Smithsonian Science » conservation biology

Heliconius butterfly genome explains wing pattern diversity

John Barrat — Thu, 17 May 2012 01:25:58 +0000

Pooling funds and putting their heads together, more than 70 scientists from 9 institutions including the Smithsonian Tropical Research Institute, sequenced the entire genome of the butterfly genus Heliconius, a brightly colored favorite of collectors and scientists since the Victorian era. Their results are published in the prestigious journal, Nature.

Image right: Based on the new sequence, scientists found that different species copy each other’s wing patterns by exchanging genes, a process thought to be very rare, especially in animals. (Photo by Mathieu Joron)

The genome of the Postman butterfly, Panama’s Heliconius melpomene, helps scientists understand how the stunning diversity of wing color patterns in tropical butterflies evolved. Heliconius species are highly distasteful. Their vivid wing patterns warn predators not to eat them. How have different butterfly species evolved similar wing patterns?

Based on the new sequence, scientists found that different species copy each other’s wing patterns by exchanging genes, a process thought to be very rare, especially in animals. Although many different species interbreed in the wild, their hybrid offspring often cannot reproduce successfully. But sometimes hybrids gain useful genes that help them adapt to changing conditions. Heliconius hybrids gain wing patterns that help them survive.

Kanchon Dasmahapatra, the a lead author of the study and a former Smithsonian fellow who worked with Jim Mallet at University College London notes: “What we discovered is that one butterfly species can gain its protective colour pattern genes ready-made from a different species by hybridizing with it–a much faster process than having to evolve one’s colour patterns from scratch.”

Some of the other genes in the sequence also surprised researchers. These butterflies, typically regarded as primarily visual insects, apparently have a rich array of genes for smelling and sensing chemicals in their environment, raising new questions about the links between perception and the origins of new species. Indeed, analysis carried out at the University of California by co-author Adriana Briscoe showed that butterflies have an even greater array of genes involved in chemical communication than moths, which depend on chemical signals for finding mates and host plants.

The study heralds a new era in genome biology and an important step in the Smithsonian’s goal to understand and sustain a biodiverse planet. Low-cost genetic sequencing opens doors to small research groups and individuals to sequence entire genomes, a technique formerly accessible only to labs with major government funding.

“Assembling a genome from scratch is still hard work: think Humpy-Dumpty,” said Owen McMillan, geneticist and Academic Dean at the Smithsonian Tropical Research Institute, “but it is getting easy, inexpensive, and is transforming how we do science. At the core, having a reference genome opens up new research possibilities and reveals previously unimagined connections.

Poachers at large in Thailand’s nature reserves despite ranger outposts

John Barrat — Fri, 11 May 2012 13:30:34 +0000

Khao Yai National Park in central Thailand covers some 1,357 square miles and, as Thailand’s oldest and most popular park, welcomes hundreds of thousands of visitors through its gates each year.

Recently, after examining hundreds of photos taken by camera traps set-up to monitor clouded leopards in the park, three Smithsonian researchers say Khao Yai also is quite popular with a different kind of visitor: poachers.

Next to the Eurasian wild pig, humans were the most common creature to show-up in the camera-trap photos, namely villagers, park staff, tourists and poachers, write Kate Jenks, JoGayle Howard and Peter Leimgruber of the Smithsonian Conservation Biology Institute in a recent issue of the journal Biotropica. Humans appeared in photos from 43 of the 217 different sites in the park where the camera traps were set, even though 78 percent of the park is zoned as a strict nature reserve/primitive area.

Images: Right, a clouded leopard in a camera trap photo. Above and below: poachers. (Photos courtesy of Kate Jenks)

Attached to trees in the forest, the camera traps use an infrared beam that can detect motion or a change in temperature to trip the camera’s shutter. The researchers considered humans in the snapshots to be “poachers” only if they were carrying a gun, a carcass or animal parts, a bag to carry forest products and animals; or if they were accompanied by a dog, Jenks explains.

Surprisingly, close analysis of the project’s some 650 photos revealed the presence of poachers very close to Khao Yai’s 21 ranger stations. Few carnivores, such as clouded leopards, were photographed near the stations.

“We expected to find higher carnivore biodiversity near the ranger outposts because those areas should be really well protected,” Leimgruber says. They are not.

In fact, Jenks says, “the ranger stations seem to be having the opposite of their intended effect. Building and staffing the outposts required the construction of roads into the park, which has provided easier access for everyone into the forest.”

This video depicts camera traps being set up in Thailand’s Pang Sida National Park, which is located adjacent to Khao Yai National Park.

In Southeast Asia poaching is fueled by demand from the traditional Chinese medicine trade, trade in wild bush meat for human consumption and forest products the researchers say. In addition, Jenks says, there are villages right up on the boundary of the park with no transition and no buffer zone. It is very easy for villagers to wander into the park.

Jenks, Howard and Leimgruber recommend increased foot patrols by park staff through the forest and continued monitoring of the impact of these foot patrols using the camera traps. Unless the human presence in and impact on the park is reduced, wildlife populations “will only shrink progressively into smaller and smaller core areas of the park” the researchers write.

(JoGayle Howard, a prominent researcher at the National Zoo who had dedicated her life to the study and conservation of endangered species, passed away last year. She had been instrumental in developing this wildlife conservation project.) –John Barrat

Article link: “Do Ranger Stations Deter Poaching Activity in National Parks in Thailand?” by Kate Jenks, JoGayle Howard and Peter Leimgruber appeared in the scientific journal Biotropica.

Heavyweight trees are forest champs at sequestering carbon

John Barrat — Thu, 03 May 2012 16:36:41 +0000

Big trees three or more feet in diameter accounted for nearly half the biomass measured at a Yosemite National Park site, yet represented only one percent of the trees growing there.

This means just a few towering white fir, sugar pine and incense cedars per acre at the Yosemite site are disproportionately responsible for photosynthesis, converting carbon dioxide into plant tissue and sequestering that carbon in the forest, sometimes for centuries, according to James Lutz, a University of Washington research scientist in environmental and forest sciences. Lutz is lead author of a paper on the largest quantitative study yet of the importance of big trees in temperate forests being published online May 2 on PLoS ONE. The research was funded by the Smithsonian Center for Tropical Forest Science.

Image right: A handful of large-diameter trees per acre, such as these incense cedars, together with remains of big trees like the three-foot-wide white fir snag and downed debris account for half the forest biomass at a Yosemite National park study site. (Image by James Lutz)

“In a forest comprised of younger trees that are generally the same age, if you lose one percent of the trees, you lose one percent of the biomass,” he says. “In a forest with large trees like the one we studied, if you lose one percent of the trees, you could lose half the biomass.”

In 2009, scientists including Lutz reported that the density of large-diameter trees declined nearly 25 percent between the 1930s and 1990s in Yosemite National Park, even though the area was never logged. Scientists have found notable numbers of large trees dying in similar areas across the West.

The new 63-acre study site is one of the largest, fully-mapped plots in the world and the largest old-growth plot in North America. The tally of what’s there, including the counting and tagging of 34,500 live trees, was done by citizen scientists. The site is part of the network of the Smithsonian Center for Tropical Forest Science, a global network of 42 tropical and temperate forest plots including the one in Yosemite.

Image left: Washington State University’s Mark Swanson pulls a tape tight around a 4-foot-wide sugar pine, one of the 34,500 live trees counted and tagged for long-term study in a Yosemite National Park study plot. (Washington State University)

One implication of the research is that land managers may want to pay more attention to existing big trees, the co-authors said. In some younger forests that lack big trees, citizens and land managers might want to consider fostering the growth of a few big-trunked trees, Lutz added.–Source: University of Washington.

National Park Service natural history collections transferred to care of the Smithsonian

John Barrat — Tue, 01 May 2012 11:34:22 +0000

The National Park Service and the Smithsonian Institution have announced a new partnership to share responsibility for selected National Park Service natural history collections, making them more readily available to researchers through the Smithsonian.

Collections will continue to be owned by the National Park Service but will be in the permanent custodial care of the Smithsonian Institution. The agreement formalizing the relationship was signed today by National Park Service Director Jonathan B. Jarvis and the Smithsonian’s Under Secretary for Science Eva J. Pell at the National Museum of Natural History.

Photo right: Jon Jarvis, Director of the National Park Service, and Eva Pell, Under Secretary for Science at the Smithsonian sign an MOU between the two organizations. The partnership gives broader access to National Park Service collections through the Smithsonian’s care and management of them. (Johnny Gibbons photo)

“This agreement benefits science, the American people, and the long-standing and historic relationship between our two organizations,” said Jarvis. “Together we are building a collection that will become an extraordinary tool for the scientific community to study biodiversity, evolution, and the distinctive character of national park ecosystems.”

The Smithsonian echoed the significance of the new agreement. “Two venerable institutions long known for protecting the nation’s heritage, are now working together to enhance care and access to specimens that document the natural environment of our national parks,” said Eva Pell, under secretary for science at the Smithsonian.

Examples of National Park Service collections that the Smithsonian could curate under the new agreement are:

138 holotypes – a specimen described in scientific literature to establish a new species – that researchers in Great Smoky Mountains National Park in Tennessee and North Carolina have discovered and described over the past 14 years.

From George Washington Memorial Parkway in Virginia, 3,000 vascular plant specimens representing 1,326 species, as well as a wide range of specimens from the Potomac River Gorge, including holotypes of shoreflies, caddisflies, and copepods (small crustaceans).

Development will reduce carbon stored in forests, Smithsonian & Harvard scientists predict

John Barrat — Mon, 16 Apr 2012 13:07:11 +0000

When most people look at a forest, they see walking trails, deer yards, or firewood for next winter. But scientists at the Harvard Forest and the Smithsonian take note of changes imperceptible to the naked eye — the uptake and storage of carbon. What they’ve learned in a recent study is that an immense amount of carbon is stored in growing trees, but if current trends in Massachusetts continue, development would reduce that storage by 18 percent over the next half century. Forest harvesting would have a much smaller impact.

Jonathan Thompson is Research Ecologist at the Smithsonian Conservation Biology Institute, Research Associate at the Harvard Forest, and lead author on the paper which appeared in the journal Ecological Applications in late 2011. “The rebounding forests of New England provide a tremendous public benefit by storing carbon that would otherwise contribute to climate change,” said Thompson. To put these findings into context he adds, “In Massachusetts, forests capture approximately 2.3 million metric tons of carbon each year. That’s equal to the amount of carbon dioxide emitted from the energy used by one million American homes annually.” He and his coauthors were able to estimate the extent to which development may chip away at that carbon sink, using an uncommon collection of long-term data and a distinct form of research known as scenario science.

Image right: From this 71-foot eddy-flux tower in a 200-year-old hemlock forest, Harvard Forest scientists have measured carbon dynamics and other ecosystem processes for more than 20 years as part of the Long-Term Ecological Research program. Located in a 35-hectare Smithsonian Global Earth Observatory plot and part of the core measurements for the National Ecological Observatory Network, this tower is a focal point for studies of the eastern hemlock tree and its impending demise from the invasive hemlock wolly adelgid, as well as phenology studies of succeeding hardwoods.
(Photos by David Foster)

For more than 30 years, scientists at the Harvard Forest have scaled towers into the forest canopy and measured the trunks of trees to track how much carbon is stored or lost from the woods each year. This treasure trove of data is part of the national Long-Term Ecological Research (LTER) Network, which is celebrating more than three decades of research this month. This important milestone is marked by six new papers released today in a special issue of the journal BioScience. The forest carbon research is one example of participatory scenario science — a growing trend in ecology featured in a paper by Thompson, David Foster, Director of the Harvard Forest, and their colleagues in the BioScience issue.

Image left: Summer Research Program students monitor soil respiration of decaying wood in a large study comparing carbon, water, and energy fluxes between harvested and unharvested sites.

Harvard Forest is one of four LTER sites in the northeastern U.S. and was awarded a grant by the National Science Foundation to join the Network in 1988. David Foster coauthored the Ecological Applications paper of 2011 and co-edited the new BioScience special issue. He notes, “With three decades of data meticulously collected as part of the LTER Network, we have reached a crucial transition where we are now able to tackle major environmental challenges, such as the fate of forest carbon, across large landscapes.”

Foster adds, “Over the last two centuries, forests have stored more carbon with each passing year in many parts of New England, but the turning point may be in sight for Massachusetts and other urbanizing landscapes if recent development trends continue.” But that’s not the end of the story for Foster: “The good news is that forests are resilient and history is not necessarily destiny. Our research makes a compelling case for expanding support for forestland protection and for the efforts of private landowners to keep their land forested. It reminds us that forests provide important infrastructure that we should invest in, just as we do major civil works projects.”

Invasive pythons in Florida now stealing bird eggs straight from the nest

John Barrat — Fri, 06 Apr 2012 11:42:00 +0000

Smithsonian scientists and their colleagues have uncovered a new threat posed by invasive Burmese pythons in Florida and the Everglades: The snakes are not only eating the area’s birds, but also the birds’ eggs straight from the nest. The results of this research add a new challenge to the area’s already heavily taxed native wildlife. The team’s findings are published in the online journal Reptiles & Amphibians: Conservation and Natural History.

Image right: Burmese pythons (Python molurus bivittatus), native to southern Asia, have taken up a comfortable residence in the state of Florida, especially in the Everglades. In addition to out-competing native wildlife for resources and habitat, the pythons are eating the native wildlife. (Photo by Sarah L. Stewart)

Burmese pythons, native to southern Asia, have taken up a comfortable residence in the state of Florida, especially in the Everglades. In addition to out-competing native wildlife for resources and habitat, the pythons are eating the native wildlife. Burmese pythons (Python molurus bivittatus) were first recorded in the Everglades in 1979—thought to be escaped or discarded pets. Their numbers have since grown, with an estimated breeding population in Florida in the tens of thousands.

Image left: Five of ten entire Guineafowl eggs regurgitated by a Burmese python. (Photo: R.W. Snow, Everglades National Park)

In an ongoing study to better understand the impact of this snake in the Everglades, scientists from the Smithsonian Institution, the National Park Service and others have been examining the contents of the digestive tracts of pythons in the area. They have shown that Burmese pythons consume at least 25 different species of birds in the Everglades, but until now no records documented this species eating bird eggs.

“This finding is significant because it suggests that the Burmese python is not simply a sit-and-wait predator, but rather is opportunistic enough to find the nests of birds,” said Carla Dove, ornithologist at the Smithsonian’s Feather Identification Lab in the National Museum of Natural History and lead author of the study. “Although the sample size is small, these findings suggest that the snakes have the potential to negatively affect the breeding success of native birds.”

Image right: Two Limpkin (Aramus guarauna) crushed but intact eggs (top) recovered from a Burmese python digestive tract and compared to a reference Limpkin specimen from the Smithsonian’s collection (below) for size and color patterns. The arrow shows fragments of eggshells from the python sample placed on the Smithsonian specimen for color comparison. (Photo by Don Hurlbert)

Scientists collected a 14-pound male python that was 8 1/2 feet long near a property with free-ranging guineafowl. The snake regurgitated 10 whole guineafowl eggs soon after it was captured. The team discovered the remains of two bird eggs in another python collected for the study―a 30-pound female more than 10 feet long. Scientists used DNA tests on the membrane of the crushed eggs and comparisons of the shell fragments with egg specimens in the Smithsonian’s collection to determine what the female snake had eaten. Their research revealed the species to be the limpkin (Aramus guarauna), a large wading bird found in marshes and listed as a “species of special concern” by the Florida Fish and Wildlife Conservation Commission.

Image left: Everglades National Park wildlife biologist Skip Snow in the South Florida Research Center lab with rooster remains recovered from a captured Burmese python. (Photo by Lori Oberhofer, National Park Service)

There are several species of snake known to eat bird eggs. Those species are equipped with pointed or blade-like extensions on the vertebrae in their esophagus that punctures the eggshell, making it easy for the snake to crush the egg and digest its contents. Burmese pythons do not have these adaptations. However, the pythons studied were so large in relation to the eggs they ingested that the scientists believe these specialized vertebrae may not have been needed.

“Our observations confirm that invasive Burmese pythons consume not only adult birds but also eggs, revealing a previously unrecognized risk from this introduced predator to nesting birds,” said Dove. “How frequently they are predating on bird eggs is hard to know.”

In an earlier stage of the study, the scientists collected more than 300 Burmese pythons in Everglades National Park and found that birds, from the 5-inch-long house wren to the 4-foot-long great blue heron, accounted for 25 percent of the python’s diet in the Everglades.

Panda habitat to be lost, shifted by climate change

John Barrat — Thu, 05 Apr 2012 12:51:57 +0000

Fewer than 1,600 giant pandas are left in the mountain forests of central China. Now a new study published in the International Journal of Ecology by scientists at the Smithsonian Conservation Biology Institute at the National Zoological Park, predicts that 16,000 square kilometers of giant panda habitat will likely be lost by the year 2080 as climate change causes panda habitat systems to shift to higher elevations and latitudes.

In other words, less than half of the giant panda’s already decreased habitat will be suitable to sustain them in 70 years. The research team used two different global climate models to make this prediction, taking into account remaining habitat, lost habitat, potential new habitat and current protected areas for giant pandas.

The study also found that habitat fragmentation will likely increase, leading to smaller areas that can support fewer pandas farther away from each other, increasing the risks of inbreeding and population collapse.

“Our research predicts that climate change will substantially decrease the amount of suitable giant panda habitat within the species’ current distribution,” said Melissa Songer, lead author of the paper and an SCBI wildlife ecologist. “But also we may see new areas becoming suitable for giant pandas,” Songer adds. “The question remains as to whether giant pandas will have the capacity and opportunity to shift to new areas.”

In addition to calling for the development of more protected areas that are aligned with climate predictions, the paper emphasizes the importance of creating corridors to reduce fragmentation. The study also has land-use implications, as agricultural land and land near human settlements are unsuitable for pandas.

Photos: Giant pandas at the Smithsonian’s National Zoo.

In addition to Songer, the authors of the panda ecology study from SCBI are Melanie Delion and Alex Biggs. The partnering author is Qiongyu Huang in the geography department at the University of Maryland. Friends of the National Zoo helped fund this research.

Preventing home invasions means fighting side-by-side for coral-dwelling crabs and shrimp

John Barrat — Fri, 30 Mar 2012 16:38:30 +0000

As any comic book lover knows, when superheroes band together the bad guys fall harder. The strength that comes in numbers is greater than the sum of its parts.

The same holds true, researchers have recently learned, when different species of crabs (genus Trapezia) and snapping shrimp (Alepheus lottini) in the central Pacific band together to defend their coral homes from hungry seastars. In these frequent conflicts “one-plus-one doesn’t always equal two, sometime it is more,” explains Seabird McKeon, a marine biologist at the National Museum of Natural History’s Smithsonian Marine Station in Fort Pierce, Fla. The crustaceans are much more effective when they fight together than when they fight alone, a process McKeon calls the Multiple Defender Effect. “It is a clear example of synergy, and one that underscores the importance of biodiversity in the ocean.”

Image right: A cushion seastar, bottom foreground, approaches a coral head of the genus Pocillopora looking for a meal. (Photos courtesy Seabird McKeon)

Even in a comic book one would be hard pressed to find an enemy more bizarre than the “cushion” seastar (Culcita novaeguineae), an animal used by McKeon in recent laboratory experiments with living corals (genus Pocillopora) and their defenders. To consume a coral, the seastar pushes its stomach outside its body and lays it over the coral like a cushion. It then hugs the coral close and “eats,” letting stomach acids and digestive juices do their work.

Image: Trapezia serenei, a tiny coral-dwelling crab.

The stationary coral is defenseless, yet the tiny crustaceans that live among its branches come to its aid, snipping and prodding an intruding seastar with their claws. “The coral itself is like a cauliflower head, a main central stem and lots of little branches,” McKeon explains. “Crabs gain protection from fish by living inside the coral structure.”

Once a mating pair of crabs takes-up residence on a coral head they do not tolerate the presence of other crabs of their same species. Crabs of other species however are ignored, as are snapping shrimp. As a result, some coral heads may have as many as five different species of defensive crustaceans living on them, all pairs of different species.

Image right: Alpheus lottini, a snapping shrimp.

In repeated experiments McKeon and colleagues measured the effectiveness of a single crab pair in preventing a seastar from eating their home coral. He found that one pair of crabs reduced the volume of coral eaten by about 19 percent, compared to a coral with no defenders. Two pairs of crustaceans working together, however, were able to reduce the volume of coral eaten by as much as 65 percent—the multiple defender effect.

The take-home lesson here, McKeon says, “is these crabs don’t allow others of their same species on their coral, yet the synergy of different pairs fighting together is critical to the defense of the coral. The multiple defender effect is an important new angle on why we must conserve biodiversity in the ocean.”

“Multiple defender effects: synergistic coral defense by mutualist crustaceans,” by C. Seabird McKeon; Adrian C. Stier of the University of Florida; Shelby McIlroy of the University at Buffalo and Banjamin Bolker of McMaster University; appeared recently in the scientific journal Oecologia.

Extremely rare Guam rails hatch at the Smithsonian’s National Zoo

John Barrat — Fri, 16 Mar 2012 12:29:02 +0000

As Washington, D.C.’s unseasonably warm winter turns into spring, a baby boom is underway at the Smithsonian’s National Zoo. Two Guam rail (Gallirallus owstoni) chicks hatched March 3 and 4; they join six others in the Zoo’s collection—three of which live at the Smithsonian Conservation Biology Institute in Front Royal, Va. This brings the total population of these small, flightless birds to 162 individuals. Each hatching is significant—the International Union for Conservation of Nature lists these birds as extinct in the wild.

In about six weeks, keepers will separate the chicks from their parents, and Zoo veterinarians will perform a routine medical exam and take feather samples to determine their sexes.

(Guam rail photos by Jim Jenkins, FONZ Photo Club)

To date, 82 chicks have hatched at the Zoo and SCBI, and each provides scientists with the opportunity to learn about the growth, reproduction, health and behavior of the species. The Zoo sent 29 Guam rails to the government of Guam for release and breeding, and an additional 25 birds have gone to other institutions to breed.

Guam rails flourished in Guam’s limestone forests and coconut plantations until the arrival of the brown tree snake (Boiga irregularis), an invasive species that stowed away in military equipment shipped from New Guinea after World War II. Because these reptiles had no natural predators on Guam, their numbers grew and they spread across the island quickly. Within three decades, they hunted Guam rails and eight other bird species to the brink of extinction.

In 1986, Guam’s Department of Aquatic and Wildlife Resources captured the country’s remaining 21 Guam rails and sent them to zoological institutions around the globe—including the National Zoo—as a hedge against extinction. The Association of Zoos and Aquariums created a Species Survival Plan for the birds. The SSP pairs males and females in order to maintain a genetically diverse and self-sustaining population.

Today, 118 Guam rails are thriving on two islands near the mainland: Rota and Cocos. The availability of release sites continues to shrink, however, due to deforestation and human expansion. Controlling the brown snake population remains a significant challenge as well, though researchers have made progress in developing a variety of barriers, traps and toxicants. Forty-four birds reside in zoos and other facilities in North America. Visitors to the Smithsonian’s National Zoo can see these birds on exhibit in the Bird House. In stark contrast to their brown-and-white-plumaged parents, Guam rail chicks sport black downy feathers.

New invasive species database allows public to ID marine invaders with a home computer

John Barrat — Mon, 12 Mar 2012 14:53:42 +0000

Mitten crabs, zebra mussels and rock vomit: These and hundreds of other non-native species have invaded coastal regions throughout the United States, often causing dramatic changes to coastal ecosystems and significant economic costs. The Smithsonian Environmental Research Center has now created NEMESIS (National Estuarine and Marine Exotic Species Information System), an online public database to provide key information about the non-native marine species throughout the nation.

Image right: Tunicate Botryllus planus. Colonial tunicates like this one are made of hundreds of tiny zooids that act as a single organism. (Photo: Rosana Rocha, Universidade de Federal de Paraná, Brazil)

The rate of new marine invasions along U.S. coasts has risen sharply in recent decades due to human-aided introductions, often unintentional. Organisms can attach directly to the hulls of ships or be taken up and transported in ballast water (water used by large ships to provide stability and trim during sailing). They can also be introduced with imports of seafood, bait and packing materials. In addition, some species have been deliberately introduced to create new fisheries, though this practice is now very rare. As trade and globalization have increased, so has the opportunity for invasions.

No part of the country is untouched by non-native species. Although most people recognize a few of the common and conspicuous invaders in nearby waters, the full scope of invasions that lurk beneath the water often go unnoticed.

Image left: Chinese mitten crab.

NEMESIS aims to provide comprehensive and synthetic information on hundreds of individual marine species in the continental United States. Created by SERC’s marine invasions lab, the database includes information on how and when invasions occurred, distribution maps and what is known about their impacts. For example, the tunicate Didemnum vexillum (commonly known as D. vex or “rock vomit”) has created serious problems on the West and East Coasts of the United States. This mat-like species grows rapidly and can completely cover aquaculture nets, shellfish beds and sensitive marine environments. The database also includes an interactive map of the U.S., where visitors can search for invaders impacting their own coastlines.

NEMESIS launched March 5 with tunicates, a group that includes the destructive rock vomit. Tunicates, also known as ascidians or sea squirts, are filter feeders that grow on hard surfaces such as docks, rocks or sandy marine sediments. Information for other groups of species will become publicly available over the next year as NEMESIS continues its rollout, starting with crabs, shrimp and crayfish.

Photo right: Tunicate Styela clava, the club sea squirt. It has caused major headaches in Canada, where fouling of fishing and aquaculture equipment cost anywhere 34 to 88 million Canadian dollars per year. (Photo: Melissa Frey, Royal BC Museum, Canada)

NEMESIS was designed in partnership with the U.S. Geological Survey. NEMESIS focuses on invasions in marine and estuarine waters, while the USGS Nonindigenous Aquatic Species database focuses on invasions in freshwater habitats of the U.S. The complementary databases were designed to be compatible, allowing for joint syntheses across marine and freshwater habitats in the U.S.

The NEMESIS database is a long-term and dynamic program that will continue to grow over time. Records are updated regularly as new species are discovered and new research becomes available. For more information on NEMESIS or recent updates, visit the NEMESIS home page and the NEMESIS Interactive Invasions Map.