Moray eel. Moray eels are legendary predators on coral reefs. Note the second set of jaws in the “throat”; these are the gill arches, which are present in all fish. Gill arches support the gills, the major respiratory organ of fish.

Lookdown. Because of its sloped head and the enlarged crest on its skull, the Lookdown appears to “look down” as it swims. These fish often swim in small schools.

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Alligator Pipefish. Pipefish may be thought of as seahorses unfurled. The numerous bony body rings are used to differentiate one species of pipefish from another.

Ox-eyed Oreo. The name Oreosoma (“mountain body”) refers to the cone-shaped bony structures on the underside of this larval specimen. Adults are more elongate, less oval, and covered with scales.

Dhiho’s Seahorse. Just over one inch long, this elegant fish is readily identified as a seahorse by its characteristic head. The body ends in a tail that can curl around and hold on to algae or coral. This species is found only in the waters around Japan.

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Roughly 10 percent of all plant species are orchids, making them the largest plant family on Earth. But habitat loss has rendered many threatened or endangered. This is partly due to their intimate relationship with the soil. Orchids depend entirely on microscopic fungi in the early stages of their lives. Without the nutrients orchids obtain by digesting these host fungi, their seeds often will not germinate and baby orchids will not grow. While researchers have known about the orchid-fungus relationship for years, very little is known about what the fungi need to survive.

Image right and below: Flowers (right) and leaves (below) of the orchid Goodyera pubescens, commonly known as the downy rattlesnake orchid, endangered in Florida. (Photos by Melissa McCormick/SERC)

Biologists based at the Smithsonian Environmental Research Center in Edgewater, Md., launched the first study to find out what helps the fungi flourish and what that means for orchids. Led by Melissa McCormick, the researchers looked at three orchid species, all endangered in one or more U.S. states. After planting orchid seeds in dozens of experimental plots, they also added particular host fungi needed by each orchid to half of the plots. Then they followed the fate of the orchids and fungi in six study sites: three in younger forests (50 to 70 years old) and three in older forests (120 to 150 years old).

Image right and below: Leaf (right)  and flowers (below) of Tipularia discolor, the cranefly orchid, endangered in New York and Massachusetts, and threatened in Michigan and Florida.

After four years they discovered orchid seeds germinated only where the fungi they needed were abundant—not merely present. In the case of one species, Liparis liliifolia (lily-leaved twayblade), seeds germinated only in plots where the team had added fungi. This suggests that this particular orchid could survive in many places, but the fungi they need do not exist in most areas of the forest.

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Image left: A desert tortoise, Gopherus agassizii. (Image by Mike Jones, courtesy Encyclopedia of Life)

“Roads are barriers to dispersal for lots of species and usually it takes many generations to show up in the genetic structure of an animal,” says one of the paper’s co-authors Emily Latch, a postdoctoral researcher at the Smithsonian Conservation Biology Institute’s Center for Conservation and Evolutionary Genetics, and now an assistant professor at the University of Wisconsin-Milwaukee. “Because tortoises have such a long life span, we didn’t think the roads would influence their genetic structure so quickly, but they did.”

The study shows for the first time that recent landscape features such as roads “can have rapid effects on the genetic structure of a localized population and are detectible almost immediately,” in as little as one generation, the scientists report. As a result, the scientists conclude, “Roads may become increasingly important in shaping the evolutionary trajectory of desert tortoise populations.”

For the study, DNA samples were taken from 859 tortoises living in an area of 23,969 acres. “A huge number of samples,” for such a small area, Latch says. Data also was taken on each animal’s sex, location, and location elevation and slope.

Image right: A tortoise in the Mojave Desert. (Image courtesy Wikipedia)

The tortoises were sampled as part of a tortoise relocation effort at Fort Irwin Army Training Center and the animals were located by having people walk map transects in the desert. They picked-up, labeled and took data and DNA samples for every tortoise encountered.

“The adult individuals were initially genotyped to develop a baseline genetic database of translocated and resident tortoises so that family groups hatched after the translocations could be identified to particular parents, and the reproductive success of translocated and resident tortoises compared,” says Smithsonian geneticist Rob Fleischer, head of the Center for Conservation and Evolutionary Genetics and senior author on the paper. “This is important to determine if translocation is really an effective mitigation step. It was serendipity that led to our finding a surprising level of genetic structure.”

Roads may inhibit gene flow in desert tortoises by the reptiles being hit by cars, picked up by travelers, and predation and disease associated with pets released by the roadside. Eroded banks and increased vegetation along desert roads also may provide places for the tortoises to burrow and forage for food, causing them to move along a road rather than to cross it.

The article “Fine-Scale Analysis Reveals Cryptic Landscape Genetic Structure in Desert Tortoises,” by Emily K. Latch, William I. Boarman, Andrew Walde, and Robert C. Fleischer appeared recently in the journal PLoS ONE.

-John Barrat

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Image left: A desert tortoise, Gopherus agassizii.  (Image by Mike Jones, courtesy Encyclopedia of Life)

“Roads are barriers to dispersal for lots of species and usually it takes many generations to show up in the genetic structure of an animal,” says one of the paper’s co-authors Emily Latch, a postdoctoral researcher at the Smithsonian Conservation Biology Institute’s Center for Conservation and Evolutionary Genetics, and now an assistant professor at the University of Wisconsin-Milwaukee. “Because tortoises have such a long life span, we didn’t think the roads would influence their genetic structure so quickly, but they did.”

The study shows for the first time that recent landscape features such as roads “can have rapid effects on the genetic structure of a localized population and are detectible almost immediately,” in as little as one generation, the scientists report. As a result, the scientists conclude, “Roads may become increasingly important in shaping the evolutionary trajectory of desert tortoise populations.”

For the study, DNA samples were taken from 859 tortoises living in an area of 23,969 acres. “A huge number of samples,” for such a small area, Latch says. Data also was taken on each animal’s sex, location, and location elevation and slope.

Image right: A tortoise in the Mojave Desert. (Image courtesy Wikipedia)

The tortoises were sampled as part of a tortoise relocation effort at Fort Irwin Army Training Center and the animals were located by having people walk map transects in the desert. They picked-up, labeled and took data and DNA samples for every tortoise encountered.

“The adult individuals were initially genotyped to develop a baseline genetic database of translocated and resident tortoises so that family groups hatched after the translocations could be identified to particular parents, and the reproductive success of translocated and resident tortoises compared,” says Smithsonian geneticist Rob Fleischer, head of the Center for Conservation and Evolutionary Genetics and senior author on the paper. “This is important to determine if translocation is really an effective mitigation step. It was serendipity that led to our finding a surprising level of genetic structure.”

Roads may inhibit gene flow in desert tortoises by the reptiles being hit by cars, picked up by travelers, and predation and disease associated with pets released by the roadside. Eroded banks and increased vegetation along desert roads also may provide places for the tortoises to burrow and forage for food, causing them to move along a road rather than to cross it.

The article “Fine-Scale Analysis Reveals Cryptic Landscape Genetic Structure in Desert Tortoises,” by Emily K. Latch, William I. Boarman, Andrew Walde, and Robert C. Fleischer appeared recently in the journal PLoS ONE.

-John Barrat

Related posts:

1. Why did the tortoise cross the road? A recent study indicates few do.
2. New study reveals desert tortoise is actually two distinct species
3. Genetic study confirms American crocodiles and critically endangered Cuban crocodiles are hybridizing in the wild

Image right: Common basilisk lizard female, Basiliscus basiliscus. (Photo by Steven Johnson)

In a study recently published in the journal Diseases of Aquatic Organisms, scientists took skin swabs from individuals of 13 different species of lizards and 8 different species of snakes caught in western and central Panama. DNA analysis of the swabs revealed that 16 percent of the lizards and 38 percent of the snakes carried the chytrid fungus on their skin. None of the reptiles that tested positive for the disease showed signs of infection or sickness comparable to what is observed in amphibians stricken with the disease.

Image left: The anolis lizard Anolis humilis. (Photo by Shawn Mallan)

“Lizards and snakes will harbor Batrachochytrium dedrobatidis at non-pathological levels,” the researchers write, and infection in reptiles is highly plausible. “By potentially maintaining the pathogen in the environment without succumbing to the disease, these reptiles may be important vectors or reservoir hosts for Batrachochytrium dedrobatidis… and may allow virulent strains of it to spread.”

While the study presents no evidence that chytridiomycosis is lethal to reptiles, its presence on the skin of reptiles in areas that have witnessed the decline of both amphibians and reptiles in recent years is cause for concern, the scientists say.

Image right: The tropical snake Imantodes cenchoa. (Photo by Geoff Gallice)

“Reptiles as potential vectors and hosts of the amphibian pathogen Batrachochytrium dendrobatidis in Panama,” by Vanessa Kilburn and David Green of McGill University and Roberto Ibanez of the Smithsonian Tropical Research Institute, was published in December in the journal Diseases of Aquatic Organisms.

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Image right: Smithsonian scientists Mary Hagedorn and Ginnie Carter freeze coral sperm in a lab on Oahu, Hawaii. (Photo by Mike Henley)

“It turns out we can produce significant numbers of developing larvae using the thawed sperm and that those larvae actually settle,” said Mary Hagedorn, a marine biologist at SCBI. Coral settling is the process in which a free-swimming, bowling pin-shaped coral larva metamorphoses into a single polyp baby coral. “This is a huge milestone for us because if the larvae couldn’t metamorphose and settle, we wouldn’t be able to successfully use the bank for conservation efforts, which is the driving force behind this important research.”

Image left: Larvae of the coral Acropora tenuis. (Photo courtesy A. Hayward and A. Negri, Australian Institute of Marine Science)

The new frozen bank includes two reef-building species of coral, Acropora tenuis and A. millepora, both of which now reside in long-term storage at the Taronga Western Plains Zoo in Dubbo, Australia. Hagedorn has already successfully applied this technology to reefs in the Caribbean and Hawaii. Though they remain alive, the banked cells are in a stasis and researchers can thaw the frozen material in one, 50 or, in theory, even 1,000 years from now. Done properly over time, researchers can rear samples of frozen material and, if necessary, place them back into ecosystems to infuse new genes into natural populations, helping to enhance the health and viability of wild stocks. The work is the result of a partnership between SCBI, Hawaii Institute of Marine Biology, Taronga Conservation Society Australia, Australian Institute of Marine Science and Monash University.

Image right: The Great Barrier Reef coral Acropora tenuis spawning. (Photo courtesy A. Hayward and A. Negri, Australian Institute of Marine Science)

Coral reefs are living, dynamic ecosystems that provide invaluable services: they act as nursery grounds for marine fish and invertebrates, provide natural storm barriers for coastlines, store carbon dioxide from the atmosphere and are potential sources for undiscovered pharmaceuticals. Yet coral reefs are disappearing rapidly because of pollution from industrial waste, sewage, chemicals, oil spills, fertilizers, runoff and sedimentation from land; climate change; acidification; and destructive fishing practices. Researchers believe that coral reefs and the marine creatures that rely on them may die off within the next 50 to 100 years, causing the first global extinction of a worldwide ecosystem since prehistoric times. According to the Pew Center on Global Climate Change, coral reefs generate up to $30 billion of the global economy each year, with more than $1 billion going to the Australian economy. The Great Barrier Reef, which stretches 1,800 miles along the Queensland coast of Australia, includes the world’s largest collection of corals.

Image left: Smithsonian staff member Mike Henley working with frozen coral. (Photo courtesy Mike Henley)

“The wildlife on the Great Barrier Reef is so fascinating, and the size and beauty of that reef is legendary,” said Mike Henley, an animal keeper in the Zoo’s Invertebrate Exhibit. Henley helped collect and freeze the Australian samples. (Read Henley’s update from the field on the Zoo’s website.) “Our colleagues at the Australian Institute of Marine Science were so very wonderful to work with, and their facility is state-of-the-art, making research and larval care easier than at any location I have ever worked before.”

While scientists have successfully used frozen sperm from coral to fertilize fresh coral eggs, their next focus is on developing techniques to use frozen coral embryonic cells to help restore coral populations. In January, Hagedorn and her collaborators will focus on culturing frozen embryonic cells to see how long they can live.

“Right now there are no tools to help address some of the diseases most devastating to the reef,” Hagedorn said. “If we can grow embryonic cells and keep them alive, this technology could be important in battling those coral diseases.”

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Image right: Some of the crustaceans collected from the bodies of Olive Ridley and green sea turtles during the survey.

Feuerstein is co-author of a recent survey documenting the crustaceans, mollusks, algae and other marine organisms that make a home on the bodies of Olive Ridley and green sea turtles living in the Pacific. For three years—2001, 2002 and 2008—on Teopa Beach in Jalisco, Mexico, Feuerstein and colleagues examined the shell, neck and flippers of female turtles that had come out onto the beach to nest, collecting and carefully documenting all the organisms—known as epibionts—they found. It is the first comprehensive survey on Pacific turtle epibionts, and was recently published in the Bulletin of the Peabody Museum of Natural History. The survey was organized by the Turtle Epibiont Project of the Yale Peabody Museum of Natural History.

Image left: Amanda Feuerstein with a nesting sea turtle. (Photo courtesy Amanda Feuerstein)

Sixteen different epibiont species were found on the turtles, Feuerstein says, including crabs, a variety of barnacles, the remora or “shark sucker,” and leeches. Most of the Pacific sea turtle epibionts are obligate—meaning they are found only on sea turtles, nowhere else.

Compared to turtles living in the Atlantic, “the Pacific turtles are coming up pretty darn clean,” says Eric Lazo-Wasme of the Peabody Museum of Natural History, lead author of the study. Similar surveys of Atlantic Ocean turtles have recorded as many as 90 epibiont species living on them. The scientists are uncertain why Pacific turtles have fewer epibionts.

“For years we considered epibionts as harmless hitchhikers on the turtles, but that opinion is starting to change,” Lazo-Wasem explains. “Barnacles in large numbers can cause significant drag on a turtle as it swims and some barnacles embed into the skin and have very long projections that pierce laterally into the skin.”  Leeches have also been shown to transmit disease.

The impetus for the survey was born out of conservation concern for sea turtles as an endangered species. Coevolutionary relationships between turtles and their epibionts, and how these relationships affect turtle health and ecology have only recently come under scrutiny, the researchers say.

Image right: Barnacles collected from Olive Ridley and green sea turtles.

The study includes photographs of and taxonomic commentary on each of the epibiont species documented and survey instructions for future studies on how to collect epibionts from sea turtles. “We wanted to make the paper one that people could really use,” Lazo-Wasem says. “We weren’t really pleased with past surveys because there was not a lot of detail in them.”

“When we endanger animals like sea turtles many other groups of animals are affected,” Feuerstein says. “Loosing one species is more complicated and tragic” than people may realize.

“Epibionts Associated with the Nesting Marine Turtles Lepidochelys olivacea and Chelonia mydas in Jalisco, Mexico: A Review and Field Guide,” appeared in the Bulletin of the Peabody Museum of Natural History and was co-authored by Eric Lazo-Wasem, Amanda Feuerstein, Theodora Pinou of Western Connecticut State University and Alejandro Pena de Niz, of the Centro Para La Proteccion y Conservacion de Tortugas Marinas.

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Images: Photos of Michaux’s sumac by Lytton Musselman

Because Michaux’s sumac grows only in areas with few trees where the vegetation has been disturbed, it has long been assumed that its seeds germinate naturally following exposure to the high-temperatures of a brush or forest fire. Decline of this plant has been attributed to the prevention and suppression of brush and forest fires by humans. In Virginia it grows in only two places: on the grounds of the Virginia Army National Guard Maneuver Training Center in Fort Picket and a mowed railway right-of-way in an undisclosed location.

In a recent series of germination experiments, the scientists exposed different sets of Michaux’s sumac seeds to dry heat temperatures of 140, 176, 212, 248 and 284 degrees Fahrenheit, some sets for 5 minutes and other sets for 10 minutes. (The temperatures were determined based on maximum wildfire surface temperatures and burn times recorded in southeastern U.S. forests.) The researchers found that temperatures above 212 degrees F. killed the seeds. Lower temperatures had virtually no impact on breaking the seed’s dormancy.

The highest germination rates—30 percent—occurred after sulfuric acid was poured on Michaux’s sumac seeds and allowed to scarify (dissolve and weaken) the seed coats. This finding, from an experiment done in 1996, has led the researchers to their next experiment using birds. “We are going to feed the seeds to quail and wild turkey to determine if that breaks the seed dormancy,” says Bolin, a research associate with the Department of Botany at the Smithsonian’s National Museum of Natural History and an assistant professor at Catawba College in Salisbury, N.C. Seed passage through the digestive tracts of frugivorous (fruit eating) birds (and exposure to the acid in the bird’s stomachs) may break the physical dormancy of these seeds and help disperse them as well, the scientists write.

The paper “Germination of the federally endangered Michaux’s sumac (Rhus michauxii), authored by Jay F Bolin, Marcus E Jones (Norfolk Botanical Garden, Norfolk Va.,) and Lytton J Musselman (Old Dominion University, Norfolk, Va.) appeared in the Summer 2011 issue of “Native Plants Journal”

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The dodo’s large size and inability to fly were adaptations that allowed this bird to survive some of the most hostile conditions and climactic events imaginable. Only in the 1600s did a force more deadly than extreme drought and volcanic eruptions lead to its extinction: humans.

Image right: Painting of a dodo head by Cornelis Saftleven. Done in 1638,  this painting may be one of the last illustrations made of a live dodo. (Image from Boijmans Museum, Rotterdam)

In a recent paper in the journal “The Holocene” a team of scientists detail the extreme conditions that caused the death of some 500,000 animals on Mauritius during the mid-Holocene at around 4000 years ago. The evidence is a thick bed of fossil bones on Mauritius that spans an area of about 5 acres—the site of a former freshwater lake bed. The fossil layer is dominated by the remains of thousands of dodos and giant tortoises, as well as many small reptiles and flying birds.

Image left: Dodo bone in a matrix of mud, seed and other fossils excavated in a dry lake bed on the Island of Mauritius. (Image copyright Kenneth Rijsdijk/Dodo Research Programme)

Using radiocarbon dating of the bones, oxygen isotope analysis of geologic features on Mauritius and nearby islands, and the study of the island’s water table, the scientists determined the animals died during an extreme drought that lasted several decades. “Dodos, tortoises, lizards and other animals gathered here because the lake was one of the few sites on the island with fresh water,” says Hanneke Meijer, an ornithologist at the Smithsonian’s National Museum of Natural History and one of the paper’s co-authors.

“It is evident that a lot of animals suffered and died during this period, and their populations were greatly reduced,” Meijer continues, “but no species, including the dodo, went extinct during this extreme drought.” Fossil evidence reveals that “all animals were still living and the island’s ecosystem was intact at the time humans arrived in the 1600s.”

Image right: The excavation site on the island of Mauritius where the remains of some 500,000 animals were found, victims of an extreme drought some 4,000 years ago. (Image copyright Mikel Rijsdijk/Dodo Research Programme)

The dodo was resilient, and perfectly adapted to the island’s habitat, Meijer explains. “The island had no predators or carnivores and the dodo had no need to flee, so it lost its ability to fly. It received a reputation as stupid because it did not flee from humans” and human-introduced predators after they arrived at the dodo’s home in the 1600s.

Today, Meijer says, the forest cover on Mauritius has been reduced by 98 percent with only a few patches of original forest remaining. Considerable resources have been directed to preserving the island’s few remaining endemic species, such as the Mauritian kestrel. (The island’s giant tortoises went extinct in the 1800s when Dutch trade ships filled their holds with these long-lived animals to use as fresh meat on long voyages to and from Indonesia. “Mauritius was a popular stop because it provided fresh water and lots of food,” Meijer says)

Image left: Researchers at the Mauritius Island excavation site sieving excavated mud for small bones, teeth and plant remains. (Image copyright Mikel Rijsdijk/Dodo Research Programme)

Should another extended drought occur similar to the mid-Holocene event, it is very likely the remaining endemic species on Mauritius would not survive as the environment is so degraded. “Even many of the native plant species in the few remaining forest patches would probably perish,” Meijer says.

“With modern climate change scientists are very interested in how island animals adapt, as their ability to move to less disturbed areas is limited,” Meijer explains. “It has always been thought that animals on islands are particularly sensitive to climate change.” In the case of the dodo and other species on Mauritias, this new study reveals an island population highly resilient to climate change.

The article “Mid-Holocene (4200 kyr BP) mass mortalities in Mauritius (Mascarenes): Insular vertebrates resilient to climatic extremes but vulnerable to human impact,” appeared recently in the scientific journal “The Holocene.” (Rijsdijk, K.F., Zinke, J., de Louw, P.G.B., Hume,J.P., van der Plicht, J., Hooghiemstra, H., Meijer, H.J.M., Vonhof, H.B., Porch, N., Florens, F.B.V., Baider, C., van Geel, B., Brinkkemper, J., Vernimmen, T. & Janoo, A., 2011. Mid-Holocene (4200 kyr BP) mass mortalities in Mauritius (Mascarenes): Insular vertebrates resilient to climatic extremes but vulnerable to human impact. The Holocene, doi:10.1177/0959683611405236)

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• an ability to raft with flotsam; as seen in the Mid-Atlantic Barrier
• use of non-reef habitats as ‘stepping-stones’; seen in the Amazon-Orinoco Plume
• large adult size and latitudinal range

In particular, the findings about the predictor of adult size sheds new light on previous thinking about dispersal, showing that variation in larval-development mode is not as significant in migratory dispersal as previously thought.

The researchers highlight the assessment of adult-biology traits when assessing which fish will have the best chances of establishing new populations.

Luiz and Madin have been exploring the dispersal patterns of tropical fish for some time, both globally and in Australia, through the SIMS facilities in Chowder Bay, Sydney.

“We have been investigating the possibility that tropical reef fish populations may start appearing in the Sydney area. As part of this research, we study the characteristics of different reef fish species to determine which traits could allow them to travel beyond the Great Barrier Reef to New South Wales, traits like those seen in this study,” Luiz says

The article “Ecological traits influencing range expansion across large oceanic dispersal barriers: insights from tropical Atlantic reef fishes” appeared in the journal “Proceedings of the Royal Society: B” in September, authored by scientists from Macquarie University, the Smithsonian Tropical Research Institute, the University of Texas, the Universidade do Algarve and the Universidade Federal de Santa Catarina.–Source: Macquarie University, Sydney, Australia

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