amphibians

Foreshadowing the Amphibian Crisis: The Wyoming Toad

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Authored by Blake Klocke, curator of amphibians for The Detroit Zoological Society

The Detroit Zoological Society (DZS) is helping a species hop back from extinction!

The Wyoming toad was once found in abundance in the Laramie River Basin. However, catastrophic population declines were observed throughout the 1970s. By 1983, the Wyoming toad was thought to be extinct. Biologists could make no clear determination for the cause of the decline.

With a bit of luck, a small population of about 20 animals was rediscovered in 1987 at Mortenson Lake, bringing hope that the species could be saved. Rescuing the species by bringing it into captivity was the only option to avoid extinction.

Amphibian Chytrid Fungus and Preventing Amphibian Extinctions

Throughout the 1980s and 1990s, amphibian declines were common around the globe – something that puzzled biologists. At the time, there was no obvious answer as to why multiple amphibian species were rapidly disappearing in Australia, Central America and the United States. In 1998, the amphibian chytrid fungus – a microscopic primitive fungi – was discovered to be the cause of disease resulting in these declines. Biologists have attributed the amphibian chytrid fungus to be the primary cause of approximately 100 amphibian extinctions and to have impacted more than 700 amphibian species. No other wildlife disease has impacted biodiversity as much as this fungus. 

The Wyoming toad is highly susceptible to the amphibian chytrid fungus. The National Amphibian Conservation Center at the Detroit Zoo was built in part as a response to the amphibian biodiversity crisis, which assisted in keeping some of the most imperiled species away from the edge of extinction. The Wyoming toads at Detroit Zoo live in a biosecure room, which keeps them safe from being potentially exposed to the disease!

Ex-situ rescue, which is when a species is brought out of the wild into captivity for conservation, is a last resort. Unfortunately, we are often left with no other options. Rescuing a species in captivity requires intensive management to maintain the population, and it’s a long-term commitment by a dedicated and passionate team.

Wyoming Toads at the DZS

The DZS was an early partner in rescuing Wyoming toads, welcoming our first toads in 1995. A Species Survival Program (SSP) was also formed in 1996 to organize efforts among zoo partners and the U.S. Fish and Wildlife Service. The amphibian team at the DZS has produced 10,730 Wyoming toad tadpoles, toadlets and adults for reintroduction since joining the program in 2001! These animals are bred at the DZS and later sent to Wyoming to be released into the wild. The Center for Zoo and Aquarium Animal Welfare and Ethics at the Detroit Zoo has also led studies that have helped improve the husbandry of Wyoming toads in captivity by comparing the preferences for substrate, which improves our care for this very important species.

Caring for Wyoming Toads at the Detroit Zoo

Mike Andrus is the primary colleague who takes care of the Wyoming toads at the DZS, and his years of experience in the amphibian department caring for these toads is one of the keys to Detroit Zoo’s success. Mike handles more than 30 toads at the Zoo

Mike Andrus is the primary colleague who takes care of the Wyoming toads at the DZS, and his years of experience in the amphibian department caring for these toads is one of the keys to Detroit Zoo’s success. Mike handles more than 30 toads at the Zoo, where he carefully cycles the temperature throughout the year, including when he places the toads in a refrigerator to hibernate. This process requires a lot of fine-tuning and experience – and prepares the toads, which are each equipped with their own individual ID to track genetics, for breeding.

Mike Andrus holds a Wyoming toad in the biosecure room.

Wyoming toad tadpole reintroductions

In June 2022, Mike traveled to Laramie, Wyoming to participate in the reintroduction of Wyoming toad tadpoles. Several thousand tadpoles were sent from SSP partners for reintroductions. It was a busy day, as tadpoles were placed in bags of about 100 animals and methodically distributed around reintroduction sites.

Tadpole reintroductions are very important to continue supporting the recruitment of new toads into the population. In the months following the tadpole reintroductions, hundreds of recently meta morphed toads are found — each one with the potential to make it to adulthood and breed in the wild.

Bags of tadpoles produced by zoos around the country and U.S. Fish and Wildlife Service acclimate before reintroduction.

Wyoming toad surveys

In August 2022, I participated in the Wyoming toad field surveys and an annual SSP meeting. The team was successful in finding many young toads, likely from tadpole reintroductions and some wild breeding. The most exciting part was finding more than 15 breeding-sized adults! Some of the toads had a small identification tag, demonstrating that reintroduced juveniles and adults from captivity are surviving in the wild.

Wyoming toads were found at all four field sites the team visited, a very good sign for a species that was once thought to be on the verge of extinction. Currently, there is no method to mitigate the amphibian chytrid fungus in the wild, but in recent years there are an increasing number of rediscoveries of species once thought to be extinct and vulnerable species persisting in the presence of chytrid.

We’re optimistic that the Wyoming toad will soon hop back from extinction!

A toad reintroduced months beforehand was found during our surveys and appeared in good health. Adult toads receive a tiny tag, much like a micro-chip for a cat or dog, that let us know who they are when they are found in the wild! 

Thank you to our SSP partners, who make saving this species possible:

• U.S. Fish and Wildlife Service

• Kansas City Zoo

• Cheyenne Mountain Zoo

• Omaha’s Henry Doorly Zoo and Aquarium 

• Como Zoo

• Mississippi River Museum

Amphibian Breeding Season

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Spring is the time of year when most amphibians in the wild are emerging from hibernation, breeding, and eventually laying eggs. This pattern also holds true for the animals at the Detroit Zoo’s National Amphibian Conservation Center (NACC). Every year in the early months of spring, the top-notch staff at the NACC facilitate hibernation, breeding and rearing for endangered amphibians from all over the world with the intention of releasing them into their respective habitats in the wild. A few of these species include Wyoming toads (Bufo baxteri), striped newts (Notophalmus perstriatus) and Puerto Rican crested toads (Peltophryne lemur). Amphibians are highly sensitive creatures who rely on the environmental conditions of their native habitats to cue their natural cycles of breeding and to maintain their overall health.  The NACC staff are experts at recreating these environmental cues.

Facilitating breeding in Wyoming toads, for example, is a complex process involving temperature changes and natural material for burrowing. The amphibian staff use a refrigerator to replicate the natural winter cool down experienced by these critically endangered creatures, and to ease them into a state of lowered activity and metabolism. The amphibians are also provided with a special mix of substrate to burrow into during this period – very similar to how Wyoming toads in the wild burrow below the frost line during the cold months.  When they warm up after this simulated winter, the toads at the NACC are ready to breed and are paired up with mates according to the recommendations of the Association of Zoos & Aquariums’ (AZA) Species Survival Plan (SSP) for Wyoming toads. An SSP is a cooperative breeding program that is overseen by AZA-accredited institutions that breed and house animal species who are endangered or threatened.

Another example of the specialized care required to breed the unique animals at the NACC is found in the reproduction patterns of striped newts. Endemic to the long leaf pine forests of Georgia and Florida, these amphibians are known to congregate and breed in temporary pools during specific times of the year when the water levels are highest.  In order to mimic these events for the striped newts at the NACC, their habitats’ water levels are lowered for a period of time – before being raised dramatically. The natural breeding cues of the striped newts are also replicated in other ways, such as changing their “photo period,” or daylight/nighttime hours, in order to simulate different seasons.  Inside the animals’ habitats, the zookeepers also place specific aquatic vegetation that the newts have been known to prefer as sites for laying eggs.

            Puerto Rican crested toads are among the many amphibians who are known to begin breeding activities during periods of heavy and sustained rainfall. Existing only in several small isolated populations within Puerto Rico, these toads emerge from hiding during seasonal rains to find a mate and reproduce.  Making use of this knowledge, the intuitive keepers at the NACC have produced a “love song mixtape” which includes the calls of male crested toads as well as the sound of heavy rainfall. While this track may not win any Grammy Awards, it serves to stimulate the crested toads into amplexus, which is an embrace used by male toads to hold onto the female and fertilize her eggs.

After countless hours of logging temperatures, researching literature and testing water quality, the real reward comes for the staff at the NACC when these fragile and endangered animals are released into the wild having received a head start towards a brighter future. This year, in the month of June, the amphibian department at the Detroit Zoo released 3,393 Puerto Rican Crested Toads, 634 Wyoming Toads and 41 Striped Newts into native habitats ranging from the dry forests of the Caribbean Islands to the plains of Wyoming. The amphibian staff take great pride in having contributed to the conservation of some of the most important animals on the planet as well as in furthering the mission of Detroit Zoological Society.

– Mark Vassallo is an amphibian department supervisor for the Detroit Zoological Society

Frog-Themed Activities in Honor of World Frog Day!

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Spring is finally here — and so is World Frog Day! The weather is gradually warming up and plants are bursting through the soil, preparing to dazzle us with their blooms. Spring also brings the beautiful sounds of frogs and toads calling to each other. In honor of World Frog Day, we are sharing frog-themed activities that can be done at home with minimal supplies.

PT Borneo eared frog

Frogs live on six of the Earth’s seven continents, all of them except Antarctica. They are all different colors and sizes. The largest species of frog, the goliath frog, measures 8” to 12” in length. That is about the size of a piece of copy paper!  The smallest known frog, one of the microhylid frogs, measures less than half an inch, about the width of a regular size paperclip. If you have children at home, pull out a paper clip and a piece of copy paper. Have them compare the items to objects around the house to see what is larger than the world’s largest frog and what is smaller than the world’s smallest frog. Comparing sizes of different things helps people build number sense, or an intuitive understanding of numbers, an important skill for all of us to master, especially young children.

Green Mantella - Adam Dewey

Michigan is home to 13 species of frogs and toads. It is usually easier to hear them calling or singing to each other, than it is to actually see them. That is because they are well camouflaged, meaning they blend in with their surroundings. It is important to know which species of frogs and toads live in certain areas. They are considered bioindicators, which means they are species of animals who are greatly impacted by the health of the environment. If the water, wetlands and other places they live are polluted or contaminated, they cannot survive. If their habitat is clean and healthy, many species or individuals will be living there, all calling out to each other in a beautiful chorus.

FrogWatch - Bullfrog

The Detroit Zoological Society (DZS) leads a FrogWatch Chapter (aza.org/frogwatch and detroitzoo.org/animals/frogwatch/) to train people, like you, to recognize and record frog calls around Michigan. The data that people submit helps DZS staff and researchers to analyze and better understand frog populations throughout our area and across the country.

IMG_0474

This spring, consider spending time outside in the evening to listen for frogs and toads. You can practice being a frog and toad researcher, or a citizen scientist, by learning the calls and recording information like date, temperature, weather conditions, the time you start and stop listening, and the species you hear. The Michigan Department of Natural Resources has short recordings of each species on their website to help you learn them. Practicing recording data is an important skill, especially for kids. Send your data to Rebecca Johnson (rjohnson@dzs.org) or Mike Reed (mreed@dzs.org). Next year, you can join us for training to become a certified FrogWatch participant. The earliest calling frogs will be starting soon, the wood frogs and spring peepers, so pick a night where the temperature is above 40 degrees Fahrenheit and head outside to listen!

 

Texas Rescue: 10 Years Later

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Maroo, a male red-necked wallaby, passed away on November 11, 2019. Although this may seem like a sad way to begin a blog entry, this is a celebration of Maroo’s life for the almost 10 years he lived at the Detroit Zoo. He was part of the wallaby mob living in the Australian Outback Adventure, and seemed to enjoy exploring this expansive space and sharing his time with others of his species. He was cared for by dedicated zookeepers and observed by attentive volunteers as well as visitors. Maroo will be missed. His story could have had a much different trajectory, had it not been for the intervention of the Detroit Zoological Society (DZS).

TR Maroo

In December of 2009, six DZS animal curators and supervisors travelled to Texas to provide expert care for more than 27,000 animals seized by authorities in the largest exotic animal rescue in the history of the United States. We were contacted after an investigation revealed inhumane treatment of these animals – including spiders, reptiles, amphibians and numerous exotic mammal species – by an exotic animal dealer who was selling them. Our staff members spent almost two months at a temporary care facility in Dallas, helping to triage and care for these animals who had been kept in dismal conditions. Not only did this include basic care, such as proper food, water and medical treatment, but it was also the first time any of these animals were treated with the respect they deserve. Unfortunately, many did not survive due to the illnesses and injuries they sustained during the time they spent as part of the exotic animal trade.

TX-Beth Johnson and Sloths

Hundreds of these animals – 961 to be exact – about two-thirds of which were amphibians, came to the Detroit Zoo to spend the rest of their lives in comfort and receive the care each one deserved. Although many of these animals have passed due to old age over the past decade, some are still at the Detroit Zoo and Belle Isle Nature Center. Two ring-tailed lemurs were among the animals rescued, and the female was actually pregnant at the time. She gave birth to healthy twins, and all four still live in the group you can observe at the Zoo. Four Linne’s sloths were cared for by our staff and have gone on to live good lives at other zoos accredited by the Association of Zoos & Aquariums. Of the four matamata turtles who arrived here, one can still be seen at the Holden Reptile Conservation Center. You can also visit two tiger salamanders at the Belle Isle Nature Center. In total, there are about three dozen of the rescued animals still living in our care. Five wallabies originally joined the mob at the Detroit Zoo as part of this important rescue effort, and Maroo was the last of this group.

TX-black spiny toads

Maroo’s story is a great example of the impact the DZS has on the lives of individual animals. The exotic animal trade is not only having drastic impacts on populations of wild animals, it is also an industry that creates and promotes severe animal welfare issues for individual animals. Our mission is Celebrating and Saving Wildlife, and our efforts to assist with rescues and provide sanctuary for animals are a critical part of this mission. The next time you visit the Detroit Zoo, look for signs identifying rescued animals and learn more about their stories.

– Dr. Stephanie Allard is deputy chief life sciences officer for the Detroit Zoological Society and oversees the Center for Zoo and Aquarium Animal Welfare and Ethics.

Notes from the Field: Protecting Amphibian Biodiversity in Peru

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You heard recently from one of our education experts about how the Detroit Zoological Society is working with Peruvian schools to conserve the rainforest through outreach and education. Conservation of the biodiversity in the Peruvian rainforest has been a priority of the Detroit Zoological Society for over a decade, and we have many programs in the rainforest that help to achieve this goal. One of our programs focuses specifically on amphibians, and that is where I have the great fortune to visit this incredible location.

Boana calcarata

There are over 600 species of frogs in Peru, with more species discovered every day. With this high number of species, Peru is called a “biodiversity hotspot.” These “hotspots” are very important to monitor for changes, because while there are many species they are all very dependent on one another. Small changes can cause drastic effects. Amphibians are some of the most sensitive animals, because their skin absorbs everything in the environment. If amphibians begins to get sick or have difficulty surviving, that is an excellent clue that something is wrong in the environment. All over the world, amphibians are currently having difficulty with changes we are seeing in the environment- because we are seeing global changes, it is extra important to study the animals in areas like the Amazon, where amphibians are in higher concentration, to try and understand patterns in these changes.

Boana calcarata call image

The convict tree frog (Boana calcarata) is a frog found in the Napo River region. This sound recording and image were made by the National Amphibian Conservation Center during a survey.

In order to keep an eye on the amphibians in the Peruvian Amazon, staff from the Detroit Zoo’s National Amphibian Conservation Center conducts surveys for frogs twice a year. This means we physically go out and look for frogs. Because we know we cannot possibly see all the frogs, also record the songs of frogs at night. Hearing the songs can help us guess numbers of animals singing and help us to hear the songs of species that are difficult to find on visual surveying. In addition to surveys, we monitor weather data in the Napo River valley. We have our own weather station that collects year-round information about the valley region. We also use small data loggers to collect immediate, specific “microclimate” changes where we visualize species breeding (for example: on a specific plant or under leaf litter). The weather data helps us understand both immediate changes in behavior of frogs, as well as changes in populations over time.

Weather stationDr. Ruth Marcec-Greaves downloads six months’ data from the weather station.

While data collection and surveying are important, fostering appreciation of animals in the local community is the primary goal of the visits to Peru. Our hope is that educating the community and creating excitement in future generations will help to preserve these animals for the future. The “Club de Protectores de Anfibios,” or Amphibian Protectors Club, is a club comprised of high school students that are local to the Napo River valley region. The club was founded in order to help impart enthusiasm for amphibians and the environment.

In Peru, there are many misconceptions surrounding frogs. There is a general belief that frogs are bad luck and should be kept away from homes. When the Detroit Zoo staff visited the Amphibian Protectors Club in June of 2019, the club members taught us how the Amphibian Protectors Club is changing the community. The club members performed a play in which they explained another local belief is that a woman will become pregnant if she spends time around frogs. Told from the perspective of high school students, this was a chilling superstition. Through the play, the students explained that by participating in the club they have learned not only that this is a myth, but also frogs are important for human health and humans need to protect frogs. The club members have taught their friends and families frogs are important and have begun to see more frogs in their villages since this change in attitude.

Night HikeAn Amphibian Protector’s Club member observes a frog up close on a night hike.

The students from the club went on an overnight excursion with the National Amphibian Conservation Center staff, where we visited one of our regular field research sites. We took a late night hike in order to see frogs calling and breeding at this special location. At this site, we saw species of frogs the students do not commonly see in their villages. After a good night rest, the club rose early in the morning to hike to the nearby canopy walkway- a breathtaking experience where the club members were able to look down on the rainforest from the treetops. While these students live in the rainforest, many of them have not seen their tropical home from this perspective. They were inspired by this view, observing the unique habitat of rare and diverse species. One club member called it “the view of the animals,” and asked very advanced questions about some of the plants and insects he observed.

Canopy

This was an incredibly rewarding trip. The students showed us that their appreciation for the amphibians is making a difference. While I will not see them in person for a few months, the students will continue to speak with me over a WhatsApp chat (they named our group “Whatsappos,” because “sapo” means toad in Spanish). While I am away, the club meets monthly to survey in their home towns and the students will send me photos and descriptions of frogs the see. Over the app, we talk about the species and have a question and answer session. Their excitement is inspiring and infectious, and I am confident their enthusiasm will be what helps save species.

– Dr. Ruth Marcec-Greaves is the director of the Detroit Zoo’s National Amphibian Conservation Center.

 

 

Detroit Zoological Society Leads Task Force to Evaluate Risks Facing Honduran Amphibians

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The International Union for the Conservation of Nature (IUCN) recently asked the Detroit Zoological Society to host an Amphibian Red List workshop in Honduras. The IUCN Red List is the world’s most comprehensive information source for understanding extinction risk for animals. To develop this list, a rigorous assessment process is conducted using all known data on each species. Based on what threats the animals are facing, e.g., habitat decline, population decline and habitat fragmentation, the animals are placed into one of eight categories:

  • Extinct – None left
  • Extinct in the Wild – None are left in the wild, but captive groups exist
  • Critically Endangered – These species are often labeled “probably extinct” and are in imminent danger of extinction
  • Endangered – These species are at high risk of extinction
  • Vulnerable – These species are at moderate risk of extinction
  • Near Threatened – These species are not currently at risk of extinction but are anticipated to be at risk in the near future
  • Least Concern – These species are not currently at risk of extinction
  • Data Deficient – Not enough information

It’s important to note that animals in the Least Concern category are still of concern and should not be ignored, but the threats facing animals in the other categories are currently causing more pressures. The Red List rating scale is often referred to as a “barometer of life”, with each category indicating the amount of pressure on a species pushing it closer toward extinction.

Hosting a Red Listing workshop for the amphibians in Honduras was an exciting and extremely intense process. Of all the countries in Central America, Honduras has the highest number of amphibians that are endemic – or found only in that country, which makes it a very important area for biodiversity. Unfortunately, Honduras doesn’t receive a lot of conservation attention and many of these amphibians are facing the threat of extinction. The Detroit Zoological Society was eager to help this underappreciated hot spot for biodiversity move forward toward understanding the conservation needs of its unique amphibians.

This IUCN assessment of amphibians was the first assessment of all amphibian species in Honduras for more than 15 years, and since the last assessment, 22 new amphibian species were discovered in the country. To assess the animals, the local Honduran amphibian experts were brought together at Universidad Zamarano outside Tegucigulpa for the workshop. With the help of myself, the IUCN facilitators, and two other amphibian experts from the U.S., we all sat down to share data on the 151 species of amphibians in Honduras and determine their IUCN categories. Holding this assessment in country was critical for the participation of these local experts who had intimate knowledge of the species, and who were able to discuss future steps in protecting species of critical need.

We learned a lot through this workshop. Although there were more species assessed in 2019 than in 2002, the overall number of species that are Extinct, Critically Endangered and Endangered all increased. This is especially concerning in this unique area of biodiversity. Because the Red List allows us to assess the specific threats facing the animals, we were able to discuss potential conservation actions needed. At the end of the workshop, a meeting was held with officials from Instituto de Conservaticion Forestal, the governmental institution similar to the U.S. Fish and Wildlife Service, in order to discuss the results of the assessments and what steps could be taken next. Additionally, we hosted a symposium at the Universidad Nacional Automona de Honduras in Tegucigalpa in order to raise awareness about the IUCN workshop and the state of amphibians in the country. More than 150 individuals attended the symposium, including government officials, researchers and students. It was encouraging to see the excitement within the country, especially in so many young students, for the preservation of amphibians. We will continue to evaluate what we’ve learned from this process and determine the next course of action to save these critical species.

– Dr. Ruth Marcec-Greaves is the director of the Detroit Zoo’s National Amphibian Conservation Center.

Notes from the Field: Saving Tree Frogs in Honduras – Part III

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In my previous two blog entries, we examined three critically endangered species of tree frogs in Honduras and shared plans for the Detroit Zoological Society and the Honduras Amphibian Rescue and Conservation Center to begin a head-start program for tadpoles of these species to help increase their populations. If you haven’t had a chance to read these entries, click here and here.

Now, let’s take a peek at what the rescue center facilities look like, and the long-term vision for in-country involvement.

The facilities are currently located in El Jardin Botanico y Centro de Invastigacion Lancetilla, a botanical garden and research center run by Universidad Nacional de Ciencias Forestales. Construction began in 2015 through a collaboration of multiple institutions, including Omaha’s Henry Doorly Zoo and Aquarium, National Autononous University of Honduras, UNACIFOR, Operation Wallacea, Expendiciones y Servicios Ampbientales de Cusuco and the Honduran forestry department. By the spring of 2018, construction was completed and our team inspected the facilities. The team included myself, staff from Omaha’s Henry Doorly Zoo and Aquarium and the rescue center’s co-founder Brandon Greaves. The inspection was to assure that the facilities are ready to provide the best care, biosecurity and welfare for animals that will arrive later in the year.

The ingenious rescue center facilities utilize shipping containers in order to provide housing for the animals. The containers (called “pods”) are ideal for amphibian conservation and care as they are secure, well insulated and easily mobilized should the facility need to be relocated. The pods have full plumbing and electricity, with climate control to suit the needs of our three target species that live in the cool mountain habitats. Each pod is outfitted with a vestibule for caretakers to prepare for a bio-secure entry (which requires clean up and changing clothes).

The pods are outfitted with habitats for up to 1,200 animals (400 from each of the three target species: exquisite spike thumb frog, Cusuco spike thumb frog, and mossy red-eyed tree frog). Water for the animals is treated with reverse osmosis in order to make it safe for amphibians. All water and other waste leaving the pods is cleaned to prevent any contamination to animals of the Lancetilla Botanical Gardens. Live food items (flies, crickets, and other insects) are bred in-house in order to provide ideal nutrition and prevent non-native insect concerns. The individual habitats inside the pods are species specific, catering to the needs of each of the three animals with current, temperature, and substrate. In short…. I would like to live in the pods!

The rescue center facilities are in excellent condition and are ready for animals. As we prepare to bring animals in for head-starting, the rescue team is searching for the perfect local Honduran in order to care for amphibians full time. This individual will train at the Detroit Zoo’s National Amphibian Conservation Center in the care of amphibians. Once head-starting has begun, we will build outreach programs involving local Honduran schools and local researchers. Ultimately, the goal is for the rescue center to be entirely Honduran-run. Our Honduran partners are enthusiastic and we are excited to see their involvement grow.

Honduras is a country that does not receive much assistance in conservation, and the Detroit Zoological Society is proud to be a part of this groundbreaking project saving amphibians in this beautiful nation. We will definitely share more updates as we begin head-starting animals soon!

– Dr. Ruth Marcec is the director of amphibians for the Detroit Zoological Society and oversees the National Amphibian Conservation Center at the Detroit Zoo.

Notes from the Field: Saving Tree Frogs in Honduras – Part II

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As part of the Detroit Zoological Society’s (DZS’s) continuing efforts to save amphibians from extinction, we recently introduced readers of the DZS Blog to three species of endangered frogs that live in the Cusuco National Park in Honduras. These species are at high risk of extinction and we aim to help their populations. If you haven’t had a chance to read my previous blog entry, click here.

Amphibians are facing an extinction crisis, and one of the most tangible causes is disease. In my previous entry, I mentioned the chytrid fungus and how it is causing amphibian deaths globally. Many theories exist as to where chytrid originated and how it spread, but regardless of the answer to those questions, the fungus has now been found in almost every environment all over the world. Removing the fungus from the environment does not seem to be a possibility since it has become so widespread, as this could potentially damage the ecosystem and other lifeforms in it. So, the question becomes: How do we save the frogs?

Frogs are most susceptible to chytrid when they are young – tadpoles and juveniles have the highest death tolls as a result of this fungus. The tadpoles of the three target species we are focusing on in Honduras (the exquisite spike thumb frog, the Cusuco spike thumb frog, and the mossy red-eyed tree frog) are especially sensitive to chytrid. The tadpoles have very strong mouths, which they need to be able to use as a “suction” to hold onto rocks in rapid waters of rivers. Doing so is vital to their survival, and as such, chytrid is particularly damaging to these animals. Chytrid is attracted to keratinized skin cells, which are found in the mouths of tadpoles. The resulting infection causes them to lose function of their mouths, which can cause them to have trouble eating and difficulty with “suction” onto rocks. The loss of this suction can cause tadpoles to be swept downstream into unsafe waters.

Photo by Jon Kolby

This is all devastating; however, we came up with an idea for how we might be able to help.

What if we could remove tadpoles from the stresses of the environment during the stage in which they are most sensitive to chytrid? Using our skills and expertise in caring for amphibians, we might be able to nurture them in a pristine environment. The lack of stress would potentially prevent symptoms of the fungus from appearing. Alternatively, if symptoms did arise, caretakers could treat the fungus to assure survival. Then, when the animals have reached adulthood, they could be returned to the wild.

This method of rearing animals through sensitive stages is called “head-starting”, and is a method frequently used with amphibians. It has shown to be beneficial in instances just like this, where adults survive better than offspring. Long term, the hope is that the increased population from the head-started animals would be enough to booster the population into stability.

Photo by Jon Kolby

The Detroit Zoological Society and the Honduras Amphibian Rescue and Conservation Center are ready to start head-starting animals. Facilities have been built in Honduras in order to provide tadpoles a safe place to live and grow until they are ready for release. In an upcoming entry on the DZS Blog, we will go inside the rescue center’s facilities and show you what the tadpole rearing experience will look like!

– Dr. Ruth Marcec is the director of amphibians for the Detroit Zoological Society and oversees the National Amphibian Conservation Center at the Detroit Zoo.

Notes from the Field: Saving Tree Frogs in Honduras – Part I

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The Detroit Zoological Society is collaborating with the Honduras Amphibian Rescue and Conservation Center to preserve three species of endangered frogs from the cloud forests of the Cusuco National Park in Honduras. The rescue center is an in-country facility that aims to re-populate these three endangered species through programs such as head starting, captive breeding, habitat protection and community outreach.

Amphibians all over the world are suffering extinctions, and the species in the Cusuco National Park are at a particularly high risk. There is a fungal disease, called chytrid, that is causing drastic population declines amphibians globally. Chytrid fungus has been particularly devastating to amphibians that live at higher elevations in the tropics, because the fungus thrives in lower temperatures and high humidity. This fungus likes to live in keratinized skin cells, and because amphibians rely on their skin to breath and exchange nutrients, it can be very deadly. The Cusuco National Park is a protected area that is home to many rare amphibian species who, unfortunately, are subjected to this fungal disease. The Detroit Zoological Society is working with the rescue center to investigate how to help save these animals from extinction.

While there are many species of amphibians in Honduras that need help, we decided to start our mission with three “target species” of critically endangered tree frogs. Once we find the best way to help these species, we can apply what we learned to others locally. These three target species are the exquisite spike thumbed frog (Plectrohyla exquisita), the Cusuco spike thumbed frog (Plectrohyla dasypus), and the mossy red eyed frog (Duellmanohyla soralia). All three of these frogs have been found to have the highest infection rates with chytrid fungus in the Cusuco National Park and are at high risk of extinction. This spring, we conducted fieldwork in Honduras, visiting the natural habitat of the three target species to help gain a better understanding of their behavior. We were able to observe some never-before-seen behaviors of these interesting animals that will help us increase our chances of protecting them.

Before I get too carried away, let me introduce you to the three species!

Photo by Jon Kolby

Exquisite spike thumb frogs are the largest tree frog in the Cusuco National Park at approximately 4 inches long. These frogs are found exclusively in the small protected area of the park, and are listed as Critically Endangered by IUCN. The frogs get their name from the large boney projection that males have on the sides of their thumbs, called a prepollex. It is theorized this special appendage is used for male combat, but combat has not yet been observed in this species. Additionally, the call of these frogs has never been heard (or at least recognized) by human ears.

Photo by Jon Kolby

Cusuco spike thumb frogs also only live in the small protected region of the Cusuco National Park; they are also listed as Critically Endangered. This species also gets its name from a prepollex in the males. Cusuco spike thumb frogs are medium-sized, growing to about 2 inches. Their call is a “quack” noise, similar to a duck. When threatened, these frogs have been observed jumping into leaf litter and burying themselves, which is unusual behavior for tree frogs.

Photo by Jon Kolby

Mossy red-eyed tree frogs are the smallest of the three target species, at a maximum of about 1.5 inches, and are also listed as Critically Endangered. As tadpoles, they have a striking green sheen to them, and they perform an odd behavior. They will flip over on their backs to swim – bellies up – in the rapids of waterfalls. Mossy red-eyed tree frogs can be heard calling with a series of chirps and clicks.

The Detroit Zoological Society and the Honduras Amphibian Rescue and Conservation Center have a plan to save these amazing animals. I’ll be sharing more details about this plan in upcoming blog entries, so stay tuned!

– Dr. Ruth Marcec is the director of amphibians for the Detroit Zoological Society and oversees the National Amphibian Conservation Center at the Detroit Zoo.

Wildlife Conservation: Breeding Eastern Tiger Salamanders

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Amphibian breeding season is here! That means it’s time to start helping amphibians get in the mood for love and romance.

The Institution of Museum and Library Sciences (IMLS) recently awarded a $500,000 National Leadership Grant for the purpose of improving reproduction within captive assurance colonies of imperiled salamanders. The Detroit Zoological Society is one of the primary partners on this grant. My doctoral research focused on salamanders, their reproductive physiology and techniques to help them breed, and that very research was the basis for the recent IMLS grant proposal.

Other partners on the grant include Mississippi State University and Omaha’s Henry Doorly Zoo and Aquarium. Now that the grant was awarded, techniques must be taught to the other partners so we can all work together in salamander conservation efforts. I recently visited Mississippi State University in order to train the other principal investigators and the graduate students involved on this salamander grant in principles of natural salamander reproduction and performing assisted reproduction techniques with salamanders.

The training session involved eastern tiger salamanders (Ambystoma tigrinum), which are regionally threatened and endangered in various areas of North America. Like many species of salamanders, the tiger salamander is very difficult to breed in human care. Similar to other species in the “mole salamander” family, tiger salamanders respond to changes in air pressure and temperature when seasonal rain storms occur. These storms are what cue breeding behavior and are very difficult to replicate in human care. Without the ability to provide the appropriate “mood”, tiger salamanders in human care will not often feel romantically inclined. Natural breeding is always the first goal when breeding animals for conservation, but sometimes this is extremely challenging. In these cases, we use alternative techniques while we perfect replicating the natural breeding environment.

In vitro fertilization is a technique used to assist salamanders and other amphibians in breeding. Most salamander species undergo internal fertilization, in which the female picks up a capsule of male sperm, called a spermatophore, which the male has deposited into the environment. The female holds the sperm in an internal pouch that she later empties over her eggs as the eggs are laid. In in vitro fertilization of salamanders, sperm is collected from males by giving them a massage. Eggs are then collected from the female into a small dish where sperm is placed on top of the eggs. Just add water, and presto, you have salamander babies. Of course, it is never just that easy, but the concept is straightforward.

I trained the other primary investigators and students in other techniques as well, including cryopreservation – or freezing and long-term storage – of salamander sperm and sperm quality assessment. The training was very successful, with nearly 100 tiger salamander babies produced. Now the trainees can go on to teach more amphibian conservationists, and we can save more species by assisting with breeding!

– Dr. Ruth Marcec is the director of the National Amphibian Conservation Center at the Detroit Zoo.