NW Climate Science Digest

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

Snow science supporting our nation's water supply

A NASA-led research campaign called SnowEx was recently launched in Colorado. The amount of water in snow plays a critical role in water availability for drinking water, agriculture, and energy, however an accurate measurement of how much water is stored in snow has remained a major obstacle for scientists. The goal of SnowEx is to create and refine the best snow-measuring techniques in order to build an accurate map of water content contained in the nation’s snow. Data collected from SnowEx will be available to the public and stored at the National Snow and Ice Data Center in Boulder, Colorado. Learn more about SnowEx.

Deep groundwater aquifers respond rapidly to climate variability

Tess A. Russo, Upmanu Lall. Depletion and response of deep groundwater to climate-induced pumping variability. Nature Geoscience, 2017; 10 (2): 105 DOI: 10.1038/ngeo2883

A new study from Penn State University and Columbia University examined the unexpectedly rapid response of deep groundwater levels to climate change in recent years. Hydrologists Tess Russo and Upmanu Lall observed that deep groundwater levels respond to climate over timescales of less than one year, despite former expectations of a multi-year time lag. From this finding, the authors concluded that changes to deep groundwater levels must be driven by a factor other than precipitation changes. They hypothesized that the driving factor could be from changes in the pumping of aquifers from agricultural industries. As climate change impacts precipitation patterns and increases the frequency of drought, the irrigation of crops must be compensated through pumping deep groundwater. The authors emphasized the need to better understand how pumping impacts deep groundwater levels in order to know how to manage the nation’s water resources.

Low snowpacks of 2014, 2015 may become increasingly common

Sproles, E. A., Roth, T. R., and Nolin, A. W.: Future snow? A spatial-probabilistic assessment of the extraordinarily low snowpacks of 2014 and 2015 in the Oregon Cascades, The Cryosphere, 11, 331-341, doi:10.5194/tc-11-331-2017, 2017.

A new study suggests that the historically low Cascade Mountain snowpack levels in 2014 and 2015 could become more common if average temperatures warm as little as two degrees Celsius. The low snowpack levels were linked to warmer temperatures and not a lack of precipitation. Based on simulations of previous and predicted snowpack, the study suggests that by mid-century, years like 2015 may happen about once a decade, while snowpack levels similar to 2014 will take place every 4-5 years. Results of the study, which was supported by the National Aeronautics and Space Administration (NASA) and the National Science Foundation, were recently published the journal The Cryosphere.

Linking the hydrologic impacts of atmospheric rivers to Rossby wave breaking on the US West Coast

Hu, H., Dominguez, F., Wang, Z., Lavers, D. A., Zhang, G., & Ralph, F. M. 2017. Linking Atmospheric River Hydrological Impacts on the US West Coast to Rossby Wave Breaking. Journal of Climate, DOI: http://dx.doi.org/10.1175/JCLI-D-16-0386.

Scientists from the University of Illinois and Scripps Institute of Oceanography recently published their study examining the connection between the landfalling of Atmospheric Rivers and types of Rossby wave breaking on the U.S. West Coast. Rossby waves in the atmosphere are wind currents associated with planetary rotation, that either rotate clockwise (anti-cyclonic) or counterclockwise (cyclonic) depending on the direction of flow. These two types of Rossby waves exhibit different angles of wave breaking when they come in contact with land, such as the U.S. West Coast. Through this study, the authors identified the main type or Rossby wave breaking associated with the Northwest coastline and the California coastline. They found that anticyclonic Rossby wave breaking is the dominant connection to extreme streamflows in the Northwest while cyclonic Rossby wave breaking was found to be responsible for extreme streamflows along the California coast.

Arid Ecosystems

Global warming will likely decrease the extent of temperate drylands

Daniel R. Schlaepfer et al. Climate change reduces extent of temperate drylands and intensifies drought in deep soils. Nature Communications, 2017; 8: 14196 DOI: 10.1038/ncomms14196

A team of international scientists collaborated to study the specific impact of climate change on drylands in the mid-latitudes (temperate region). The authors analyzed projections of changes in soil moisture and ecological droughts which have major influences on vegetation productivity in temperate drylands. Findings from this study suggest that temperate drylands may decrease by 30% by the end of the century and be converted into subtropical drylands. Additionally, the authors found that deep soil layers are projected to become increasingly dry during the growing season.

Genetic recapture identifies long-distance breeding dispersal in Greater Sage-Grouse

Todd B. Cross, David E. Naugle, John C. Carlson, and Michael K. Schwartz. 2017. Genetic recapture identifies long-distance breeding dispersal in Greater Sage-Grouse (Centrocercus urophasianus). The Condor 119:1, 155-166

Dispersal can strongly influence the demographic and evolutionary trajectory of populations. Yet, for many species, little is known about dispersal, despite its importance to conservation. This study investigated dispersal patterns among spring breeding congregations of the Greater Sage-Grouse (Centrocercus urophasianus), a species of conservation concern that ranges across 11 western U.S. states and 2 Canadian provinces. To do this, the team examined a microsatellite DNA dataset of 3,244 Greater Sage-Grouse sampled from 763 leks throughout Idaho, Montana, North Dakota, and South Dakota, USA, across 7 years. They recaptured ∼2% of individuals, documenting 41 instances of breeding dispersal, with 7 dispersal events of >50 km, including 1 of 194 km. They saw 39 recaptures on the same lek up to 5 yr apart, supporting the paradigm of philopatry in lekking species. They found no sex differences in breeding dispersal distances or in the tendency to disperse. Importantly, they did document movements within and among state-delineated priority areas of conservation importance, further supporting the need to identify movement corridors among these reserves. These results can be used to better inform the assumptions of count-based population models and the dispersal thresholds used to model population connectivity and potential range shifts related to climate change.

Do invasive alien plants benefit more from global environmental change than native plants?

Liu, Y., Oduor, A. M. O., Zhang, Z., Manea, A., Tooth, I. M., Leishman, M. R., Xu, X. and van Kleunen, M. 2017. Do invasive alien plants benefit more from global environmental change than native plants?. Glob Change Biol. doi:10.1111/gcb.13579

A recently published study compared the effects of climate change on non-native and native plants. Authored by an international team of scientists, the article used previous studies to compile a database of 74 non-native plant species and 117 native plant species in response to changes in mean levels of precipitation, temperature, atmospheric CO2 concentration and nitrogen deposition. Findings from the study showed that non-native species outperformed native species in every factor of climate change measured except for increased drought (decreased precipitation). These results indicated an increase in spread of non-native plants with future climate change.

Biodiversity/Species and Ecosystem Response

How migratory birds respond to balmier autumns

Adrienne Berchtold, Ira Nightingale, Caitlin Vandermeer, Scott A. MacDougall-Shackleton. Experimental temperature manipulations alter songbird autumnal nocturnal migratory restlessness. Animal Migration, 2017; 4 (1): 1 DOI: 10.1515/ami-2017-0001

A new paper reports the results of lab experiments to investigate how temperature influences the urge to migrate in songbirds. The study was led by Adrienne Berchtold from the Advanced Facility for Avian Research at the University of Western Ontario. Her team focused on the white-throated sparrow, a species known to rely on weather to time its annual autumn journey from Canada to the southern U.S. They used specially-designed cages equipped with high-tech monitoring gear to track patterns of activity while varying room temperatures. When the temperature dropped to 4ºC, the birds became restless at night, signifying they were in a migratory state. When the temperature was raised to 24ºC, none of the birds showed signs of migratory restlessness, indicating an urge to stay. These results suggest that increases in autumn temperatures could delay migration. Another possibility is that the birds could decide to forego migration altogether, as is happening in certain populations of American Robins.

Towards a threat assessment framework for ecosystem services

Martine Maron et al. 2017. Towards a Threat Assessment Framework for Ecosystem Services. Trends in Ecology and Evolution. DOI: 10.1016/j.tree.2016.12.01

Ecosystem services, or the ways in which people benefit from nature, are essential for human well-being, but are less understood, particularly when it comes to services at risk of undersupply. University of Queensland scientist, Martine Maron, led a study recently published in Trends in Ecology and Evolution that developed a framework for identifying threatened services by analyzing supply and demand. The authors hope the framework can be used in concert with existing assessments of threat to species and ecosystems in order to progress toward more effective land management. The study’s co-author, Matthew Mitchell, provided an example of poorly managed land in an interview with the University of Queensland; “An example we often see in our cities is the loss of vegetation and its ability to intercept rainwater and reduce flooding. People continue to develop flood-prone areas while also clearing vegetation and building on upstream slopes, so floods are becoming more common and damaging.”

Migratory bird phenology in a changing climate

Biologist, Madeleine Rubenstein, discussed current research initiatives studying the impact of climate change on wildlife phenology in an article from The Wildlife Society. In the article, Rubenstein writes about the known effects climate change has on wildlife phenology, including the timing of bird migration, plants putting out leaves, and insect emergence. The author explains how wildlife phenology normally exhibits a synchrony among species, but turns into a cacophony with anthropogenic change to climate. The United States Geological Survey’s National Climate Change and Wildlife Science Center and the Department of Interior's Climate Science Centers are heading key research initiatives to better understand phenological shifts across various ecoregions. Read the article to further learn about the diversity of research currently underway, as well as projects containing citizen science opportunities.

More warm-dwelling animals and plants as a result of climate change

Diana E. Bowler et al. 2017. Cross-realm assessment of climate change impacts on species’ abundance trends. Nature Ecology & Evolution; 1 (3): 0067 DOI: 10.1038/s41559-016-0067

A massive comprehensive study of the long-term effect of increasing temperature on species population size has been published in Nature Ecology and Evolution. The study examined population trends of approximately 1,000 species from 22 local/regional communities since 1980. The research team consisted of 27 institutions spanning scientific institutions, state authorities, non-governmental organizations, and citizen science groups. Species examined ranged from birds and butterflies, to terrestrial, freshwater and marine communities. Every species was first identified for whether they prefer warm or cool temperatures, and then assessed for changes in population size. The study observed a positive relationship between temperature preference and population size in terrestrial communities, meaning warm-dwelling species showed a larger increase in population size than cold-dwelling species. The strongest evidence was found in the most mobile species, such a birds, butterflies and terrestrial invertebrates. Results from the aquatic communities were not significant, however similar positive trend in marine fish was identified. The findings from the study confirmed that changes in ambient temperature directly impact the population size of species.

Winners, losers among fish when landscape undergoes change

Jonathan W. Moore, Julian D. Olden. Response diversity, nonnative species, and disassembly rules buffer freshwater ecosystem processes from anthropogenic change. Global Change Biology, 2016; DOI: 10.1111/gcb.13536

Jonathan Moore from Simon Fraser University and Julian Olden from the University of Washington recently published a study in which they examined the relationship between freshwater fish ecosystems and human land development. The authors analyzed data of 533 fish species from 8,100 stream locations across the contiguous U.S. For each species, the researchers collected data on nutrient excretion in order to quantify their role in the recycling of nutrients within their freshwater ecosystem. By doing so, the study built an unprecedented national-level map of nutrient excretion by freshwater fish. The authors then analyzed species response to human land development and found a diversity of sensitivities across fish species, including a particular contrast between native and non-native fish. Through modeled projections of increased land-use change, the study showed an estimated decrease in fish nutrient excretion for 63% of the ecoregions studied, and that this loss of excretion would be 84% greater in the absence of non-native species, which seem to act as a buffer to ecosystem change.

Climate and Weather Reports and Services

Critical feedbacks between Earth systems and human systems are missing from current climate models

Safa Motesharrei et al. 2016. Modeling Sustainability: Population, Inequality, Consumption, and Bidirectional Coupling of the Earth and Human Systems. National Science Review; nww081 DOI: 10.1093/nsr/nww081

Researchers from the University of Maryland recently published an article in the National Science Review urging climate scientists to increase their collaboration with social scientists and engineers in order to construct a more comprehensive model of the Earth-Human system. The authors wrote that key Human System variables such as demographics, inequality, economic growth, and migration are often not coupled with Earth System models, causing the current climate models used to miss important feedbacks in the Earth-Human system. Follow the links below to learn more about their proposed method for environmental modeling.

‘Blob’ in Pacific Ocean ramps up ozone levels above Western U.S.

Jaffe, D. A., and L. Zhang. 2017. Meteorological anomalies lead to elevated O3 in the western U.S. in June 2015, Geophys. Res. Lett., 44, doi:10.1002/2016GL072010.

The anomalous mass of warm sea surface water that persisted across the northeastern Pacific Ocean in winter through early summer of 2014-2015 (known as the “Blob”) has corresponded with an enhanced ozone layer across a large portion of the western U.S. Values of this enhancement were taken from the Mount Bachelor Observatory. These findings were published in Geophysical Research Letters and authored by researchers from the University of Washington. The authors concluded that the high ozone concentration was associated with increased temperatures, reduced cloud fraction, increased stagnation, and increased biogenic emissions.

Coastal/Marine Ecosystems, Ocean Acidification, Sea Level Rise

New approach to projecting sea-level suggests higher coastal flooding potential

Goodwin, P., Haigh, I. D., Rohling, E. J. and Slangen, A. 2017. A new approach to projecting 21st century sea-level changes and extremes. Earth's Future. doi:10.1002/2016EF000508

Our understanding of future increases in flooding potential around the world's coastlines depends on projections of future global mean sea level (GMSL) rise. Yet, the two main approaches for projecting 21st century GMSL rise—i.e., process-based versus semi-empirical—give inconsistent results. This paper reports the results of a novel hybrid approach to GMSL projection. The projections from this hybrid approach were found to be consistent with the dominant process-based GMSL projections from the Climate Model Intercomparison Project phase 5 (CMIP5) ensemble. However, when observations were used to provide the historic constraints, the authors found higher ice-melt sensitivity and additional ensemble-mean GMSL rise of around 13–16 cm by the end of the century. They assess the impact of this additional GMSL rise on the increase in frequency of extreme sea level events for 220 coastal tide-gauge sites. Accounting for regional effects, they found a 1.5–8 times increase in the frequency of extreme sea-level events for their higher GMSL projections relative to CMIP5.

Carbon cycling in Pacific coastal wetlands

Janousek, C.N., Buffington, K.J., Guntenspergen, G.R. et al. 2017. Ecosystems doi:10.1007/s10021-017-0111-6

A group of scientists led by Karen Thorne of the USGS Western Ecological Research Center and funded by the Northwest Climate Science Center recently published a paper from their study of coastal wetlands in the journal Ecosystems. The paper describes the results of their experiments across a
 latitudinal and climate gradient of tidal marshes in the Northeast Pacific to evaluate how climate change may affect the ability of coastal wetlands to cycle and sequester carbon. Results could help land managers build climate resilience into coastal wetlands.


Spatially explicit measurements of forest structure and fire behavior following restoration treatments in dry forests

Ziegler, J.P., Hoffman, C., Battaglia, M. and Mell, W., 2017. Spatially explicit measurements of forest structure and fire behavior following restoration treatments in dry forests. Forest Ecology and Management, 386, pp.1-12.

A new study from Colorado State University investigated the effect of forest restoration treatments on fire resiliency. Restoration treatments in dry forests often use silvicultural techniques in an attempt to rebuild historical characteristics of forest structure, however this has been known to cultivate a less complex forest structure due to the use of non-spatial metrics. Rather than building a complex forest structure similar to historical conditions, it is suggested that this treatment could lead to increased homogeneity in forest structure. The authors of this study explored fire behavior following these restoration treatments and found that the two objectives (fire reduction and altering forest structure complexity) were non-competing. Their results suggest that current restoration-based harvests can simultaneously fulfill objectives of altering structural complexity and of reducing fire behavior.

New practitioners’ guide to modifying and applying spatial data for local use

LANDFIRE’s suite of spatial data layers is a valuable resource for land managers because they stretch “wall-to-wall” across the U.S.; are created with a consistent methodology; and are updated over time. The data are designed to support broad-scale land management activities, and users are encouraged to critique and modify them as needed for local application. The new guide Modifying LANDFIRE Geospatial Data for Local Applications (Helmbrecht and Blankenship, 2016) provides an easy-to-understand introduction to each of the LANDFIRE products; explains where and how to look for common problems with the data; and offers guidance on how to complete common modification tasks. This guide is an excellent resource for anyone working with LANDFIRE data, but will be especially helpful to users who need to refine the data for local application.

Announcement on The Nature Conservancy’s Conservation Gateway.

Climate change and the eco-hydrology of fire: will area burned increase in a warming western USA?

Donald McKenzie of the U.S. Forest Service and Jeremy Littell of the Alaska Climate Science Center recently published a paper on the drought-fire relationship across the western U.S. Specifically, the authors examined the correlations between water-balance deficit and annual area burned. Findings from this study suggest that the relationship between drought and fire will change with future climate rather than exhibit a consistent and stationary dynamic. The authors concluded that studies predicting future wildfire area must include potential changes in the drought-fire dynamics that will likely occur in a warming climate in addition to factors already considered such as changes in vegetation.


Forest effects on snow in the Pacific Northwest

Dickerson-Lange, S. E., Gersonde, R. F., Hubbart, J. A., Link, T. E., Nolin, A. W., Perry, G. H., Roth, T. R., Wayand, N. E., and Lundquist, J. D. 2017. Snow disappearance timing is dominated by forest effects on snow accumulation in warm winter climates of the Pacific Northwest, USA. Hydrol. Process., doi: 10.1002/hyp.11144.

A team of scientists led by Susan Dickerson-Lange from the University of Washington used multi-year snow observation data to study snow-forest interactions in the Pacific Northwest United States. The authors quantified the difference in snow magnitude and disappearance timing between forested and open areas, and used these findings to determine whether snow is retained longer in the forest or in the open. The study found that comparative snow disappearance timing from forested to open areas ranged from synchronous to snow retention in the open for up to 13 weeks longer than the forested area. The opposite trend was observed in locations with high wind speeds. Analysis of these findings led the authors to identify forest canopy change (via harvest of natural disturbance) to be the driving difference in snow duration between forests and open areas in the Pacific Northwest.

What happens to canopy cover after mountain pine beetle outbreak and timber harvest?

T. Ryan McCarley et al. 2017. Landscape-scale quantification of fire-induced change in canopy cover following mountain pine beetle outbreak and timber harvest. Forest Ecology and Management; 391 (164-175). DOI: http://dx.doi.org/10.1016/j.foreco.2017.02.015

Scientists from the University of Idaho recently published results from a study investigating the individual impacts of the three most dominant agents of forest change: wildfire, timber harvest, and bark beetle outbreaks. Using the 2012 Pole Creek Fire in central Oregon, the authors analyzed pre- and post-fire LiDAR data of the forest to quantify the impact of each agent of change on the forest canopy cover. The authors found that areas of the forest with higher tree mortality due to the Mountain Pine Beetle outbreak yielded greater fire-induced reduction in canopy cover. A similar pattern was observed for areas characterized by the oldest and most intense harvest treatments.

Large-scale experiment on the rural Olympic Peninsula to test innovations in forest management

Scientists at the University of Washington and Washington State Department of Natural Resources intend to test a management approach that mimics natural disturbance patterns and processes across a portion of the Olympic Peninsula, an area known for having the most rainfall in the lower 48 states, high tree-growth rates and old-growth forests. Their experiment will compare different types, intensities and patterns of disturbance and regrowth within 16 watersheds on the western Olympic Peninsula. It will also look at how forest management can sustain rural communities that depend on the forest. Considering community well-being in resource management is growing widely, and the experiment will try to achieve a balance of providing for both people and the ecosystem they are a part of. Bernard Bormann, director of the UW’s Olympic Natural Resources Center near Forks, Washington, is a lead author of the study proposal.

Land Use

Selenium deficiency promoted by climate change

G.D. Jones; B. Droz, P. Greve; P. Gottschalk; D. Poffet; S.P. McGrath; S.I. Seneviratne; P. Smith; L.H.E. Winkel. Selenium deficiency risk predicted to increase under future climate change. PNAS, 2017 DOI: 10.1073/pnas.1611576114

Selenium is a trace element found in soil that varies in concentration depending on soil type. Low selenium concentrations are associated with high pH, oxygen availability, and soils with low clay and organic carbon content (regions such as Germany, Denmark, Scotland, Finland and certain Balkan countries). Because selenium is essential to human health, areas of selenium deficiency supplement the trace element via enriching crop fertilizers. A team of European scientists used current knowledge of soil-selenium interactions to model how selenium concentrations will be impacted by climate-induced changes in soil. The authors found that by the end of the century (2080-2099), selenium levels are expected to decrease in 66% of croplands. The authors stressed the need to study current management techniques used by regions of selenium deficiency (such as Finland) in order to mitigate the health risks of decreased selenium intake in humans.

Special Reports / Announcements

Scientists uncover huge reservoir of melting carbon under Western United States

Saswata Hier-Majumder, Benoit Tauzin. 2017. Pervasive upper mantle melting beneath the western US. Earth and Planetary Science Letters; 463: 25 DOI: 10.1016/j.epsl.2016.12.04

Geologist Saswata Hier-Majumder from the University of London’s Department of Earth Sciences led a study recently published in Earth and Planetary Science Letters reporting the discovery of a layer of melting carbon, 350 km below the surface of the Western United States. The authors used a network of seismic sensors to characterize the layers of the deep sub-surface. Below the Western U.S. exhibited a layer with particular seismic patterns that indicated high temperatures and partial melt. They calculated the layer to be 1.8 millions square km and approximately 25-70 km in thickness. Such characteristics led the authors to conclude that this layer could be a regional reservoir of melting carbon.

Taking Action

Oregon Climate and Health Resilience Plan

The Oregon Health Authority (OHA) launched the new Climate and Health Resilience Plan on February 2, 2017. The plan offers a selection of strategies and policy priorities for state, local, and tribal public health practitioners and partners. Follow the link below to read the plan, and learn more about how OHA is helping to educate the public in climate and human health.

Tribal and Indigenous Peoples Matters

After 90 years, salmon are returning to upper Sultan River

In June, 2016, the Snohomish County Public Utility District began a project to remove the sluiceway of the Sultan River dam in order to improve salmon passage. The project was completed in October and within a few weeks coho redds were spotted upriver of the dam, a part of the river they had not reached in almost 90 years. Read more about the project and other upcoming projects on the Sultan River here.

New tools and approaches for working with diverse knowledge systems in ecosystem assessments

Tengö, M., R. Hill, P. Malmer, C. M. Raymond, M. Spierenburg, F. Danielsen, T. Elmqvist, C. Folke. 2017. Weaving knowledge systems in IPBES, CBD and beyond—lessons learned for sustainability. Current Opinion in Environmental Sustainability. 26–27:17–25

In a paper recently published in Current Opinion in Environmental Sustainability, a team of researchers from the Stokholm Resilience Centre identified five key tasks for knowledge system integration. Their work builds on the Multiple Evidence Base approach, highlighted in the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). The five tasks form a framework that the authors hope will guide successful collaborations between indigenous and local knowledge and western science to enhance governance for sustainability. The goal of the researchers was to create space for different actors and institutions to take part in knowledge-sharing processes that are equitable and empowering. The authors use case studies from the Convention on Biological Diversity and IPBES to discuss their framework.