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

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 I

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

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.

Wildlife Conservation: Lending Amphibian “Sexpertise” to Other Accredited Zoos

I recently participated in a partnership to save an incredible species of amphibian: the blue spotted salamander (Ambystoma laterale). This animal is regionally endangered in parts of the Midwest and about 10 years ago, the Iowa Department of Natural Resources started a partnership with Omaha’s Henry Doorly Zoo. They wanted to breed these salamanders for release at locations where they once thrived but have now disappeared. Having had little success in doing so thus far, the organizations reached out and requested my amphibian “sexpertise”. I travelled to Omaha to deploy some of my special reproductive techniques with the blue spotted salamander assurance colony living there.

It comes as no surprise that these salamanders proved very difficult to breed. Blue spotted salamanders need an extraordinary amount of “salamander romance” in order to breed naturally. These animals undergo winter brumation (a hibernation-like state). In the spring, they will emerge from brumation when it begins to rain and when the temperature rises in order to migrate to breeding ponds. Their migrations can be over several miles, and most salamanders return to the same pond every breeding season. In captive breeding situations, we attempt to recreate the cues that the salamanders take from the wild in order to get them “in the mood” for breeding. We cool them down and offer them the opportunity to undergo brumation. We place them in rain chambers so they can experience an “indoor storm”. We also attempt to create a naturalistic pond for them to breed in with proper vegetation and leaf litter.

Sometimes, despite our best efforts, the natural cues we provide artificially are not enough to trigger breeding. Many amphibians are having difficulty breeding in the wild, due to changes in the climate and their habitat. Given that the natural environment is not currently providing ideal cues for breeding, it is especially difficult to perfectly recreate environmental breeding cues for animals in human care. When captive animals do not breed in response to the cues we provide, we often use hormone treatments to give them a little boost. These hormone protocols are meant to trigger breeding behaviors as well as the release of sperm and eggs. In the best-case scenario, the application of hormones will result in the animals breeding on their own. In the worst-case scenario, the animals will not breed on their own after the application of hormones and an in vitro fertilization (an artificial fertilization of the eggs with the sperm in a petri dish) will take place.

We used a combination of natural cues and hormones to stimulate breeding in the blue spotted salamanders. The amount of hormones I gave to the female blue spotted salamanders was determined by how developed their eggs looked on ultrasound. While giving the animals hormones resulted in many interesting behaviors, the salamanders did not breed on their own. After giving them time to breed on their own without success, I attempted in vitro fertilization. In order to perform this technique, I needed to collect eggs from the females and sperm from the males. There was one big problem with attempting this technique – the male blue spotted salamanders were not producing sperm. Fortunately, I had a back-up plan!

The blue spotted salamander is no ordinary salamander. In the wild, many female blue spotted salamanders breed through a special adaptation called kleptogenesis, meaning that they steal sperm. You read that correctly: sperm thieves. Most salamanders undergo internal fertilization. This occurs when the male deposits the sperm in a ball – called a spermatophore – into the environment. Through a courtship dance, the spermatophore is collected by the female. These special female blue spotted salamanders will find and collect spermatophores deposited by males from other, closely related, species (including Jefferson’s salamanders, tiger salamanders, and small-mouth salamanders). This is the part where it becomes complicated. Rather than using the sperm to fertilize their eggs and have hybrid offspring, an enzyme in the sperm activates the egg which begins to grow into an embryo. The rest of the sperm is discarded, and the offspring which develop are essentially clones of the mother. Knowing that blue spotted salamander females are often sperm thieves, I had the Omaha Zoo’s resident male tiger salamanders (Ambystoma tigrinum) on standby. I was able to collect sperm from the tiger salamanders in order to use in the in vitro fertilization of the blue spotted salamander eggs.

Unfortunately, the eggs did not fertilize with the tiger salamander sperm. While we did not achieve offspring, we learned what we need to do differently next time around. We certainly will not give up on these amazing animals. We will try to breed the blue spotted salamanders again later this year, using slightly different techniques.

Thank you to our partners at Omaha’s Henry Doorly Zoo and the Iowa DNR.

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

Amphibian Conservation: Fired Up About Salamanders

From the days of old, salamanders have captured the imagination of humankind. Long ago, when people would place logs in a fire, brightly colored salamanders would often come scurrying away from the flames. Of course, this was because the salamander’s hiding place was burning, but people in medieval times assumed that the salamander was a creature that came from the flames. People supposed that salamanders were imbued with mystical properties and they became the alchemic symbol for the element of fire.

Despite this long-time association with flame, salamanders are unlikely to be found near a toasty fire. There are more than 600 species of salamanders known, and most of them prefer cool, damp places to live. These critters are often found in a variety of places, including under logs, in rock crevices, high in trees, or living in cool bodies of water, ranging from puddles to fast moving rivers.

Unlike lizards, which look similar to salamanders, salamanders have moist, scale-less skin. Salamanders use their unique skin to intake water, absorb nutrients, and even breathe.

Most species of salamanders are born with a larval stage, similar to the tadpole stage of a frog. The larval salamander is aquatic, has external gills, and has no limbs upon hatching. As the larva grows, it develops legs. Many species of salamanders undergo metamorphosis, losing their gills and undergoing other small body changes as they transfer from water to land.

Salamanders are critical indicators of environmental health, and are key players in the health of ecosystems. These animals serve as sentinels for anything that is changing in the environment. Such changes include pollution, disease or climate change. Almost 50 percent of salamander species are threatened with extinction, according to the International Union for Conservation of Nature (IUCN). The Detroit Zoological Society is working toward preventing these wonderful creatures from going extinct through breeding and release programs, habitat restoration and population surveys.

We invite you to celebrate these remarkable creatures with us during a special event called Salamander Saturday on May 6. National Amphibian Conservation Center staff and volunteers will provide informative zookeeper talks, storytelling, games and crafts. This event is free with Detroit Zoo admission. Sneak a peek at salamanders and learn all about these unique animals during this fun family event.

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

Take Part in the Detroit Zoo’s FrogWatch USA Conservation Program

By late winter and early spring, many people are looking forward to warmer weather, longer days and the fun the coming months will bring. I also look forward to this time of year, not only because of the warmer temperatures, but also the rains of spring and the wonderful creatures that will wake from their long, winter hibernation.

I am, of course, referring to frogs and toads! Here in southeast Michigan, most amphibians depend on rain to help them get “in the mood” for the breeding season. Soon after moving from deep winter to early spring, frogs and toads will make their presence known in full chorus, emitting sounds that also help to protect them from predators.

In 2011, the Detroit Zoological Society began hosting a local FrogWatch USA chapter to collect data on the frogs and toads living in the tri-county area. FrogWatch USA is an amphibian conservation and citizen science program managed by the Association of Zoos & Aquariums (AZA). Citizen science programs teach volunteers to collect data using the same protocol and methods, so all data can be can be counted as part of a scientific research project. One scientist working alone could never collect the amount of information a group of citizen scientists can.

There are currently 144 chapters of FrogWatch USA held throughout the U.S. and data has been collected since 1998. Training classes are primarily taught at AZA institutions, but may also be offered at nature centers, museums or colleges. The project focuses on frogs and toads – both amphibians and some of the most sensitive creatures on the planet. They are also indicators of a wetland’s health – if something toxic or lethal invades the wetlands where they live, they will be the first species to become sick, die or disappear.

All monitoring is done outdoors, so it gives volunteers the opportunity to spend time outside in the wetlands and natural areas of their community. Monitoring helps provide important information from each site, such as the diversity, population size and health of the particular frog or toad species that is present; whether or not there are rare or invasive species in the area, and what the overall health of the wetland is. Knowing what species are present at a sight can even help improve the management and protection of a wetland and all species living there.

Four-hour volunteer training sessions are offered at the Detroit Zoo just prior to the frog and toad breeding season, which is just about to begin. Each session includes:

  • An overview of what amphibians are and why they are valuable to the environment
  • Descriptions and key characteristics of the types of wetlands found in Michigan where frogs and toads may be found
  • Information about the locations of monitoring sites and the ability for participants to register
  • An explanation of the monitoring protocols that volunteers will use in the field
  • Information about how to identify the 14 native Michigan frog and toad species by their breeding calls (Identifying a species by its breeding call is by far the best part of the process. Even though it may be a bit challenging at first, surveying by ear is easy on both the surveyor and the frogs and toads, and it can be a lot of fun.)

Once training is complete, a volunteer’s first priority is to find and register for a site to monitor.  While most volunteers come in already knowing where they want to survey, some do not and we help them find locations in the area. Some sites are in backyards where frogs have been heard for years and others are in wetlands seen from afar and believed to be full of amphibians. Once the nighttime temperature is above 35 degrees Fahrenheit, volunteers can monitor at their sites throughout the FrogWatch season, typically February to August, at most twice a week.

Monitoring must take place at least 30 minutes after sunset. Darkness not only brings more amphibians to life but it also puts the noisy daytime animals, such as birds, to sleep. Whether volunteers have hiked into a wetland via a trail full of crunching leaves or are sitting on their back porch as quiet as can be, everyone must allow at least two minutes for the creatures around them to acclimate to their presence. Immediately after two minutes have passed, volunteers will listen for exactly three minutes to identify each species they hear. At the end of three minutes, the monitoring session is complete.

Monitoring the same site year after year is a great way to keep track of the health of frogs, toads and wetlands. If we lose amphibians, we lose a very precious resource and some really amazing creatures.

I hope you can attend one of the FrogWatch USA training sessions coming up at the end of this month, in February and in March. It is a fun and easy amphibian conservation program that anyone can take part in! Click here for more information: https://detroitzoo.org/press-release/leap-conservation-joining-frogwatch/

– Rebecca Johnson is the associate curator of amphibians for the Detroit Zoological Society and works in the National Amphibian Conservation Center.

Veterinary Care: Cutting-edge Technologies in Amphibian Conservation

Last week I was able to attend a very exciting advanced conservation training course to learn assisted reproductive technologies (ART) in amphibians. The meeting was hosted by the Omaha Zoo, and was offered by the Amphibian Taxon Advisory Group (ATAG). I was one of a small group of zoo and conservation scientists invited to learn cutting-edge technologies that have the potential to have a tremendous impact on the conservation of endangered amphibians.

At the Detroit Zoo, we’ve been using hormone treatments to help with reproduction in Wyoming toads and Puerto Rican crested toads for more than 10 years. Recently, Dr. Andy Kouba from Mississippi State University has been able to modify these treatments for use in other species, and to develop techniques for collecting eggs and sperm for in-vitro fertilization (IVF). Two years ago, I traveled to his laboratory to learn these techniques for dusky gopher frogs, and within a few months we became the third zoo to reproduce amphibians via IVF.

The goal of the ART course was to provide in-depth information concerning reproduction in frogs, toads and salamanders. This course was taught by Dr. Kouba and two of his colleagues, and represented the first time that husbandry staff, veterinarians and conservation researchers have come together to discuss assisted reproductive technologies. The attendees brought together a wealth of knowledge, and experiences working with hellbender salamanders, Chinese giant salamanders, Oregon-spotted frogs and others. We talked about the impacts of hibernation, temperature, humidity and social cues on reproduction, and the challenges we have encountered in the past. We learned about the historic use of hormones in amphibians, and how this information can be adapted to new species. We also learned how to gently collect spermic urine from male amphibians, and to stimulate females to lay eggs. We learned how to examine developing tadpoles under a microscope, and cyroperservation techniques for sperm. We also learned how to use ultrasound to monitor egg development in females. During the week, we put these skills to practice, and were able to produce fertilized eggs from Puerto Rican crested toads, American toads, tiger salamanders and Asian black spiny toads (for the first time!).

At the Detroit Zoo, we have number of very endangered species of amphibians, including some that have never or only rarely reproduced outside of the wild. Over the next few months, we will be able to start using cryopreservation to save genetics from these critically endangered species. The skills learned at the ART course will allow us to continue to be leaders in amphibian conservation, and to hopefully successfully breed Japanese giant salamanders, giant waxy tree frogs, and other endangered species at the National Amphibian Conservation Center.

– Dr. Ann Duncan is the director of animal health for the Detroit Zoological Society and oversees the Ruth Roby Glancy Animal Health Complex.