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Scientists face endangered species conundrum

Bay Area marsh bird at nexus of endangered and invasive species


A clapper rain along the shore of San Francisco Bay. Photo via USFWS.

Staff Report

FRISCO — Conservation biologists in the San Francisco bay area say they’re facing a conundrum, as they try to remove an invasive salt marsh grass while recovering an endangered bird that has come to rely on the non-native plant.

In a study published last month in the journal Science, researchers at the University of California, Davis said that an all-out push to eradicate the marsh cordgrass could hamper efforts to recover the clapper rail, a bird on the brink because of urban development and loss of wetlands.

Their results showed that, rather than moving as fast as possible with eradication and restoration, the best approach is to slow down the eradication of the invasive species until restoration or natural recovery of the system provides appropriate habitat for the endangered species.

Scientists in the southwestern U.S. have faced similar issues as they try to remove invasive tamarisk, which has come to provide habitat for rare southwestern willow flycatchers. Continue reading

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Global warming making things tough for native trout in the northern Rockies


Cutthroat trout. Photo courtesy National Park Service.

30-year study shows how warmer stream temperatures are linked with hybridization

Staff Report

FRISCO — Scientists studying trout in the northern Rockies say warmer stream temperatures and lower spring flows in mountain streams is increasing the pace at which introduced rainbow trout and native cutthroats interbreed. Hybridization has already contributed to the decline and extinction of many native fishes worldwide, including all subspecies of cutthroat trout in western North America.

The long-term research shows that, while hybridization used to be limited to lower stream reaches, during the past 30 years, it has quickly spread upstream as temperatures warm. According to the scientists, the process is irreversibly reducing the genetic integrity of native westslope cutthroat trout populations. Genetically pure populations of westslope cutthroat trout are known to occupy less than 10 percent of their historical range. Continue reading

Environment: Study says overpopulation of deer at root of invasive plant problem in Pennsylvania forests

Ecosystem breakdown more complex than just invasive species

Colorado mule deer.

Colorado mule deer. bberwyn photo.

By Summit Voice

FRISCO — Valiant weed warriors, who have made it their mission to try and eradicate non-native plants, may want to think about the bigger ecological picture as they plan their weekend weed pulls.

A new study led by the University of Pittsburgh’s Susan Kalisz suggests that, in some cases, invasive plants overwhelm native ecosystems because of an overpopulation of deer. The density of deer in the United States is about four to 10 times what it was prior to European settlement of North America. That density, Kalisz posits, is the main reason garlic mustard is crowding out native plants, such as trillium, which are preferred food for wild deer. Continue reading

More quagga mussels found in Lake Powell; Is the Lower Colorado River ecosystem at risk?

Quagga mussels coating a flip-flop in Lake Mead. PHOTO COURTESY NATIONAL PARK SERVICE.

Quagga mussels coating a flip-flop in Lake Mead. PHOTO COURTESY NATIONAL PARK SERVICE.

National Park Service seeking input on mussel management plan

By Summit Voice

FRISCO — The battle to keep Lake Powell free of non-native mussels is tilting toward the aquatic invaders and federal resource managers are concerned the invaders may spread into Glen Canyon.

As of January, the National Park Service reported finding — and removing — about 1,300 hundred adult quagga mussels, and managers at the reservoir said they’re finding more as the season progresses.

In response, the park service is developing a quagga-zebra mussel management plan to help the the agency decide what tools are appropriate to support the ongoing management of invasive mussels in Glen Canyon now that quagga mussels are present in Lake Powell. Continue reading

Global trade contributing to the spread tree-killing bugs

Study says new approaches needed to control spread of pathogens

A close up of an Emerald Ash Borer insect and the feeding tunnels the insects create under ash bark. Insect Photo: David Cappaert, Michigan State University. Tunnel Photo: NPS Photo

A close up of an Emerald Ash Borer insect and the feeding tunnels the insects create under ash bark. Insect Photo: David Cappaert, Michigan State University. Tunnel Photo: NPS Photo.

By Summit Voice

FRISCO — The new infestation of tree-killing emerald ash borers in Boulder is just one symptom of a global trend recently identified by scientists from the universities of Southampton, Cambridge, Oxford and St Andrews.

The findings, published Nov. 15 in the journal Science, suggest that the number of pests and disease outbreaks in trees and forests across the world has been increasing.

There is growing concern that aspects of globalization — in particular, high volumes and new forms of trade — may increase the risk of disease spreading and provide opportunities for genetic re-assortment which can enhance the ability of an organism to cause disease. Continue reading

Global warming ups threat of invasive species in the Arctic


Spitsbergen is the largest of the islands in the Svalbard Archipelago. It sits well inside the Arctic Circle, just south of 80 degrees north latitude. Visit this NASA Earth Observatory page for information on this image.

Warmer ocean temperatures, more ship traffic will open the door for new marine organisms

By Summit Voice

FRISCO — Scientists are warning that warmer ocean temperatures in the far north will open the door for aquatic invaders that could devastate native marine ecosystems.

So far, cold water temperatures have prevented most harmful low latitude species from establishing themselves but the threat of invasive species will grow as the oceans warm and as ship traffic increases in the Arctic, said an international team of researchers led by PhD candidate Chris Ware from the University of Tromsø in Norway.

All in all, the researchers expect a much greater pressure on the marine ecosystems of the Arctic, where fishing is very important for the population in Norway and Greenland. Continue reading

Environment: Federal scientists say they’ve found a way to detect invasive mussels in their larval stage



Zebra (left) and quagga mussels are spreading in lakes and reservoirs, with the potential for huge impacts to aquatic ecosystems, hydropower facilities and water delivery systems.

By Summit Voice

FRISCO — Federal scientists said they’ve developed ways to detect invasive quagga and zebra mussels while they’re still in the larval stage. That could help resource managers beef up protective measures before the mussels establish themselves in reservoirs and lakes.

“Early detection of mussel larvae does not mean that the water body will necessarily become infested,” said Curt Brown, director of research and development for the U.S. Bureau of Reclamation. “Early detection provides a warning for managers that a water body is being exposed to mussels through some pathway, so they can consider additional means to prevent further introduction.” Continue reading

Fragmented forests lead to ‘ecological armaggedon’


When it comes to forest habitat, bigger is better.

Population isolation, invasive species decimate native species in forest islands

By Summit Voice

FRISCO — Small islands of forest don’t offer much in the way of protection for wildlife, according to a new study showing rapid extinction of species in habitat fragmented by development of a large reservoir in Thailand.

The findings suggest that species living in rainforest fragments could be far more likely to disappear than was previously thought. In the 20 year study, researchers witnessed the near-complete extinction of native small mammals.

“It was like ecological Armageddon,” said Luke Gibson from the National University of Singapore, who led the study, published in the journal Science. “Nobody imagined we’d see such catastrophic local extinctions.” Continue reading

Oceans: Native predators won’t halt lionfish invasion


Invasive lionfish won’t be controlled by native predators, leaving human intervention as the main option for management. Photo courtesy NOAA.

Active removal by humans probably the only option for removal

By Summit Voice

FRISCO — Invasive lionfish have colonized the Caribbean and have moved up the Atlantic Coast of the U.S. as far as North Carolina, where they now threaten local fish populations, according to marine biologists at the University of North Carolina.

Not only that, but the spiny invaders are out-predating fish like sharks and barracudas, threatening to throw coral reef ecosystems out of whack. The only recourse is human intervention, the scientists said after publishing a paper in the journal PLOS ONE. showing that native predators won’t have much luck supressing the unwanted guests.

“Lionfish are here to stay, and it appears that the only way to control them is by fishing them,” said John Bruno, professor of biology in UNC’s College of Arts and Sciences and lead investigator of the study.  Continue reading

National Park Service plans ‘mussel blitz’ at Lake Powell


A USGS map shows the spread of invasive mussels in the U.S.

Divers to scour main marinas in search of invasive species

By Summit Voice

FRISCO — After finding 14 adult quagga mussels attached to moored vessels and dock structures at the Wahweap Marina in Lake Powell, the National Park Service is planning a four -day “mussel blitz” to try and remove any more of the invasive aquatic pests.

Starting June 10, 25 to 30 divers will be in the water at Wahweap and Antelope Point Marinas to assess the extent of quagga mussels. Divers and staff from the National Park Service (NPS), Aramark, Antelope Point Marinas, and other local, state, and federal agencies will inspect moored boats, docks, cables, and the buoy field in the marina areas during the intensive 4-day effort. The location, size, and quantity of the mussels removed will be recorded to help scientists determine the origin and scope of the problem. Continue reading


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