Smithsonian Science » ecology

Japanese giant salamanders given to the National Zoo by Asa Zoological Park in Hiroshima

John Barrat — Fri, 23 Jul 2010 16:48:31 +0000

The Smithsonian’s National Zoo recently acquired Japanese giant salamanders given to the Zoo by the City of Hiroshima Asa Zoological Park. This donation will be the foundation of a new long-term breeding program in the United States and may play an important role in saving amphibians around the globe. “Our Japanese colleagues at the Asa Zoo have successfully applied decades of work and science to Japanese giant salamanders in the field and at their zoo,” said Dennis Kelly, director of the Smithsonian’s National Zoological Park. “It is an honor for the National Zoo to be entrusted with the offspring from their efforts, and we look forward to collaborating with them to save this magnificent species.”

Japanese giant salamanders live in cold, fast-flowing streams in Japan. Their numbers have been greatly reduced over the years because of agricultural development and habitat modification.

Photo left: Rick Quintero (left), the primary Japanese giant salamander keeper at the Smithsonian’s National Zoo, feeds the Zoo’s new juvenile salamanders for Japanese Ambassador Ichiro Fujisaki (right). Fujisaki was at the Zoo on July 22 to help celebrate the arrival of the salamanders, a gift from the City of Hiroshima Asa Zoological Park. (Mehgan Murphy photo)

“In conserving salamanders, we conserve the ecosystems in which they live,” said Ed Bronikowski, senior curator at the Zoo. “People share those same ecosystems, so what is good for the salamanders is good for many species, including us. We hope our visitors will learn from this generous gift to embrace our own diverse native salamander populations and protect healthy ecosystems for all.”

The National Zoo has experience caring for Japanese giant salamanders since as early as 1940, but with this gift, the Zoo hopes to become the first in the United States to successfully breed this species, which has not been bred outside of Japan in at least 100 years.

During the donation ceremony on July 22, kids from Great Falls Elementary School in Great Falls, Virginia were present to help name one male salamander. The students were asked to choice between two names selected by the ambassador – Hiro, derived from Hiroshima, the salamanders’ home in Japan and Asa, of the City of Hiroshima Asa Zoological Park. Hiro won the student’s vote! –Jessica Porter

Meet the Scientist: Dr. JoGayle Howard of the Smithsonian’s National Zoological Park

John Barrat — Tue, 20 Jul 2010 13:22:19 +0000

Tropical tree study shows interactions with neighbors plays an important role in tree survival

John Barrat — Thu, 08 Jul 2010 11:29:16 +0000

Home to jaguars, harpy eagles and red-eyed tree frogs, tropical forests support some of the rarest species on the planet and are the most biodiverse ecosystems on land. Understanding why some species are common while others are exceedingly rare has been a challenge in these mega-diverse forests. New results from a massive study at the Smithsonian Tropical Research Institute show that interactions among community members play an important role in determining which organisms thrive.

“Based on information about the survival of more than 30,000 seedlings of 180 species of tropical trees, we found that seedlings of rare species are much more sensitive to the presence of neighbors of their own species than seedlings of common species are,” said Liza Comita, the primary author on the study and now a postdoctoral fellow at the U.S. National Center for Ecological Analysis and Synthesis. “Not only does this tell us where to look for the mechanisms that explain why certain species are rare, but it also provides potential clues about how to conserve rare species that are most vulnerable to extinction.”

Photo left: Botanist Liza Comita measures the stem diameter of a seedling on the Smithsonian Tropical Research Institute’s Barro Colorado Island in the Panama Canal. (Christian Zieglar photo)

The lowland tropical forest on Panama’s Barro Colorado Island is the site of a huge long-term study focusing on plant diversity: more than 400,000 individual trees and shrubs of more than 300 species have been marked, mapped and measured every five years for the past 30 years. A unique window on climate change and other large-scale processes, the experiment was originally set up because two ecologists, Robin Foster, now at Chicago’s Field Museum, and Stephen Hubbell at UCLA, a co-author on this paper, had an argument about how life organizes itself.

What determines the members of a community? The study site—a patch of forest the size of nearly 100 football fields—is large enough to include individuals of many rare species that would not be present in smaller studies. After realizing that many of the processes that shape diversity happen early in a tree’s life, researchers decided to expand the study to include an annual survey of seedlings growing in the forest understory. This study of seedlings, led by Comita, Hubbell and Panamanian botanist and co-author Salomón Aguilar, has now been going for nearly a decade and has yielded new insights into this diverse forest.

For years, researchers have noticed that individual plants surrounded by neighbors of the same species do not grow and survive as well as individual plants surrounded by other species. Some evidence suggests that this is either because pests and pathogens move more readily among individuals of the same species or because they are competing with each other for the same resources.

“It became clear with this seedling survival survey that even though neighbors can be shaded out by individuals of the same or of other species, there are real differences in the survival of different species depending on how many of their neighbors are the same species,” said Helene Muller-Landau, staff scientist at the Smithsonian and adjunct professor at the University of Minnesota. “Some of our colleagues are working on the specific mechanisms that explain these differences, and we look forward to seeing their results, which will be published soon.” –Beth King

Introducing the parasitic dinoflagellate: Tintinnophagus acutus

John Barrat — Fri, 25 Jun 2010 16:51:54 +0000

In the microscopic world of marine protists, many species drift in the ocean currents unstudied and nameless. This is no longer the case for the parasitic dinoflagellate Tintinnophagus acutus. SERC plankton ecologist Wayne Coats recently finished an extensive description of the organism and thus earned naming rights.

Photo right: Tintinnophagus acutus dinospore, with a flagellum.

Of the approximately 2,000 known species of living dinoflagellates, about 150 are parasitic. These organisms can alter the marine food web, in some cases destroying prey that consumers like copepods and larval fish rely upon. Coats first spotted T. acutus in the 1980s, in plankton samples he had collected from the Chesapeake Bay. Through his microscope, he noticed a ciliate being edged out of its lorica (shell) by a dinoflagellate. It looked different from others he had observed.

Describing a species is a serious undertaking. In the case of T. acutus, Coats and his collaborators documented its microscopic life cycle, conducted extensive DNA analysis and unearthed scientific papers dating back to 1873—when parasitic dinoflagellates were first noted by German scientist Ernst Haeckel.

Much of Coats’ work involved understanding, questioning and clarifying various accounts of similar dinoflagellates that have been written over the years. He read studies published in French, German and English. This thorough research resulted in more than the introduction of T. acutus: it provided new understanding of the evolutionary relationships among parasitic dinoflagellates and it better defined their position within the dinoflagellate lineage of the tree of life.

Photo left: The host lorica (shell) contains the host ciliate Tintinnopsis cylindrica (upper part), which is being consumed by the parasitic dinoflagellate Tintinnophagus acutus (bottom, yellow). (Wayne Coats photos)

Protist phylogeny has never been Coats’ primary focus. T. acutus is the second species that he has named and described. This fall Coats will retire from SERC; he says he expects to have time to describe a few more species of parasitic dinoflagellates. –Tina Tennessen

Transmitters unveil long-distance movements of orchid bees

John Barrat — Thu, 27 May 2010 17:42:51 +0000

In their daily search for food, blue-green orchid bees zip through increasingly scarce patches of tropical forest pollinating rare flowers. Now, for the first time ever, researchers at the Smithsonian Tropical Research Institute are able to track the routes of these creatures by gluing tiny transmitters to the backs of individual bees. The data they are collecting is yielding new insight into the role bees play in tropical forest ecosystems.

“When people disturb and destroy tropical forest they disrupt pollination systems,” says entomologist David Roubik, senior staff scientist at the Tropical Research Institute. “Now we can track orchid bees to get at the distances and spatial patterns involved in pollination—vital details which have completely eluded us in the past.”

The team trapped 17 iridescent blue-green orchid bees called Exaerete frontalis –a species common in the rainforest. “These bees easily carry a 300-milligram radio transmitter glued onto their backs,” says Martin Wikelski, director of the Max Planck Institute of Ornithology and a research associate at the Smithsonian. “By following the radio signals with a hand-held antenna, we have discovered that male orchid bees spend most of their time in small core areas, but will take off and visit areas farther away.

One male even crossed over the shipping lanes in the Panama Canal, flew 5 kilometres, and returned to Barro Colorado Island a few days later. Such long distance flights, the researchers say, support the claim that bees are major agents of gene flow, connecting widely-dsipersed orchids or other plants which they alone pollinate, over fragmented landscapes and for an extended time. This study proves that “bees are key evolutionary players in allowing orchids and other tropical plants to evolve into diverse taxa that are each spatially rare and thus require long-distance pollination,” the researchers write.

In the past, researchers have struggled to determine the distances that bees travel by following individuals marked with paint, or using radar, which doesn’t work well when trees are in the way. “Carrying a transmitter may reduce the distance that the bees travel. But even if the flight distances we record are the minimum distances that these orchid bees can fly, they are impressive, long-distance movements,” said Roland Kays, curator of mammals at the New York State Museum and a STRI research associate. “These data help to explain how the orchids these bees pollinate can be so rare.”

The Smithsonian Tropical Research Institute, the U.S. Environmental Protection Agency, the New York State Museum and the National Geographic Society all provided support for this study. Its co-authors are affiliated with the University of Arizona, Tucson, Cornell University, EcolSciences, Inc. and the New York State Museum.

May Smithsonian symposium marks research contributions of scuba

John Barrat — Wed, 19 May 2010 12:16:04 +0000

Organisms are best understood by observing them directly in their habitat. For marine organisms, however, their salt water surroundings makes this a challenge to scientists. Scuba has changed that. For example, initially coral was believed to be a plant. Eighteenth-century scientists used microscopes to classify coral as an animal, but it was not until scuba was developed that researchers were able to study coral in its natural habitat for long periods of time. This led to a much clearer understanding of coral, its communities and ecosystems.

Right: Smithsonian Scientific Diving Officer Michael Lang in Florida.

Allowing scientists to stay underwater for extended periods has made scuba equipment an invaluable tool for the study of marine and freshwater environments. Since its development in 1943, scuba (self-contained underwater breathing apparatus) has enabled researchers to dive longer and deeper and closely study millions of underwater species and their vibrant ecosystems.

To mark scuba’s important contribution to underwater science, the Smithsonian Institution is convening dozens of scientists on May 24 – 25 at the National Museum of Natural History for a special symposium: “Research and Discoveries: The Revolution of Science through Scuba.” Open to the public, anyone wishing to attend this symposium should register online at the Web site: www.si.edu/sds/

Photo left: Brown elegance coral

“Without scuba our dive times would be restricted to the few minutes we can hold our breath, clearly not long enough to make scientific observations or collect samples,” says Michael Lang, director of the Smithsonian’s Marine Science Network and the Smithsonian’s Science Diving Program. “With thorough entry-level training, scientific scuba is a simple enough tool to enable its effective and safe use at many remote research sites.”

Photo right: A Smithsonian dive team. (Photo by Dan Miller)

Scuba is not a finished product, however. As technological advancements are made, scuba will continue to grow and be an even greater resource to science and discovery. “As our knowledge of decompression sickness increases and engineering solutions for scuba regulators and dive computers evolve, the envelope of our working window in the underwater world will likely expand, opening up new depths and habitats for research and exploration,” Lang says.

Net survey: For quarter century, scientists have been counting creatures traveling Chesapeake Bay tributary

John Barrat — Thu, 06 May 2010 12:58:53 +0000

For fish, crabs and other creatures living in the Chesapeake Bay, the many creeks, rivers or subestuaries that feed the Chesapeake are enticing avenues to explore for food and refuge. These tributaries also provide important nursery and spawning habitat for many of the Bay’s aquatic residents. More than 25 years ago, researchers at the Smithsonian Environmental Research Center’s Fish and Invertebrate Ecology Lab began taking weekley surveys of the species that make their way in and out of Muddy Creek. This waterway flows through the center’s grounds in Edgewater, Md., and feeds into the Rhode River, which then feeds into the Chesapeake Bay.

View Muddy Creek and the Rhode River in a larger map

To survey the animals swimming up and down Muddy Creek, researchers use a fish weir—an expanse of nets, gates and boardwalks—that temporarily blocks aquatic traffic. Once a week, the researchers close the weir, set out the nets and identify and count all the species that get trapped. They began collecting data in 1983.

This type of fine-scale surveying, done on a weekly basis, is rare. It’s even more unique to have such long-term data. Many ecological studies are funded for just a few years at a time. These short time frames make it difficult for scientists to observe changes and patterns in species populations and composition.

In honor of the 2010 U.S. Census, staff at the Smithsonian Environmental Research Center have created this slide show of a recent spring survey. The salinity on this April day was fairly low and nearly a dozen golden shiners (a freshwater minnow) were caught along with several estuarine-resident and a few diadromous (fish that migrate between fresh and saltwater) species. Among the highlights: a sizeable snapping turtle, many white perch in spawning condition, juvenile American eels and a parasite.

Human activity and environmental conditions can affect which species are swimming in Muddy Creek. The water is brackish and salinity levels change seasonally and from year to year. During winter and early spring, when freshwater flow is usually the highest, researchers will generally catch more freshwater species like bluespotted and banded sunfish–-two protected species in Maryland. During periods of high salinity, researchers can catch many species indicative of the higher saline lower Bay such as red drum, spotted sea trout and Spanish mackerel. –Tina Tennessen

Shipping industry sends help as project in Panama tackles amphibian crisis

John Barrat — Fri, 23 Apr 2010 13:34:26 +0000

As a disease known as amphibian chytrid fungus continues to wipe out amphibian species worldwide, frogs in Panama are finding a safe haven in a seemingly unlikely spot—between the metal walls of shipping containers once used to transport ice cream, strawberries, coffee beans, flowers and pharmaceuticals. Two of six refrigerated containers to be donated by the shipping company Maersk Line arrived this week at Summit Municipal Park in Panama City, Panama, where the Smithsonian Institution and partners are working to save amphibians in imminent danger of extinction.

Photo right: The limosa harlequin frog (Atelopus limosus) is one of 54 species that Amphibian Ark has identified as a priority rescue species for the Panama Amphibian Rescue and Conservation Project. (Click to enlarge)

“Each container provides us with critical space to house animals that may represent the last chance for the survival of their species,” said Brian Gratwicke, a National Zoo research biologist and the international coordinator for the Panama Amphibian Rescue and Conservation Project. “The containers are now self-contained ‘amphibian rescue pods’ that have been specially modified to control the climate and keep diseases out.”

The rescue pods will be part of the project’s Amphibian Rescue Center at Summit Municipal Park, which will also include a lab with a quarantine facility. After frogs are collected in the field, they will be quarantined for 30 days before being moved to the rescue pods that will serve as their new home. In addition to the two containers that are now in Panama, Maersk Line has agreed to donate two containers per year for the next two years to the project, for a total of six. Shipping company APL has also donated one container this year. Each container offers 995 cubic feet of space to house these animals. The seven together will more than double the amount of captive space the project currently has in Panama to safeguard endangered amphibians.

Photo left: Shipping company Maersk Line has agreed to donate up to six used shipping containers similar to this one to the Panama Amphibian Rescue and Conservation Project. The containers will serve as rescue pods for endangered amphibians.

“Maersk Line’s support of the amphibian rescue project is aligned with our long-term focus on sustainability,” said Mike White, head of Maersk Line’s North American organization. “Although we are pleased to donate these containers, the more valuable contribution is our expertise and resources. Our team’s assistance with documentation and transportation allows Brian’s group to concentrate on the overall effort.”

Amphibian Ark, an organization that mobilizes support for ex-situ (“out-of-the-wild”) conservation, has identified 54 amphibian species as rescue species for the Panama Amphibian Rescue and Conservation Project. At least 198 amphibian species live in Panama, of which 70 are listed as “critically endangered,” “endangered” or “data deficient” by the International Union for Conservation of Nature. Amphibian Ark estimates that about 500 amphibian rescue pods are needed to save the world’s 500 critically endangered amphibian species. Buying, outfitting and installing a single container costs about $50,000.

Photo right: Each shipping container offers 995 cubic feet of space to safeguard endangered species. (Photos by Brian Gratwicke)

“This requires an amount of resources that is insurmountable for the amphibian rescue community,” said Kevin Zippel, Amphibian Ark’s program director. “With a relatively small investment, the shipping industry has made a huge impact on one of the greatest conservation challenges that humanity has ever faced. We are currently seeking additional contributions of this kind.”

The mission of the Amphibian Rescue and Conservation Project is to rescue amphibian species that are in extreme danger of extinction from amphibian chytrid disease sweeping through Panama. The project’s focus is on developing appropriate technologies to control the amphibian chytrid fungus, so that one day captive amphibians may be reintroduced to the wild. Project participants include Africam Safari, ANAM (Autoridad Nacional del Ambiente), Cheyenne Mountain Zoo, Defenders of Wildlife, Houston Zoo, Smithsonian’s National Zoological Park, Smithsonian Tropical Research Institute, Summit Municipal Park and Zoo New England.

Amazon farmers who vanished centuries ago were remarkably innovative

John Barrat — Mon, 19 Apr 2010 05:28:35 +0000

Little is known about the long-vanished Arauquinoid, an Indian culture that thrived centuries ago in French Guiana, other than they were innovative farmers. The Arauquinoid were gone long before Columbus landed in the new world, yet what archaeologists and other scientists have recently learned about their farming methods comes through the auspices of some unlikely collaborators—ants, termites and earthworms. In addition, what scientists are learning about Arauquinoid farming methods may have important implications for today’s sustainable farms.

Image right: A pre-Columbian raised field in French Guiana filled with small, round mounds for growing crops.

Centuries ago these natives grew maize, manioc and squash upon a matrix of raised beds in flat, regularly flooded coastal marshes. Scooping slices of topsoil from the marsh they flipped them together and upside down, creating mounds which they topped with soil from other areas. Crops were planted, tended and harvested on this matrix of small islands.

Using aerial photographs, researchers have recently located a number of long abandoned “fossil” agricultural fields used by the Arauquinoid in coastal French Guiana. Follow-up examination of the soil and associated fragments from cooking implements, done in part by scientists at the Smithsonian Tropical Research Institute in Panama, have revealed microscopic starch grains from corn and manioc. Squash phytoliths also were recovered from soil analysis.

Image left: The aerial photograph at top shows different types of raised fields in a complex in French Guiana. The bottom image is an interpretation of these earthworks based on stereoscopic ananlysis and field studies.

This new research has revealed that in areas considered unsuitable for farming today, “pre-Columbian farmers constructed thousands of raised fields in the seasonally flooded coastal savannas of the Guianas,” scientists write in a paper published recently in the Proceedings of the National Academy of Sciences. ”They built conspiciuous earthworks, including raised fields, canals and ponds, that enabled them to practice intensive permanent agriculture in this low-lying region with highly seasonal rainfall.” The study combined archeology, archeobotany, paleoecology, soil science, ecology and aerial imagery and was carried out by scientists from a number of organization, including the University of Bayreuth in Germany, the University of Montpellier II and Centre d’Ecologie Fonctionnelle et Evolutive in France, the University of Exeter, and the Smithsonian Tropical Research Institute in Panama.

Image right: A matrix of raised mounds in an abandon field in a part of French Guiana named Savane Grande Macoua. Only the mounds are above water level.

In a region that receives on average four meters of rain each year, scientists were puzzled why the mounds have not eroded into obscurity over the centuries. They discovered that ants and termites, living in the raised mounds since before they were abandoned by the Arauquinoid, have continually rebuilt them with large quantities of new organic matter. Earthworms, attracted to this rich soil, kept the mounds porous, allowing rain to percolate through without washing them away. Grasses and other plants keep the mounds stable. A survey of the ants and termites in these former agricultural swamps, revealed that their nests occur entirely on the mounds, with none in the low, often submerged, areas surround them.

Researchers now speculate that as the fertility of the mounds decreased with continued crop growing, these ancient farmers may have let their mound-matrix fields lay fallow, allowing ants, termites and worms to replenish the soil’s nutrients. This largely forgotten practice of growing crops in marshes and allowing ecological engineers such as ants and termites to replenish nutrients is a technique that may have practical uses in modern sustainable farms, the researchers write.

Smithsonian ecologist John Parker discusses his work with invasive plants and white-tailed deer

John Barrat — Fri, 19 Mar 2010 18:48:59 +0000