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The latest updates on the LTER Network, new research papers, and announcements. 
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April 2017
 
LTER in the News
News from the National Science Foundation Other Media
Recent LTER Publications
Macrosystems ecology: A key subfield matures | Ecology Letters

mushroomsEcosystems ecology, landscape ecology, macrosystems ecology. It’s easy to think of these subdisciplines as big, bigger, biggest—but there’s a good deal more to the distinction than the scale of interaction they address. A recent “Idea and Perspective” article in Ecology Letters traces the origins and foundations of the field of macrosystems ecology, and advances a new hypothesis to describe how anthropogenic influences change the scales of ecological processes.

The article highlights the importance in macrosystems ecology of cross-scale emergences and teleconnections (such as the role of the soybean trade in Brazilian deforestation or the Pacific Decadal Oscillation in boreal forest fires). It also emphasizes the potential (not yet fully realized) for incorporating social-ecological science into macrosystems thinking.
 
 The authors, led by Kevin Rose, a freshwater ecologist at Rensselaer Polytechnic Institute and Monica Turner, a landscape ecologist at the University of Wisconsin, describe their spatio-temporal anthropogenic rescaling (STAR) hypothesis—along with many concrete examples of the ways that anthropogenic influences expand, shrink, speed up, and slow down ecological processes. Historically, ecological relationships have operated within predictable bounds, but these scaling changes open up a much wider envelope of human influence.  

Rose et al. emphasize that the generation of useful and testable hypotheses is critical to the maturation of this budding field. They follow through on that assertion by categorizing the characteristics likely to lead to expansion or speeding v. those likely to lead to contraction or slowing. Greater connectivity, they argue, favors expansion and offer examples such as reactive nitrogen dispersion through the atmosphere. Greater heterogeneity mainly favors slowing and contraction, as when a patchy landscape impedes dispersion of species.

The existence of long-term, large scale research programs such as LTER and NEON—as well as advances in remote sensing and data integration—support the ability to generate and test macroecological hypotheses. And macrosystems ecology, they argue, may well be our best shot at understanding and solving ‘wicked’ environmental dilemmas.
 —Marty Downs
The grazing effect: How bison impact plant water use | Plant and Soil
 
city lotWhen one envisions a grassland community, imagery of tall grasses and bison often come to mind. Bison are an iconic species on the landscape, and they also impact the structure and function of the grassland ecosystem in important ways.  Using natural variations in the abundance of oxygen isotopes, researchers at the Konza Prairie LTER found that  grazing influenced plant water use through changes in diversity.

The researchers found that grazers increase the proportion of shallow water used by two grassland species, A. gerardii and R. glabra, allowing them to access water sources that weren’t being used by other species. The shift in proportional water uptake was related to differing plant communities in grazed and ungrazed watersheds, rather than the amount of soil moisture or root biomass. Grazed locations have greater plant diversity, which creates more numerous and smaller hydrological niches, possibly leading to lower competition for water. Thus, niche partitioning may be very sensitive to changes in plant diversity within this heterogeneous ecosystem.
 
The presence of grazers—but not fire history—modified the functional niches in this tallgrass prairie plant community by altering the depth of water uptake and degree of niche overlap. The results of this study demonstrate that disturbances such as grazing can have strong impacts on plant functioning at small scales, which can have important consequences for local watersheds and grassland communities.
 —Erin O'Reilly
Putting the “urban” in disturbance: Applying ecological frameworks to cities  | Ecosystem Health and Sustainability
 
firefliesThe concept of “disturbance” is a core theme of the LTER Network and central to ecological science. How does the idea of disturbance need to change when applied to the interactions of an urban metropolitan region rather than a “natural” system? Ecologists often consider the process of urbanization itself to be a form of disturbance, but that is a habit that has to change, say the authors of a recent paper in Ecosystem Health and Sustainability. People, technology, and infrastructure have to be defined as part of the system when studying cities, they say.
 
Drawing on examples from Baltimore, Phoenix, and other cities, the authors apply the disturbance framework of Peters, et al  (2011) to several specific examples of urban disturbance. By specifying the system to include built infrastructure, social norms, and energy and resource flows, as well as biotic components, the authors are able to explain why and how some disturbances (such as the Baltimore fire of 1904 or flooding in Scottsdale Arizona) have larger effects or unexpected recovery pathways compared to other similar disturbances.
 
Many of the specific observations about how urban disturbances may be magnified or mitigated will not be surprising to urban planners—but the systematic application of an ecological disturbance framework creates the opportunity to learn from patterns of past disturbances in order to better predict the effects of changes in urban structure or disturbance patterns.
 
Ecologists used to thinking about disturbances such as hurricanes or pest outbreaks will recognize many similar patterns in these urban case studies. And they will be familiar with the need to fully specify the scale and scope of the system they are studying (if not in the habit of including governance systems within that scope). The habit that may be most important to change, argue the authors, is that of thinking of the very existence of people as disturbance.
 
—Marty Downs
Divergent water regimes’ influence algal diversity  | Freshwater Biology

hippopotamus in Okavanga DeltaWetlands exist on every continent save Antarctica and manifest as a variety of habitats, from salt marshes to mangrove forests. They provide important ecosystem services, such as water purification and flood protection—often tied to their high productivity and diversity.
 
Wetlands are especially vulnerable to changing water withdrawals and climate because their unique ecology relies on receiving pulses of freshwater. A team of researchers from the Florida Coastal Everglades LTER explored how hydrologic disturbance is impacting algal species diversity in two globally significant marshes.
 
In the Florida Everglades, water flow is strictly managed and regulations have begun to reduce withdrawals from the watersheds that feed the marsh. In Botswana’s Okavango Delta, flood amplitude is much higher and hydropower dams are being developed upstream. Researchers compared the effect of two factors that are strongly influenced by water regimes—flooding frequency and phosphorous availability—on algal species richness. The study provides baseline measurements that will aid in understanding the impacts of watershed changes in the coming years. 
—Amanda Kelley
Synthesis
workshop participants
Searching for Synergies

An LTER-NEON Synergies workshop, held March 29-31, explored the potential for strengthening and deepening the relationship between these two major research organizations and expanding ties to other networks such as the Critical Zone Observatory (CZO), Long Term Agricultural Research (LTAR) and Global Lake Ecological Observatory (GLEON) networks. The Long-Term Ecological Research (LTER) Network and National Ecological Observatory Network (NEON) have complementary approaches to long-term, large scale ecological research and improving coordination offers great potential for shared learning.

“Understanding the causes and consequences of ecological change is one of the most important challenges confronting the scientific community,” said Tim Kratz, National Science Foundation Program Officer for Macrosystems Biology and Early NEON Science. “This workshop to explore synergies between NEON and LTER helped clarify areas where these two powerful approaches can be brought together to make significant progress to meet this challenge.”

LTER-NEON Synergies
Twenty-four workshop participants—including senior organizational leadership and a wide assortment of data users—met at the National Center for Ecological Analysis and Synthesis (NCEAS) to discuss how the different lenses each network employs could provide perspective for the other. “Workshop participants were able to highlight exciting synergies between LTER and NEON that will develop over the next 30 years,” said workshop organizer Peter Groffman, who chairs the LTER Science Council. “Perhaps the key synergy is that NEON is going to provide important new information on how ecosystems are changing and LTER will continue to provide understanding of the mechanisms underlying that change.”

As participants in the LTER-NEON Synergies workshop introduced themselves and their connections to LTER and NEON, it was striking how many individuals had launched their careers through undergraduate or graduate research experiences at LTER sites—manipulating plant diversity at Cedar Creek, sorting litter at Harvard Forest, harvesting biomass at Toolik Lake, and so on. The intimate knowledge of site and system represented by those experiences is central to the work of the LTERs, where teams of site-based scientists guide experiments and data collection based on Network-wide research themes, such as primary production, movement of organic matter, movement of inorganic matter, population dynamics and trophic interactions, and disturbance.

workshop participantsNEON, on the other hand, offers a suite of measurements across many sites with standardized data collection from sensors located on towers, in the soil, and in aquatic systems, sampling of select organisms, including small mammals, insects, fish, plants, invertebrates, and microbial communities, and remote-sensing data collected by airborne observatories. The top-down approach implemented by NEON produces a large body of highly comparable data, but offers less flexibility for addressing site-specific questions. With up to 14 co-located LTER and NEON sites, there are obvious opportunities for data sharing and interpretation, but the discussion went deeper to address approaches for

  1. applying LTER’s understanding of land use history, landscape organization, scales of ecological organization, and disturbance regimes, for example, to help interpret NEON data and sampling designs, and
  2. using NEON data, with its finer temporal resolution, new organisms, and disease focus, to help interpret and expand the scope of LTER core research areas.

Participants outlined a journal article describing concrete approaches and describing examples of these types of synergy. “This was a fun and challenging workshop bringing together diverse perspectives on how the LTER and NEON scientific networks can synergize,” said Cove Sturtevant, NEON Staff Scientist. “We made a lot of progress toward a blueprint that I think can accelerate the use of NEON data in impactful science as the Observatory reaches full operability.”

The workshop also examined the role of conceptual and quantitative models in guiding a new era of continental scale ecological research. The discussion focused on how LTER and NEON offer opportunities to think about the nature of prediction and uncertainty. The wealth of long-term data from LTER sites in almost all NEON domains could, for example, help NEON scientists to interpret the variability and extremes that they observe as sites begin to accumulate new data streams.

Researchers discussed a variety of approaches to modeling and prediction, including conceptual frameworks, scenarios, and model intercomparison/data assimilation. A follow-up workshop is being planned to dig deeper into the potential for syntheses of LTER and NEON models and data as well as for involving other networks.

Participants at the workshop included a core organizing committee—drawn from LTER and NEON leadership, with representation from many co-located research sites—and also a wide range of junior researchers and data users. Recognizing the importance of engaging the next generation of ecological leaders, organizers invited applications from throughout the ecological research community. Over 60 researchers applied for one of the 11 slots.

—Marty Downs
Announcements
Go Copepod-Crazy!
The 13th International Conference on Copepoda will be held July16-21 in Los Angeles-San Pedro, CA. Mark Ohman (CCE PI) and Scripps Institution of Oceanography are hosting a pre-conference workshop with renowned specialists providing a a comprehensive and state-of-the-art introduction to the diversity, morphology, systematics and biology of benthic, planktonic and symbiotic copepods. Deadlines: April 30 for workshop applicationsMay 1 for conference abstracts.
Earth Educators Rendezvous
The third annual Earth Educators' Rendezvous takes place from July 17-21 in Albuquerque, NM. Early registration deadline is May 1. Participants can learn about new teaching approaches, discover opportunities to get involved in research programs, prepare for an academic career, or discuss how to approach teaching and learning challenges in their classroom. 
Have a paper or event that you would like LTER Science Update to highlight?
Email nco-comm@lternet.edu with details by the 7th of the month.
Photo Credits (top to bottom): NASA Visible Earth, KNZ LTER, BES LTER, Michael Jansen (CC BY-ND 2.0), Marty Downs/LTER-NCO CC BY-SA 4.0

This material is based upon work supported by the National Science Foundation under award # DEB-1545288, 10/1/2015-9/30/19. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
Copyright © 2017 LTER Network Office, All rights reserved.


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