottles? A fresh vintage? Does it matter?
Steve Jackson, USGS, Southwest CSC
Managing Climate Change Refugia for Biodiversity Conservation Toni Lyn Morelli, USGS, Northeast CSC
A co-production approach for implementing refugia science into adaptive management in the Northwestern U.S. Aaron Ramirez, National Center for Ecological Analysis and Synthesis, NCCWSC & CSC Ecodrought Postdoc
Jessica Blackband, University of Oklahoma, South Central CSC Alex Bryan, USGS, Northeast CSC Jeremy Littell, USGS, Alaska CSC Renee McPherson, University of Oklahoma, South Central CSC Esther Mullens, University of Oklahoma, South Central CSC Adrienne Wootten, University of Oklahoma, South Central CSC
Other attendees at NAF include Mary Ratnaswamy, USGS, Director of the Northeast CSC, Ryan Boyles, USGS, Deputy Director of the Southeast CSC, and Holly Barton, Tribal Climate Science Liaison, Southwest CSC.
We routinely encounter uncertainty when we make decisions – from picking a new morning coffee to choosing where to live. Even decisions that are supported by science contain some level of remaining uncertainty, such that making choices may remain uncomfortable and challenging. Scientists from the USGS Georgia Cooperative Fish & Wildlife Research Unit (Georgia Unit), together with the Department of the Interior Southeast Climate Science Center (SE CSC) and other partners are developing tools that decision makers can use to more formally account for uncertainties when moving forward with conservation and resource management.
Uncertainty inherently arises from incomplete or imperfect information. Our own societal uncertainties can result from people having differing values, world views, attitudes or emotions, which may then influence individuals’ choices or support for policies. For example, people who share a common goal and are presented with identical information may still make different choices. Ecological uncertainties also may remain due to unexplained variation in the natural world, which we’re not yet able to perfectly understand with available technologies and resources.
In the context of conservation and wildlife management, the potential for uncertainty to influence decisions is perhaps most obvious when we think about predicting how actions (or non-actions) will have lasting impacts into the future. Our abilities to precisely predict future conditions and determine the exact consequences of our actions are, and will remain, limited. Numerous climatic and ecological changes persist on the horizon, and their eventual consequences are not completely understood. Even so, these changes are expected to impact important natural resources and the people that depend on them. In turn, planners and resource managers are expected to incorporate expected changes into their forecasts. Although uncertainty about the future can make hard choices even more challenging, it does not necessarily need to be a roadblock for the advancement of science and policy.
In a fact sheet developed last year, USGS Georgia Unit scientist Dr. Brian Irwin and his collaborators laid out four principles for helping support conservation decision making in the face of uncertainty:
Structure the decision. Formalizing the decision-making process can help navigate the challenges posed by socio-ecological uncertainties. Several key steps are suggested that include: specifying objectives, identifying options, making predictions about likely consequences, assessing trade-offs, and evaluating uncertainties.
Recognize how values motivate. Even if perfect knowledge were obtainable, decision making would still be driven by value-based objectives. Reconciliation of values and knowledge is required to solve decision problems.
Heed evidence. Once a relevant uncertainty is identified for a needed decision, alternative plausible hypotheses should be defined and tested so that the empirical support for competing hypotheses can be established. As new evidence is acquired, incorporating what has been learned should lead to more informed and more justifiable future decisions.
Recognize how risk tolerances may vary. Even when objectives are shared, individuals can still react differently to uncertainty. Accounting for uncertainty within a decision making framework helps make possible risks more transparent and helps define paths towards progressively well-informed future choices.
This project brought together scientists, decision makers, planners, and resource managers across universities and federal and state agencies for a workshop on the topic of “Communicating and Using Uncertain Information in Conservation Decision Making.” This workshop, along with the products developed for the project, advance a decision-analytic perspective within the conservation community to support effective conservation in the face of uncertainty.
The Georgia Unit and Southeast CSC are also collaborating on two other projects led by Dr. Clint Moore to provide science that will inform conservation planning for several species native to the Southeast. One project aims to develop a decision support system for the selection of conservation actions that will lead to a viable landscape supporting the gopher tortoise population. Gopher tortoises are a keystone species with declining populations throughout their southeastern U.S. range. This work will incorporate elements of the structured decision making process around predictive models of habitat suitability and population connectivity to guide the assembly of conservation reserves that promote persistence of the tortoise within Georgia. Another recently initiated project will build on the gopher tortoise research as well as species data contributed by other partners to identify habitat requirements for the gopher tortoise and four other priority at-risk species – Florida pine snake, gopher frog, southern hognose snake, and striped newt – for the ultimate aim of identifying conservation actions expected to improve the status of these species.
This story was originally written for the Wildlife Management Institute's Outdoor News Bulletin. This article was prepared by the USGS Georgia Cooperative Fish and Wildlife Research Unit and the Southeast Climate Science Center. This project was funded by the Southeast Climate Science Center, one of eight regional centers that aim to provide natural and cultural resource managers with science and tools related to the impacts of climate change on fish and wildlife.
Picture on Page: Fog after a storm on the Sante Fe River, Florida. Credit - Alan Cressler
Published Date: November 18th, 2017
This opportunity has now closed.
The United South and Eastern Tribes (USET) is hiring for a position as the Northeast and Southeast Climate Science Centers' Tribal Liaison.
Brief Description of Duties to Be Performed: The Office of Environmental Resource Management (OERM) Tribal Climate Science Liaison will serve as a technical expert on climate change issues, resource vulnerability, and climate adaptation actions to Tribal nations in the USET region, and more broadly in the combined region comprising the Department of Interior’s Northeast Climate Science Center and Southeast Climate Science Center (NE CSC and SE CSC). The Tribal Climate Science Liaison will be responsible for developing and implementing a communication, education and outreach program; identifing climate research needs and priorities; and providing climate adaptation planning support to Tribal nations. He/she will also integrate program and research results into budget documents, annual reports, or other documents. The Tribal Climate Science Liaison will participate in a network of Tribal climate science liaisons within the Climate Science Center system; and a national workgroup of Tribal organizations, Tribal colleges, and other partners to address policy and resource issues associated with Tribal climate resilience. This position will be based at the University of Massachusetts-Amherst.
Minimum Requirements: Ph.D. degree preferred, or Master’s degree with at least three years of experience, in an area of science relevant to climate change and Tribal issues, including the social sciences and public health;
Familiarity with recent climate change research and resources within applicant’s area of expertise; with the ability to assist in development and evaluation of research proposals, methods and outcomes;
Experience applying comprehensive knowledge of principles of climate science, biology, ecology, and related sciences to strategic planning with the goal of maintaining science relevance and linkage to societal needs;
Knowledge of consensus building and group facilitation processes as illustrated through previous collaborations with federal, Tribal and state agencies, academic institutions, and other organizations;
Demonstrated knowledge of, and previous involvement in, issues that Tribal communities in the USET region are facing that could be addressed through research in climate change impacts;
Understanding of Tribal nations, values, needs, and traditional ecological knowledge; with the ability to work within the customs and traditions of diverse Tribal nations, such as reflected among USET member Tribal nations.
Strong oral and written communication skills, especially the ability to articulate relevant climate change-related issues and program products and concepts to Tribal nations and non-scientists generally;
Demonstrated ability to work both independently and as a collaborative team member along with the ability to organize, prioritize, document and manage multiple projects.
Ability to travel and work irregular hours as necessary.
This position is funded for one year by the Department of Interior. While NE CSC and SE CSC are working on making this a long-term position, that is contingent upon availability of funds.
Position posted: April 5, 2017 Closing Date: Open until filled
Please email cover letter and résumé to: Tammy Neptune, Human Resources Dept. United South and Eastern Tribes, Inc. Email: firstname.lastname@example.org. Subject line: Tribal Climate Science Liaison
Published Date: November 18th, 2017
Would you give a few minutes a year to reveal the future of forests?
What would be the easiest citizen science project ever? Watching paint dry? Falling off a log? Maybe. But what would you, or anyone else, learn from that?
Researchers in the Southeast are starting a citizen science project almost as easy but much more important. Its called A Tree’s Life and all you need to do is monitor red maple growth in your yard. They even give you the supplies. It’s really just one supply called a dendrometer, and it does most of the work.
The team wants to measure trees because they have a very important job to do. Trees take carbon dioxide (a greenhouse gas) from the air and release oxygen. Even more important, though, is that they use the carbon to build more tree tissue. That’s how they grow, and as they grow, they store carbon that would otherwise remain in the atmosphere.
Trees provide many other services like filtering air and water, providing shade to reduce energy costs, and generally make life better. Unfortunately, warming from urbanization and from climate change can reduce tree growth due to water stress, pests, and other factors. In other cases warming might make trees grow more and become healthier due to a longer growing season.
The problem the researchers want to address is that no one knows how trees in different habitats (urban, suburban, rural) and different latitudes will respond. So how can one predict the rate of carbon accumulation in the atmosphere, and thus climate change, if we don’t know how the primary terrestrial carbon sinks – trees – will respond? We can’t. Can we predict where urban trees and forests will thrive or decline? Not very well.
The project goal is to monitor the growth, and thus carbon sequestration, of hundreds or thousands of trees to help figure this out. If you have a red maple and a few minutes each year, please help. You will contribute to an understanding of how climate change and urbanization will affect forest health and carbon sequestration by trees.
North Carolina’s Cape Lookout lighthouse has survived threats ranging from Civil War raids to multiple hurricanes, but the Outer Banks site can’t escape climate-related changes such as rising sea levels, coastal erosion and flooding from stronger storms.
A North Carolina State University study in Climatic Change found little research exists on how to protect cultural resources like those at Cape Lookout National Seashore, a 56-acre site that includes historic buildings in addition to the iconic lighthouse and scenic beaches.
“Cultural heritage sites provide a lot of benefits, from sociocultural value in giving a community its unique identity to economic benefits from recreation and tourism,” says lead author Sandra Fatorić, a postdoctoral researcher with NC State’s College of Natural Resources. “We see a significant gap in knowledge of how to adapt to climate change and preserve cultural resources for future generations.”
Researchers searched worldwide for peer-reviewed studies of cultural resources – archaeological sites, natural landscapes and historic buildings – at risk due to climate change. About 60 percent of the studies referenced sites in Europe, most commonly in the United Kingdom. Another 17 percent of the research covered sites in North America, a majority of them in the United States. About 11 percent dealt with resources in Australia and the Pacific Islands and 10 percent mentioned Asia, mostly China. All but six of the 124 studies were published in English-language journals, with South America and Africa rarely represented in the research.
“We were struck by how recent much of the research was, with the first article appearing in 2003,” Fatorić says, adding there’s a need for more multidisciplinary work and research that involves local residents and stakeholders. “That process reveals what a community most values about a site.”
Co-author Erin Seekamp, an associate professor and tourism extension specialist in the Department of Parks, Recreation and Tourism Management at NC State, is working with stakeholders to set priorities for protecting cultural resources at Cape Lookout as part of a project with the Department of Interior’s Southeast Climate Science Center. Seekamp and Fatorić are evaluating 17 buildings in terms of their significance and their value to the site’s operations, working with managers from the National Park Service and North Carolina State Preservation Office. The research team, which includes U.S. Geological Survey analysts Mitch Eaton and Max Post van der Burg, is combining this information with earlier research by Western Carolina University’s Rob Young which found that most of the buildings at Cape Lookout are at high risk from flooding, erosion and rising sea levels.
“We’re looking at all of the options for each structure,” Seekamp says. “Which buildings should be maintained? Which could be moved to higher ground? Does that change the character of the site? Does changing a building’s use – from storage to visitor programs, for example – affect its relative value?”
“Park managers face difficult decisions in prioritizing which resources to protect,” Seekamp says. “We hope to develop a method that will help with decisions on protecting Cape Lookout’s historic buildings as well as informing policy for protecting cultural resources at other national parks facing climate adaptation.”
Image on Page: Cape Lookout Lighthouse; By Erin Seekamp
Published Date: November 18th, 2017
With 2016 drawn to a close, we're looking back at the Facebook, Twitter, and Instagram posts highlighting research from the USGS National Climate Change & Wildlife Science Center (NCCWSC) and the DOI Climate Science Centers (CSCs). In Part 1 of our review, we re-visited 5 of our most popular posts of 2016. Check out 4 more posts below!
Forecasting the Future of Whitebark Pine
Photo: Whitebark pine in Yellowstone National Park (R.G. Johnsson, NPS)
Shout out to Yellowstone National Park, celebrating its 144th birthday this week! If you’ve visited Yellowstone, chances are you’ve hiked through one of its iconic stands of whitebark pine. The whitebark pine is a keystone species in high-elevation forests, providing food for a variety of birds and animals, including the grizzly bear.
While whitebark pine once covered vast swaths of Yellowstone, its populations have been decimated over the last 30 years by invasive pests like mountain pine beetles and white pine blister rust (a fungus). Climate change may be the root cause: warmer, drier weather is stressing whitebark pines while simultaneously allowing invasive populations to soar – until the late 1990s, winter temperatures were generally too cold for these critters to survive. Scientists at the North Central Climate Science Center are using models to forecast how Yellowstone's whitebark pine populations will fare as the climate continues to change. Research findings will benefit park managers as they evaluate management alternatives for the whitebark pine and the species it supports. Learn more.
Photo: Honey bee extracts nectar (John Severns, public domain)
Honey bees may be the ultimate diet masters! Although “junk foods” (like spilled soda and other leftover treats that will be so abundant this Memorial Day Weekend) abound in city environments, bees opt for flower nectar over processed sugars. That’s what researchers supported by the Southeast Climate Science Center discovered in a recent study. This finding is surprising, given that many other urban animals feed on human foods. It suggests that urban flowers and green spaces may be especially important for sustaining healthy pollinator populations. Learn more: http://go.usa.gov/cJvMd
Graphic: Projected seasonal changes from increasing temperatures and precipitation changes (UMCES-IAN)
Climate change is projected to cause increased temperatures and more rainfall in the northeastern and midwestern U.S., which actually could mean more drought. Why? Precipitation patterns will become more variable, with more rain falling during extreme precipitation events, and longer gaps separating rainfall events. Combined with warming temperatures, this equates to more frequent, short-term droughts. Researchers with the Northeast Climate Science Center are working to understand what this will mean for people and ecosystems. Learn more: bit.ly/2dNygK9
The Impacts of Alaska's Retreating Glaciers on Coastal Ecosystems
Photo: Chenega Glacier in Prince William Sound, Gulf of Alaska (Julie St. Louis, USFWS)
Many Alaskan glaciers are retreating (melting) as average temperatures warm. What happens to all that ice? As glaciers melt, their contents are released into streams and rivers and swept away to the ocean. Although melting occurs relatively slowly, the sheer size of glaciers means that massive quantities of freshwater and nutrients, such as iron and nitrate, are being added to coastal ecosystems each year. Researchers supported by USGS’s National Climate Change and Wildlife Science Center studied the impacts from melting glaciers in the Copper River region of the Gulf of Alaska and what they might mean for plants, plankton, and fish. Big changes may be on the horizon for these ecosystems - as more melting means more nutrients to support vegetation growth - but it’s tough to predict specifics at this point. Learn more: http://go.usa.gov/cuWPx
This article was originally posted on the ECOIPM blog, run by the Frank Lab at North Carolina State University.
Climate change is generally considered bad for people, earth’s biomes, and, of course, polar bears. But as the climate warms will all critters suffer? Will they all be affected the same way? No. In addition to the losers who slowly fizzle out under the oppressive heat, there will be winners who benefit from warming.
An animal’s response to climate change depends largely on two things: the amount of warming in a habitat and the physiological limits of the animal. It has been shown pretty convincingly that animals closer to the equator are more sensitive to warming than animals farther north. I know what you are thinking, “but tropical animals are hot all the time, they should be used to it.” I thought the same thing, but how it works is that since they are hot all the time, they live close to their thermal limits. So for animals in hot places, a little more heat pushes them over the edge.
Therefore the biological effects of climate change are expected to vary geographically, particularly for ectothermic (cold-blooded) animals such as insects. Elsa Youngsteadt and other folks in the lab took a road trip to test the hypothesis that insects at high latitudes, where it is cold, should generally benefit from warming whereas insects at low latitudes should have mixed responses: some should benefit, but others should be pushed over their thermal limits.
In a brilliant new paper, Elsa reports her findings from this trip. The team sampled insects from street trees in the hottest and coolest parts of four cities – Raleigh, Baltimore, Queens, and Boston – taking advantage of the urban heat island effect as a natural warming experiment.
In the lowest latitude city, Raleigh, some taxa (groups of organisms) became more abundant with warming while others declined. This suggests that, although some species benefited from warming, just as many species suffered. In the coldest and highest latitude city, Boston, most insect groups were unaffected or became more abundant, suggesting that warming was good for most species living in a frigid northern metropolis. Just as predicted! This doesn’t happen very often.
It seems good that not all taxa tank in Raleigh – but the fact that some benefit and others decline could be ecologically disruptive, too: Maybe a parasitoid and its host respond differently, or a predator and its prey. This sort of mismatch could lead to extinction of higher trophic levels (e.g., large predators) if the prey does poorly, or herbivore outbreaks if the predator fails.
I’ll warn you upfront, this paper is dense and there are probably a lot of new concepts packed in that most people will need time to unpack. However, capturing the response of a whole community to a couple degrees of warming is novel and worth the read. Think about the responses of your favorite organisms. Not just in cities but across the globe.
This project was funded by the Southeast Climate Science Center, which is managed by the USGS National Climate Change and Wildlife Science Center. The center is one of eight that provides scientific information to help natural resource managers and communities respond effectively to climate change.
Photo: Moth on the trunk of a tree. Public Domain.
Published Date: November 18th, 2017
The Interior Department’s Climate Science Centers, managed by USGS, are helping the National Park Service pinpoint the specific impacts of climate change on parks and their cultural and natural resources. Doing so will help managers answer a critical question: which resources will require human intervention to ensure their continued existence?
The Cape Lookout Lighthouse in 1883, Cape Lookout National Seashore. NPS photo(Public domain.)
On the East Coast of the United States, rising seas are lapping at the foundations of historic sites and structures. With this rise in sea level comes elevated storm surges, increasing the risks of flooding and shoreline erosion.
These impacts of climate change are making the future more uncertain for structures like Cape Lookout National Seashore’s historic lighthouse, a beacon of our nation’s rich maritime past.
Protecting these national treasures and other cultural resources is no easy task for the National Park Service, mandated to preserve culturally significant areas and artifacts. Forces of nature have always been a threat, but now climate change is poised to inflict even more significant damage. Perhaps this is the biggest threat to date. According to the NPS, several thousand historic sites are threatened by a rapidly changing climate.
In light of these and other climate-related threats, the Interior Department’s Climate Science Centers, managed by USGS, are helping the NPS pinpoint the specific impacts of climate change on parks and their cultural and natural resources. Doing so will help managers answer a critical question: which resources will require human intervention to ensure their continued existence?
In this two-part series on climate change and cultural resources, we look at research to help NPS managers preserve historic sites and structures. Part Two, on Jamestown and the Colonial National Historical Park, will be published next.
Keeping Our Lighthouses and Other Maritime Resources
The barrier islands of Cape Lookout National Seashore entice visitors with remote beaches, wild horses and historic maritime attractions. For a cultural experience, visitors can tour the park’s two historic villages, Portsmouth (est. 1753) and Cape Lookout (est. 1887), and climb the steps of its iconic mid-19th century lighthouse. This lighthouse notably managed to survive the Civil War, during which time it was disabled, raided, and caught up in efforts to both darken and illuminate the coast for Union troops, depending on which side was in control.
Today, the relics of this region’s maritime past are threatened by stronger storms and hurricanes, rising seas and shoreline erosion.
To secure the future of Cape Lookout’s cultural resources, the DOI Southeast Climate Science Center is testing a new approach for prioritizing climate adaptation actions. Erin Seekamp, an associate professor in the Department of Parks, Recreation & Tourism at North Carolina State University and a researcher working with the Southeast CSC, is developing a method to identify cultural resources most in need of management action.
Says Seekamp: “Because so many coastal resources are highly vulnerable to climate-related impacts, resource managers will have to make tough decisions about which ones to maintain in their current historic condition, which to adapt using storm-resilient materials, which ones to elevate or move, and which ones to let go.”
Seekamp’s method calculates a value for each cultural resource, based on its vulnerability to climate change, its historical significance and its importance for the park’s day-to-day operations and education efforts. These non-monetary scores allow resources to be ranked in terms of their need for management action.
Seekamp is testing this approach in Cape Lookout, where she is ranking 17 buildings in the Portsmouth and Cape Lookout historical districts.
“The districts and their cultural resources are vulnerable to climate change-related impacts such as storm-related flooding and erosion and sea-level rise,” Seekamp said. In fact, an assessment of the vulnerability of the park’s historic buildings, completed by Rob Young of Western Carolina University, rated most of these buildings as highly vulnerable because of storm-related flooding, erosion and sea-level rise.
An essential component of Seekamp’s approach has been active engagement with stakeholders, including personnel with the NPS and the North Carolina State Preservation Office. “Decision-making is a value-laden process and cultural resources are imbued with diverse values. Stakeholders provide guidance on how we determine which factors should be considered, and can help us refine our methods as the project continues,” Seekamp said.
Ultimately, Seekamp hopes that the method her team is developing can be used to prioritize cultural resources beyond Cape Lookout. “After we complete this pilot study, our goal is to develop a process that can be applied to all historic buildings at Cape Lookout, to other types of cultural resources in other parks, and, ultimately, to help the NPS make regional and landscape-level decisions about cultural resource climate adaptation.”
The Southeast CSC is part of a national network of eight regional DOI Climate Science Centers, managed by the USGS National Climate Change and Wildlife Science Center (NCCWSC). The CSCs provide scientific information to help natural and cultural resource managers respond effectively to climate change.
Photo: The 1859 Cape Lookout Lighthouse and keeper's quarters. Credit: Erin Seekamp, NCSU
Published Date: November 18th, 2017
The Southeast is currently undergoing high rates of population growth, urbanization, and land use change while also facing challenges brought by climate change, including sea level rise and more frequent extreme weather events. These changes are threatening and will continue to threaten wildlife and their habitats in the region, as well as infrastructure and important resources like freshwater. Recognizing these problems, state fish and wildlife agencies, together with federal and non-governmental partners, have initiated and recently released version 1.0 of the Southeast Conservation Adaptation Strategy (SECAS).
The SECAS aims to establish a connected network of landscapes and seascapes that supports thriving fish and wildlife populations and improved quality of life for people across the southeastern United States and the Caribbean.
The announcement of SECAS 1.0 came on Monday October 17, 2016 at the Southeast Association of Fish and Wildlife Agencies (SEAFWA) annual conference in Baton Rouge, LA where the SECAS Conservation Leadership Summit was held. The first half of the Summit was spent with state agency leadership from nearly all of the 15 SEAFWA member states. They heard presentations from Landscape Conservation Cooperative (LCC) staff and from a Southeast Climate Science Center sponsored researcher about SECAS and case studies from their own staff on how SECAS can be used. On the second day of the meeting, the state agencies unanimously approved continuing to move SECAS forward.
Photo: LCC and SE CSC Staff at the SEAFWA Meeting.
Published Date: November 18th, 2017
New research from North Carolina State University (and supported by the Southeast Climate Science Center) finds that urban warming reduces growth and photosynthesis in city trees. The researchers found that insect pests are part of the problem, but that heat itself plays a more significant role.
“Earlierstudies have shown that urban warming increases pest abundance in street trees,” says Emily Meineke, lead author of a paper describing the work. “We wanted to know how urban warming and pest abundance affect tree growth, since trees pull carbon out of the atmosphere and convert it into biomass. This is important, because we know that high levels of atmospheric carbon play a role in climate change.” Meineke did the work while a Ph.D. student at NC State. She is now a postdoctoral researcher at Harvard.
To explore this issue, researchers went to 20 pairs of willow oak trees (Quercus phellos) across Raleigh, North Carolina. At each site, one tree was treated with an oil that kills insect pests, and the second tree was left untreated. The sites were located across a variety of different urban temperatures, and air temperature was monitored at each site over the course of the experiment.
The researchers tracked the growth of all 40 trees for two years. Growth was assessed in two ways: by measuring the circumference of each tree’s trunk, and by measuring how much specific branches grew on each tree. The researchers also measured each tree’s photosynthesis, which is how trees capture carbon from the atmosphere and is a key marker of tree health.
The researchers found that scale insects and spider mites – well known tree pests – were more abundant at hotter sites. Specifically, they found that spider mite populations more than doubled when a site’s average temperature crossed a threshold of 16.4 degrees Celsius (61.5 degrees Fahrenheit). Scale insects, however, showed a linear relationship with temperature. In other words, the hotter it got, the more scale insects there were.
The researchers also found that warming negatively affected tree photosynthesis and growth, regardless of whether pests were present.
“Trees that didn’t have pests had more branch growth than trees with pests,” Meineke says. “But trees at warmer sites had less trunk growth, which accounts for more tree biomass, regardless of pests.”
The researchers then plugged these results into a model to determine the extent to which urban warming impacted carbon storage for all of the willow oaks in Raleigh.
“We found that urban warming reduced carbon storage by all of Raleigh’s willow oaks by 12 percent, or 27 metric tons per year,” Meineke says.
“We think the findings are generalizable to other tree species and other cities, especially hotter cities like Atlanta, but additional work needs to be done to determine whether that’s the case,” Meineke says.
The paper, “Urban warming reduces aboveground carbon storage,” is published in the journal Proceedings of the Royal Society B. The paper was co-authored by Elsa Youngsteadt, an entomology research associate at NC State; Rob Dunn, a professor of applied ecology at NC State; and Steve Frank, an associate professor of entomology and plant pathology at NC State. The work was supported by the Department of the Interior’s Southeast Climate Science Center, under cooperative agreement numbers G11AC20471, G13AC00405 and G15AP00153; by the U.S. Department of Agriculture’s National Institute of Food and Agriculture, under grant number 2013-02476; and by the National Science Foundation under grants 0953390 and 1136703.