Martens recolonized Isle Royale in the '90s, showing island's dynamism

August 24, 2018, University of Wisconsin-Madison

After decades of trapping, the last known American marten was spotted on Isle Royale in 1917. Fifty years later, in 1966, the National Park Service planned to reintroduce martens to the national park situated in Lake Superior, but nobody knows if the agency ever followed through. Then, in 1993, martens were confirmed on the island for the first time in 76 years.

Whether these small, forest-dwelling carnivores—valued historically for their fur—had been hiding there the whole time, found their way back, or were introduced in the 1960s without any records has remained a mystery for the last quarter century.

But in new research published today (Aug. 23, 2018) in the journal Scientific Reports, University of Wisconsin-Madison researchers in the Department of Forest and Wildlife Ecology, collaborating with the National Park Service, traced the recolonization to martens likely arriving in the 1990s, shortly before they were spotted.

Genetic studies of martens from Isle Royale and nearby populations in America and Canada showed that the contemporary population came from nearby Ontario, Canada. The animals likely wandered over on an ice bridge in the winter, the researchers speculate.

The results provide much-needed context about the natural history of an island long considered an unspoiled wilderness, but one with a long history of ecological disruptions and recoveries. The island park may be best known for the ebb and flow of its wolf and moose populations, which have been tracked for 60 years.

With additional wolves set to be relocated to Isle Royale in the coming months, the new research provides ecologists and land managers with a fuller picture of how dynamic even seemingly isolated island ecosystems can be.

After all, say the researchers, if the house-cat-sized marten can find its way over, islands like Isle Royale may be less isolated and static than we think.

Jonathan Pauli, a professor of forest and wildlife ecology at UW-Madison, has studied martens for years as part of efforts to understand how communities of wild animals respond to human disturbance. In 2015, his group provided evidence that martens had long escaped detection on islands in southeastern Alaska prior to deliberate reintroduction efforts in the 20th century. And in work published in 2016 with graduate student Phil Manlick, Pauli called into question the effectiveness of periodic augmentations of reintroduced marten populations in Wisconsin, where the once-extirpated carnivore remains an endangered species.

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Study examines life history of imperiled rattlesnake-Scientists show how climate, geography impact Eastern Massasauga – via Herp Digest

NORTHERN ILLINOIS UNIVERSITY, Press Release 2/16/17

A new study is bringing attention to a little known and imperiled rattlesnake that slithers among the wetlands in regions surrounding the Great Lakes.

The Eastern Massasauga rattler was once common in such states as Indiana and Illinois. Until recent years, it could still be found in Chicago's Cook County. But the reptile's range and numbers have been steadily declining. In 2016, the snake was listed as threatened under the U.S. Endangered Species Act.

In the new study, Northern Illinois University biological sciences professor Richard King and his former student Eric Hileman examine the life history of the Eastern Massasauga, revealing important local climate impacts on the snake that should be carefully weighed when developing conservation strategies.

"Our results provide evidence that climatic variation in the Great Lakes region strongly influences body size, individual growth rates and key aspects of reproduction," says Hileman, first author of the study published in PLOS ONE, a journal of the Public Library of Science. Hileman earned his Ph.D. in biological sciences from NIU in December and is now a postdoctoral fellow in biology at Trent University in Ontario, Canada.

Hileman, King and more than 40 co-authors gathered and synthesized more than a century of data on the snakes from study sites across the range of the Eastern Massasauga. Most of the data was culled from studies conducted from the mid-1990s forward at sites in Illinois, Indiana, Wisconsin, Michigan, Iowa, Ohio, Pennsylvania and New York, as well as Ontario, Canada.

The scientists found strong evidence for geographic variation in six of nine life-history variables. Among the findings:

            •           The average body size of the snake and the size of its offspring increased with increasing mean annual precipitation, possibly because wetter climates yield greater prey abundance. 

            •           Litter sizes decreased with increasing mean temperature, and increased by one offspring for each 1.89-degree increase in latitude, even when maternal size was held constant.

"It's been rare to look within a species and show that these patterns exist," King says. "The study results demonstrate that a one-size-fits all conservation strategy is not appropriate. Rather, assessments of extinction risk and the design of management strategies need to account for geography.”

The Eastern Massasauga snakes are generally found in wet prairies or sedge meadows, where the reptiles employ a sit-and-wait strategy to catch and feed on small mammals. Adult size ranges from about 2 feet to 2 ½ feet in length. While venomous, the snakes are not particularly aggressive or dangerous to work with.

"You're not likely to encounter them unless you're looking for them," King says. "It's easy to walk right by one. They're very cryptically colored to look like dead leaves and cattails, so they blend in exceedingly well."

The reptiles suffered habitat loss from extensive drainage of land for agriculture and development. As recently as the 1970s, some states had bounties on the snake.

With concerns over whether they would persist in the wild, the remaining snakes in Chicago's Cook County were taken into a captive breeding program in 2010, King says.

"In Illinois, they've nearly blinked out entirely," he adds. "We're probably down to one location in the southern part of the state that has a stable population. They seem to have stronger holds in Michigan and southern Ontario.”

The study authors believe findings will aid Eastern Massasauga recovery efforts.

"The life-history parameter estimates will be essential for improving models related to extinction risk and climate change," Hileman says. "The results from these predictive models can subsequently be used to develop site-specific management strategies."

Invasive species not best conservation tool, study shows

Make matters worse for native mollusks

Date:April 6, 2016

Source:University of Guelph

Harnessing an invasive fish species sounded like a promising conservation tool to help reverse the destruction wreaked by zebra mussels on endangered native mollusks in the Great Lakes -- except that it won't work, says a University of Guelph ecologist.

In a novel twist on invasive species ecology, a research team led by integrative biology professor Joe Ackerman found that the round goby fish -- an invader in Ontario waters -- only makes matters worse for native mollusks already driven to near-extinction by an earlier zebra mussel invasion.

The Guelph team's paper appears today in the Royal Society Open Science journal.

Ackerman worked with lead author and former master's student Maude Tremblay and Todd Morris, a researcher at Fisheries and Oceans Canada.

Suspension-feeding mussels living on the bottom of lakes and streams help to clean water used for everything for drinking to fishing and other recreation.

Read more ...

Invasive species in the Great Lakes by 2063

Date:

January 29, 2015

Source:

McGill University

Summary:

The vulnerability of the basin to future invaders has been demonstrated by a new study that calls for regulations to mitigate this threat. The Great Lakes have been invaded by more non-native species than any other freshwater ecosystem in the world. In spite of increasing efforts to stem the tide of invasion threats, the lakes remain vulnerable, according to scientists. If no new regulations are enforced, they predict new waves of invasions and identify some species that could invade the Lakes over the next 50 years.

Continued ...

Chicago goes to war with Asian carp

By Pallab GhoshScience correspondent, BBC News, Chicago

The US city of Chicago is considering drastic measures to prevent giant fish infesting North America's Great Lakes.

Authorities are thinking of blocking the city's canal system to stop Asian carp entering Lake Michigan.

Such a move could cost up to $18bn (£11bn) and cause huge economic disruption to the city.

Cheaper options are also being examined, including making burgers out of the fish and eating them to extinction.

This species of carp, as the name suggests, is native to the Far East.

They were originally introduced to southern US states more than three decades ago to control algal build-up in sewage treatment plants. But they escaped into the Mississippi River and proliferated, making their way north towards the Great Lakes.

More than a metre in length, they have displaced indigenous fish species along the way.

Read more

Asian Carp Threaten U.S. Great Lakes

Two species of Asian carp could drive native fish out of the Great Lakes, according to a new government report that warns against letting these invasive fish gain a foothold in this new territory.

Bighead and silver carp in Midwestern rivers pose a "substantial environmental risk" to the Great Lakes, particularly Lakes Michigan, Huron and Erie, according to a risk assessment released today (July 16) by Canadian and U.S. scientists.

"Ever since these non-native fish first escaped and began to breed prolifically in the rivers of the Midwest, the questions everyone has been asking are: Can a breeding population survive in the Great Lakes, and would it be a significant problem if they did?" Now we know the answers, and unfortunately they are yes and yes," Marcia McNutt, the director of the U.S. Geological Survey, said in a statement.  "This study will help scientists and resource managers in Canada and the U.S. determine how and where to redouble their efforts as they continue to prevent the establishment of these invasive fish."

Read on:  http://www.livescience.com/21625-great-lakes-invasive-carp.html

Sea Lampreys Fear the Smell of Death: Repellant Could Be Key to Better Controlling Destructive Invasive Species

ScienceDaily (Aug. 6, 2011) — A repellant for sea lampreys could be the key to better controlling one of the most destructive invasive species in the Great Lakes, says a Michigan State University researcher.


Scientists have seen the effect alarm cues have on lampreys. When scents from dead sea lampreys are poured into a tank of live ones, the lampreys' efforts to escape are dramatic. In the past, these reactions were simply dismissed as novel. But Michael Wagner, MSU assistant professor of fisheries and wildlife, sees this reaction as a potential game changer.


"Sea lampreys are one of the most costly and destructive Great Lakes' invaders," said Wagner, who published his results in the current issue of the Canadian Journal of Fisheries and Aquatic Sciences. "The effectiveness of the odor combined with the ease in which it's obtained suggests that it will prove quite useful in controlling sea lampreys in the Great Lakes."

Discovering an effective repellant puts research to control sea lampreys on a new path.

Scientists had proven that the destructive species rely on the odor emitted by past generations of larvae to navigate into streams with suitable spawning grounds. Upon arrival, another odor emitted by mature males lures females onto nests to complete spawning. Based on these observations, existing research has fully focused on using pheromones to attract sea lampreys into traps. Once caged, they are destroyed or sterilized and released back into the wild so they can be tracked but cannot reproduce.

But with many scent and environmental cues in natural waterways, using pheromones to attract sea lampreys doesn't always work. On the other hand, repellants -- even in miniscule amounts -- may prove to be much more effective in diverting and corralling them, Wagner said.

"It's kind of like a stop light, a noxious odor that causes them to run away from its source," he said. "By blocking certain streams with these chemical dams, sea lampreys can be steered away from environmentally sensitive areas and into waterways where pesticides could be used more effectively to eliminate a larger, more concentrated population of sea lampreys."

This approach would allow agencies that control invasive species to save money, use less pesticide and manage other resources more efficiently to have a bigger impact on controlling the invasive species, Wagner added.

"Thanks to this exciting new research on alarm substances, we believe we are on track to bring sea lamprey control to a whole new level," said Robert Lambe, chairperson of the Great Lakes Fishery Commission.

Wagner is continuing his research to isolate the exact chemical compound that causes the alarm. His work is supported by MSU's AgBioResearch and the Great Lakes Fishery Commission

http://www.sciencedaily.com/releases/2011/08/110805163544.htm

Lake invaders may be killing birds

Scientists suggest invasive mussels in the Great Lakes may be responsible for the deaths of thousands of migratory birds.

The hunt is on in the upper reaches of Lake Michigan to count what's believed to be thousands of bird carcasses that have washed ashore this fall — a staggering toll blamed on the disruptive powers of invasive species that have taken root in the Great Lakes.


The great debate in the Asian carp crisis, still playing out in federal court and the halls of Congress, is whether the feared fish has the capability of establishing a thriving population in the Great Lakes. If so, bighead and silver carp will almost certainly, and dramatically, alter commercial and recreational fishing in the nation's largest freshwater body.

But what if, as some scientists suggest, the Great Lakes' natural defenses — plankton shortages, lower water temperatures, greater water depth and swift-moving currents — keep Asian carp from sustaining themselves in large numbers? Will the threat have been avoided?

The answer is that all invasive species bring consequences that few can predict, leading scientists to ponder the thousands of gulls, loons, mergansers and other migratory birds whose remains wash ashore along the white-sand beaches in northern Wisconsin and Michigan's upper peninsula each fall.

There is a somewhat controversial theory for this annual die-off, which by some estimates has claimed more than 100,000 birds in the last 15 years, and it involves a type of naturally occurring but deadly botulism linked to the spread of invasive zebra and quagga mussels, which entered the Great Lakes decades ago aboard ocean vessels.

"There's still a lot about this we don't know," said Joe Kaplan, of the Michigan-based nonprofit Common Coast Research & Conservation. "The one thing we do know is that it's killing a lot of birds that are important to us.


"This is a very serious problem that deserves more attention."

Like Asian carp, zebra and quagga mussels reproduce rapidly and overwhelm their environment. Scientists feared densely packed clusters of mussels would take a toll on industry, colonizing in water pipes, intake valves, and air conditioning and cooling systems. And they have.

The U.S. Geological Survey, which has studied zebra and quagga mussels for more than 20 years, rank them among the most destructive "biological invasions into North America." But few could foresee the carnage that has followed.

Zebra mussels and quagga mussels filter naturally occurring botulism and other toxins from the water. Round gobies, another problematic invasive species, eat the mussels, and birds, in turn, eat the gobies.

"The evidence is there to suggest this is happening, but it's circumstantial evidence because we haven't found any proof of it," said Tom Cooley, a biologist at the Michigan Department of Natural Resources. "All we can really do at this point is to continue to monitor what's happening and maybe something in the lakes will turn around."

Michigan's DNR and the Common Coast Research & Conservation are among the organizations, including the USGS and the National Wildlife Health Center, studying the deadly phenomena that this year is expected to kill as many or more birds than died in the oil spill in the Gulf of Mexico last summer.

Scientists don't know how long botulism or similar toxins have been killing birds in the Great Lakes, but the first sizable counting came in 1999, when researchers recorded 311 birds off the shores of Lake Erie. The following year, they found 8,000 around the Great Lakes and the death counts have remained in the thousands every year since.

For now, the deaths appear limited to the northern Great Lakes region, where the concentrations of mussels and birds are higher. But so little is known about the environmental factors that contribute to these deaths that scientists can't rule out large numbers of dead birds washing up along the shore closer to Chicago and western Michigan.

After two "low years" the death toll seems to have risen again this fall, Kaplan said, with perhaps as many as 50 dead birds recovered for every mile of beach. That may be because the unusually hot summer around the Great Lakes produced more algae, which feeds the mussels' population explosions. Or it may be attributed to other factors scientists haven't yet explored.

"We're still learning," Cooley said.

The die-off has devastated the populations of a number of important and protected bird species, but the discovery of many hundreds of common loons, a threatened species in Michigan, has given researchers a rallying point to draw attention and hopefully more funding to this issue, Kaplan said.

But with so much money already being spent to minimize the spread of invasive species within the Great Lakes, and recently to stop another from entering, Kaplan said he realizes this fight may be unwinnable.

"Unfortunately, we don't begin to really study an issue until we see entire systems collapse or get out of control," Kaplan said. "But that comes at a high cost."

By Joel Hood, TRIBUNE REPORTER

http://www.chicagotribune.com/news/local/ct-met-lake-michigan-bird-deaths-20101127,0,918715.story

Not One, But Two Kinds Of Males Found In Invasive Round Goby Fish

ScienceDaily (June 18, 2009) — Scientists have found the existence of two types of males of a fiercely invasive fish spreading through the Great Lakes, which may provide answers as to how they rapidly reproduce.

The research, published in the Journal of Great Lakes Research, looks at the aggressive round goby, a bottom-dwelling fish which infested the Great Lakes watersheds around 1990.

Presently, they are working their way inland through rivers and canal systems and can lead to the decline of native species through competition and predation.

Researchers at McMaster University discovered evidence that in addition to round goby males which guard the nest from predators and look after their offspring, there exists what scientists call "sneaker" males – little males that look like females and sneak into the nests of the larger males.

"The existence of these two kinds of males will help scientists understand how round gobies reproduce, how quickly their populations grow, and track how these populations change over the course of invasion," says Julie Marentette, lead author and a Ph.D. student in the department of Psychology, Neuroscience & Behaviour at McMaster University. "This has the potential to have a significant impact on how researchers tackle what has become a very difficult problem in the Great Lakes."

Because males expend lots of energy or eat less while guarding their nests, and attracting females while providing care can be difficult, males in some species have found a sneakier way to mate, Marentette explains. Instead of courting females and protecting the young, some males will parasitize the courtship –and sometimes the parenting duties –of conventional males. They do this by sneaking into the nests of big males or pretending to be females.

"Prior to our findings, only one type of male reproductive behaviour would have been incorporated into projections and modeling analyses of the population dynamics of round goby invasive capacities", says Sigal Balshine, associate professor in the department of Psychology, Neuroscience & Behaviour and academic advisor on the study. "Our results will shed light on how populations of this invasive species are likely to grow and spread through time and space."
The McMaster scientists compared the physical, hormonal and sperm traits of hundreds of males, and found that the nest-guarding, parental males were big, black and had wide heads. The small female-like sneaker males were tiny, mottled brown and had narrow heads. Both types of males produced sperm, but sneakers produced more sperm than the parental males, and had bigger testes. By contrast, parental males have bigger glands used to produce pheromones that attract females.

Funding for the research was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Fund for Innovation, the Ministry of Research and Innovation and the Department of Fisheries and Oceans (DFO).

http://www.sciencedaily.com/releases/2009/06/090615112225.htm