Monday, September 15, 2008

Week of September 14, 2008

Updated 9/18

Oak wilt - a new threat in New York State

George W. Hudler, Cornell University Cooperative Extension

Thanks to keen observations by several homeowners in Schenectady County, New York and prompt action by Cornell Cooperative Extension educator Chris Logue, plant pathologists at Cornell recently confirmed for the first time that oak wilt - a lethal disease of red oaks in the upper Midwest and mid-Atlantic states and Texas – is now present in New York State. So far, oak wilt is only known to occur in the state in an area equal to about three city blocks in Scotia. However, as word of the discovery spreads and more people learn to identify symptoms of the disease, Cornell Plant Disease Diagnostic Laboratory staff expect to process more samples from various localities elsewhere and, from them, to get a better picture of just how widespread the disease is.

Oak wilt is caused by a fungus – Ceratocystis fagacearum. Scientists don’t know for sure where the fungus came from; it may have been introduced to North America from some other part of the world or it may have evolved as a variant of some closely related endemic fungus growing on another plant. C. fagacearum grows in the water-conducting vessels of host trees and as it does, it causes the vessels to produce gummy plugs that prevent water transport, eventually causing tree death. The mode of action of the fungus in oaks is similar to that of the Dutch elm disease pathogen in elms, but there are few other similarities between the two organisms and their hosts.

All species of oaks native to New York State are susceptible to oak wilt to some degree, but those in the red oak "group" (e.g. northern red oak, black oak, pin oak) are much more likely to die soon after they contract the disease. Movement of the pathogen in these trees is so rapid that it may kill trees in as little as three weeks. White and bur oaks are more resistant to the disease (but they are not immune) and may survive for many years after infection, losing just a few branches each year. However, each individual tree reacts differently from others in the same species and it is difficult, if not impossible, to predict how long an infected bur or white oak will live. Article (PDF)


What's killing off our salt marshes?


Up and down the Eastern Seaboard, the coastal wetlands are dying, and no one knows for sure why this is happening.

First observed in the Florida panhandle in 1990, the shoreline degradation, called sudden wetland dieback, has been observed in hundreds of locations from Louisiana to Maine. Scientists say that while it's normal for coastal marsh vegetation to have its bad years, they have never seen marsh grass die and not recover, until now.

There are a number of suspected causes, with a species of fungus -- Fusarium -- as one of the prime suspects.

But there are other suspects in the lineup, experts say. These include drought, rising sea levels, rising soil acidity, the purple marsh crab, tiny nematode worms and the heating of the Earth's atmosphere.

Things have been happening to the marshes since the beginning of time, but this, we think, is new," said Wade Elmer of the Connecticut Agricultural Experiment Station in New Haven, Connecticut.

In his laboratory, Elmer tends to dozens of plastic flowerpots where he grows Spartina alterniflora, the marsh grass that grows on the very edge of Long Island Sound, and the species that's mysteriously dying. He's trying to determine which of the various species of Fusarium that's infecting them.

"Here are all of the species of Fusarium," said Elmer, hefting a textbook as big as a telephone directory, each page describing a different species.

"One idea is that there is slightly more nitrogen in the soil -- and that, with rising sea levels and maybe a drought, is causing a tipping point," Elmer said. "There's evidence that as the lower marsh becomes wetter and wetter -- and maybe the increasing temperature has something to do with -- the grass doesn't do as well."

It's possible that the dieback might be a poorly understood natural phenomenon -- perhaps something that occurs every several hundred years. But the Earth's climate is clearly getting hotter from human activity, and this has stressed ecosystems around the globe, marsh grass included, experts say.

"Our tidal marshes formed about 3,000 years ago when sea levels were low, and for a long time the seas were rising at a rate of only 1.5 millimeters per year," Rozsa. "Now we're looking at forecasted rates on the order of three or four millimeters per year. With that, we don't think that the marshes can sustain themselves as these big, flat expanses like we see today -- they'll only exist in narrow bands along the shore." Elmer agreed. "We'll see just a thin ribbon of marsh in New England," he said.

Scientists say that sudden wetland dieback is apparently an Eastern Seaboard problem -- it hasn't been observed on the West Coast, nor on the shores of the other continents.

The onslaught of the invasive Phragmites -- the tall wetland grass with its characteristic feather-like fronds -- is not part of the die-off equation. "Phragmites can't tolerate the salt levels that Spartina can -- it's found a little farther inland," Elmer said. "In fact where Phragmites has died, we'll find that the Spartina has died before it."

Some researches have suspected that the purple marsh crab, Sesarma reticulatum, has a role in the dieback equation. The tiny nocturnal crab has been known to have a "lawnmower" effect on Spartina. But Elmer sees the crab and its damage as more of an effect, not the cause, of an unhealthy marsh. The purple marsh crab is a omnivore, consuming both plants and small animals.

Stephen Smith, a scientist with the Cape Cod National Seashore, said that there is a clear correlation between Spartina loss and crab density. He notes that the population of purple marsh crabs in dieback areas is 10 times what it should be.

"You can plant Spartina alterniflora anywhere on these marshes, and it will grow -- so long as you protect them for these crabs," he said.

"In places where they're not protected, the grass is chewed down to a nub. We don't see a situation where the grass turns brown and dies -- it's there one day and gone the next." The question for future research, Smith said, is finding out why purple marsh crab populations are exploding and why they're choosing Spartina over other items their diet. Article


Aiming to build a better habitat in Pennsylvania

By Tom Venesky,

DENNISON TWP, Pennsylvania. – Joe Lukashunas waded into an inhospitable tangle of weeds and thorns and saw potential.

Never mind that the old farm fields in Nescopeck State Park had been overrun with invasive plant species for decades, Lukashunas is hopeful the area can be transformed into fields of native plants and grasses that will be a boon to wildlife.

And he’s not the only one.

Several conservation groups have partnered with state and federal agencies to combat invasive plant species that have taken over more than 70 acres of the former Hoda farm located in the park. The only reminder of the farm is a lone silo standing along the road, while the fields behind it have reverted into jungles of invasives such as multi-flora rose, autumn olive and Japanese barberry.

Within three years, the groups hope to convert the old farm to an oasis of native plants and grasses that provide food and cover to game species, songbirds and insects.

Participating groups include the Honey Hole Longbeards Chapter of the National Wild Turkey Federation, Northeast Pennsylvania Chapter of Pheasants Forever, Ruffed Grouse Society, Department of Conservation and Natural Resources, Pennsylvania Game Commission, Natural Resource Conservation Service and the North Branch Land Trust. Article


New York City: Forest Stewardship Volunteering
Wednesday, September 24, 2008
1:00 p.m.–4:00 p.m.

Enjoy the outdoors and be a steward of your local natural areas! To assist the ongoing forest restoration project at Conference House Park, we will remove invasive plant species, preventing their spread and encouraging our native plant and animal community to recover. As needed, we might also plant, seed, or mark with flagging some of our native species. Come and learn while you lend a hand toward a healthy ecosystem!

Please RSVP if you plan to attend. For RSVPs and questions, please call Cheri Brunault at (718) 390-8021, or email at This event is rain or shine. Hope to see you there! Link


'Mean, aggressive' crayfish invades Falcon Lake, Winnipeg, Canada

FALCON LAKE -- While on a holiday scuba diving in Falcon Lake a summer ago, Mark Lowdon came upon crayfish that acted like no crustacean known to Manitoba.

Normally, crayfish just scoot away, but this one acted more like an escaped cast member from the children's television show SpongeBob SquarePants. The crayfish stood its ground, rearing up its full 13-centimetre length and clicking its overly-large claws. "You want a piece of me?" it seemed to snarl.

Lowdon, a marine biologist, caught several of the crayfish, emptied all the food out of the cooler, and put the creatures inside to take to staff at federal Fisheries and Oceans.

It was exciting to make the discovery, but bad news for Manitoba's lakes. Lowdon had found Manitoba's first rusty crayfish, an aggressive, invasive species from the Ohio River basin that wipes out indigenous northern crayfish like ours. Article


USGS to host Congressional briefing on climate change and invasive species

Invasive cheatgrass is altering historical fire regimes throughout the western United States, exposing native ecosystems not adapted to fire to more frequent and intense fire events. Invasive aquatic species including invertebrates, fish, and the fish disease VHS continue to colonize the Great Lakes at an alarming rate. The increased uncertainties posed by climate change compound the challenges facing resource managers throughout the United States as they grapple with growing populations of invasive species.

Come learn how the USGS and its partners are working to provide and apply the science needed by resource managers and policy makers to anticipate and address the impacts of climate change and invasive species on the landscape.

What: The USGS will host a congressional briefing on how science can be used to anticipate and address the impacts of climate change and invasive species on the landscape.

Who: Pam Fuller, U.S. Geological Survey; Mike Pellant, Bureau of Land Management; Gary Whelan, Michigan Department of Natural Resources.

Where: 2325 Rayburn House Office BuildingWashington, D.C.

When: Friday, September 19, 20089:30 a.m.

Hosts: Congressman Earl Blumenauer, Congressman Vernon Ehlers, Congressman Wayne Gilchrest, Congressman Jim Moran

Sponsors: Ecological Society of America, Climate Change Science Program, Northeast-Midwest Institute

For more information about the briefing, visit Link


Invasive Species Strike Team introduced in New Jersey

BEDMINSTER, NJ —The Upper Raritan Watershed Association (URWA), in partnership with Friends of Hopewell Valley Open Space (FoHVOS), has announced the creation of the Central Jersey Invasive Species Strike Team. This Strike Team represents the state’s first comprehensive effort toward invasive plant management through a public-private partnership.

With funding provided from the Bunbury Foundation, Conservation Resources Inc., the Conserve Wildlife Foundation, Merck and Co., and the 1772 Foundation, these organizations are pooling their expertise and resources to reduce the spread of invasive plants. They are working to find and destroy new populations of invasive species on public and private lands in New Jersey’s Highlands and Piedmont regions. In addition, they are reaching out to private landowners and public land managers to encourage them to remove invasive plants from their landscapes and replace them with native plants.

Anyone interested in learning more about invasive plants and the problems they are causing in New Jersey is encouraged to consider becoming a volunteer member of the strike team. All volunteers will learn to identify the targeted invasive plants and will put their knowledge to work removing them from sites across Central Jersey. The project team will host a kickoff event at Duke Farms in Hillsborough on Sept. 30 from 2 to 4 p.m. For more information about the strike team, contact team leaders Melissa Almendinger at 908-234-1852, and Michael Van Clef 609-730-1560. Article


Weed It Now on the Appalachian Trail

SHEFFIELD, MA — September 16, 2008 — The Appalachian Trail is a haven for thousands of hikers annually. However, the Trail is also home to other – unwelcome – guests: invasive plants.
To rid the Trail of these harmful species, The Nature Conservancy, National Park Service, Connecticut AT Committee of the Appalachian Mountain Club and Appalachian Trail Conservancy announced today that they have joined together in a removal effort near the Connecticut and Massachusetts border. The work is part of a five-year conservation initiative to remove non-native, invasive plants from over 9,000 acres of the Berkshire Taconic forest plateau.

Entitled "Weed It Now" (WIN), the project received support and funding through the United States Department of Agriculture’s Natural Resources Conservation Services. The Nature Conservancy drafts a scope of work and negotiates management agreements for invasives species control with willing public and private landowners across the Berkshire Taconic forest. To date the Conservancy has worked with 75 landowners and treated invasive species on 7,000 acres of land. This is the first time treatment will occur on federal land used for the Appalachian Trail.

"The 'Weed It Now' restoration program is vital to the preservation the Appalachian Trail near the Massachusetts and Connecticut border," said Betsy Lyman of the National Park Service. "This project will help in protecting this ecologically rich landscape from further environmental degradation, ensuring its survival for future generations." Article


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