H11L-01 INVITED
Long-Term Environmental Research Programs – Evolving Capacity for Discovery
Long-term forestry, watershed, and ecological research sites have become critical, productive nodes for environmental science research and in some cases for work in the social sciences and humanities. The Forest Service's century-old Experimental Forests and Ranges and the National Science Foundation's 28- year-old Long-Term Ecological Research program have been remarkably productive in both basic and applied sciences, including characterization of acid rain and old-growth ecosystems and development of forest, watershed, and range management systems for commercial and other land use objectives. A review of recent developments suggests steps to enhance the function of collections of long-term research sites as interactive science networks. The programs at these sites have evolved greatly, especially over the past few decades, as the questions addressed, disciplines engaged, and degree of science integration have grown. This is well displayed by small, experimental watershed studies, which first were used for applied hydrology studies then more fundamental biogeochemical studies and now examination of complex ecosystem processes; all capitalizing on the legacy of intensive studies and environmental monitoring spanning decades. In very modest ways these collections of initially independent sites have functioned increasingly as integrated research networks addressing inter-site questions by using common experimental designs, being part of a single experiment, and examining long-term data in a common analytical framework. The network aspects include data sharing via publicly-accessible data-harvester systems for climate and streamflow data. The layering of one research or environmental monitoring network upon another facilitates synergies. Changing climate and atmospheric chemistry highlight a need to use these networks as continental-scale observatory systems for assessing the impacts of environmental change on ecological services. To better capitalize on long-term research sites and networks, agencies and universities 1) need to encourage collaboration among sites and between science and land manager communities while 2) maintaining long- term studies and monitoring efforts, and staffing the collaboration in each partner organization, including positions specifically designated as liaisons among the participating communities.
H11L-02
30 years of change in understory plant communities along the Tanana River, Alaska: Revisiting the concept of turning points
In interior Alaska, the most productive forests occur along the floodplain of the glacially fed Tanana River. The Bonanza Creek Experimental Forest (BCEF) is located approximately 20 km southwest of Fairbanks, Alaska and was established in 1963 to include representative floodplain forests along the Tanana River. Both the sequence and the mechanisms of succession have been relatively well studied along the Tanana River, where biological and physical "turning points" are hypothesized to be the main proponents of plant community succession. However, prior research has concentrated almost exclusively on four dominant woody taxa: willows, thin-leaf alder, balsam poplar, and white spruce. Comparatively little is known about successional changes in the understory taxa, including shrubs, herbaceous vascular plants, and nonvascular mosses and lichens. Long-term monitoring in BCEF not only provides a unique opportunity to investigate the relationships between vegetation and climate over a 30-year period, but also increases our knowledge and understanding about floodplain successional dynamics. Here, we analyze vegetation and climate data collected since 1977 located in the BCEF at the Bonanza Creek Long-Term Ecological Research (BNZ- LTER) site in order to address the following questions: 1) Are there identifiable understory turning points that mirror the overstory changes in succession? 2) Have changes in climate been manifested in unexpected understory vegetation changes? When examining understory vegetation, we found that the sites established in the 1970s rarely follow the traditional succesional paradigm. In addition, we found changes in functional abundance and diversity in late succesional stands that could indicate vegetation patterns related to associated changes in climate.
H11L-03
Size Matters: Utility of Basin-Wide, Long-Term Data Sets for Advancing Knowledge of Ecosystem Processes
Western North American landscapes are marked by extensive natural disturbances and human
perturbations. Persistence of native species in these dynamic systems requires diverse and vagile life
histories and conservation strategies based on data collected at appropriate spatial and temporal scales.
Most experimental forests and watersheds have focused on understanding processes at the scale of
hillslopes and small headwater catchments (< 20 km2), but scaling to larger basins (> 1,000
km2) using principles of aggregation has proven problematic, suggesting a need for process
understanding at larger scales. At larger scales, land and water management policies are more important
than impacts associated with small projects, and the spatial patterns of impacts from large-scale natural
process, such as climate variability, major storms, wildfire, and insect outbreaks, become substantially more
influential. Within two large (> 7,000 km2) mountainous Idaho river basins, we are developing long-
term data sets to describe biological and physical processes influencing aquatic habitat, and the distribution,
diversity, and persistence of fish. In the Middle Fork Salmon River, the abundance of ESA-listed, native
Chinook salmon have been monitored annually for more than 55 years. Since 1995, we have supplemented
these long-term dataset with annual spatial censuses of spawning distributions and collection of samples for
landscape-level genetic analyses. Biological data are being integrated with basin-scale predictions of salmon
spawning habitat distributions, estimates of sediment motion and bedload transport, basin-scale patterns of
spatial autocorrelation in water temperatures, and continuous remote sensing of selected stream channels
via airborne laser altimetry. In the Boise River Basin, we have examined the effects of historic wildfires and
contemporary climate change on habitat distributions for ESA-listed bull trout and other native salmonids.
Comparisons between scales of debris-flow run out paths and fish habitat patches reveal important
geomorphic controls on population structure and vulnerability to physical disturbances. Basin-scale effects of
fire and post-fire debris flows on riparian vegetation, stream temperature, water yield, foodwebs, and fish
physiology (rates of growth and maturity) are also being examined, as are spatiotemporal changes in channel
morphology and spawning habitat due to network routing of post-fire sediment inputs. Using results from
these two basins, we provide examples to illustrate how large-scale and long-term data can reveal outcomes
that might not be predicted from local-scale studies. Managing in an ever more dynamic and rapidly changing
landscape will require considering larger scales and tradeoffs between large vs. local scale process. As
policies and paradigms rooted in reach and individual scale process become increasingly untenable,
emerging science integrating multiple scales will become increasingly important. Larger experimental units
that encompass a mix of management activities may be a critical addition to the portfolio of experimental
forests and watersheds.
http://www.fs.fed.us/rm/boise/
H11L-04
USDA Experimental Watersheds for Studies of Ecohydrology
This work identified 81 U.S. Department of Agriculture (USDA) experimental watersheds, forests and ranges with data records of more than 20 years measuring important ecosystem dynamics, such as variations in vegetation, precipitation, climate, runoff, water quality and soil moisture. Information on data archiving and web-based access is presented. New analyses of network-wide, long-term data from USDA experimental watersheds were used to test commonly held assumptions about the long-term variability of rainfall and runoff. Results emphasized the need for continuous, interdisciplinary data records spanning more than 20 years across a wide range of ecosystems within and outside the conterminous United States to draw correct conclusions about ecohydrological feedbacks. Three areas of further investigation were identified to best exploit the unique spatial distribution and long-term data of USDA experimental sites: convergence, cumulative synthesis and autocorrelation.
H11L-05
Decadal Patterns of Retention of N and S in the Experimental Bear Brook Watershed in Maine
Watershed-scale experiments (typically substituting time-for-space) are complementary to regional gradient assessments (space-for-time) and plot-scale or laboratory-scale experiments. At the Bear Brook Watershed in Maine (BBWM), a whole watershed N+S addition experiment has been underway since 1989 to complement on-site plot experiments, and to assess the assumptions of models of acidification and recovery related to the original Clean Air Act (1970) and Amendments (1990). The 10 ha West Bear watershed has been experimentally acidified with 1800 eq dry (NH4)2SO4 /ha/yr, with the 11 ha East Bear watershed serving as the reference. Between 1989 and 2006, the reference site averaged less than 900 eq/ha/yr net export of SO4 when dry deposition was estimated as 130% of wet. West Bear export increased to 2000 eq/ha/yr five years after treatment began, and has retained an average 900 eq/ha/yr SO4, or about half of the experimental treatment since the peak export period. Dissolved inorganic nitrogen has been largely retained in both the reference (94%) and treated (84%) catchments despite high N loading in the experiment. Retention in the West Bear watershed has been higher than projections from MAGIC (Model of Acidification of Groundwater in Catchments) that indicated that stream concentration and mass export of SO4 would continue to increase to values much greater than observed at the peak five years into the experiment. The increase in SO4 flux slowed after the initial rapid increase from the start of the treatment, suggesting that a new steady-state has been reached. West Bear's apparent resistance to further change despite continued loading indicates an unexpectedly high SO4 retention. These results have implications for model assumptions and predictions of export and retention of SO4 under current scenarios of decreased acidic deposition.
H11L-06
The FORWARD Project: Incorporating Long-Term Hydrologic Datasets Into Detailed Forest Management Plans for the Canadian Boreal Forest
The Forest Watershed and Riparian Disturbance (FORWARD) Project has collected data on weather, soils, vegetation, streamflow and stream water quality under relatively undisturbed conditions, as well as after experimental forest harvest, in partnership with industrial forest operations within the Boreal Plain and Boreal Shield ecozones of Canada. Research-based contributions from FORWARD were integrated into our Boreal Plain industry partner's 2007-2016 Detailed Forest Management Plan. These contributions consisted of three components: 1) A GIS watershed and stream layer that included a hydrological network, a Digital Elevation Model, and Strahler classified streams and watersheds for 1st- and 3rd-order watersheds; 2) a combined soil and wetland GIS layer that included maps and associated datasets for relatively coarse mineral soils (which drain quickly) and wetlands (which retain water), which were the key features that needed to be identified for the FORWARD modelling effort; and 3) a lookup table was developed that permits planners to determine runoff coefficients (the variable selected for hydrological modelling) for 1st-order watersheds, based upon slope, vegetation and soil attributes in forest polygons. The lookup table was populated with output from the deterministic Soil and Water Assessment Tool (SWAT), adapted for boreal forest vegetation with a version of the plant growth model, ALMANAC. The runoff coefficient lookup table facilitated integration of predictions of hydrologic impacts of forest harvest into planning. This pilot-scale effort will ultimately be extended to the Boreal Shield study area.
H11L-07 INVITED
Small watershed-scale research and the challenges ahead
For the past century, Federal mission science agencies (eg. USFS, NRCS, ARS, USGS) have had the long-
term agency goals, infrastructure, and research staff to conduct research and data collection in small
watersheds as well as support these activities for non-Federal partners. The National Science Foundation
has been a strong partner with the Federal mission science agencies, through the LTER network, which is
dependent on Federally supported research sites, and more recently with the emerging CUAHSI, WATERS,
CZEN, and NEON initiatives. Much of the NSF-supported research builds on the foundations provided by
their Federally supported partners, who sustain the long-term, extensive monitoring activity and research
sites, including making long-term data available to all users via public interfaces. The future of these
programs, and their enhancement/expansion to face the intensifying concurrent challenges of population
growth, land-use change, and climate change, is dependent on a well-funded national commitment to basic
science. Such a commitment will allow the scientific community to advance our understanding of these
scientific challenges and to synthesize our understanding among research sites and at the national scale.
Small watersheds serve as essential platforms where hypotheses can be tested, as sentinels for climate
change, and as a basis for comparing and scaling up local information and syntheses to regional and
continental scales. The science guides resource management and mitigation decisions and is fundamental to
the development of predictive models. Furthermore, small-watershed research and monitoring programs are
generally undervalued because many research questions that can be addressed now or in the future were
not anticipated when the sites were initiated. Some examples include: 1) the quantification, characterization,
and understanding of how emerging contaminants, personal care products, and endocrine disruptors affect
organisms – substances that could not be detected until the recent increased sensitivity of modern
techniques; 2) the recognition of changing climate and its effects on already-stressed water resources and
ecosystems; 3) more integrated monitoring and modeling of ecosystem processes and quantification of
ecosystem services. Historical hydrological and biogeochemical information available at USGS and other
watershed-research and -monitoring sites can now be used in conjunction with active monitoring of biota and
biological processes (especially those involving plants, invertebrates and microbes). The results will help
provide a more nationally consistent framework for evaluating ecosystem health, and assessing ecosystem
services, in the face of changing climate and land-use.
These, and related science questions and societal issues are complex and require strong collaborations
across disciplinary and organizational boundaries. Along with a well-funded national commitment to basic
watershed research, the USGS continually seeks to strengthen its small-watershed and ecosystem-science
programs through partnerships with NSF, State, and Federal agencies. Given the growing U.S. population,
continual development in water-scarce regions, and general water- and soil-resource stress under competing
national interests and priorities, the role of basic watershed-scale research and monitoring is essential
because of its unique niche in the development of the improved environmental understanding and predictive
models needed by resource managers.
http://water.usgs.gov/