Modeling forecasts consistently have demonstrated that the geographic ranges of Rocky Mountain trout species will shrink by some 20 to 90 percent over the next 50 to 100 years as climate change accelerates in the region. Predicted water temperature increases in high-elevation rivers and streams, coupled with reduced water flows, are certain to add to existing stresses for Rocky Mountain trout.

What Models Cannot Do

A native bull trout swims in the cool waters of the Flathead River near Glacier National Park, Montana. The tail end of a native Westslope cutthroat trout can be seen below.

The models themselves, however, don’t provide the regional or local information that resource managers need to take action now to offset the negative effects of climate change on the diversity and abundance of trout species in an individual watershed.

Consequently, USGS researchers and their colleagues at the U.S. Forest Service and Colorado State University wanted to see if closely examining existing and past land-use and habitat changes in five key Rocky Mountain river basins could help provide the kind of detailed, geographically specific information that resource managers need. Over the past century, intensive land use and development have altered some of these aquatic systems, with cascading effects on ecosystems and popular trout fisheries.

The importance of the study’s findings, published in the scientific journal Fisheries, stems from the fact that the analyses did not include predictions into the future, but were driven by real observations across the western United States.  The analyses are the result of actual data across some of the coldest regions of the lower 48; they give a glimpse of what is likely to occur in the future.

Under a rapidly changing climate of the Rocky Mountains, the authors wrote, many trout populations and species will be able to adapt, but others, overwhelmed by future changes, will not survive.

“It’s not enough to know that significant habitat reductions are expected to occur for native trout of the Rocky Mountains over the next 50 to 100 years,” said Clint Muhlfeld, a USGS scientist and co-author on the paper.  “To help native trout species survive into the future, managers need solid scientific information to take decisive action now.”

River Basins and Trout in the West Already Impacted by Climate Change

The researchers assessed five river systems of the Rocky Mountain west where native trout and climate have been documented: the Flathead River Basin in northwest Montana and southeast British Columbia, the Boise River Basin in central Idaho, the Green River Basin in western Wyoming, the Rio Grande Headwaters Basin in southern Colorado, and the rivers and streams of the Greater Yellowstone Ecosystem in Montana and Wyoming.

Because climate change has been ongoing for multiple decades, although at a slower pace than forecasted for the future, the study showed that it is already possible in many instances to see the early indications of stream ecosystem responses to climate change and to use that information to make decisions about the future. It also demonstrated that the importance of different kinds of stressors varies from basin to basin and depends on local factors.

“Most exciting, however, is that the study clearly illustrates that real data are available now that can be used to understand the local effects of climate change and how those changes threaten native trout populations,” Muhlfeld said. “With that information, managers can take science-based actions that can be refined as more information becomes available through time.”

Warmer Temperatures, Earlier Snowmelt, and Reduced Summer Flows the New Norm

On Iceberg Lake in Glacier National Park, ice from the glacier is breaking up and melting at a rapid rate. Cold, glacier fed waters provide crucial habitat for native aquatic species such as trout, and as the ice is disappearing, so are the ideal habitats to sustain native ecosystems.

The researchers found that the average annual air temperature had increased across all five of these basins over the last 60 years, that spring snowmelt runoff is also occurring sooner, that streamflows in summer are lower, and that winter flooding is increasing in some areas.  All of these findings, said Muhlfeld, have important implications for the future of Rocky Mountain trout fisheries.

In fact, noted Muhlfeld, Rocky Mountain trout populations in all of the river basins they studied are already exhibiting signs of stress, such as having to migrate farther upstream to find more suitable habitat, competing with invasive species for habitat and food, and hybridizing with some invasive fish species. Other stresses include a greater risk of eggs being washed away from increases in winter flooding, increased wildfire risks in streamside ecosystems, and reduced summer habitat due to lower flows.

Fishing as Part of the National Heritage Affected

“Fishing in our national parks and charismatic streams such as the Yellowstone River is part of our heritage,” added Robert Al-Chokhachy, another USGS scientist who co-authored the paper. “The  increase in angling closures over the past decade due to the effects of higher temperatures and reduced streamflows also illustrates how climate shifts are likely to have profound socio-economic impacts,” Al-Chokhachy added.

Where to Go From Here

The authors emphasized that it is still early enough that fast-acting, proactive management decisions over the next few decades will minimize losses of these economically and ecologically important trout populations during this transitional century.

“The challenge now is to identify what actions are possible to mitigate the effects of climate change in order to provide these fishes with an opportunity to adapt,” Al-Chokhachy said.

This study was funded by the USGS National Climate Change and Wildlife Science Center, which is helping meet the challenges of climate change and its effects on fish, wildlife and their habitats.

For More Information:

Climate Change and Native Salmonids Collaborative Research Site

Native Fishes of the Northern Rockies

Climate Change in Mountain Ecosystems

(Videocast) Climate Connections: Questions from Glacier National Park, MT

USGS researcher Craig Allen stands on the edge of Mesa Alta, amid diverse forest and woodland in the uplands of northern New Mexico; note some recently dead ponderosa pine and Douglas-fir in the field of view. Forest drought stress is strongly correlated with tree mortality from poor growth, bark beetle outbreaks, and high-severity fire.

For hundreds of years, forests of piñon pine, ponderosa pine and fir trees have covered millions of acres of mesas, plateaus and mountains in the semi-arid southwestern United States. Like forests everywhere, they provide food and shelter for countless species and help anchor vital watersheds and soils of the region.

But their days may be numbered. Based on a new study co-authored by the USGS, projected climate change impacts suggest a grim picture for current forests in the U.S. Southwest.

Research led by A. Park Williams of the Department of Energy’s Los Alamos National Laboratory came to this conclusion by comparing the tree-ring record to climate data collected in the Southwest since the late 1800s. The researchers aligned some 13,000 tree-core samples with known temperature and moisture data, further blending in known historical events such as documented megadroughts that drove the ancient Pueblo Indians out of longtime settlements such as Mesa Verde, Colorado.

Worst Forest Drought Stress in 400 Years

What they found was this: since 2000, southwestern U.S. forests have experienced more drought stress than during any other period in more than 400 years. What’s interesting about this is that precipitation totals since 2000 haven’t been exceptionally low, but temperatures have been exceptionally high. These high temperatures have caused the atmosphere’s ability to evaporate water from soil and plants also to be exceptionally high.

Think of the atmosphere as a water-thirsty sponge: the warmer the air, the thirstier the sponge.  When the summers are too hot and dry, the trees lose much of the water that they otherwise would have used for growth. If this happens too often, trees become stressed and more vulnerable to disturbances like forest fires and bark beetle infestations.

Forest Growth Rates Predictable Using Climate Records            

When Williams and the other researchers, including USGS scientist and study co-author Craig D. Allen, compared southwestern tree-ring records to climate records, they found that southwestern forest growth rates can be predicted very effectively using just two climate variables: winter precipitation and summer-fall atmospheric evaporative demand.

The researchers were able to predict future forest growth rates using these climate and tree-growth relationships, combined with projections of future climate trends. The results: all climate models project warming to cause large increases in summer-fall atmospheric evaporative demand (thirstier sponge). No models project large increases in winter precipitation. If the climate models are correct, forest growth will decrease substantially in the coming decades primarily due to increasing drought stress from warmer growing season temperatures.

Tree Rings Link Past and Current Drought Stress

Drought and beetle-killed piñon pines in Walnut Canyon National Monument near Flagstaff, Arizona, amid a few surviving trees. Forest drought stress is strongly correlated with tree mortality from poor growth, bark beetle outbreaks, and high-severity fire.

The tree-ring records in the Southwest extend back in time for more than 1,000 years. This allowed the researchers to investigate how future forest drought-stress likely will compare to periods of major drought stress in the past. The tree-ring records indicate that two “megadrought” events, during the 1200s and again in the 1500s, occurred in the past 1,000 years. Past research has shown that both of these events probably coincided with widespread forest die-off in the Southwest. So, the researchers treat forest growth rates during those extreme megadroughts as a benchmark for drought conditions strong enough to cause widespread forest die-off. If warming occurs as rapidly as projected by climate models, forest drought-stress conditions are likely to exceed those historic megadrought conditions on a regular basis by the 2050s. In fact, the study forecasted that during the second half of this century, about 80 percent of years are projected to exceed those megadrought levels.

Williams says the current drought event, which began in 2000, demonstrates how close southwestern forests already may be to reaching drought-stress levels unprecedented in at least a millennium. The team concluded that forest drought stress during 4 of the past 13 years (about 30 percent), including 2011 and 2012, matched or exceeded megadrought-type levels. The only other 13-year periods when megadrought-type conditions were reached with such frequencies in the past 1,000 years were during the megadroughts themselves.

What’s Going to Happen to Southwestern Forests in the Future?

Sunset as seen through the smoke of a prescribed burn in the Jemez Mountains, New Mexico. The burn was conducted to restore fire as an ecosystem process and reduce hazardous tree densities and fuel loads due to more than 100 years of fire suppression. Foreground trees (Douglas-fir and aspen) were killed during the Cerro Grande fire in 2000. Forest drought stress is strongly correlated with tree mortality from poor growth, bark beetle outbreaks, and high-severity fire.

As trees become more stressed from increasingly hot, dry summers, eventually they will not be able to continue to grow in their current locations, and fires and beetle infestations will take an increasing toll. We can expect to see increased numbers of trees dying, with many not being replaced. Eventually, if warming trends continue as projected by state-of-the-art climate models, the current forests will give way to ecosystems more tolerant of prolonged, severe drought. This would mean substantial changes in forest species composition to more drought-tolerant trees, or even forest-replacing shrublands and grasslands.

The article, “Temperature as a potent driver of regional forest drought stress and tree mortality,” appears in the October 2012 Nature Climate Change. Authors are A. Park Williams (LANL), Craig D. Allen (U.S. Geological Survey), Alison K. Macalady (University of Arizona), Daniel Griffin (University of Arizona), Connie A. Woodhouse (University of Arizona), David M. Meko (University of Arizona), Thomas W. Swetnam (University of Arizona), Sara A. Rauscher (LANL), Richard Seager (Columbia University), Henri D. Grissino-Mayer (University of Tennessee), Jeffrey S. Dean (University of Arizona), Edward R. Cook (Columbia University), Chandana Gangodagamage (LANL), Michael Cai (LANL), Nate G. McDowell (LANL).

For More Information:

• Seeing the Forest and the Trees: USGS Scientist Links Local Changes to Global Scale

• Craig D. Allen Staff Page

• Western Mountain Initiative: Effects of Climate and Global Change on Western Mountains

• Climate Change: The Science of Impacts

Nest in a Salt Marsh, San Francisco Bay

Salt marshes may help slow the rate of climate change in the future, as rising and warmer oceans will enable them to more quickly capture and remove carbon dioxide from the atmosphere, according to a study published in the journal Nature this week.

Carbon dioxide is the predominant “greenhouse gas” that traps heat and warms the atmosphere.

Marshes and Carbon

“Our research suggests that the value of these ecosystems in capturing atmospheric carbon might become much more important in the future, as the climate warms,” said Matthew Kirwan, a University of Virginia environmental scientist, and the lead author of this USGS-funded and supported research.

In fact, said Kirwan, the research forecasts that under faster sea-level rise rates, salt marshes could bury up to four times as much carbon as they do now. “The study forecasts that marshes will absorb some of that carbon dioxide, and if other coastal ecosystems – such as seagrasses and mangroves – respond similarly, there might be a little less warming,” said Kirwan.

One of the most interesting facets about salt marshes is they are perhaps the best example of an ecosystem that actually depends on carbon accumulation to survive climate change: the accumulation of roots in the soil builds their elevation, keeping the plants above the water, Kirwan noted.

Salt marshes store significant quantities of carbon by taking carbon dioxide out of the atmosphere through their leaves, and then storing it in their roots. As plants die, the carbon becomes part of the soil and helps the marsh survive sea level rise.

“Coastal wetlands are among the most economically and ecologically valuable ecosystems on Earth, with their services estimated worth about $15,000 an acre,” said Matthew Larsen, associate director for climate and land use research at the U.S. Geological Survey. “They provide clean water, abundant food, wildlife habitat, and protection from storms. This and other USGS research aims to understand and forecast the vulnerability of coastal wetland systems to global change and identify ways that managers can effectively respond to global change effects.”

Marshes and Sea Level Rise

Kirwan cautioned that the study also showed that marshes can survive only moderately fast rates of sea level rise. To survive, the elevation of the soil surface has to build vertically through time. If the seas rise more quickly than the marsh can build up, marshes drown and die off.

“At fast levels of sea level rise, no realistic amount of carbon accumulation will help them survive,” Kirwan noted.

And, said Kirwan, if marshes are drowned by fast-rising seas, they no longer would provide a significant carbon storage capacity.

The Value of Marsh Ecosystems

Salt marshes, made up primarily of grasses, are important coastal ecosystems that provide a variety of ecosystem services for wildlife, fisheries, and people. They help protect shorelines from storms, provide diverse wildlife habitat for birds, mammals, fish, and mollusks. They also build up coastal elevations by trapping sediment during floods, producing new soil from roots and decaying organic matter. New Orleans, for example, is separated from the Gulf of Mexico almost entirely by marshes.

Little Blue herons in a Louisiana marsh.

DOI manages 35 million acres of low-lying coastal areas, including marshes and thousands of miles of shoreline. The U.S. Fish and Wildlife Service alone manages about 5 million acres of coastal wetlands.

“This research can help decision makers understand and prepare for how coastal areas may fare in response to climate change,” said Glenn Guntenspergen, a USGS researcher who leads a project on Coastal Marsh Response to Climate and Land Use Change Project that this study was a part of.  Kirwan and his co-author, Simon Mudd, a geosciences researcher at the University of Edinburgh in Scotland, used computer models to predict salt marsh growth rates under different climate change and sea level scenarios.

For more information, visit:

Coastal Marsh response to Climate and Land Use Change Project

Climate and Land Use Change Research and Development Program

The world’s longest-running Earth-observing satellite program — Landsat — turns 40.

The world’s longest-running Earth-observing satellite program — Landsat — is 40 years old.

NASA — working in cooperation with the U.S. Department of the Interior (DOI) and its science agency, the USGS — launched the first Landsat satellite on July 23, 1972. The resulting 40-year archive of Earth observations from the Landsat fleet forms an impartial, comprehensive, and easily accessed register of human and natural changes on the land.

Remote-sensing satellites, such as the Landsat series, help scientists to observe the world beyond the power of human sight, to monitor changes, and to detect critical trends in the conditions of natural resources. Data supplied by Landsat supports the improvement of human and environmental health, energy and water management, urban planning, disaster recovery, and crop monitoring.

Through 40 years of continuous coverage, the Landsat series of Earth observation satellites has become a fundamental global reference for scientific issues related to land use and natural resources. Landsat is valued all over the world as the gold standard of land observation. No other satellite program, in our nation or in any other country, comes close to having the historical length and breadth, the continuity and the coverage, of the Landsat archive.

A Versatile Perspective

Landsat satellites can give us a view as broad as 12,000 square miles per scene while characterizing land cover in units the size of a baseball diamond. In one instant look from over 400 miles in space, a single Landsat scene can record the condition of hundreds of thousands of acres of grassland, agricultural crops, or forests.

A comparison of the images illustrates the significant growth in the greater D.C. area. Major urban development can be seen the surrounding communities of Rockville, Greenbelt, and Suitland, Maryland. The expanded Woodrow Wilson Bridge, connecting Springfield, Virginia, with Oxon Hill, Maryland, is evident. The record of surface change is used by urban planners and local officials to evaluate the rate and direction of growth in the area.

Landsat images from space are not just pictures. They contain many layers of data collected at different points along the visible and invisible light spectrum. Consequently, Landsat images can show where vegetation is thriving and where it is stressed, where droughts are occurring, where wildland fire is a danger, and where erosion has altered coastlines or river courses.

Landsat images reveal subtle, gradual changes, such as Wyoming rangelands greening up after a drought, as well as massive landscape changes that occur in rapidly growing urban areas. Landsat can also provide inexpensive assessments of sudden natural or human-induced disasters, such as the number of acres charred by a forest fire or the extent of tsunami inundation.

Impartial information freely available

The Department of the Interior’s policy of releasing the full Landsat archive at no cost allows everyone to have access to this important resource, allowing researchers in the private sector and at universities to generate even more data applications — applications that serve commercial endeavors in agriculture and forestry, that enable land managers in and out of government to work more efficiently, and that define and tackle critical environmental issues.

Landsat and innovation

Landsat has sparked innovation in Earth systems research and in commercial applications of the data from its inception in the mid-1960s.  Since 2008, when Landsat images were made available free of charge, there has been a remarkable burst of innovative science applications of the data.

For example, Landsat data played a central role in an award-winning type of mapping that tracks water use. Using Landsat imagery supplied by USGS in combination with ground-based water data, the Idaho Department of Water Resources and the University of Idaho developed a novel method to create water-use maps that are accurate to the scale of individual fields. Water-use maps help save taxpayer money by increasing the accuracy and effectiveness of public decisions involving water — for instance, in monitoring compliance with legal water rights. In 2009, the Kennedy School of Government at Harvard University cited Idaho’s original design for these maps as an outstanding innovation in American government.

The National Land Cover Database (NLCD 2006) produced by USGS and the federal interagency Multi‑Resolution Land Characteristics Consortium (MRLC) from Landsat imagery is a massive database that describes the surface condition of each 30-meter cell of land in the conterminous U.S. One such cell is approximately the area of a baseball diamond. The range and accuracy of the database enables land managers, urban planners, agricultural experts, and scientists with many different interests (for instance, climate change or invasive species) to identify critical characteristics of the land for a wide variety of investigations.

In the beginning

By the mid-1960s, some civilian geologists, geographers, and agronomists were familiar with imaging potential of classified Earth-observing satellites and had also studied the surprisingly detailed land-surface photos taken by early astronauts using hand-held cameras.

In 1966, with NASA still heavily committed to the Apollo Program in preparation for what would be a 1969 moon landing, the USGS convinced Interior Secretary Stewart Udall to hold a press conference announcing Interior’s new Project EROS, the acronym for Earth Resources Observation Satellites, and, furthermore, that Interior’s first satellite would launch in 1969!

In a statement that echoes true to this day, Udall said, “…the time is now right and urgent to apply space technology towards the solution of many pressing natural resources problems being compounded by population and industrial growth.” This bold announcement succeeded as a catalyst for what eventually became the world’s first civilian land-imaging satellite, developed by NASA and launched on July 23, 1972.

Six years earlier, Udall had said the satellite would be “…just the beginning of a great decade in land and resource analysis for a burgeoning population.”  Today we celebrate not one but four great decades in Earth science from space.

USGS created the “Earth as Art” series to provide a unique avenue of insight about the geography of selected Landsat scenes that have an artistic resonance. This image is titled “Malaspina Glacier.” The tongue of the Malaspina Glacier, the largest glacier in Alaska, fills most of this image. The Malaspina lies west of Yakutat Bay and covers 1,500 sq mi (3,880 sq km).

On the horizon

NASA is preparing to launch the next Landsat satellite, the Landsat Data Continuity Mission (LDCM), on February 11, 2013, from Vandenberg Air Force Base in California. LDCM will be the most technologically advanced satellite in the Landsat series. LDCM sensors take advantage of evolutionary advances in detector and sensor technologies to improve performance and increase reliability. Once it successfully achieves orbit, LDCM will join the Landsat 5 and Landsat 7 satellites as Landsat 8 to continue the Landsat data record.

Join the celebration

NASA and USGS held a news conference,  July 23, to highlight the accomplishments of the Landsat program at the Newseum in Washington, DC.

NASA Television and the NASA website provided live briefing coverage and will maintain archived video of the event. Visit NASA TV or NASA Goddard Multimedia.

For information about “Landsat at 40” anniversary features:

• 10 most significant images from the Landsat record;
• U.S. regions selected for the “My American Landscape” contest;
• announcement of the top five Landsat “Earth As Art” images,visit NASA Landsat.

For details about the Landsat program, including current operations and situational updates, visit USGS Landsat.

Ice Waves. Along the southeastern coast of Greenland, an intricate network of fjords funnels glacial ice to the Atlantic Ocean. Landsat 7 Image.

During a span of 40 years, since 1972, the Landsat series of Earth observation satellites has become a vital reference worldwide for understanding scientific issues related to changes on the Earth’s surface.

To celebrate the 40th Anniversary of Landsat, the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA) would like your help in selecting the top five “Earth as Art” images from the more than 120 images in the collection.

The poll is now open and will close on July 6.

Learn more and get details on how to cast your vote.

The top five “Earth as Art” images will be announced on July 23 in Washington, D.C. at a special event commemorating the launch of the first Landsat satellite.

Information as Art

Built by NASA and operated by the USGS, Landsat satellites supply Earth scientists, land-resource managers, and policy makers with objective data about changes across the global landscape. Some changes, like major floods or volcanic eruptions, come quickly; others, like urban sprawl or regrowth from forest fires, appear gradually. Landsat impartially records these and many other changes to the land that are induced by people or nature.

Beyond the scientific information they confer, some Landsat images are simply striking to look at — presenting spectacular views of mountains, valleys, and islands; forests, grasslands, and agricultural patterns. By selecting certain features and coloring them from a digital palate, the USGS has created a series of “Earth as Art” perspectives that demonstrate an artistic resonance in land imagery and provide a special avenue of insight about the geography of each scene.

NASA is preparing to launch the next Landsat satellite in 2013, which will be turned over to USGS for operations and data distribution.

The Lena River, some 2,800 miles (4,500km) long, is one of the largest rivers in the world. The Lena Delta Reserve is the most extensive protected wilderness area in Russia. It is an important refuge and breeding grounds for many species of Siberian wildlife. Landsat 7 Image.

More Information

Earth as Art Image Gallery

Earth as Art at the Library of Congress (exhibit extended through August 31, 2012)

USGS Landsat

NASA Landsat

Contest URL:  http://eros.usgs.gov/eaa_voting/

This stretch of Iceland's northern coast resembles a tiger's head complete with stripes of orange, black, and white. The tiger's mouth is the great Eyjafjorour, a deep fjord that juts into the mainland between steep mountains. The name means "island fjord," derived from the tiny, tear-shaped Hrisey Island near its mouth. The ice-free port city of Akureyri lies near the fjord's narrow tip, and is Iceland's second largest population center after the capital, Reykjavik. Landsat 7 Image.

A composite image of Landsat tracks from 2001

How do we ensure a future of clean water supply, abundant energy resources, and preparedness for and safety during natural hazard events, among other critical needs?

We start with science.

The USGS is focused on some of the most significant issues society faces. Our mission is to provide leaders, land and resource managers, and the public with the tools necessary to meet these challenges.

Now we need your help to ensure that our science is headed in the right direction. Based partly on feedback we received from the public last year, we have created draft strategies for each of our major areas of research.

To read and comment on the drafts, visit our Start with Science site. There you’ll also find background information on this effort, including the teams of scientists creating the draft strategies.

Commenting is open from June 4 through July 31 — visit usgs.gov/start_with_science today to help shape the USGS of tomorrow!