Monday, January 24, 2011

Week of January 24, 2011

Musseled-Out Native Species Return to the Hudson

by Rebecca Kessler

When zebra mussels make the news, it's usually because they've invaded yet another water body. Not this time, though. In New York's Hudson River, zebra mussels appear to be declining as displaced native species stage a comeback.

Zebra mussels are striped, nickel-sized mollusks native to western Asia. Since they first appeared in the United States in 1988 as stowaways in ship ballast water, their habit of starving out native invertebrates and fouling equipment has made them serious aquatic pests. When they showed up in the Hudson in 1991, freshwater ecologist David Strayer and his colleagues at the Cary Institute of Ecosystem Studies in Millbrook, New York, were prepared—if not to stop them then at least to study their effects. Cary researchers had been regularly sampling plankton and water chemistry within the Hudson's 150-kilometer freshwater estuary for 5 years and had started sampling riverbed invertebrates the previous year. The data set's unparalleled length and continuity has enabled Strayer's team to detect changes in the population and effects of an invasive species that have eluded researchers elsewhere.

Zebra mussels hit the Hudson hard. They quickly gobbled up most of the river's plankton, the researchers discovered. Native mussels, clams, and other invertebrates plummeted to as little as 1% of their original populations. "It looked really, really grim," says Strayer.

Then to everyone's surprise, around 2001 the native mussels stopped declining. Strayer and his colleagues feared it was a temporary respite, but the trend persisted, and in 2007 they reported a solid, albeit incomplete, comeback. This summer, they documented native zooplankton—tiny floating animals—rebounding, too, and an increased death rate among large zebra mussels.

For the current study, published last week in the journal Oecologia, Strayer and colleagues scrutinized their long data set, estimating the survival rate of each age class of zebra mussels over time and the amount of water the mussels filter as they feed. They also looked for population trends in native invertebrates, including clams, nematodes, and flatworms.

Since zebra mussels first invaded the Hudson, the team found, their annual survival rate has fallen by 99% and their water filtration by 82%. It could be that native blue crabs or some other predator are eating more zebra mussels or their larvae, or perhaps some undetected pathogen or parasite is keeping them in check. As for the native invertebrates, they are approaching their preinvasion numbers....

Read the full story at link.


Monday, January 17, 2011

Week of January 17, 2011

Rules on invasive species stall; delay may be costly

By JIM LYNCH, The Detroit News

A year after the Asian carp’s threat to the Great Lakes threw a national spotlight on invasive species, critics say no definitive action on the issue’s two key focal points has been made.

Ballast water from oceangoing ships, considered the largest source of invasive species in the Great Lakes, remains largely unregulated. And the Mississippi River system, where the Asian carp is firmly entrenched, remains connected to the Great Lakes.

While there has been progress on both issues behind the scenes, conservationists say the pace is unacceptable and leaves the Great Lakes playing a game of Russian roulette year after year.

"Maybe another year or two of waiting doesn’t seem daunting, but if you get a new invasion of some species like zebra mussels that shows up in six months, then you could have a catastrophe on your hands," said Andy Buchsbaum, regional director of the National Wildlife Federation’s Great Lakes Regional Center.

For years, environmental groups pushed for federal laws that would have forced oceangoing ships to meet a discharge standard for ballast water released into the Great Lakes. According to some calculations, ballast water has been responsible for up to 80 percent of invasive species that have reached the lakes. And those species have an estimated $200 million-a-year impact on the region.

Invasive viruses have killed thousands of fish. Foreign species like the round goby crowd out native fish. And invasive crustaceans compete with native creatures for the same food.

Plants and industrial sites that utilize the region’s lakes are among the operations that have felt the impact of invasive species over the years. Many such operations are forced to clean water intake valves of creatures like the zebra mussel on a regular basis to maintain flow levels.

"We do it every year, and it costs us about $10,000 each time," said Chuck Bellmore, who operates Mount Clemens’ water filtration plant on the shore of Lake St. Clair. "We’ve been doing it now since 1991."


After a ballast proposal passed in the U.S. House of Representatives in 2008, the legislation languished in the Senate, and no bill was ever enacted. In 2011, there are no new proposals for a sweeping federal bill.

In place of a legislative solution, efforts to control ballast water are moving forward on two administrative fronts. The U.S. Coast Guard is putting together regulations that set a numerical value on the number of organisms that can be discharged per cubic meter of water.

And Great Lakes states are crafting their own ballast rules that could set a discharge standard. Both approaches could require the use of new technologies to clean up water before it enters the Great Lakes.

But even in a best-case scenario, approval and enforcement are at least a year off.

Read the full story at link.


What Triggers Mass Extinctions? Study Shows How Invasive Species Stop New Life

Courtesy of the National Science Foundation

An influx of invasive species can stop the dominant natural process of new species formation and trigger mass extinction events, according to research results published today in the journal PLoS ONE.

The study of the collapse of Earth's marine life 378 to 375 million years ago suggests that the planet's current ecosystems, which are struggling with biodiversity loss, could meet a similar fate.

Although Earth has experienced five major mass extinction events, the environmental crash during the Late Devonian was unlike any other in the planet's history.

The actual number of extinctions wasn't higher than the natural rate of species loss, but very few new species arose.

"We refer to the Late Devonian as a mass extinction, but it was actually a biodiversity crisis," said Alycia Stigall, a scientist at Ohio University and author of the PLoS ONE paper.

"This research significantly contributes to our understanding of species invasions from a deep-time perspective," said Lisa Boush, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.

"The knowledge is critical to determining the cause and extent of mass extinctions through time, especially the five biggest biodiversity crises in the history of life on Earth. It provides an important perspective on our current biodiversity crises."

The research suggests that the typical method by which new species originate--vicariance--was absent during this ancient phase of Earth's history, and could be to blame for the mass extinction.

Vicariance occurs when a population becomes geographically divided by a natural, long-term event, such as the formation of a mountain range or a new river channel, and evolves into different species.

New species also can originate through dispersal, which occurs when a subset of a population moves to a new location.

In a departure from previous studies, Stigall used phylogenetic analysis, which draws on an understanding of the tree of evolutionary relationships to examine how individual speciation events occurred.

She focused on one bivalve, Leptodesma (Leiopteria), and two brachiopods, Floweria and Schizophoria (Schizophoria), as well as a predatory crustacean, Archaeostraca.

These small, shelled marine animals were some of the most common inhabitants of the Late Devonian oceans, which had the most extensive reef system in Earth's history.

The seas teemed with huge predatory fish such as Dunkleosteus, and smaller life forms such as trilobites and crinoids (sea lilies).

The first forests and terrestrial ecosystems appeared during this time; amphibians began to walk on land.

As sea levels rose and the continents closed in to form connected land masses, however, some species gained access to environments they hadn't inhabited before.

The hardiest of these invasive species that could thrive on a variety of food sources and in new climates became dominant, wiping out more locally adapted species.

The invasive species were so prolific at this time that it became difficult for many new species to arise.

"The main mode of speciation that occurs in the geological record is shut down during the Devonian," said Stigall. "It just stops in its tracks."

Of the species Stigall studied, most lost substantial diversity during the Late Devonian, and one, Floweria, became extinct.

The entire marine ecosystem suffered a major collapse. Reef-forming corals were decimated and reefs did not appear on Earth again for 100 million years.

The giant fishes, trilobites, sponges and brachiopods also declined dramatically, while organisms on land had much higher survival rates.

The study is relevant for the current biodiversity crisis, Stigall said, as human activity has introduced a high number of invasive species into new ecosystems.

In addition, the modern extinction rate exceeds the rate of ancient extinction events, including the event that wiped out the dinosaurs 65 million years ago.

"Even if you can stop habitat loss, the fact that we've moved all these invasive species around the planet will take a long time to recover from because the high level of invasions has suppressed the speciation rate substantially," Stigall said.

Maintaining Earth's ecosystems, she suggests, would be helped by focusing efforts and resources on protection of new species generation.

"The more we know about this process," Stigall said, "the more we will understand how to best preserve biodiversity."

The research was also funded by the American Chemical Society and Ohio University.

Read the story at link.



Non-native Fish Species Identified in New Hampshire Waters

Concord, NH - The state departments of Environmental Services (DES) and Fish and Game announced today the discovery of the rosyside dace (Clinostomus funduloides), a non-native species of fish previously unknown in New Hampshire. The species was found inhabiting Hewes Brook, a tributary of the Connecticut River in Lyme. The discovery was made in summer 2010 by DES biologists during routine biological monitoring activities. The species’ identity was recently confirmed by three independent researchers. “While the origin of this species in New Hampshire is uncertain, it seems likely to have been introduced by human intervention,” said David Neils, DES biologist.

“The introduction of aquatic non-native species to New Hampshire waters presents a serious danger to the ecological integrity of our waterways, as well as our ability to enjoy them,” stated Thomas Burack, DES Commissioner. New Hampshire laws and administrative rules prohibit the introduction of non-native species. Specifically with regard to fish and wildlife, the New Hampshire Fish and Game Department Administrative Rules control the possession and importation, and prohibit the release of, non-indigenous or non-naturalized fish species to New Hampshire waters. The same rules also prohibit the possession of live fish, other than approved baitfish species when leaving any freshwaters of the state.

“Anglers are unlikely to catch the rosyside dace using hook-and-line because of its small size, but incidental capture is possible by means of baitfish trapping,” said Jason Smith, Fish and Game biologist. Smith recommends that if fish caught are suspected to be the rosyside dace or any other non-native aquatic species previously undocumented in New Hampshire, individuals should immediately release them back into the waters from which they were captured, and contact either the Fish and Game Inland Fisheries Division (603-271-2501) or the DES biology section (603-271-8865).

“There is no indication at this point that the rosyside dace could cause recreational or economic problems; however, ecological impacts to the native fish community are possible depending on the ability of the species to expand its range and successfully propagate,” said Glenn Normandeau, Fish and Game Executive Director. At the time of sampling, 85 individuals were captured. However, based on observations, DES biologists estimated the population to be in the hundreds.

The rosyside dace is a member of the minnow family (Cyprinidae) and typically inhabits small streams with adults ranging from two to four inches in length. Its native distribution is recognized as extending from the Delaware River drainage in Pennsylvania to the Savannah River drainage in Georgia, as well as portions of the Ohio River basin. It is not known to occur in the Connecticut River or its tributaries, other than Hewes Brook, at this time.

Over the course of the next several months, biologists from both agencies will be working together to document where the rosyside dace occurs and to determine how it may have been introduced to New Hampshire. For more information, contact David Neils, DES senior biologist, at (603) 271-8865 or david.neils @ .

This message brought to you by the New Hampshire Department of Environmental Services, 29 Hazen Drive, Concord, NH 03302. Comments or Questions can be directed to Jim Martin at james.martin @


Call for Abstracts

Florida Exotic Pest Plant Council’s
26th Annual Symposium, Maitland, Florida

May 17th – 20th, 2011

We invite abstract submissions for contributed oral or poster presentations at the 2011 FLEPPC Annual Symposium. This year’s theme is “Exotics on the Run: Leveling the Playing Field for Native Plants”. The meeting will be held Tuesday, May 17th through Friday, May 20th in Maitland, Florida, at the Sheraton North Hotel.

Deadline for Abstract Submissions: January 31, 2011

Program Topics: Submissions are welcome for any area of invasive plant species investigation, including but not limited to:

Risk Assessment
Policy and Regulation
Evolutionary Biology
Interdisciplinary Projects


Abstracts must include the following information:
• Title of the proposed paper
• Full name and professional title of the author, organization to which s/he belongs, mailing address, phone number(s), and email address
• If there are multiple authors, please provide the above information for each.
• Text of the abstract (limit of 400 words)

General rules regarding abstracts: Please do not include figures, tables or mathematical equations in the abstract. Use standard abbreviations for units of measure. Other abbreviations and acronyms should be spelled out in full at first mention, followed by the abbreviation/acronym in parentheses. If you use references, provide the journal, volume, year and page numbers.

A letter or notification of acceptance or rejection will be emailed to the author(s) no later than February 15th, 2011. Online submission of abstracts is strongly encouraged. If web access is not available, please submit abstracts to: Jessica Spencer, U.S. Army Corps of Engineers, 701 San Marco Boulevard, Jacksonville, FL 32207 904-232-1696 voice; Email: jessica.e.spencer @


Tuesday, January 11, 2011

Week of January 10, 2011

A new invasive reported for the Catskill Mountains

Five-leaf aralia (Eleutherococcus sieboldianus) is an ornamental that has invasive tendencies and is very threatening to natural communities. Please report any occurrences you find in the Catskill Mountain region to Meredith Taylor at the Catskill Center for Conservation and Development. Photo documentation is always appreciated!

Meredith Taylor
Catskill Regional Invasive Species Partnership Coordinator
The Catskill Center for Conservation and Development


Les Mehrhoff passes away

Leslie J. Mehrhoff, 60, passed away suddenly on Wednesday, December 22nd 2010 at his home in Willington, Connecticut. Born March 16th, 1950 in Morris Plains, New Jersey to Leslie and Jessie Mehrhoff, he leaves behind his beloved wife, Olga; daughter, Jessie; and field-dog, Moxie. Les received his B.S. from New England College in Henniker, New Hampshire. He went on to receive his M.S. and PhD. from the University of Connecticut in Storrs. Before retiring in July of 2009, Les worked for the Department of Ecology and Evolutionary Biology at UConn as the curator of the George Safford Torrey Herbarium.

A naturalist, he sought involvement in organizations including, but not limited to, the Connecticut Botanical Society, New England Wildflower Society, and the Torrey Botanical Club. He also participated in various committees such as the Arnold Arboretum at Harvard University, CT chapter of The Nature Conservancy, The CT Invasive Plant Working Group, and served as one of the project managers of the Invasive Plant Atlas of New England (IPANE).

Les was also a champion in the defense of all living things, from releasing insects found indoors to the safety of their natural habitat, to eradicating invasive species through his teachings and field work. As an avid fan of the UConn Men’s Soccer team, Les could be found proudly cheering from the stands.

Les’ legacy will be carried on by the many people he inspired and befriended. A celebration of Les’ life will be held in Storrs, CT at a later date. In memory of Les, please perform an act of kindness for the preservation of our environment.

Please visit for online memorial guestbook.