At a symposium organized by a team of scientists from the U.S. Long Term Ecological Research (LTER) Network during this year’s Ecological Society of America (ESA) annual meeting in Austin, TX, researchers highlighted the role of long-term research in providing an ecological context for addressing many of the Earth's most pressing problems related to planetary stewardship.
The symposium had two major goals:
- To use results from 30 years of LTER to show how long-term research can uniquely contribute to the understanding needed to preserve and enhance Earth’s life support systems
- To describe ways in which this legacy can be leveraged to contribute to the ecological theory necessary to address emerging environmental challenges
Symposium organizers included G. Philip Robertson, David R. Foster, Chris Boone, Daniel L. Childers, and Sarah E. Hobbie. The organizers noted that the recent emergence of socio-ecological research within the Network, a development that provides a new way of understanding linkages between social and ecological systems, was particularly important. Robertson observed: “Planetary stewardship depends on this understanding – without it, the development of workable policy solutions to some of the most recalcitrant environmental problems of today, ranging from water resource depletion to climate change vulnerability, will remain difficult to design and even more difficult to achieve.” He noted that new frameworks and long-term research are needed to help us understand how humans perceive the critical services provided by ecosystems, how these perceptions change behavior and institutions, and how behavioral and institutional change in turn feeds back to affect ecosystem structure and function and thereby the ability of ecosystems to deliver future services.
The presentations focused on the unique and emerging contributions of long-term ecological research to ecological science, to science education, and to society. The presentations synthesized major work, current innovative thinking, possible new approaches, and emerging directions in ecological research; identified directions for LTER growth in the integration of national observatories—such as the National Ecological Observatory Network (NEON)—and major ecological programs; and underscored the special importance of eco-informatics to long-term research, which is critical for science and education.
David R. Foster (HFR/Harvard University) wrapped up the presentations with an overall summary of the efforts of the various speakers.
For easy reference, the following are summaries of the six presentations:
- Emergence and future role of long-term socio-ecological research for planetary stewardship by Scott L. Collins (SEV/University of New Mexico)
Background: Interdisciplinary collaborations are essential for a research agenda on earth stewardship. In addition, researchers must develop fruitful interactions with policy makers, managers and the public to put planet earth on a path toward sustainability. We must acknowledge the fact that the human population will continue to grow significantly over the next century and that growing population will place additional demands on ecological systems and ecosystem services. The Long-Term Ecological Research Network has developed a research framework built around press-pulse dynamics that is explicitly interdisciplinary, long-term, and multi-site that can serve as a guide for collaborative research across the network, as well as provide a starting point for communication and outreach with policy makers and the public.
Results: This presentation described the main components of the press-pulse dynamics framework (press-pulse interactions, ecosystem structure and function, ecosystem services, human responses and outcomes), and briefly compared it to other related frameworks for social-ecological research. Implementation of the framework was illustrated by a detailed application on population growth in Albuquerque, New Mexico, and how that growth affects competing water use and demands in the region. The presentation described the key drivers of postwar population growth, along with the spatial patterns of urban growth and land use, and ended with a description of the consequences of land use change on water quantity and quality in the Middle Rio Grande region, to illustrate how the components and interactions of the press-dynamics model play out in this rapidly growing urban area in the southwestern U.S. - Long-term experiments: Insights from the past and emerging role of multi-site experiments by Alan K. Knapp (SGS/Colorado State University)
Background: Manipulative experiments have long been central to advancing ecological understanding, and while short-term experiments are much more common, long-term (LT) experiments have had a foundational role in ecology. The NSF-funded LTER program has been conducting site-based research for more than three decades, with LT experiments figuring prominently in the research portfolios of many of the sites within the LTER network. Although there are certainly many valuable LT experiments outside the LTER network, arguably the largest and most diverse collection of LT experiments are associated with the LTER program, and thus an assessment of the role of these LT experiments in the LTER Network and the broader scientific community, as well as the collective lessons learned from these experiments is warranted as the LTER program continues into its 4th decade.
Results: Our review of LT experiments across the LTER network revealed many unique insights into long-term patterns and processes that, in many cases, only became apparent after many years of study. In some cases, answers to the questions motivating these experiments were opposite when based on short-term (3-5 year) responses vs. LT responses (>6 years). Further, many of the longest running experiments have become research platforms for other investigators allowing for both opportunistic research to be conducted that was outside the original expectation for the experiment, as well as more detailed mechanistic studies to be nested within these experiments. Over time, the complexity of LT experiments has increased with many more multi-factor experiments specifically related to global change issues ongoing across the network today. However, it is clear that given the scale and scope of global change drivers, coordinated, multi-site and multi-factor experiments are needed, yet these are rare in the LTER network. Such a network of LT experiments would be particularly valuable if it was strategically designed to take advantage of the long-term observations and contextual understanding extant within the LTER platform, as well as other long-term field sites outside the LTER network. - Future scenarios of landscape vulnerability and resilience to global change by Jonathan R. Thompson (HFR /Harvard University)
Background: The LTER network is committed to integrated socio-ecological research designed to foster a sustainable future. Overarching questions include: How will global change alter the futures of regional social-ecological systems? And, how and why do regional social-ecological systems differ in vulnerability, resilience and adaptability to global change? Addressing these questions poses many new challenges. Indeed, research to anticipate ecological change within coupled human and natural systems is met by massive uncertainties, reciprocal feedbacks, and surprises. Scenario thinking to inform quantitative modeling of landscape change and attending ecological responses is among the most promising approaches to emerge. Scenarios typically begin as suites of qualitative narratives—developed by regional stakeholders including social and ecological scientists—that describe an envelope of plausible futures based on contrasting assumptions. The narratives inform and are, in turn, informed by integrated spatial models of socio-ecological change. Scientists have developed a diversity of approached for coupling qualitative scenarios and quantitative simulations. This presentation reviewed LTER-affiliated scenario projects from the H. J. Andrews Experimental Forest in Oregon, the North Temperate Lakes program in Wisconsin, the Harvard Forest in Massachusetts, and the Bonanza Creek research site in Alaska. This work has informed prescient planning and policy and generated a rich set of fundamental research questions.
Results: After thirty years, the LTER Network is at the forefront of understanding long-term environmental change. Accordingly, the LTER community of scientists is poised to focus on forward-looking socio-ecological research that can identify areas of vulnerability and resilience to future global change. The core strengths of the LTER—its history of long-term, place-based studies, its commitment to integrative research across disciplines, and the diversity of landscapes, stakeholders, and disturbance regimes represented by the sites—make it ideally suited to address these questions in a scenario framework. - The disappearing cryosphere: Impacts and ecosystem responses to rapid cryosphere loss by Andrew Fountain (MCM/ Portland State University)
Background: The Earth’s Cryosphere – ice in all its forms, including glaciers, sea, lake and river ice, snow, and permafrost – harbors 82 percent of the freshwater on the planet. The Cryosphere plays a critical role in the global heat budget, regulates global sea level, insulates soil from subfreezing air temperatures and most importantly, serves as a seasonally-rectified water supply for human consumption, irrigation, nutrient transport and cycling, freshwater resources, and waste disposal. Cryosphere loss imposes enormous threats to these ecosystem services and, in turn to the global economy. A one-meter sea level rise alone, projected over the 21st century, represents an estimated economic impact of $1 Trillion. The extent and rates of cryosphere loss are increasingly well-monitored and our ability to project future rates of geophysical decline is improving. However the ecological consequences and especially the nature, extent and economic impacts on human society and institutions are still poorly understood.
Results: Nutrient (e.g. organic matter and inorganic nutrients) mobilization appears to follow seasonal cryosphere recession across systems, but with earlier snow or ice melt, the phasing or phenology of mobilization events and biological responses appear to be shifting in time. Nitrate pulses in streams follow snowmelt in temperate forests, but with earlier seasonal snow melt, plants may not be able to take advantage of newly-available nitrogen. Thinner snowpacks can result soil drying and tree root loss, leading to increased nitrate in streams that was not taken up by the missing roots. In addition thinner snow pack results in habitat loss for some large mammals and changing grazing patterns for others. Shrinking alpine glaciers and buried ice changes high alpine hydrology significantly and reduces habitat critical to some alpine fauna. Sea ice loss has had contrasting effects on marine phytoplankton productivity along a north-south climate gradient off the west Antarctic Peninsula. Nearly all known climate-ecosystem feedbacks resulting from cryosphere loss are positive: warming and melting intensify and promote further warming and cryosphere loss. Identifying and modeling cryosphere feedbacks has become a closely-pursued research priority, stimulated by catastrophic Arctic sea ice loss and tundra melting. Responsible stewardship of our planet in the face of rapid cryosphere loss poses a grand challenge for ecologists to confront in the coming decade.
- Water supply sensitivity and ecosystem resilience to land use change, climate change, and climate variability by Julia A. Jones (AND/Oregon State University)
Background: Climate warming is predicted to decrease snowpacks, increase winter flooding, increase summer water use by vegetation, and reduce summer streamflow. This presentation used up to 60-year-old records of climate and stream flow from LTER sites to assess the sensitivity of water yield from ecosystems to climate variability. We quantified changes in air temperature, precipitation, and streamflow at eight headwater, undisturbed, forest ecosystem sites with long-term streamflow and climate records: Andrews, Coweeta, Hubbard Brook, Fernow, Fraser, Luqillo, Marcell, and Niwot Ridge, using linear regression and Mann-Kendall tests on annual, seasonal, and daily data.
Results: Annual minimum temperatures have increased significantly for all sites except for Niwot Ridge. Increased minimum temperatures were most frequent in summer (5 sites), followed by spring (4 sites), winter (3 sites), and fall (2 sites). Annual precipitation changed significantly at only two sites (increases at Hubbard Brook and Niwot Ridge). Despite warming, few sites display expected responses of streamflow to climate change at annual or seasonal timescales. Runoff ratios (discharge divided by precipitation) measure ecosystem water use and facilitate comparisons among sites over time. Spring runoff ratios declined significantly at three sites (Andrews, Fraser, and Hubbard Brook), and winter runoff ratios increased at two sites (Fernow, Hubbard Brook). No sites experienced decreases in summer runoff ratios. Analysis of daily records showed an advance of a couple of weeks in the snowmelt-streamflow pulse at sites with seasonal snowpacks (Andrews, Fraser, Hubbard Brook, Marcell). However, sites and/or seasons with actively transpiring vegetation have not experienced expected trends, apparently as a result of vegetation succession or altered transpiration in response to changes in climate. Experience and results emerging from up to six decades of studies at LTER sites can help assess responses, adaptation and resilience to climate variability and change. Although water yield from headwater ecosystems has responded to climate change, many sites display evidence of ecological resilience to climate change, and hydrologic responses to climate change are smaller than responses to experimental vegetation treatments. Work is needed to examine how far downstream climate change effects on hydrology can be detected. These findings demonstrate the power of long-term ecological research to synthesize ecosystem process understanding to respond to new issues and provide relevant input to ecosystem management in the face of climate change.
- Integrating science and society: the role of long-term studies in environmental stewardship and policy by Charles T. Driscoll (HBR/ Syracuse University)
Background: Long-term research can play a critical role in addressing “Grand Challenges” in environmental stewardship. This presentation examined efforts at five LTER study sites across the U.S. to inform policy, management and conservation decisions related to forests at local, regional, and national scales. The case studies we presented explored different approaches, challenges and successes in synthesizing, translating and communicating research that is relevant to public policy. The topics included: effects of air pollution on ecosystems through the “Science Links” program at Hubbard Brook; fire management and impacts on indigenous peoples at Bonanza Creek; forest management at H.J. Andrews; land conservation through the “Wildlands and Woodlands” initiative at Harvard Forest; and tools to promote urban forestry at the Baltimore Ecosystem Study.
Results: We discussed a range of tools including stakeholder engagement and the integration of local knowledge, the use of dynamic models to analyze potential consequences of policy and management decisions, and the practice of adaptive management to incorporate new knowledge into future decisions. We then summarized the lessons learned from these boundary-spanning efforts, including the insight that decades-long research programs build credibility for outreach initiatives; the value of LTER sites as regional hubs for outreach efforts; the importance of scientific synthesis and translations, and management tools framed in relevant terms; and that outreach efforts can be made more effective through strategic partnerships. Finally, we considered questions such as: What characterizes successful boundary-spanning efforts? How can the role of long-term research in resolution of environmental challenges be enhanced? What role should NSF-funded science play in addressing the Grand Challenges of our time?