Sea lampreys impact rivers for months, perhaps years, due to their disturbance of streambeds when they spawn, say University of Maine researchers.
Robert Hogg, a master’s graduate who participated in the study, writes in a journal article that sea lampreys (Petromyzon marinus) are ecosystem engineers.
The physical disturbance caused by their “nest-building activity was significant and persistent” and increased “habitat heterogeneity” and favored “pollution-sensitive benthic invertebrates and, possibly, drift-feeding fish,” according to the researchers.
Sea lampreys increase the complexity of a streambed by “creating and juxtaposing shallow, swift, rocky habitat patches with deep, slow, sandy habitat patches,” says the article. The effects are “similar to those of Pacific salmon.”
As an adult, sea lampreys are parasitic fish that resemble eels. They use their circular mouths filled with circular rows of teeth to latch onto other fish and feed on their blood.
Hogg and the research team examined spawning sea lampreys in Sedgeunkedunk Stream, a tributary of the Penobscot River, in 2010 and 2011. The team says it conducted the study during “a modest run” of sea lampreys, since access to Sedgeunkedunk Stream had only recently been restored due to dam removal.
“The scale of this reported influence, therefore, is a fraction of the potential ecological impact that larger populations of sea lampreys may formerly have delivered to habitats throughout their native range,” the scientists say.
The research team also included UMaine Associate Professor of Freshwater Fisheries Ecology Stephen Coghlan Jr., Joseph Zydlewski with the U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit, and Kevin Simon of the University of Auckland in New Zealand.
The team’s research results are included in “Anadromous sea lampreys (Petromyzon marinus) are ecosystem engineers in a spawning tributary,” which will be published in the June edition of Freshwater Biology.
Contact: Margaret Nagle, 207.581.3745
Image Description: Lamprey
Understanding more about the relationship between weather and maple sap flow, and how Maine syrup producers will adapt to climate change is the focus of research being conducted by a University of Maine graduate student.
Jenny Shrum, a Ph.D. candidate in the ecology and environmental sciences graduate program in the UMaine School of Biology and Ecology, is attempting to unravel the biophysical relationships between weather and sap flow. The goal is to better understand what drives flow and how expected trends in climate may affect the processes and harvesters in the future.
Shrum plans to collect on-site weather station data and sap flow rates at three test sites and to interview small- and large-scale producers to determine if those who have been managing sugar maple stands for years will be more or less resilient to climate change, and if large-scale producers will be better equipped to adapt. Her research is supported by the National Science Foundation and EPSCoR through UMaine’s Sustainability Solutions Initiative and its Effects of Climate Change on Organisms research project.
The physiological process for sap flow is not completely understood, Shrum says. It involves a complex interaction between freezing and thawing of the xylem tissue within the tree, and the molecule sucrose which maple trees use to store carbohydrates between seasons.
“When the tree defrosts, the frozen liquid in the tree becomes fluid and that provides a medium for the sugars that are stored in the trunk to get to the branches,” Shrum says, adding that in order to continue flowing, the ground also has to be defrosted so the tree can pull in water during the next freeze cycle and recharge the positive pressure in the trunk to restart sap flow.
Sugar maple trees grow as far north as New Brunswick and as far south as Georgia, yet maple syrup is only produced commercially in the 13 most northern states because of the colder weather, Shrum says.
In Maine and other northern areas, more than one freeze-thaw event happens during the winter. This lets the process repeat and allows the season to last between six and eight weeks as opposed to a few days, which is likely in southern states such as Georgia and Missouri, where maple trees grow but aren’t commercially tapped. Warm weather or microbial build-up in taps usually ends the season, according to Shrum.
In Maine, the season usually starts sometime between the middle of February and the middle of March, and continues for about six weeks, Shrum says.
“This winter has been really weird; we’ve had really warm weather and really cold weather and as far as sap flow, that might be a good thing,” Shrum says. “But not enough is known.”
One change that has been proven is the start time of the sap season.
“Studies are starting to show that the preferred block of time for tapping is starting earlier if you base it on ideal temperatures,” Shrum says, citing a 2010 Cornell University study by Chris Skinner that found that by 2100, the sap season could start a month earlier than it does now.
For big-time operations, Shrum says an earlier season probably won’t be a problem because they can just tap their lines earlier, but she’s not sure how smaller Maine operations will adapt.
“They might not be able to change their season,” she says. “A lot of the smaller operators have multiple jobs; they make money off maple syrup, but also in other fields such as woodcutting or construction. It just so happens maple syrup is a block of time when they’re not doing anything else, so it makes sense. But if that season changes, it might not fit into their schedule as well.”
Shrum will interview a variety of producers — small- and large-scale operators, people who have been tapping trees for 30 or more years and people who started within the past five years — to learn the reasons for tapping and better understand resilience within these groups.
To record weather and sap flow data, Shrum, who holds a bachelor’s degree in biology from Humboldt State University, will deploy weather stations at maple tree stands in Albion, Dixmont and Orono. She’s also using iButtons to record soil temperatures and time-lapse photography of the buckets to record hourly sap flow rates. She can then relate flow rates to variables the weather stations record, such as temperature, precipitation and sunlight.
Although climate change is likely to affect sap flow, Shrum is confident there will always be maple syrup made in Maine.
“None of the climate change scenarios that have come up result in maple trees not growing in Maine. We’re definitely still going to have freezing events in Maine; it’s not going to get so warm that that’s not going to happen,” she says.
Shrum says maple syrup could become a big commodity in Maine if more of a market was created through government incentive plans, and if the state decided to make it a priority — similar to Vermont.
“Everything is good about maple syrup. There’s very little that’s controversial about it, and the biology is fascinating,” Shrum says.
Contact: Elyse Kahl, 207.581.3747
Image Description: maple syrup
To female coastal plain swamp sparrows, male bill size matters.
When looking for a mate outside of their pair bond, female coastal plain swamp sparrows (Melospiza georgiana nigrescens) choose males with large bills, according to a University of Maine-led study conducted along Delaware Bay.
Small-billed males are more at risk of being cheated on by their mates. Males with larger bills than their avian neighbors, on the other hand, sire a greater percentage of young birds in their territory, says Brian Olsen, assistant professor in UMaine’s School of Biology and Ecology and Climate Change Institute.
Thus, Olsen says, sexual selection may explain why males have larger bills than females along the Delaware coast.
“Conventionally, bird bills have been considered one of the premier examples of how diet shapes morphology: the right tool for the right job,” he says.
For the past 40 years, researchers have explained differences between the shapes of male and female bills by differences in diet. But Olsen and his colleagues say their research suggests that female mating preferences alone could do it.
“It really makes me wonder how much of bill shape, or the shape of any other structure for that matter, is due to mating preferences instead of better survival,” Olsen says.
Olsen and his fellow researchers also found that bill size increases with age. So, by selecting males with larger bills, females are picking a mate that has the right stuff to survive and successfully defend a territory over multiple years.
“In other words,” says Olsen, “the genes of older males have been tested and proven worthy, and females who prefer to mate with the largest-billed males can then pass these good survivor genes on to their offspring.”
Since the difference in large and small bills is only a few millimeters, Olsen says he doesn’t know how female swamp sparrows make the distinction. He suspects song may play a role, since male bill shape can greatly influence singing.
Russell Greenberg of the Smithsonian Migratory Bird Center at the National Zoological Park; Jeffrey Walters of Virginia Tech’s Department of Biological Sciences; and Robert Fleischer of the Center for Conservation and Evolutionary Genetics at the National Zoological Park also participated in the study.
The team’s research article, “Sexual dimorphism in a feeding apparatus is driven by mate choice and not niche partitioning,” was published in the November 2013 issue of Behavioral Ecology.
Contact: Beth Staples, 207.581.3777
A University of Maine wildlife ecologist will utilize a $1.49 million National Science Foundation grant to improve protection of small natural landscape features that significantly impact the larger ecosystem.
The four-year project, “Of Pools and People,” will inform conservation management of relatively tiny natural resources — such as vernal pools, prairie potholes and desert springs — that maintain biodiversity in urbanizing landscapes, says Aram Calhoun, professor of wetland ecology and director of the Ecology and Environmental Sciences Program.
The collaborative eight-member research team will offer insights to safeguarding these important resources, particularly on private lands. Small natural resources often can be saved while development, forestry and agriculture activities continue, Calhoun says.
Prevailing conservation strategies often do not fully utilize management opportunities, Calhoun says, sometimes because interactions among biophysical and socioeconomic components — the regulator, community and landowner decision-making — are not understood.
This project, funded by the Dynamics of Coupled Natural and Human Systems Competition (CNH) Program of the NSF, began Sept. 1.
UMaine researchers joining Calhoun on the Senator George J. Mitchell Center Sustainability Solutions Initiative (SSI) project are: Malcolm Hunter Jr., Libra professor of conservation biology; Kathleen Bell, associate professor in the School of Economics; Michael Kinnison, professor of evolutionary applications in the School of Biology and Ecology; Cynthia Loftin, associate professor in the Department of Wildlife Ecology and leader of the U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit; and Krista Capps, postdoctoral research fellow in sustainability science. In addition, Dana Marie Bauer, assistant professor in the Department of Earth and Environment at Boston University, and Erik Nelson, assistant professor of economics at Bowdoin College, are participating in the research.
SSI is a partnership between UMaine and other higher education institutions that seeks to produce knowledge and initiate action that addresses human needs and preserves the planet’s life-support systems.
In addition to giving stakeholders efficient and flexible management tools, researchers will share results and mentor a range of students and faculty, including those in rural and Native American schools, and integrate findings into interdisciplinary courses and citizen-science programs.
Contact: Beth Staples, 207.581.3777
Image Description: vernal_pool
Water clarity, a strong indicator of water quality, is deteriorating in Maine lakes, according to a University of Maine graduate student’s study.
The decline, says Ian McCullough, may be a trend toward eutrophication — a process in which excess nitrates and phosphates, generally due to fertilizers and sewage, stimulate growth of algae, which depletes oxygen in the water.
Using satellite-based remote sensing, McCullough found a decrease in average statewide lake clarity from a depth of 4.94 meters in 1995 to 4.38 meters in 2010.
Water clarity, he says, ranged from 4 to 6 meters during the time frame, and consistently worsened from 2005 to 2010.
McCullough divided the state, which has more than 5,500 lakes and ponds larger than 10,000 square meters, into three regions: northeastern, south-central and western. He assessed data from 547 lakes for the study.
McCullough found lakes with reduced clarity occurred disproportionately (in 52 of 63 lakes) in larger lakes in the remote northeastern and western regions. Clarity in these two regions decreased from 5.22 meters in 1995 to 4.36 meters and 4.21 meters, respectively, in 2010.
Climate changes that impact algal growth and changes in forest cover due to timber harvesting may have contributed to the disproportionate decline in these regions, he says.
Meanwhile, lake clarity in the south-central lake region remained at 4.50 meters from 1995 to 2010 and lakes with improved clarity occurred most often in this region (in 52 of 72 lakes).
The proportion of eutrophic lakes (those with excessive nutrients and dominated by aquatic plants and algae) increased from 35.3 percent in 1995 to 42.6 percent in 2010. While the proportion of mesotrophic lakes (medium levels of nutrients and a high diversity of plants and animals) was unchanged, the proportion of oligotrophic lakes (lacking in plant nutrients and having an abundance of dissolved oxygen) decreased from 14.8 percent in 1995 to 6.8 percent in 2010.
Taken together, McCullough says these results suggest a general trend toward eutrophication in Maine lakes.
Although the results are potentially discouraging, McCullough says individual property owners and lake associations can employ various mitigation strategies. They include enhancing or restoring shoreline buffers with native vegetation, updating septic systems in lakeshore homes, controlling invasive species and minimizing impervious surfaces in lake watersheds.
In addition, statewide programs such as LakeSmart and the Maine Volunteer Lake Monitoring Program already partner with local lake associations to educate and engage people about protecting and restoring healthy lake ecosystems.
McCullough, who earned his master’s in ecology and environmental science at UMaine, is a graduate student researcher at University of California, Santa Barbara.
His study is titled “Landsat imagery reveals declining clarity of Maine’s lakes during 1995–2010.” Co-authors are Cynthia Loftin, a UMaine associate professor and leader of the U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit; and Steven Sader, UMaine professor of forest resources.
The Society for Freshwater Science published the study online in June 2013.
Contact: Beth Staples, 207.581.3777
Image Description: Water_clarity
The effects of Hurricane Sandy’s devastation on plant and bird communities in coastal marshes from Maine to Virginia are the focus of a 10-state study by researchers from the University of Maine, University of Connecticut, University of Delaware and Maine Department of Inland Fisheries and Wildlife.
Information gathered from more than 1,700 sites before and after the October 2012 hurricane will advance researchers’ understanding of how major disturbances affect these populations and what characteristics make a marsh more vulnerable.
The data will also provide information on the allocation of millions of dollars of federal restoration funds, coastal management planning and the status of species at risk of endangerment.
The yearlong study was awarded nearly $200,000 from the National Science Foundation and is part of the Saltmarsh Habitat and Avian Research Program, which was founded by a group of academic, governmental and nonprofit collaborators — including UMaine — to provide tidal-marsh bird conservation information.
Brian Olsen, assistant professor in UMaine’s School of Biology and Ecology, is a co-principal investigator of the study. Maureen Correll, an ecology and environmental Ph.D. student in Olsen’s lab, is working on the project as part of her dissertation. Two additional student researchers from UMaine are expected to participate in the study.
Other co-principal investigators include Tom Hodgman, senior wildlife biologist at the Maine Department of Inland Fisheries and Wildlife; Chris Elphick, associate professor of ecology and evolutionary biology at the University of Connecticut; and Greg Shriver, associate professor in the Department of Entomology and Wildlife Ecology at the University of Delaware.
Before Hurricane Sandy, Olsen’s team was working on a study to assess the distribution and densities of tidal-marsh birds from Maine to Virginia. The study was intended to give the U.S. Fish and Wildlife Service more information on bird populations that are in danger due to the loss of tidal marshes from sea level rise, particularly the saltmarsh sparrow, Olsen says.
Hurricane Sandy struck in the middle of the researchers’ survey range after they had collected data for two years, giving them information from both inside and outside the storm’s path. The team sought NSF funds to conduct the surveys again to see which birds and marshes were most affected within the hurricane’s range. The marshes outside the storm’s path will serve as control sites, Olsen says.
“What predicts whether you’re a winner or a loser if a hurricane hits you is really an open question,” Olsen says.
The study will also test two common ecosystem stress hypotheses among researchers. One of those hypotheses, Olsen says, is that stresses on an ecosystem build up over time, making the addition of any new stress more dramatic than if it were to act alone. Multiple stresses can bring any species of the entire community closer to collapse with every additional stress.
“The hurricane ends up being the straw that broke the camel’s back,” he says.
Another common theory says multiple stresses eliminate the weak players, leaving only the strong ones.
“When the hurricane comes in, all the sensitive players have already been eliminated by previous stressors and you’re only left with the ones that are robust to stress; they can handle it, and the hurricane has little effect,” Olsen says.
Based on this theory, the pristine tidal marshes — ones that have more sensitive plants and animals that aren’t accustomed to stress — may appear to have been more affected by the hurricane, he says.
“I’d really like to understand what makes marshes sensitive to large-scale disturbances and how marshes are likely to respond to the predicted increase in storm frequency and intensity in the future,” Olsen says. “What makes them sensitive and what’s likely to happen as the climate changes?”
Researchers will also pay attention to whether urban development had any effect on how the storm affected the marshes.
“You get the same hurricane that’s barreling down on two different marshes. Do marshes that are completely developed right up to the marsh edge fare better, worse or the same as those that are in pristine habitats in national parks? Does conservation do anything to birds that are still around or does that not matter when there’s a wall of water coming down on you? We get to ask that for a fleet of different species,” Olsen says.
Saltmarsh sparrows, clapper rails, Nelson’s sparrows, seaside sparrows, willets and black ducks are the six major bird species in the study. Plant species the team will study include smooth cordgrass (Spartina alterniflora), salt hay (Spartina patens), seashore saltgrass (Distichlis spicata) and black needlerush (Juncus gerardii).
The surveying of saltmarsh sparrows is important because the team is able to track the species’ entire range and population. The species is also declining fast and talks have begun on whether to list them under the Endangered Species Act. The team’s data on the birds will be used to help make that determination, Olsen says.
Using the information from hundreds of marshes with different characteristics, Olsen’s team hopes to be able to predict what causes ecosystems to shift from one type of tidal marsh to another following a major storm, or more dramatically, what causes shifts from tidal marsh to open water or beach dunes. By determining these factors, researchers will have a better understanding of where to focus energy for conservation and where to expect ecosystem shifts in the future, Olsen says.
“We’ve visited a couple places already this summer where last year it was a beautiful tidal marsh with picturesque streams, and now it’s sand dunes or open water; it’s just gone,” he says.
The team hopes their information will help influence agencies using Hurricane Sandy relief funds to restore wildlife communities by prioritizing the marshes that would benefit the most from conservation efforts and have the lowest chance of being destroyed by a similar storm in the future.
Contact: Elyse Kahl, 207.581.3747
Image Description: Olsen
Massachusetts native Kristine Hoffmann feels right at home in her wading boots in vernal pools in Orono, Maine.
As a youngster, she enjoyed exploring a spring wetland close to her Bay State backyard. And these days, vernal pools — forest floor depressions that fill with water in the spring and generally dry out in late spring or early summer — are again an interest for Hoffmann.
The University of Maine doctoral student is studying the breeding ecology, habitat selection and life histories of the blue-spotted salamander (Ambystoma laterale), including the distance they emigrate from vernal pools.
Hoffmann recently followed one salamander 280 meters from a local vernal pool, multiple times the distance she anticipated.
“When I saw this job, it felt like coming home,” Hoffmann says of her dissertation research. “It’s a great opportunity.”
In recent years, vernal pools have become a topic of discussion and concern due to a worldwide decline of amphibians, some of which breed in the vernal pool in which they were born.
In order for blue-spotted salamanders to be conserved, Hoffmann says vernal pools and the adjacent forestland need to be protected. When vernal pools and the critical land around them are destroyed, amphibians are lost, biodiversity decreases and food availability for other species is compromised.
Current Maine regulations state that “the basin depression of ‘significant’ vernal pools must not be disturbed,” says Hoffmann, “and at least 75 percent of the critical terrestrial habitat within 250 feet of the high-water mark must remain intact and forested, with native understory and woody debris.”
Those regulations, though, protect fewer than 25 percent of Maine vernal pools, and Hoffmann says that might not be enough to ensure long-term conservation of other salamanders, as well as wood frogs and fairy shrimp that also breed in vernal pools in the state.
Hoffmann says data from her research may inform proposed legislation about zones of consultation in Maine.
Because vernal pools don’t have inlets or outlets and because they dry up, salamanders are at risk from fewer predators than they would be in ponds and lakes.
But there’s a trade-off of sorts — they’ve had to adapt to breed quickly — they arrive early to the pool and hatch and undergo metamorphosis within weeks. The impetus is strong — they have to lose their gills and grow lungs before the seasonal pool is gone.
After blue-spotted salamanders grow lungs, they spend much of their life underneath leaves in the surrounding moist woodlands in eastern central North America, the Atlantic Provinces and northern New England. The nocturnal amphibians with long tails can grow as long as 5.5 inches.
Seven days a week, Hoffmann treks to several Orono-area vernal pools. She dons a broad hat, blue jeans and long sleeves to ward off mosquitoes — a staple of salamanders’ diet.
In a sun-dappled forest near a pollen-coated vernal pool Hoffmann checks whether the adult salamanders she implanted with radio transmitters have moved.
If they have, she marks the new spots with flags then notes factors including canopy density and soil temperature and moisture level.
Hoffmann implanted the transmitters — which will emit signals for about 45 days — during a short surgery in which they were anesthetized in a UMaine lab.
In mid-June, Hoffmann was awaiting the first of this year’s juvenile salamanders to emerge from the pools.
Much of what she’s already learned from her research has resulted in more queries. For instance, she questions why after the mass spring migration there were 700 female salamanders and just three males in one area pool.
There are now two types of blue-spotted salamanders, Hoffman says — Ambystoma laterale and unisexual salamanders, which are the result of prior hybridizing. Today, the unisex salamander steals sperm from the Ambystoma laterale.
Hoffmann will study both blue-spotted salamanders and the unisex salamanders to see what effects genotype (different genetic compositions), female body size and environmental factors have on egg mass structure and fertility.
She’ll also examine which environmental factors — pond depth, canopy density, distance to roads and presence of other breeders in the pool — impact breeding site selection. And she’ll explore whether juvenile habitat choice differs between the genotypes.
“We keep finding out things. We’ve found salamanders with three genomes or four or five genomes,” she says, wondering aloud what that might mean for the salamanders’ health and life expectancy. “If we [humans] get one extra chromosome, we get Down syndrome.”
UMaine undergraduates Eleanor D’Urso from Branford, Conn., Catherine Herr from Cape May, N.J. and Ian Lookabaugh from Lubec, Maine, are assisting Hoffmann with the research.
D’Urso and Lookabaugh are fifth-year wildlife ecology majors and Herr is a fifth-year student majoring in wildlife ecology and mathematics.
Katherine Sypher, an Orono High School junior is also assisting with the study through the OHS-University of Maine Summer Research Experience Program. The program seeks to increase high school students’ science, technology, engineering and mathematics (STEM) skills.
Sypher says it’s an ideal summer job — she’s paid to work outside while learning and applying practical knowledge.
Contact: Beth Staples, 207.581.3777
Image Description: salamander
A state-of-the-art sensor buoy system has been deployed in Jordan Pond at Acadia National Park to begin a high-tech water quality monitoring program in light of recent concerns about decreasing clarity in what is considered one of the clearest lakes in Maine.
The monitoring program is made possible by a partnership led by Friends of Acadia, Acadia National Park and the University of Maine’s Climate Change Institute. Canon U.S.A., Inc., a leader in digital imaging solutions, is the official sponsor for the program. Through Canon’s support, Friends of Acadia was able to purchase a NexSens CB-400 Data Buoy and hire a full-time aquatic scientist, Courtney Wigdahl of Topsham to monitor the study.
Friends of Acadia is a nonprofit organization dedicated to projects that preserve and protect Acadia National Park and Mount Desert Island communities. Wigdahl is an alumna of the University of Maine, where she did her Ph.D. and postdoctoral research with Jasmine Saros, associate director of the Climate Change Institute.
The 187-acre Jordan Pond is 150 feet deep — the deepest and the second largest of the 26 lakes and ponds on the island. Described as one of Acadia’s most pristine lakes with exceptional water quality, Jordan Pond is the water supply for Seal Harbor.
Since 1985, the Park Service has manually monitored water quality on a monthly basis throughout Acadia’s waterways. In Jordan Pond, data analysis has shown that water clarity has been declining since the mid-1990s. In the past four years alone, water clarity has shifted from 14 meters to 12 meters, as measured using a secchi disk.
To determine the potential causes of clarity loss, as well as the effects on the broader ecosystem, the water quality monitoring will be automated with the help of the buoy sited in the deepest part of Jordan Pond. With the latest sensor technology, the buoy will monitor nearly 100 data points every day, including the amount of algae and organic material in the water column, and water pH and temperature. The data will be compiled and transmitted every 15 minutes to a receiving station located at the Jordan Pond House Restaurant.
The buoy, which will be visible approximately 2 feet above the water surface, will be in Jordan Pond for the next four months, and then will be redeployed in the spring.
The automated monitoring will provide a more comprehensive perspective on water conditions, and inform decisions about lake protection measures. Just as important, it will monitor conditions before, during and after major weather events to understand the changes the pond undergoes.
“This is likely not an isolated case. We think it is indicative of what’s happening in many lakes in Maine,” says Saros, who has been studying the lakes in Acadia National Park for the past five years, looking at the effects of and recovery from acid rain, and the effects of climate change. “Many lakes in Maine are brown because of natural organics. Jordan has a low concentration of that, but it may be increasing.
“If the changes in Jordan Pond are largely because of air pollution reduction, it’s important to know that the lake is returning to a previous state and the reduction in clarity is not a concern,” says Saros, who will lead the data analysis. “If it’s more of a sign of changes in climate with the increased frequency and severity of storms, we will be more concerned and will have to consider what we can do to mitigate the effects. For the park and for lakes across Maine, it is an important question.”
By next year, Jordan Pond’s high-resolution sensor data will be available to the public on a website and at an information kiosk at the Jordan Pond House Restaurant. The data also will be entered in the Global Lake Ecological Observatory Network (GLEON), which shares and interprets information from around the planet in an effort to understand the role and response of lakes to a changing environment.
Wigdahl will be blogging about her work with the buoy on the Friends of Acadia news site.
A Wall Street Journal article about the Canon U.S.A. sponsorship with Friends of Acadia is online.
Contact: Margaret Nagle, 207.581.3745; 207.949.4149
Image Description: Jordan Pond
Juvenile wood frogs emigrating from their birthplaces in vernal pools into the terrestrial ecosystem may transfer mercury they accumulated during larval development into the food web, according to a team of University of Maine researchers.
The team, led by U.S. Geological Survey and UMaine wildlife ecologist Cynthia Loftin, conducted its study at four short-hydroperiod (likely to dry by mid-June) seasonal woodland pools in Acadia National Park on Mount Desert Island, Maine.
The researchers found mercury levels in the 1- to 2-week-old embryos were near or below detectable amounts, indicating that transfer of mercury from mother to eggs was absent or minimal. However, mercury accumulated rapidly in the 6- to 8-week-old tadpoles.
Mercury, a heavy, toxic metal, occurs naturally and is introduced into the environment by metal processing, coal burning and mining. People are exposed to mercury by eating contaminated fish and wildlife. Over time, low-grade mercury exposure in people can impact cognitive thinking and fine motor skills.
While concentrations of total mercury differed among the pools and were greatest in the unburned softwood-dominated setting, the levels increased in all pools throughout the season. The pools dried in June and refilled with September and October rain.
Wood frogs can travel some distance from their natal pools. During summer, fall and winter, they live in wetlands and on land. In the winter, they hibernate underneath leaf litter, woody debris and soil. They return to pools in the spring to mate.
For a better understanding of the transport of this contaminant from seasonal pools into the surrounding environment and potential for uptake into the terrestrial food web, future studies should focus on the ratio of total mercury to methylmercury (produced by burning of fossil fuels) in embryos, tadpoles and juvenile frogs leaving natal ponds, according to the research team, writing in the journal Northeastern Naturalist.
Loftin teamed with Aram Calhoun, professor of wetland ecology; Sarah Nelson, assistant research professor at the Senator George J. Mitchell Center; Adria Elskus, associate professor of biological sciences; and Kevin Simon, assistant professor in the School of Biology and Ecology, to conduct the study.
Image Description: wood frogs
Encouraging people to be engaged in sustainability efforts today that will make a difference tomorrow begins with a look back, says a team of University of Maine resource economists. Reflecting on societal decisions that have come to bear and learning from those aspects that we regret, or for which we are grateful or indifferent could lead to the ultimate motivating question: What actions will the future regret and what will it be thankful for?
Retrospective thinking — learning to evaluate reactions to the legacy we leave — is a means of raising awareness of the potential implications of current actions on the future, according to UMaine School of Economics researchers Mark Anderson, Mario Teisl and Caroline Noblet, writing in the journal Ecological Economics.
It is broadly understood that successful sustainability awareness and action require intergenerational equity and stakeholder engagement. It also is generally argued that we cannot presume to know future preferences — both individual and collective — that change over time.
For a community to engage the future as stakeholders in sustainability, the researchers propose four steps, which will be tested in a survey this spring.
“Reflecting on what about previous decisions contributed to or detracted from sustainability is a concrete exercise in intergenerational thinking,” according to the economists, whose research is supported by Maine’s Sustainability Solutions Initiative, a program of UMaine’s Senator George J. Mitchell Center.
Image Description: Sustainability