How is Earth's Water System Linked With Land Use, Climate Change and Ecosystems?

Answers may be in new NSF Water Sustainability and Climate research

How will climate change affect the connections between water sustainability and hydrologic processes?

To better understand how planet Earth's water cycle works, the National Science Foundation (NSF) and the United States Department of Agriculture's National Institute of Food and Agriculture (NIFA) awarded grants totaling almost $27 million through the Water Sustainability and Climate program.

WSC is part of NSF's Science, Engineering and Education for Sustainability investment.

NSF's Directorates for Geosciences; Engineering; and Social, Behavioral & Economic Sciences support the WSC awards.

"Among the most urgent challenges facing the world today is ensuring the adequate supply and quality of water, especially in light of burgeoning human needs and climate variability and change," says Marge Cavanaugh, NSF acting assistant director for Geosciences.

"Whereas the water imperative is global, WSC recognizes that water availability and quality issues must be examined at local scales where most water decisions are made," says Cavanaugh. "That's why WSC projects are placed-based, and each examines how global and regional climate changes are playing out in terms of water balance at the local scale."

WSC Category 1 awards are workshop planning grants; WSC Category 2 grants cover observatories and modeling; WSC Category 3 awards are for modeling.

"Water is a critical component to the success of American agriculture, yet there is a lack of understanding of how climate variability, land use and other environmental factors affect the water supply," says Sonny Ramaswamy, director of the National Institute of Food and Agriculture. "These projects will allow us to better understand water sustainability and allow our producers and rural communities to prepare for future changes."

The goal of the new WSC projects--including studies of Rocky Mountain pine beetles, Los Angeles' water supply and the Sierra Nevada snowpack--is to understand and predict the interactions of Earth's water system with climate change, land use, the built environment and ecosystem function and services.

For example, more than four million acres of forests in Colorado and Wyoming are dying. The main culprit is the mountain pine beetle, a species of bark beetle native to the woodlands of western North America. Recent hot, dry summers and mild winters have led to an infestation of the beetles.  It may be the largest forest insect blight ever seen in North America.

The result is stunning: dead trees lined up like so many fallen forest soldiers. But the invisible changes in watersheds in the Rocky Mountains, including the headwaters of the Platte and Colorado Rivers, may be a longer-lasting legacy.

Farther west, Los Angeles, like many cities in semi-arid regions, relies on centralized redistribution for its water supply. Water is transported hundreds of miles from mountain to city to support agricultural and urban needs in southern California. But water allocations from the mountain sources that feed L.A.'s water supply are declining.  Drought, over-extraction and competing water needs have taken their toll.

In many arid and semi-arid regions of the world, including much of the western United States, water resources management plans are based on the assumption that the snowpack that accumulates in winter holds the majority of the water. This snowpack gradually melts, replenishing reservoirs as their supplies are meted out to satisfy human water and power demands.

Nowhere is that more true than in California's Sierra Nevada. This remote and sparsely populated mountain range supplies water and power for millions of people downstream. Will the Sierras be able to sustain that supply in the decades and centuries to come?

Only 2.5 percent of Earth's water is freshwater, and 98.8 percent of that is locked away in ice or hidden in groundwater. Less than 0.3 percent of all freshwater is in lakes, rivers and the atmosphere.

How can we better manage and predict water availability for future generations, given alterations to the water cycle caused by climate change and by more direct human activities?

The answers require a holistic understanding of complex water cycle and water resource processes, the feedbacks in a water system, and the vulnerability and resilience of water systems to climate and other human-caused change.

A water system comprises a drainage basin and its physical, chemical and biological constituents, including water networks, ecosystems, the built environment, the oceanic and atmospheric systems that govern evaporation and precipitation in the basin and the source water bodies and terminal lakes or seas into which the water flows.

There have been few attempts to study the entire water system with an integrative, systems science approach. WSC researchers will do just that.

This analysis of the planet's water system--of the feedbacks and links among climate change, ecosystems, built environments and human activities--will lead to the improved understanding, prediction and management of water resources, scientists believe.

"Earth has approximately 1,386 million cubic kilometers of water, most of which is the saltwater of oceans and seas," says Cavanaugh.

"What decisions will we make about the rest, the freshwater that's 'technically' available to us? Those decisions are for societies to make, and water sustainability researchers are working through WSC to fully inform those complex decisions."

-NSF-

Study Ties Forest "Greenness" in Western U.S. to Snowpack Extent

Mid-elevation mountain ecosystems most sensitive to rising temperatures and changes in snowmelt

Results of a new study tie forest "greenness" in the western United States to fluctuating year-to-year snowpack extent.

The results show that mid-elevation mountain ecosystems are the most sensitive to rising temperatures and to changes in precipitation and snowmelt.

University of Colorado-Boulder scientist Noah Molotch and colleagues used satellite images and ground measurements to identify the threshold at which mid-level forests sustained by moisture change to higher-elevation forests sustained by sunlight.

A paper reporting the results was published yesterday in the journal Nature Geoscience.

Molotch is the lead author. Co-authors are Ernesto Trujillo of the University of Colorado-Boulder and Ecole Polytechnique Fédérale de Lausanne in Switzerland; Michael Golden and Anne Kelly of the University of California, Irvine; and Roger Bales of the University of California, Merced.

"The research demonstrates yet another complexity in the response of mountain ecosystems to increasing temperatures," says hydrologist Tom Torgersen, program director in the National Science Foundation's Division of Earth Sciences, which funded the research. "High-elevation mountain forests are typically temperature-stressed and low-elevation mountain forests are often water-stressed.

"At mid-elevations, 'everything is just right'--until it goes wrong." Torgersen says, "Higher temperatures lead to reduced snowpack and reduced water availability, leaving trees at mid-elevations more stressed and more prone to fires."

The ability to identify this "tipping point" is important, Molotch says, because mid-level forests--at altitudes from roughly 6,500 feet to 8,000 feet--are where many people live and visit. They're also linked with increasing wildfires, beetle outbreaks and rising tree mortality.

"These results provide the first direct observations of snowpack-forest connections across broad scales," says Molotch.

"Finding the tipping point between water-limited [mid-elevation] forests and energy-limited [high-elevation] forests defines the region of the greatest sensitivity to climate change--the mid-elevation forests--which is where we should focus future research," he says.

Although the research took place in the Sierra Nevada mountain range in California, it's applicable to other mountain ranges across the West.

Climate studies show that the snowpack in mid-elevation forests in the western United States and other forests around the world has been decreasing over the past 50 years because of regional warming.

"We found that mid-elevation forests show a dramatic sensitivity to snow that fell the previous winter in terms of accumulation and subsequent melt," said Molotch, also a scientist at NASA's Jet Propulsion Laboratory in Pasadena.

"If snowpack declines, forests become more stressed, which can lead to ecological changes in the distribution and abundance of plant and animal species, and to more vulnerability to fires and to beetle kill."

Molotch says that about 50 percent of the greenness seen by satellites in mid-elevation forests is linked with maximum snow accumulation from the previous winter, with the other 50 percent related to soil depth, soil nutrients, temperature and sunlight.

"The strength of the relationship between forest greenness and snowpack from the previous year is very surprising," Molotch says.

The researchers initially set out to identify the various components of drought that lead to vegetation stress.

"We went after mountain snowpacks in the western U.S. because they provide about 60 to 80 percent of the water in high-elevation mountains," says Molotch.

The team used 26 years of continuous data from the Advanced Very High Resolution Radiometer, a space-borne sensor flying on a National Oceanic and Atmospheric Administration satellite, to measure the forest greenness.

The researchers compared it with long-term data from 117 snow stations maintained by the California Cooperative Snow Survey, a consortium of state and federal agencies.

In addition, the scientists used information gathered from "flux towers" in the southern Sierra Nevada mountain range. Instruments on these towers measure the exchanges of carbon dioxide, water vapor and energy between the land and the atmosphere.

Instruments on the towers, which are some 100 feet high, allowed scientists to measure the sensitivity of both mid-level and high-level mountainous regions to both wet and dry years--data that matched up well with the satellite and ground data.

"The implications of this study are profound when you think about the potential for ecological change in mountain environments in the West," says Molotch.

"If we look ahead to the time when climate models are calling for warming and drying conditions, the implication is that forests will be increasingly water-stressed in the future and more vulnerable to fires and insect outbreaks."

In the context of recent forest losses to fire in Colorado and elsewhere, the findings are something that really deserve attention, Molotch says.

"This tipping-point elevation is very likely going to migrate up the mountainsides as climate warms."

The research was also funded by NASA.

 -NSF-

Native Plants in Urban Yards Offer Birds "Mini-Refuges"

Landscaping with native vegetation helps local bird species

Yards with plants that mimic native vegetation offer birds "mini-refuges" and help to offset losses of biodiversity in cities, according to results of a study published today in the journal PLOS ONE.

"Native" yards support birds better than those with traditional grass lawns and non-native plantings.

Researchers conducted the study through the National Science Foundation's (NSF) Central Arizona-Phoenix Long-Term Ecological Research (LTER) site, one of 26 such sites around the globe in ecosystems from coral reefs to deserts, from forests to grasslands.

"To a desert bird, what's green is not necessarily good," says Doug Levey, program director in NSF's Division of Environmental Biology. "Arizona birds don't view lush urban landscapes as desert oases. The foraging behavior of birds in greener yards suggests that there's less food for them there than in yards with more natural vegetation."

The research, led by scientists Susannah Lerman and Paige Warren of the University of Massachusetts-Amherst, and Hilary Gan and Eyal Shochat of Arizona State University, looked at residential landscape types and native bird communities in Phoenix, Ariz.

It's among the first to use quantitative measures and a systematic approach--including 24-hour video monitoring--in yards to assess and compare foraging behavior of common backyard birds.

The scientists found that desert-like, or xeric, yards had a more even bird community and superior habitat compared with moist, or mesic, grass lawns.

"We already know that bird communities differ, and that there are more desert birds found in a desert-type yard," says Lerman.

"With this study, we're starting to look at how different yards function--whether birds behave differently by yard type. We're doing that using behavioral indicators, especially foraging, as a way of assessing birds' perceptions of habitat quality between differing yard designs."

Lerman and colleagues conducted the experiment in 20 residential yards at least 1.8 miles apart, making it unlikely that the same birds would visit more than one study yard.

Half the yards were desert-like, while the others had green lawns.

From February through April 2010, homeowners removed bird feeders before and during a 24-hour experimental data collection period.

The researchers set up feeding stations--seed trays--in each yard to simulate resource patches similar to ones where birds feed in the wild. Plastic trays contained 0.70 ounces of millet seed mixed into six pounds of sand. The trays were placed on low stools and left out for 24 hours.

Later, Lerman removed the trays, sifted out and weighed uneaten seed to the nearest 0.01 gram. The amount of seed remaining quantified the giving-up densities (GUD), or the foraging decision and quitting point for the last bird visiting a seed tray.

Trays were videotaped for the entire 24-hour experiment.

The experiment assumed that an animal behaving optimally would stop foraging from a seed tray when its energy gains equal the "costs" of foraging, Lerman says.

Costs include predation risk, digestion and missed opportunities to find food elsewhere.

As time spent foraging at a seed tray increases, so do the costs associated with foraging. When a bird first arrives at the tray, seeds are easy to find, but that gets harder as the tray becomes depleted.

Each bird makes a decision about whether to spend time searching in the tray or to move on to a new patch in the yard.

The "giving up" point will be different for different species and in different environmental conditions. Birds visiting seed trays in yards with more natural food available will quit a tray sooner than birds in resource-poor yards.

Since the method only measures the foraging decisions for the last species visiting the seed tray, the researchers devised a mathematical model for estimating the foraging decisions for all visiting species.

Using the videotapes, they counted every peck by every bird for each tray to calculate the relationship between the number of pecks and grams of seed consumed for each seed tray. This was the GUD-peck ratio for the last species visiting the seed tray.

They then estimated the seed consumption--GUD ratio for all other species visiting the seed tray based on the number of pecks per tray when each species quit.

"We know how many pecks each species had and can put that number into the model and calculate the number of grams at that point," Lerman says. This greatly enhances the GUD method by expanding the ability to assess foraging decisions for all species visiting trays.

In all, 14 species visited the trays, 11 of which visited both yard types. Abert's towhee, curve-billed thrasher (a species unique to the Sonoran desert), house finch and house sparrow were the most widespread tray visitors.

Species that visited trays in both yard designs consumed more seed from trays placed in mesic yards, indicating lower habitat quality compared with xeric yards.

Similarly, foragers in the desert-like yards quit the seed trays earlier due to greater abundance of alternative food resources in those yards, spending more time foraging in the natural yards and less at the seed trays.

Lerman says that by videotaping the trays, counting pecks and measuring giving-up points by species, the research also advanced the GUD method, allowing researchers to disentangle some of the effects of bird community composition and density of competitors, and how these factors affect foraging decisions between two different landscape designs.

The results build upon evidence that native landscaping can help mitigate the effects of urbanization on common songbirds, she says.

 -NSF-

NSF Invites Media to Apply for Opportunity to Report on U.S.-sponsored Antarctic Research

Application deadline is August 24, 2012; deployments scheduled for December 8-15, 2012

The National Science Foundation (NSF), manager of the U.S. Antarctic Program, is accepting written requests from professional journalists to report on scientific research supported by NSF's Office of Polar Programs (OPP) in Antarctica.

Selected journalists will deploy to Antarctica for approximately one working week.

NSF annually chooses a small group of journalists, representing a range of news organizations, to make individual visits to McMurdo Station, NSF's logistics hub on the continent. In addition, reporters visit Amundsen Scott South Pole Station (weather permitting), and report on NSF-sponsored research at field camps in close proximity to McMurdo.

For additional background on the U.S. Antarctic Program, please see the Arctic Sciences Web page on the NSF website.

OPP and NSF's Office of Legislative and Public Affairs jointly manage and coordinate media visits to the Polar Region.

Examples of projects that will be open to media visits include:

- A site near McMurdo Station where a unique drill is being tested as part of the Whillans Ice Stream Subglacial Access Research Drilling Project, a six-year, interdisciplinary deployment studying glaciology, microbiology, geochemistry and oceanography of the ecosystem. Media also may be able to speak to WISSARD researchers returning from the field. It will not be possible for reporters selected as media visitors to visit the remote WISSARD field camp.

- The South Pole Telescope and IceCube Neutrino Observatory at NSF's Amundsen-Scott South Pole Station.

- The Long-term Ecological Research (LTER) Project in the McMurdo Dry Valleys

- Studies of population dynamics of penguins and seals in McMurdo Sound

How to apply: Applicants must submit a written expression of interest in participating in the program, the equivalent of no more than two printed pages, detailing the outlet(s) in which the reporting will appear and a description of the audiences for those outlets.

Competition for the opportunity to deploy is expected to be intense, as Antarctic logistics are a constraining factor on how many people may deploy. Logistical limitations make it nearly impossible to modify itineraries once in Antarctica.

A panel consisting of science and logistics staff from the Office of Polar Programs and media officers from NSF's Public Affairs office will review all proposals and select finalists. The panel will look for proposals that indicate an understanding of the nature and challenges of NSF's scientific enterprise in the Antarctic as well as the desire and ability to communicate that understanding to the public.

Application Deadline: August 24, 2012--U.S. media receive preference in selection.

Application: Applications that indicate solid working knowledge of the U.S. Antarctic program and its science goals and the ability to communicate the research being undertaken to a wide audience stand the best chance of selection.

Debbie Wing, the NSF public affairs officer responsible for OPP, can provide access to NSF-supported researchers who are scheduled to be in the field during the deployment period to assist reporters in obtaining information about the science they may expect to see while in Antarctica.

Freelancers are eligible for consideration but must supply with their letter of application evidence of a firm commitment, on their employer's letterhead, from the prospective employer to publish or air their work.

General reporting about Antarctica, travel or logistics are not given priority. The program does not support feature-film proposals. Documentary filmmakers may consider applying to the Advancing Informal STEM Learning Program managed by NSF's Education & Human Resources directorate.

Medical: In order to deploy to Antarctica, it is necessary to pass rigorous medical and dental examinations.  These examinations are conducted at the finalist's expense by a personal physician and dentist, using USAP medical screening forms, which will be evaluated by USAP-contracted medical experts. Certain medical conditions detected during the physical and dental examinations may disqualify a candidate from visiting Antarctica, even if initially selected as a media visitor.

Expenses: Reporters selected for the media visit, or their employers, pay for round-trip transportation to--and accommodation in--Christchurch, New Zealand.  Reporters must visit NSF headquarters in Arlington, VA., at their own expense for pre-trip planning. NSF furnishes, at no cost to participants, cold-weather clothing solely for use in the field, as well as housing, transportation, and food while in Antarctica.

Note: From time to time, the NSF has received requests for media opportunities from reporters who plan to travel to Antarctica at various times of the year via non-governmental means. Such requests are reviewed on a case by case basis. Such requests should be directed to the NSF media officer listed below.

Where to Send Applications: Contact the NSF media officer listed below by phone or by email as soon as possible to express interest. Send the application letter to:

National Science Foundation

Office of Legislative and Public Affairs

4201 Wilson Boulevard, Suite 1245

Arlington, VA 22230

Attn: Debbie Wing, (703) 292-5344 / dwing@nsf.gov

 -NSF-