Monthly Archives: April 2011

Locked in a race: where is the finish?

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Atelopus varius

The harlequin frog, Atelopus varius, disappeared from cloud forest streams in Costa Rica and Panama during the 1990s probably due to chytridiomicosis. Its sudden decline will negatively impact highland streams, its natural habitat, suggest ongoing ecological research. (Photo by: Brian Kubicki)

The visionary entomologist E. O. Wilson wrote in 1988 that, “overall we are locked into a race. We must hurry to acquire the knowledge on which a wise policy of conservation and development can be based for centuries to come.” In the case of the great die-off of amphibians that is currently taking place, coping with the loss of biodiversity requires a thorough understanding of how ecosystems respond to (often abrupt) disruptions.  One hundred years of tropical research in Panama by staff and visiting scientists at the Smithsonian Tropical Research Institute (STRI) leads to the wisdom we need to make smart conservation decisions.

Many amphibian populations are in severe decline throughout Central and South America, and many species, especially stream-dwelling amphibians, teeter at the brink of extinction. The ecosystems they inhabit are experiencing abrupt disruptions. For example, the harlequin frog, Atelopus varius, was relatively common in the headwaters of the Rio Lagarto in Costa Rica during a population census from 1982 to 1983. A second census between 1990 and 2002 recorded no harlequin frogs (La Marca et al., 2005).

Zero.

The toad genus Atelopus, which contains 113 species, has suffered catastrophic population declines affecting at least 43 species. In the same census effort that recorded the decimation of the Atelopus varius population, ten other species of Atelopus showed zero individuals in the second round only half a decade later.

Rapid amphibian population declines are happening at the regional level as well as at the species level. The best-tested explanation for what has caused the rapid and severe declines and numerous extinctions in the wild suggests that the fungal disease chytridiomicosis is the driving mechanism. Chytridiomicosis has progressed like a wave from Costa Rica in 1980 to eastern Panama today. A similarly destructive wave advances on susceptible, mostly highland, frog populations in Ecuador and Colombia. Currently, the epidemic wave front moves through central Panama at a rate of 17 km per year.

Atelopus glyphus

Frogs are an irreplaceable component of the highland stream ecosystem. In their absence, streams cannot cycle key nutrients effectively, and all species that depend on this habitat will be negatively affected. Recent results from the Tropical Amphibian Declines in Streams (TADS) research project strongly suggest that tropical streams have no backup when frogs populations decline rapidly. (Photo by Walter Dodds)

Research continues on the causes of chytridiomicosis and on mitigation strategies, but we need to do research on the effect of the declines on freshwater highland tropical stream ecosystems to successfully direct conservation efforts and accurately predict ecosystem-level changes. Amanda Rugenski, a post-doc at Southern Illinois University’s Department of Zoology, recently gave a talk at the Smithsonian Tropical Research Institute in Gamboa, Panama about the ecological consequences of amphibian declines in streams. Her research looks at pre- and post-decline streams and quantifies any changes in how the streams function as an ecosystem with and without amphibians.

The spreading epidemic in Panama offers the opportunity to compare similar stream sites across the chytridiomicosis wave front. If chytridiomicosis, a water-bone pathogen, is directly responsible for the observed declines, these before and after surveys will identify the ecological services that will be lost in the near future.

The project, Tropical Amphibian Declines in Streams (TADS), uses a technique called ecological stoichiometry to understand how key nutrients like carbon, nitrogen, and phosphorus are cycled through the stream’s food web. Because amphibians link aquatic environments–which they inhabit as tadpoles–to terrestrial ones, where they feed on insects as adult frogs, they serve as an important conduit of energy, linking the two food webs. The main question is whether stream ecosystems will be able to cope with amphibian declines.

The answer is that there is no replacement for the role amphibians play. Using nitrogen isotope tracers, Amanda discovered that tadpoles are essential to cycle nitrogen through the food web in stream habitats. When there are no tadpoles, nitrogen just flows downstream and is unavailable to other consumers. Altered nutrient flows and fluxes, and slower cycling rates affect other organisms as they cascade down the food web, resulting in different numbers of microorganisms, algae, and mayflies and of frog-eating snakes and birds. Tadpoles influence what grows where in the stream, the amount of water sediment, the availability of key nutrients and energy sources, and the overall function of the stream ecosystem.

Much has been written about the loss of biodiversity resulting from the rapid declines of amphibian populations. A paper listed in the STRI bibliography published this year in EcoHealth predicted, using DNA barcode techniques, that about a third of frog species have already been lost. Now, the effects of the declines from an ecosystem standpoint point to amphibian’s key and irreplaceable role in stream habitats.

The effort to understand enough to conserve and predict future amphibian populations has recently accelerated to match the rate at which chytridiomicosis advances. But we remain locked in the race.

–Charlie Hruska, Columbia University and Panama Amphibian Rescue and Conservation Project volunteer

Do I look like an Easter egg?

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Blue Poison Dart Frog (Dendrobates pumilio)
Dyeing poison frog (Dendrobates tinctorius)

Cute Frog of the Week: April 11, 2011

The brightly colored beauty known as the dyeing poison frog, Dendrobates tinctorius, likes to spend its free time under the cover of mossy rocks in the lowland tropical forests of Brazil, French Guiana, Guyana and Suriname. These cuties like their forest homes to be humid during the day but cool at night. Rocky streams with running water are a must. While these guys usually like to stay on the ground, some have been found at heights up to 5 meters in trees. When it comes to mating, the dyeing poison frogs are quite the amorous amphibians. Mating behavior starts with the male calling from his position in tree leaves or on the ground. The female is attracted by his calls and strokes the male’s snout and back in a typical poison frog courtship sequence. The male then leads the female to his chosen spot, where a clutch of 2-6 eggs are laid. How romantic! But life isn’t always so sweet for these beautiful creatures. One major threat these little guys face is that they are illegally collected for pet trade. Luckily, the International Union for Conservation of Nature lists the species as least concern because of their wide distribution and presumed large population. Their range also includes some protected areas, so don’t expect these fanciful frogs to “dye” out anytime soon!

Photo credit: Brian Gratwicke, Panama Amphibian Rescue and Conservation Project

Every week the Panama Amphibian Rescue and Conservation Project posts a new photo of a cute frog from anywhere in the world with an interesting, fun and unique story to tell. Be sure to check back every Monday for the latest addition.

Send us your own cute frogs by uploading your photos here: http://www.flickr.com/groups/cutefrogoftheweek/

Hey, sexy!

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Mexican tree frog (Smilisca baudinii)

Mexican tree frog (Smilisca baudinii)

Cute Frog of the Week: April 18, 2011

This svelte silhouette belongs to a Mexican tree frog, Smilisca baudini, who is defying gravity with its leaf-clinging sticky toe pads. It’s probably waiting for the sun to go down, when exciting frog stuff really begins. If there’s been rain, look out—that’s prime breeding time. Males duet with females, forming wonk, wonk sounds into love songs. If a successful pairing occurs, they’ll find a shallow pool for the 2,500-3,500 eggs the female will release across the surface. During the day, you can find these guys sheltering under loose tree bark, burrowed in damp soil, or curled up in a big banana leaf. As a species considered of least concern by the International Union for Conservation of Nature, they can afford to chill out. Still, it doesn’t hurt to keep an eye out for that occasional spider or fly snack and, of course, beware of those frog-eating snakes!

Mexican tree frogs range in color from brown to green and can even change according to the circumstance. They always retain their classic pattern of dark patches that spreads across their backs and legs. A chunky frog with rather short legs, the Mexican tree frog is the largest tree frog found in the United States, with females reaching as large as 90 mm (3.5 inches). In the States they’re only found in Texas, though, and are most commonly found throughout Central America.

Photo credit: Joe Milmoe, U.S. Fish and Wildlife Service.

Every week the Panama Amphibian Rescue and Conservation Project posts a new photo of a cute frog from anywhere in the world with an interesting, fun and unique story to tell. Be sure to check back every Monday for the latest addition.

Send us your own cute frogs by uploading your photos here: http://www.flickr.com/groups/cutefrogoftheweek/

I come in all shapes and sizes.

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Strawberry Poison Dart Frog (Oophaga pumilio)
Strawberry Poison Dart Frog (Oophaga pumilio)

Cute Frog of the Week: April 11, 2011

The strawberry poison dart frog, Oophaga pumilio, is an amazingly beautiful little creature that normally reaches only 17 to 24 mm in length. Even though these cuties are tiny, their poison is potent. Like other poison dart frogs, skin coloration is this frog’s protection mechanism, indicating its toxicity and telling predators to stay away. This species has at least 15 different morphs, or forms, and can range in color patterns from blue with no spots to olive green and yellow with black flecks. In one of its most common forms, also known as the “blue jeans form,” the head and body of the poison dart frog are bright red or orange, with blue or black lower parts, giving the illusion that this tiny cutie is wearing pants! Males also have a special tan-grayish vocal pouch under the throat, which they use to defend their territory in the humid lowlands and forests of Costa Rica, Nicaragua and Panama.

These guys are fiercely territorial, sometimes defending territory that is up to 3 meters apart from other males! If someone provokes them or enters their “hopping” grounds, they aren’t afraid to challenge their opponents to a wrestling match. Another interesting fact about these dart frogs is that when it comes to breeding, the females really wear the pants. The females take matters into their own hands and approach the males to initiate breeding. Once the female has laid her eggs, it’s up to the male to tend to the clutch and keep them moist by—are you ready for this?—emptying  his bladder on them until they hatch. The females will then carry the tadpoles on her back to small pools in bromeliads and will feed the offspring  by laying unfertilized eggs in with the tadpoles as their primary food source. Both parents invest some serious time and resources in raising their young. Sounds like they deserve the “Parents of the Year” Award, right? While these brightly colored beauties do face threats, such as habitat loss and over-collection for the pet trade, there is some good news: These cuties are listed as least concern by the International Union for Conservation of Nature because of their wide distribution, tolerance of a degree of habitat modification and presumed large population.

Hop on, little guys!

Photo credit: Mehgan Murphy, Smithsonian’s National Zoo

Every week the Panama Amphibian Rescue and Conservation Project posts a new photo of a cute frog from anywhere in the world with an interesting, fun and unique story to tell. Be sure to check back every Monday for the latest addition.

Send us your own cute frogs by uploading your photos here: http://www.flickr.com/groups/cutefrogoftheweek/

Notes from the Field: Finding the Limosa harlequin frog

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Jenyva Turner, Cheyenne Mountain Zoo animal keeper

Jenyva shows off an Atelopus limosus the Cheyenne Mountain Zoo team captured during the February expedition. (Photo courtesy of the Cheyenne Mountain Zoo)

Wanted: Adventurous expedition members to hike into the jungles of Panama looking for the rare Atelopus limosus. Must be willing to hike long hours in rugged, muddy terrain and in thigh-deep water, and ready to be wet, hungry, tired, and not afraid of spiders, snakes, scorpions, and lots of insects.

SIGN ME UP!!!

How could I pass up an opportunity to hike, explore, and camp in the jungle, all while helping save a species? This February was my first trip to Panama, however I followed the blog posts from other Cheyenne Mountain Zoo team members during previous expeditions to Panama, so I felt like I had already been there. I knew it was going to be a challenging trip, both physically and mentally. Would we find frogs? That was my biggest concern. As we all know, the chytrid fungus is taking its toll on frog populations around the world and the rare Atelopus limosus is not immune to chytrid’s deadly sting.

Atelopus limosus was our target species since the Panama Amphibian Rescue and Conservation Project only had one female and four males in captivity. The future of the species appeared to depend on our findings. It was the “dry season” in Panama (although, being from Colorado, rain every day does not seem very “dry”!) and therefore, was the best time to find females, as they would be coming down to the streambeds to lay their eggs. The males would be there waiting.

We hiked along the stream and carefully searched the moss-covered rocks for the small, highly camouflaged black and green frogs. It was tough to be quiet and sneak up on our target as we sloshed around streambeds, stepped over branches, and slipped on rocks. We paid especially close attention to areas of the stream where the water moved a little faster. Atelopus limosus lay their eggs in faster-moving water to reduce competition from other frog species and reduce predation. The tadpoles are specially designed with little suction cup disks on their bellies to help them hold onto the rocks and keep them from being washed away. Pretty cool!

Our team found just four Atelopus limosus during our time in the field, but we were able to give hope to the species as one of those caught was a young female. We handed off our precious cargo to the capable staff at the Summit Zoo, who take their job and role in frog conservation very seriously. They are working hard to care for and propagate many other amphibian species besides Atelopus limosus to ensure the sounds of frogs continue to be heard in the jungles of Panama.

Here’s a video of Antonia Chastain, a member of the Cheyenne Mountain Zoo team, finding out first-hand how difficult it is to catch an Atelopus limosus during the February trip:

—Jenyva Turner, Cheyenne Mountain Zoo animal keeper (and first-time frog finder!)

Not your average extraterrestrial

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Red-backed poison dart frog (Ranitomeya reticulata)
Red-backed poison dart frog (Ranitomeya reticulata)

Cute Frog of the Week: April 4, 2011

The cutie known as the red-backed poison dart frog can be found out and about during the day in the lowland tropical rainforests of Peru and Ecuador. Like all poison dart frogs, these beauties are vividly colored and patterned, which advertises their poison. Red-backed poison dart frogs have black legs with a cobalt or sky-blue mesh pattern, a black belly, and a back that ranges in color from fiery orange to scarlet in color, hence the name “red-backed.” While they are mostly terrestrial, meaning they tend to stay on the ground, these cuties also like to climb an occasional tree trunk (so does that make them an extra-terrestrial?). Luckily this frog is no alien and sightings are frequent. In fact, the International Union for the Conservation of Nature says these cuties are a widespread species with a stable population and large areas of suitable habitat remaining. It is also illegal to export these beautiful amphibians from their homes in Peru and Ecuador, which helps keep this special species safe from the pet trade.

Photo credit: Brian Gratwicke, Panama Amphibian Rescue and Conservation Project

Every week the Panama Amphibian Rescue and Conservation Project posts a new photo of a cute frog from anywhere in the world with an interesting, fun and unique story to tell. Be sure to check back every Monday for the latest addition.

Send us your own cute frogs by uploading your photos here: http://www.flickr.com/groups/cutefrogoftheweek/