USGS to Receive New Great Lakes Research Vessel plus 5 more
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- USGS to Receive New Great Lakes Research Vessel
- Recovering Soil Fertility after Forest Fires
- Pika Populations Affected by Climate in the Great Basin
- Coping with the Cold - How Rock Sandpipers Survive Alaskan Winters
- Lake Mead Aquatic-Science Research Documents Substantial Improvements in Ecosystem
- Invasive Pike Persist When Preferred Prey Decline
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USGS to Receive New Great Lakes Research Vessel Posted: 11 Apr 2013 07:00 AM PDT Ann Arbor, Mich. – The U.S. Geological Survey awarded a contract last Friday for the construction of a large research vessel for Lakes Huron, Michigan, and Superior to Burger Boat Company of Manitowoc, Wis. The vessel will replace the 38-year-old Grayling, bringing the USGS Great Lakes Science Center (GLSC) large vessel fleet up-to-date. The new Grayling will be stationed at the USGS base in Cheboygan, Mich., and will incorporate modern marine standards and state-of-the-art technology to more safely and effectively conduct fisheries research. "I am delighted to have achieved this important milestone that will benefit the Great Lakes region for many decades," said USGS GLSC Director Russell Strach. "This investment would not have been possible without the support from many key partners. The new research vessel will come fully equipped with 21st century laboratories and scientific instrumentation to support fishery science for the Great Lakes." The funding for this expenditure was accrued from two prior appropriations and held in an account that was not affected by the sequester. The replacement vessel is expected to be a commercial grade 78-foot vessel, and will be designed and constructed for a 40 to 50-year service life. This vessel will be capable of performing critical scientific and mission-related tasks, including dragging nets along the lake bottom, catching fish, and using sound-waves to detect fish and assess their abundance. "The entire Burger team is very excited to be awarded this significant contract," said Jim Ruffolo, President and CEO of Burger Boat Company. "The Grayling will further reinforce Burger’s commitment to designing and constructing quality vessels that meet each owner’s specific requirements, whether they are custom yachts or commercial vessels." This new contract will create additional highly skilled shipbuilding jobs at the Manitowoc shipyard, and the project will help support numerous companies that supply raw materials and equipment for the project. For over 50 years the USGS GLSC has operated a unique and valuable deepwater fish ecology and assessment program that is the foundation for fisheries management throughout the Great Lakes. Burger, at 150 years old, is one of the world's oldest shipyards. From its facility in Manitowoc, Wis., Burger's craftsmen have built hundreds of high quality vessels as long as 260 feet (80 meters) that can be found in ports around the world. Today, Burger continues its legacy of designing and building vessels to the highest standard from its fully updated shipyard. JMS Naval Architects of Mystic, Conn., developed the preliminary design of the new Grayling. The USGS GLSC maintains a fleet of fishery research vessels on each of the Great Lakes to meet the scientific research needs of state, tribal, and federal resource managers for understanding and effectively managing the Great Lakes fishery. For more information on the USGS GLSC, visit their website. |
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Recovering Soil Fertility after Forest Fires Posted: 03 Apr 2013 11:00 AM PDT CORVALLIS, Ore.— New scientific findings published in Ecology reveal that interactions of climate, soils, shrubs, and a natural nitrogen fertilization process affect regrowth of forests following wildfire in southern Oregon and northern California. Managers can use this information to consider post-fire management practices, including fertilization and shrub-removal. Scientists studying forests that burned in 1987 discovered an interesting pattern in a natural fertilization process. The highest levels of natural nitrogen fertilization occurred at cool, dry sites where tree growth is slow and where nitrogen for growth is needed the least. In contrast, the lowest nitrogen additions occurred at warm, moist sites where tree growth and associated nitrogen needs are greatest. This counterintuitive result occurred because natural nitrogen fertilization by nitrogen-fixing shrubs was suppressed by competition with oaks, maples, and other vegetation where tree growth was greatest, in warm, moist sites. Nitrogen, an essential nutrient for tree growth, often is lost during a forest fire. An important way to recover forest fertility is an ecological process called biological nitrogen fixation. Some common shrubs, like Ceanothus, form unique relationships with bacteria and convert inert nitrogen gas from the air into forms of nitrogen in the soil that the trees can use for growth. Free-living soil bacteria also fix nitrogen. This natural process is the main source of nitrogen fertility in forests. The scientists found that the rate at which Ceanothus shrubs added nitrogen to the system could be suppressed as tree biomass increased. Even though warm, wet sites stimulated the growth of nitrogen-fixing shrubs, these conditions stimulated the growth of other plants even more. Eventually, these changes limited the recovery of nitrogen fertility in the most productive sites. According to Stephanie Yelenik, the lead author of the study, nitrogen additions by Ceanothus shrubs and by free-living soil bacteria provided an average of 7.5 pounds of nitrogen per acre per year. Over the 22 years following the major fire when the forest’s vegetation and nitrogen burned, this added up to about 165 pounds of nitrogen per acre. Although probably insufficient to fully replace wildfire nitrogen losses on the study sites, these contributions were substantial. Yelenik was affiliated with Oregon State University at the time of the study. "There are important related results. Biological nitrogen fixation involving Ceanothus shrubs was up to 90 times greater than contributions from free-living soil microorganisms," said USGS scientist Steve Perakis, who participated in the study. "The contribution from Ceanothus would be even greater if other plants didn't compete so strongly. So ultimately competition among different plant species governed nitrogen input in the forests studied." "The loss of nitrogen to wildfire has always been of concern to managers; however, the enormity of this loss only recently has been quantified," said Tom Sensenig, a U.S. Forest Service ecologist. "This study not only informs managers about the importance of shrubs for restoring nitrogen, but identifies the dynamics among species and the specific processes influencing nitrogen fixation and recovery across differing sites. Principally, this new information will help in developing post-fire management options and plans for specific forest types in this region. For example, on drier lower-quality sites, Ceanothus, the most prevalent nitrogen-fixing shrub identified, could be retained to the greatest extent possible by only treating the minimal vegetation necessary to assure seedling survival. On wetter, higher-productivity sites, treating more competitive species at a higher intensity may be more effective for maximizing nitrogen recovery, while benefiting seedling survival as well." According to Yelenik, without additional fire or other forms of disturbance, Ceanothus largely disappears from productive sites in about 30 years as the tree canopy shades out the understory vegetation. Because Ceanothus is the major player in biological nitrogen fixation, from then on, nitrogen levels may remain consistently low in sites that have the necessary temperature and moisture conditions to promote rapid tree growth. On these sites, there may be opportunities to conduct vegetation management or to allow low-severity fires to burn as a way of encouraging the presence of nitrogen-fixing shrubs in the forest understory. The study sites were located in forested mountains of the Klamath Region. This region is prone to wildfires, and the frequency and severity of the fires shape vegetation patterns. The study occurred 20 to 22 years after fire in sites that were salvage logged in the first 2 to 3 years after fire and then planted with conifer trees. Perakis believes the results are best applied to this region, but the interactions between climate, soils, shrubs, and natural nitrogen fertilization merit study elsewhere to see if similar constraints to nitrogen fixation occur in other forests recovering from fire. The publication is Yelenik, S.G., S.S. Perakis, and D.E.Hibbs. 2013. Regional constraints to biological nitrogen fixation in post-fire forest communities. Ecology. |
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Pika Populations Affected by Climate in the Great Basin Posted: 13 Mar 2013 09:38 AM PDT BOZEMAN, Mont. – Climate factors such as snowpack and precipitation are playing an increasingly important role in the abundance of American pikas in the Great Basin, according to a continuing ecological study by the U.S. Geological Survey, University of Montana and Montana State University. Pikas are diminutive herbivores that resemble hamsters and live exclusively in rocky slopes across many mountain ranges in the American West. This study contributes to a legacy of more than 100 years of pika studies in the Great Basin – the internally draining area between the Sierra Nevada and Rocky Mountains. In the Basin, researchers are recording pikas' shrinking distribution, and finding their population sizes increasingly responsive to climate change but difficult to predict. The size of pika populations did not correlate with the extent of habitat present in either the 1990s or 2000s, according to the researchers, who were revisiting sites where pikas were first recorded in historical surveys going back more than a century. Given how strongly pikas are tied to their rocky habitat, this current finding challenges the assumption that just because physically suitable habitat is present – even in remote, apparently relatively undisturbed locations – that pikas will continue to occupy those habitats. Researchers also investigated the potential impact of climate stress on pika density. The results suggested that climate change may be adding another filter for suitability of habitats. "Precipitation during June-September and amount of snowpack appeared to be the most powerful predictors of pika density in the 2000s," said USGS research ecologist Erik Beever, lead author of the study. "Precipitation appears to be important because it can influence the amount of food available for pikas in the summer, and an insulating snowpack can minimize exposure of pikas to extreme cold-stress," Beever said. Across the western United States, snow-water equivalents have been declining and temperatures have been rising since the 1930s. Perhaps the most surprising result was the direct relationship between population size and probability of future extinctions of local pika populations. "When we consider extinction risk, we intuitively think that smaller populations are at the highest risk," Beever said. "We looked at the record of extinctions up to 1999, and calculated the risk of future site-level extinction. We were surprised to find that sites with higher extinction risk in 1999 had larger populations in 2003-2008," he said. The authors suggest that this non-intuitive result may reflect changes in the rules governing abundance between the 1990s and 2000s surveys (perhaps ushered in by recent climate change), lags in response of abundance to extinction risk, or other mechanisms. Researchers revisited sites of historical (1898-1956) pika records and performed surveys of pika abundance from 1994 to 1999 and from 2003 to 2008 to understand the factors predicting pika population sizes. The study, "Understanding relationships among abundance, extinction and climate at ecoregional scales," to be published in the journal Ecology, is available online. |
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Coping with the Cold - How Rock Sandpipers Survive Alaskan Winters Posted: 30 Jan 2013 07:30 AM PST ANCHORAGE, Alaska —The upper Cook Inlet is the world's coldest site that regularly supports wintering shorebirds. The rock sandpiper is the only shorebird found in this region during winter and is a species that is uniquely adapted to survive the winter chill, according to new research by biologists with the USGS Alaska Science Center. USGS scientists determined that on average 8,000 rock sandpipers spend the winter in upper Cook Inlet each year and that harsh winter conditions may actually contribute to the success of these birds. "The rock sandpiper is a unique bird: outfitted for wintering over in cold northern climates and confined to a narrow inlet where tides maintain access to food in spite of ice cover," said USGS Director Marcia McNutt. "I never cease to be amazed at the adaptability of nature to the planet's extreme environments." Rock sandpipers that winter in upper Cook Inlet feed principally on clams that are buried in mudflats. Sea and shore-fast ice in winter periodically cover up 80 percent of mudflats used by rock sandpipers. However, scientists found that upper Cook Inlet’s extreme tides and the scouring action of ice blocks swept away by these tides keep feeding grounds accessible during winter. "Rock sandpipers appear to have better insulation against the cold due to heavier plumage and a thick layer of fat. That fat fuels their higher winter metabolism and provides insulation, much like blubber in marine mammals" says Dan Ruthrauff, a wildlife biologist with the USGS Alaska Science Center and lead author on the new research. The birds found in upper Cook Inlet in winter are known as the Pribilof Island rock sandpiper. Their breeding range is restricted to just four islands in the Bering Sea: St. George, St. Paul, St. Matthew, and Hall islands. USGS estimated the size of the breeding population at around 20,000 individuals. In some years, winter survey totals in upper Cook Inlet closely match the breeding population estimate, further emphasizing the importance of the region's intertidal habitats to this unusual sandpiper. The recent research by USGS on rock sandpipers in upper Cook Inlet, Alaska, are "Coping with the cold: an ecological context for the abundance and distribution of rock sandpipers during winter in upper Cook Inlet, Alaska" which will be published by the journal Arctic in September, 2013; "Identical metabolic rate and thermal conductance in rock sandpiper (Calidris ptilocnemis) subspecies with contrasting nonbreeding life histories", published in the journal Auk in January, 2013; and "Small population size of the Pribilof rock sandpiper confirmed through distance-sampling surveys in Alaska", published in August, 2012 by the journal Condor. The articles were written by Daniel Ruthrauff, Robert Gill, Jr., Lee Tibbitts, and Colleen Handel of the USGS Alaska Science Center, along with international collaborators Anne Dekinga and Theunis Piersma of the Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands, and Maksim Dementyev, a biologist with Moscow State University, Russia. |
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Lake Mead Aquatic-Science Research Documents Substantial Improvements in Ecosystem Posted: 29 Jan 2013 01:41 PM PST Additional Partnerships: University of Nevada, Reno and University of Nevada, Las Vegas Additional Contacts: Dan Balduini, USFWS, 702-515-5480, daniel_balduini@xxxxxxx and Peter Soeth, Reclamation, 303-445-3615, psoeth@xxxxxxxx LAS VEGAS, Nev. — Lake Mead National Recreation Area's water quality is good, the sport fish populations are sufficient, and the lakes provide important habitat for an increasing number of birds. This positive trend is documented in a new report published today that leads to a better understanding of the natural resources of Lake Mead and Lake Mohave, and the issues that may affect natural resource management of Lake Mead NRA. "While the Lake Mead ecosystem is generally healthy and robust, the minor problems documented in the report are all being addressed by the appropriate agencies, and are showing substantial improvement since the mid 1990's," said U.S. Geological Survey hydrologist, Michael Rosen, the lead scientist for the report. "This is thanks to proactive enhancements to wastewater treatment facilities for the Las Vegas Metropolitan area, the installation of wetlands in Las Vegas Wash, and the treatment of legacy pollutants from industrial areas near Las Vegas Wash." Lake Mead provides significant benefits that have contributed to the modern development of the southwestern United States. The lake provides important aquatic habitat for a wide variety of wildlife including endangered species, and a diversity of world-class water-based recreational opportunities for more than 8 million visitors annually. It supplies critical storage of water supplies for more than 25 million people in three western states (California, Arizona, and Nevada). Storage within Lake Mead supplies drinking water and provides for the generation of hydropower to deliver electricity for major cities including Las Vegas, Phoenix, Los Angeles, Tucson, and San Diego. It also provides water for irrigation of more than 2.5 million acres (almost 4000 square miles or more than twice the size of the state of Delaware) of croplands. Major findings detailed in the report include the following:
The report was prepared cooperatively by the U.S. Geological Survey, National Park Service, U.S. Fish and Wildlife Service, Bureau of Reclamation, Nevada Department of Wildlife, Southern Nevada Water Authority, BIO-WEST, University of Nevada, Reno, and University of Nevada, Las Vegas. The full report, USGS Circular 1381, "A synthesis of aquatic science for management of Lakes Mead and Mohave," is available online. Note to editors: B-roll available from USGS upon request. |
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Invasive Pike Persist When Preferred Prey Decline Posted: 23 Jan 2013 10:00 AM PST January 23, 2013 – Invasive northern pike in southcentral Alaska are opportunistic and adaptable predators that feed on multiple native fish species when their preferred prey, native salmonids, are no longer abundant, according to a new study released in Ecology of Freshwater Fish. In the study, scientists with the U.S. Geological Survey's Northern Rocky Mountain Science Center and the Alaska Department of Fish and Game describe the importance of salmonids and other native fish species to pike diets in the Susitna River basin of Alaska. As a result, this invasive predator can continue to thrive while impacting native species. "In southcentral Alaska, outside of the native range of the northern pike, fish have no natural defenses to these voracious predators, making them 'easy pickins' once the northern pike was introduced," said USGS Director Marcia McNutt. "The consequences of this unfortunate act may not end with the salmon, but could cascade to other portions of affected ecosystems and the human economy." The economic and cultural costs of salmonid declines are considerable, as are the severe ecological consequences because these fish are a key food source for numerous species throughout Alaska. "We sampled 274 pike in a stream where salmon are still abundant and we found over 600 salmon in the stomachs of these pike. Several of the pike had greater than 20 juvenile salmon in their stomachs." said Adam Sepulveda, USGS scientist and lead author of the study. Researchers observed that pike preferred juvenile salmonids, but will feed on other native fish species such as lamprey and sculpin when salmonids are less abundant. In addition, the study found that smaller pike are the primary predators of native salmonids, indicating that tools that are effective at suppressing smaller pike, in addition to larger pike, are needed. Invasive pike were introduced into southcentral Alaska in the 1950's and are thought to be a leading cause for the decline of salmonid species important to sport and commercial fisheries. "In places like Alexander Creek, where northern pike are well established, we have seen a complete loss of salmon fisheries and the closure of several businesses that once depended on them." said Kristine Dunker, biologist with the Alaska Department of Fish and Game and co-author of the study. The study illustrates that the adaptability of invasive pike can reduce abundance of multiple species. The article is titled "Introduced northern pike predation on salmonids in southcentral Alaska" and can be viewed at the following website. More information about impacts and prevention of aquatic invasive species can be found on the USGS Northern Rocky Mountain Science Center web site.
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