NW Climate Science Digest

Aquatic Resources, Stream Flow, Hydrology in the Western U.S.

Impacts of Climatic Variation on Trout: A Global Synthesis and Path Forward

Kovach, R. P., Muhlfeld, C. C., Al-Chokhachy, R., Dunham, J. B., Letcher, B. H., & Kershner, J. L. (2015). Impacts of climatic variation on trout: a global synthesis and path forward. Reviews in Fish Biology and Fisheries, 1–17. doi: 10.​1007/​s11160-015-9414-x

Due to the lack of studies quantifying climate-induced impacts on trout, Kovach et al. (2016) synthesized existing research to review the current understanding of how trout ecology may be affected by climate variation, specifically due to temperature and streamflow changes. Rigorous meta-analysis was difficult to accomplish because of the limited number of current studies, however a consistent positive relationship was found between summer streamflow and trout demography and growth. Temperature was a less influential factor on trout ecology, though a negative relationship was found between summer and fall temperatures and trout demography. The authors concluded that more research must be conducted on climate-induced changes to trout ecology, as trout are a group of fish with global economic, ecological, and cultural importance.

A New Publicly Available Database of Watershed Metrics for the United States

Hill, Ryan A., Marc H. Weber, Scott G. Leibowitz, Anthony R. Olsen, and Darren J. Thornbrugh, 2016.The Stream-Catchment (StreamCat) Dataset: A Database of Watershed Metrics for the Conterminous United States. Journal of the American Water Resources Association (JAWRA) 52(1): 120-128. DOI:10.1111/1752-1688.12372

A new dataset containing landscape metrics for upstream watersheds and catchments in the conterminous United States has been developed by the Environmental Protection Agency’s Office of Research and Development. Called the Stream-Catchment (StreamCat) Dataset, this tool allows the distribution of catchments and watersheds to be visualized for the conterminous United States. The database has been made available to the public which allows researchers and managers to access landscape information without the need for specialized geospatial expertise. The extensive resource will be useful for better understanding and characterizing river systems in the United States. This article, published in the Journal of the American Water Resources Association, detailed the development and main features of the dataset, including specific landscape features used; scripts and algorithms built to produce watershed summaries; and quality assurance procedures for ensuring data consistency.

Assessing the Effectiveness of Stream Restoration Monitoring in the Northwest

Stephen Bennett, George Pess, Nicolaas Bouwes, Phil Roni, Robert E. Bilby, Sean Gallagher, Jim Ruzycki, Thomas Buehrens, Kirk Krueger, William Ehinger, Joseph Anderson,Chris Jordan, Brett Bowersox & Correigh Greene. 2016. Progress and Challenges of Testing the Effectiveness of Stream Restoration in the Pacific Northwest Using Intensively Monitored Watersheds. Fisheries. 41(2):92-103.

The Pacific Northwest, due to its large populations of endangered anadromous fish populations (salmon and steelhead), has seen major efforts toward implementing stream restoration. While these efforts are seen as ecologically sound, little research has been done to understand the relationship between freshwater habitat improvement and increased fish populations. Therefore, 17 watershed projects have been implemented to test the validity of this relationship. In this recently published article, Bennett et al. (2016) assessed the scope and status of these 17 projects and reported current challenges and suggestions for improving experimental designs that fit into an adaptive management framework. Based on their assessment, the authors confirmed that intensive monitoring of watersheds is a sound approach for measuring the success of stream restoration, though they found funding and coordination between participants and stakeholders to be significant challenges.

Factors Impacting Flow of Headwater Stream Networks in Central Idaho

Whiting, John A. and Sarah E. Godsey, 2016. Discontinuous headwater stream networks with stable flowheads, salmon river basin, Idaho. Hydrological Processes, in press. doi: 10.1002/hyp.10790

A new study from Idaho State University examined the hydrologic mechanisms affecting changes to the flow path of streams in Central Idaho's Frank Church-River of No Return Wilderness. Whiting & Godsey (2016) presented survey data of active drainage networks in four headwater streams. The authors found that stream discharge varied with the total length of the active drainage networks, though less so than past studies have shown. The study also compared active drainage network length along entire flow paths of the watershed and found that a majority of the changes in length were due to downstream discontinuities, with more stable flow paths occurring near the stream’s head. Additionally, geologic characteristics were examined for the various watersheds and found that streamflows originating below 2,200 m were controlled by bedrock and thus more stable than those originating at higher elevations and surrounded by less compact soils.

Biodiversity/Species and Ecosystem Response

Climate Change Impact on American Pika using Improved Species Distribution Models

Schwalm, D., Epps, C. W., Rodhouse, T. J., Monahan, W. B., Castillo, J. A., Ray, C. and Jeffress, M. R. (2016), Habitat availability and gene flow influence diverging local population trajectories under scenarios of climate change: a place-based approach. Glob Change Biol. doi:10.1111/gcb.13189

Species distribution models (SDMs) are used to project the impact of climate change on species’ ecological niches, but often paint an overly simplistic picture that is limited to climate-occupancy interactions. In this new study, Oregon State University scientists used more complex modeling to research the impact of climate change on the American pika. The study incorporated climate, gene flow, habitat configuration, and microhabitat complexity to build separate SDMs for pika populations inhabiting eight U.S. National Park Service units, a distribution that represents pika variety across the U.S. The results displayed highly variable occupancy patterns across the western U.S., suggesting important local-scale differences in the realized niche of the American pika. The study also found that habitat composition and connectivity were among the most influential variables in predicting pika occupancy for all study areas. This is an important result because SDMs rarely include these two variables, stressing the importance of including fine-scale factors when assessing current and future climate impacts on species’ distributions.

Snow Decline Impacts Snowshoe Hare Fitness

Zimova, M., Mills, L. S. and Nowak, J. J. (2016), High fitness costs of climate change-induced camouflage mismatch. Ecol Lett, 19: 299–307. doi:10.1111/ele.12568

A recently published study from North Carolina State University examined the individual and population-level impacts of decreased snow cover duration on snowshoe hares. Snowshoe hares undergo seasonal color molts from white to brown that align with changes in snow cover from winter to spring, but could be threatened by a climate change-induced phenological mismatch. Zimova et al. (2016) tracked 186 snowshoe hares in Western Montana and found a strong selection on coat color molt phenology. The weekly survival of hares that mismatched their habitat was measured to be 4-7% lower than hares with camouflaged coats. The study concluded that this climate-change induced phenological mismatch will result in massive population declines over the next century unless individual variation in molt phenology allows for evolutionary adaptation.

Climate and Weather Reports and Services

Improved Winter Projections for the Northwest U.S.

Isla R. Simpson, Seager, R., Ting, M., & Shaw, T. A. (2015). “Causes of change in Northern Hemisphere winter meridional winds and regional hydroclimate.” Nature Climate Change, 6, 65-71, doi:10.1038/nclimate2783

Changes to hydrology, particularly precipitation, have long been a challenge to climate modelers. As a result, there is a wide range of projections for how rainfall will change in the Northwest United States. Isla Simpson and other scientists from the Lamont-Doherty Earth Observatory at Columbia University, evaluated existing models in order to see whether the wide range could be narrowed. The scientists systematically eliminated atmospheric responses to climate change that did not directly affect precipitation in the Northwest. By doing this, they were able to identify consistencies across all models, and pegged one atmospheric response as the key stimulus for precipitation changes- a strengthened jet stream. The authors then focused on how well each model simulated the jet stream and discovered that models with weaker simulations generally exhibited more extreme increases in Northwestern precipitation. This finding carries important implications, as many winter projections could be overestimations.

Coastal/Marine Ecosystems, Ocean Acidification, Sea Level Rise

Seagrass Genome Reveals Angiosperm Adaptation to Life in a Marine Environment

Olsen, J. L., Rouzé, P., Verhelst, B., Lin, Y.-C., Bayer, T., Collen, J., et al. 2016. The genome of the seagrass Zostera marina reveals angiosperm adaptation to the sea. Nature, advance on. Retrieved from http://dx.doi.org/10.1038/nature16548

A recent study published in Nature reported the genome of Zostera marina, the first marine angiosperm to be fully sequenced, according to the authors. The sequenced genome exposes the adaptations angiosperms have undergone in order to survive in their marine environment. Many genomic losses were found, including the genes regulating stomatal structure, UV protection, and other structural and physiological functions. Among the discovered gains in its genome were functions that enable angiosperms to adjust to higher salinity as well as maintain ion homeostasis in a marine environment. The article concluded by suggesting the importance of this sequenced genome as a resource both for understanding how marine ecosystems will adapt to future climate change, as well furthering evolutionary biology of plant adaptation capabilities.

Assessing Coastal Manager Science Needs

Thorne, K.M., Powelson, K.W., Bui T.D., Freeman, J.Y. Takekawa, C.M., Janousek, C.N., Buffington, K.J., and D.L. Elliott-Fisk 2016. Assessing coastal manager science needs and disseminating science results for planning. Data Summary Report Prepared for the California and North Pacific Landscape Conservation Cooperatives. USGS Western Ecological Research Center, Vallejo, CA. 110 pp.

In this new report, The USGS Coastal Ecosystems Response to Climate Change program collected and analyzed extensive field data of elevation, inundation, tidal range, accretion, and plant communities to assess the vulnerability of tidal wetland habitats to climate change. The report informs management decisions at a local level through monitoring site conditions and developing site-specific sea-level rise response models. The program also spoke with managers, biologists, tribes, and other stakeholders in order to facilitate communication concerning the results of sea-level rise response models. In-person workshops were held with decision makers and stakeholders involved with six Pacific coast estuaries in order to discuss site-specific science results and manager needs.


Current Knowledge of Fire Effects on Aquatic Ecosystems

Bixby, Rebecca J., Scott D. Cooper, Robert E. Gresswell, Lee E. Brown, Clifford N. Dahm, and Kathleen A. Dwire. 2015. “Fire Effects on Aquatic Ecosystems: An Assessment of the Current State of the Science”. Freshwater Science 34 (4). University of Chicago Press, Society for Freshwater Science: 1340–50. doi:10.1086/684073.

A report synthesizing the current research on how freshwater ecosystems are impacted by fire disturbance was published in the journal, Freshwater Science. The report summarized the effect of fire on many environmental variables, such as vegetation in watersheds, hydrology due to altering microclimates and sedimentary processes, water quality, the amount of organic matter transported through river systems, and changes to aquatic biota. In addition to outlining the state of knowledge on fire effects to aquatic ecosystems, the report concluded with a list of seven research topics required to expand our understanding.


New Forest Vulnerability Index for Predicting Forests Stress and Mortality

Mildrexler, D., Yang, Z., Cohen, W. B., & Bell, D. M. (2015). A forest vulnerability index based on drought and high temperatures. Remote Sensing of Environment, 173, 314–325. http://doi.org/10.1016/j.rse.2015.11.024

Scientists at Oregon State University have produced a new forest vulnerability index (FVI), a system that maps potential forest stress and tree mortality in the Northwest United States due to climatic changes such as higher temperatures and extreme droughts. Mildrexler et al. (2015) used variables such as evapotranspiration, land surface temperature, and precipitation to produce a monthly water balance that was calculated into a forest stress index (FSI). The authors then analyzed the change in local FSI from 2003 to 2012 and used that gradient to produce localized, monthly FVI values. Locations with increased forest stress over the study period produced positive FVI values and indicated expected forest vulnerability for that month. Positive FVI values were concentrated in the months of August and September. In addition, the authors distinguished between forest type groups and examined differences in FVI values for various groups. The study found that drier forest type groups, including Ponderosa Pine, Juniper, and Lodgepole Pine, displayed higher vulnerability.

A Synthesis of Drought Impacts on Forests in the United States

Vose, J.M.; Clark, J.S.; Luce, C.H.; Patel-Weynand, T., eds. 2016. Effects of drought on forests and rangelands in the United States: a comprehensive science synthesis. Gen. Tech. Rep. WO-93b. Washington, DC: U.S. Department of Agriculture, Forest Service, Washington Office. 289 p.

The U.S. Department of Agriculture (USDA), Forest Service, Research and Development scientists, and Duke University have authored and released a comprehensive report that provides input to the National Integrated Drought Information System (NIDIS), the National Climate Assessment (NCA), and up-to-date drought resilience and adaptation information. The NIDIS was an act signed into law in 2006 and reauthorized by Congress in 2014. The system integrates and supports the research of drought monitoring and forecasting at the national, state and local levels. The National Climate Assessment (NCA) is a national evaluation of how climate change is impacting U.S. forests, rangeland, as well as other land and water resources, and is produced every 4 years. This report, titled Effects of Drought on Forests and Rangelands in the United States: A Comprehensive Science Synthesis, identified key issues concerning both scientists and stakeholders. Included were topics ranging from drought characterization; effects of drought on forest ecology and processes; and the socio-economic consequences of drought. In addition to the full report linked below is a summary of the report’s findings specific to the Northwest United States.

Land Use

Managing for Climate Change on Federal Lands of the Western U.S.

Kemp, K. B., J. J. Blades, P. Z. Klos, T. E. Hall, J. E. Force, P. Morgan, and W. T. Tinkham. 2015. Managing for climate change on federal lands of the western United States: perceived usefulness of climate science, effectiveness of adaptation strategies, and barriers to implementation. Ecology and Society 20(2): 17.

Federal agencies in the United States have started to include climate change science in their management planning due to recent national mandates. This article, published in Ecology and Society, is one of the first to examine the effectiveness of these mandates as perceived by managers. The study surveyed 77 U.S. Forest Service and Bureau of Land Management personnel across Idaho and Montana. The authors found that most resource managers were incorporating climate change language into planning documents but leaving climate change science out of the current projects. The perception of the managers was that existing non climate-related management strategies, such as thinning and prescribed burning, were more likely to lead to climate change adaptation within their organizations. This was because existing strategies already have public and agency support and are more geared toward localized and existing land management goals. Common issues identified by the study’s participants included lack of management-relevant climate change science, inconsistent agency guidance, and insufficient time and resources.

Special Reports / Announcements

Ecological Drought Across the Country: Understanding the Impacts Region by Region

The regional Climate Science Centers and the National Climate Change and Wildlife Science Center are collaborating with University partners to better understand the effects of drought on wildlife and ecosystems of different regions of the United States. This nationwide project hopes to identify key resources threatened by prolonged water deficits, as well as the potential effects of drought on ecological systems. The project will utilize the University of Maryland’s Integration and Application Network to conduct one workshop with each Climate Science Center in order to compile current research concerning drought effects on different regions of the U.S. The product of this project will be a national report of the current knowledge of ecological drought in the United States.

Taking Action

Aligning National Forest Management Plan with Current Climate Change Science

The Francis Marion National Forest in South Carolina is currently reworking its forest plan in order to accommodate newly understood challenges to the region. Due to increased climate change science information for the region, as well as a growing population, the national forest has decided to take action by incorporating this new information into its forest management plan. Using online tools such as the Template for Assessing Climate Change Impacts and Management Options (TACCIMO), the forest managers have already assessed the Francis Marion National Forest and documented a comprehensive review of existing climate change science specific to the region. Additionally, the review outlined new adaptive management strategies to be incorporated into the forest plan. These strategies encompass the main concerns for the national forest, including the spread of non-native species, the growth of urban development, and the need for further monitoring in order to better respond to climate-induced forest vulnerabilities. The team is currently in the development stage.

Methodology for Tidal Wetland and Seagrass Restoration - A Newly Approved Protocol

The Verified Carbon Standard has approved a new methodology for encouraging the restoration of coastlines across the globe. The methodology, developed by Restore America’s Estuaries and Silvestrum, in collaboration with others, outlines the protocol for quantifying greenhouse gas reductions for coastal restoration projects. By reducing greenhouse gases, such projects would be eligible for carbon credits. The goal of this methodology is to provide more funding for future restoration projects. It is significant because it is the first study to apply such a method to the coastal habitat, a region holding great ecological importance as well as important habitat for climate mitigation.

Methodology for Tidal Wetland and Seagrass Restoration - A Newly Approved Protocol

The Verified Carbon Standard has approved a new methodology for encouraging the restoration of coastlines across the globe. The methodology, developed by Restore America’s Estuaries and Silvestrum, in collaboration with others, outlines the protocol for quantifying greenhouse gas reductions for coastal restoration projects. By reducing greenhouse gases, such projects would be eligible for carbon credits. The goal of this methodology is to provide more funding for future restoration projects. It is significant because it is the first study to apply such a method to the coastal habitat, a region holding great ecological importance as well as important habitat for climate mitigation.

Tribal and Indigenous Peoples Matters

Climate Change as Perceived by Indigenous Peoples

In this news article from Oregon State University, Samantha Chisholm Hatfield, a post-doctoral researcher with the Oregon Climate Change Research Institute, described her research on utilizing Traditional Ecological Knowledge to understand the perspective of Siletz tribal members on climate change. According to Chisholm Hatfield, due to the continuity with which Northwest tribes interact with their environment (i.e. the myriad of traditions that place tribes in the same spaces year after year), they are more perceptive to, and affected by, the impact of climate change. Her research, funded by the NW CSC, NPLCC, and CIRC, consisted of interviews with 25 Siletz tribal members with the goal of illustrating that climate change implicates more than ecological changes for Native peoples. In this article, Chisholm Hatfield claimed that there is a deeper cultural connection to the environment than many nonnative populations realize.