frogs, bison, overkill, and extinction

I left home and drove through the Flint Hills of Kansas on my way to the airport to catch my flight to Panama City. It was a frigid morning, and the tallgrass prairie was starkly beautiful. The sun was rising and the light gave a slight orange/pink hue the wind-burnished patches of snow clinging to the northern slopes of the rolling hills. The old big bluestem grass stalks were buffeted by the winds. This was the kind of morning that made me glad not to be living as the indigenous people did during this inhospitable time of year. This was the type of morning where the Native Americans, and later the European settlers that invaded the area, would have stayed inside till the sun took the bite off the bitter windy cold. The icy landscape was stark contrast to the tropical mountain rainforest that I was headed to.

As I drove through these prairie hills, my mind started worrying on the idea of extinction, ecological loss, and the modern world. Only a fiftieth of tallgrass prairie remains in the North America, much of it in the Flint Hills of Kansas and Oklahoma. As I drove to the east, and out of the Flint Hills, the land was taken over by croplands. In a few minutes I was witnessing the transition that altered the vast North American prairies when Europeans broke the sod in the 1800’s. Much of the Midwest’s productive cropland was once a sea of grass.
The Flint Hills only retain grassland by lucky accident. The shallow rocky soils make them better for raising cattle than cropland. The ranchers burn yearly to keep the trees at bay and the cattle simulate the herds of grazing bison that historically roamed the prairie. Where fire has been suppressed, the trees invade. Prairie is becoming more imperiled in the Flint Hills because of the human influence changing the natural fire frequency that occurred. This effect is particularly pronounced in areas with higher population densities where people have built their houses out in the country… an effect that we will see has parallels in Panama.

Bison (popularly referred to as buffalo) are a “keystone” species that shaped prairie ecology, and their loss from the prairies could be considered analogous to the loss of the frogs in the jungle streams. The researchers I work with in Kansas have found that bison are key in maintaining the very high diversity of plants found in tallgrass prairies. There are literally hundreds of species of plants in a healthy prairie. The bison stimulate this productivity by grazing the main grasses that would outcompete the forbs (leafy plants). They also leave fertilizer packets (dung and urine) that stimulate plants that require higher nitrogen conditions. Bison disturb areas with their hoof-prints, their wallows where they take dust baths, and the trails they cut through areas as the herd moves across the landscape. The tadpoles, in the streams, do analogous things. They graze selectively, they disturb some areas more than others, and they excrete and enrich areas with their fecal pellets.

As impressive as the accounts were of massive bison herds on the prairies, there were once much more impressive herds of large mammals that roamed the prairies. Humans were responsible for even move extensive alteration of the natural ecosystems of North America. Before the end of the last ice-age approximately 10,000 years ago, the plains and forests of North America once were home to an astounding diversity of large animals. When tribes of hunter-gatherers that ultimately became the Indians of North America crossed the land bridge and spread across North America, they found a land of plenty.
The diversity of North America rivaled that of the plains of Africa. Camels, horses, huge bison, ground sloths, saber-tooth cats, giant beavers, giant armadillos, mammoths and mastodons were here. These large animals had no evolutionary experience with humans, and within a few human generations they were hunted to extinction.

Similar extinctions of large animals occurred in Central and South America as people swept in from Siberia, through North America and to the south. The America’s are not unique. In Australia, New Zealand, Madagascar and many other smaller islands the archeological and fossil record is unequivocal. When humans arrive, the large animals disappear. Marsupials disappeared from Australia, giant flightless birds were slaughtered in New Zealand, giant birds and lemurs were hunted to extinction in Madagascar. People are consistent in their heavy-handed environmental presence. We are the most successful species because we shape each environment we enter to meet our own needs.

The ecological effects of the extinction of the large herbivorous mammals and their predators are not well understood, but they were probably significant. Some species of plants remain that have large fruits with seeds that are only dispersed successfully over any distance when they pass thought the guts of large animals. The animals ingest the large fruits and carry the seeds within them substantially away before depositing the seeds with a packet of fertilizer. But, animals large enough to pull down tree limbs and graze the crowns of trees no longer range across the landscape.

One difference between historic extinctions and the ongoing disappearance of the frogs of high-elevation Central American habitats is that we can study the ecosystem effects of the removal of an entire taxonomic group in Panama. Perhaps these studies will help us understand the unintended ways that humanity is influencing global ecology and aid in mitigating or minimizing future impacts. At least it could help document some of the negative consequences that could come about from extinctions or extirpations of species.

Getting the team back to Panama

Now, I was starting to see the direct evidence of the die off as it came through, provided by my colleagues on the ground as the disease wave passed. Scott sent photos of dying frogs around to the group. Alex had videos of dying frogs. The frogs look duller skinned and are lethargic. Their skin is sloughing off of their bodies. The frogs that are not quite dead are not able to right themselves when turned on their backs.

During the die off, the Scott and the other researchers that were there collected as many dead frogs as they could find. He sent a picture of gallon pickle jars full of preserved dead frogs. The frogs in the jars will be identified, but not all species are collected before they decompose.

The species apparently contract the disease when they contact other sick frogs or come in contact with the stream. Some of the species in the trees might avoid contact for some time, but eventually, they will become infected. Thus, the die off is fairly concentrated, but some obscure species might hold on for a few weeks or months after the main epidemic sweeps through the jungle. Some of the species of frogs will probably never be known to science and will be lost in nature before they are described. Watching these videos and seeing these pictures made me even more apprehensive about returning to El Valle.

This group was to be slightly different from the last. Matt, Bob, Alex, Piet, and Cathy all were coming. In addition Karen Lips was going to be able to participate (if her luggage made it this time). Emma Rosi-Marshall from Loyola University is a professor who had been working with Bob on the effects of flooding and other influences of the dams in Grand Canyon. She had also been involved with the nitrogen tracer work our groups were doing in the U.S. She was interested in advanced techniques to separate the nitrogen label from the sediments.
Emma’s recent project with Matt on the effects of genetically engineered corn on stream invertebrates had generated considerable interest in the press. The paper she wrote for the Proceedings of the National Academy of Sciences with her colleagues documented how the toxin engineered in corn to kill the corn borer can enter agricultural streams where it could harm caddis fly larvae. Caddis larvae are important members of the stream community. The agribusiness community was extremely unhappy with her results, and she was attacked for them.

The tactic is familiar. Rachael Carson wrote the famous book, Silent Spring, that brought to light the problems with pesticide use. She was attached personally after critics could not rebut her scientific reporting. Tommy Edmondson, a professor at University of Washington, documented the decline of Lake Washington from sewage pollution generated by cities in the Seattle area. He carefully presented the scientific facts and left the politics out of his public statements. His critics could not assail the science, so resorted to attacks on his character. Emma had experienced a similar backlash.

Emma had strong expertise on stream food webs, and was a welcome addition to the project. Emma is a very boisterous and enthusiastic woman who loves to talk and argue science. She is an original thinker, and driven to do the best research that can be done. She is a tireless worker who is difficult to keep up with. I can see how she complements Bob, because he is the typical absent minded academic, and Emma is organized and gets down to business. Now we had the benefit of this dynamic duo.

Matt’s new graduate student Amanda, was also participating; she and Piet were already down in Panama working and she would stay and do the long term work after the rest of us returned to the US. As I would find out, Amanda was quite the character and had fantastic experience doing field work in streams.

A fantastic array of frogs

What is it about frogs and popular culture? They seem to be a very fashionable small animal. Unlike insects or snakes, almost everybody likes frogs. It could be that there is not a natural aversion toward frogs because they will generally not bother you if you don’t bother them. Human’s evolutionary history does not include natural selection for avoidance of frogs like it does for avoidance of snakes. A frog jumping underfoot seen out of the corner of the eye catches attention. A snake slithering through the grass underfoot caught with the corner of the eye causes me to jump. Some princesses are even willing to kiss frogs (not a snake or a rat, but a frog, yes).

Some species of frogs have extremely potent toxin in their skins (the legendary poison dart frogs), but it is only dangerous if you eat or touch them. So, while we have a long evolutionary history of avoiding more aggressive toxic snakes and spiders, there is no similar danger from frogs through human history. Frogs have big eyes, and seem mostly un-threatening. Better yet, there are fantastically colored and shaped frogs that are fascinating to anybody who appreciates the natural world. Frog enthusiasts may not be as common as bird lovers, but there are plenty of them out there.

This attraction to frogs makes it all the more ironic that they are disappearing from under our very noses. If all the ticks and chiggers were disappearing, I would have difficulty working up as much emotion over it.

I asked Scott Connelly to send me pictures of frogs from the El Valle forests, and those that were dying from the disease in Panama. I had not seen many of these frogs when I was in Panama before because some are quite rare or active in other seasons. Still, I was curious about what was being lost. Scott is also deeply affected by the extinctions. He takes any chance he can to give public lectures using his extensive collection of photographs. He is surprised by how few people know about these frog extinctions, including other biologists. My experience parallels his on this score.

What Scott finds most amazing about these frogs is the astonishing diversity of form and function. For example reproductive strategies vary widely among species. Some frogs simply lay their eggs and leave, others care for the young. Male poison dart frogs of some species keep the eggs they fertilize on leaves wet by bringing water from nearby pools or tree holes. When the eggs hatch these males then transport the tadpoles on their backs to a suitable small pool and release them there to mature. Some frog species live in trees, others only on the ground. They all have different diets or other variations in their way of life.

Bufo coniferous is the green climbing toad found in El Valle. The adult looks like a typical warty (but attractive) greenish toad, but as a juvenile, it has brilliant red dots on its “warts”. Another member of the same genus, Bufo haematiticus is the blackbelly toad. This toad is light tan or grey on top and dark brown on bottom, with an attractive mottling of dark and light brown on the inside of its legs. It is thought to be abundant and not in much threat of extinction, but the chytrid was recently found to infect this species in high altitude areas.

Then there is Cochranella euknemos, the San Jose chochran frog. It is a pleasing, small, light green frog with all black eyes and a body covered with tiny neon yellow dots. This frog lives near streams in the vegetation and its populations are declining according to the Global Amphibian Assessment.

And there are more- Eleutherodactylus musous is a small, green, splotched frog that has protrusions of green and brown all over its body, and looks more like a clump of moss than a frog. Up to now this adaptation has aided the species survival because the camouflage helps it escape predation. This adaptation will do it no good against the chytrid. This frog only lives in the mountains of Panama and will probably go extinct from the disease. One cousin of this frog, Eleutherodactylus bufoniformis, the rusty robber frog, is an inch long round bodied animal that lies very flat to the ground. It has a splotchy skin that makes it look like a rock in the bottom of the stream or in the forest where it sits completely camouflaged.

There are even more colorful frogs. Rana warszewitchii, the brilliant forest frog, lives close to streams in forested areas and its tadpoles develop in the streams. It has a short trilled soft call. This forest frog is slender and brown with bright green splotches on its back, a yellow stripe in its groin and two bright yellow spots on the backs of its upper hind legs. One side of the bottom of each back leg is brown with black spots and the other side is pinkish red. It truly is a brilliant forest frog.

The coronated tree frog, Anotheca spinosa has striking strips of silver and pearl on its sides. It looks like a cross between a grey zebra and a triceratops dinosaur. It is three or four inches long, with bone spines on its neck; supposedly these spines are used to fight other male frogs to defend breeding holes high in the trees. After breeding, the female continues to return to the hole and lay additional eggs. The earlier batch of larvae consumes the eggs that the female lays. Presumably the purpose of the later eggs is to feed the earlier tadpoles.

Hemiphractus fasciatus is a 3 inch, buff, tan-colored, horned tree frog, with a flat five-pointed head. It has irregular splotchy bumps over its body. This frog looks more like a leaf than an animal. Initially scientists could not keep it alive in culture until they figured out it only eats other frogs. The habit of eating other frogs explains why it is only found in areas with high densities of other frogs. This frog does not need standing water to breed, although it is found in extremely humid forests, because the eggs are carried on the back of the female.

The jungle around Rio Maria is also the habitat of Dendrobates auratus, the green and black poison dart frog. These frogs have active males that sing a trilling note while perched on twigs or rocks above the ground. If multiple females are attracted they wrestle each other to mate with the male.

This is a personal favorite because we have some as family pets in aquaria at home and at work. We purchased frogs that were bred by a co-worker in the US, but unwittingly contributed to pet frog collection just by buying them. It is possible that much of the spread of the chytrid disease is caused by the pet trade in frogs. Furthermore, some species of frogs have been collected toward extinction for the pet and zoo trade. While this may be a way to preserve species, rarely are adequate records kept of collection location and breeding lines, so the genetics of the frogs is not preserved.

Dendrobates minutus, is the blue-bellied poison frog. This tiny frog is one of the few poison dart frogs that is not collected for the pet trade. It is a beautiful frog with alternating yellow and black stripes along its entire body. It has bright blue spots on its lower belly.

The above are only a few of the more than hundred species of frogs that could be found at El Valle. The main remaining species of frogs from this area now are in quarantined aquaria or have populations that also occur in lower, warmer elevation areas where the disease apparently is not fatal.

Lessons from extinctions

Frog extinctions from the chytrid fungus are particularly troublesome because there is literally nothing that be done to stop them. Helplessness is a bad feeling, particularly for a scientist. Generally, a scientist thinks that we can control much of our world through knowledge. Species out of the wild can be propagated. If there is no way for them to survive in the wild, then they are doomed to be caged creatures. Somehow, animals in zoos do not seem the same to me.

I have mixed feelings about captive animals. A recent visit I made to an aquarium with extensive coral reef fish exhibits illustrates the paradox. I was thinking how much more I enjoyed seeing fish in the wild by scuba diving or snorkeling. Then it occurred to me that the resources used for me to travel to a coral reef were tremendous, and that the environmental damage would be immense if each of the visitors to the aquarium traveled to see all these fishes in their native habitat. The educational value of having these fish available for public viewing is high. Still, an animal or plant that only exists in zoos or botanical gardens seems more like a collector’s item than anything relevant to the natural world. For many of the frog species that are threatened by the chytrid disease, life in captivity is the only way the species will avoid complete extinction.

The El Valle Amphibian Rescue Center is attempting to save 1000 animals from 40 species. They are concentrating on 15 priority species now, and building capacity to save more. The center started in the same hotel (Campsetre) where we stayed. Heidi and Edguardo felt they had to do something, and rented rooms to set up aquaria in them. They collected frogs from areas where the disease had not invaded. They experimented with ways to kept the caged frogs from getting the disease, including washing with Clorox solutions, and heavy use of disinfectants of any materials that entered the area from outsize.

Since then, the El Nispero Zoo at El Valle de Antón and a number of US zoos (notably the Houston zoo and the Atlanta zoo) and conservation agencies have supported building a center to house the animals. The Houston Zoo manages contributions to frog conservation efforts.

In captivity, each frog must be kept quarantined from any materials that might bring the disease into their cages and as far as is known can never be released into the wild. To make the job even more difficult, it is not possible to maintain just a few frogs of each species because a minimum amount of genetic diversity is necessary to save a species. So, many individuals of each species must be housed. Furthermore, little is known about the mating and food requirements for many of the species, so research into these details is required.

Edgardo and Heidi were the first local collaborators (they became closer collaborators when they got married) on the conservation project, and now several zoos have pitched in to consult and provide financial support. Many hours of work a day at the Rescue Center are required to keep the frogs healthy including collecting the insects that each species needs to survive. Before the Rescue Center gained the ability to culture them in the lab, these insects had to be collected from the wild.

The golden frogs like termites, and many of the other frogs like cicadas, crickets, or other insects. The very small frogs need fruit flies or other tiny insects. A huge amount of work goes into cleaning cages, treating sick frogs, quarantining frogs that have been collected, keeping track of where each frog came from and recording breeding activity. This last is important to avoid inbreeding on one hand and to avoid breeding what might be distinct sub-species from different areas on the other.

Videos were coming out on the frog extinctions and the rescue center. I saw interviews of Edgardo, and pictures of the facilities and Heidi and Edgardo collecting insects to feed the frogs. Soon I would be able to visit and see for myself.

What are the lessons from the Panamanian frog extinctions? One is that diseases can wipe out species before people can find a cure. We are part of the natural world and are not exempt from the generalization. A disease could arise that kills much or all of humanity. With rapid air travel, pandemic’s are more likely. With more contact with wild animals, the probability increases that an animal disease will jump to humans. When people live in close contact with livestock (particularly pigs and waterfowl) development of diseases is particularly likely. It is not impossible that one of these diseases will be lethal enough to sweep through humanity causing mass mortality. If it can happen to frogs, it might happen to us.

Another lesson from the frog extinctions is that we need to preserve the species we can because we will lose many anyway from the unintended consequences of human activity. As already stated, humans are causing massive extinctions. If some of those can be avoided, the unintended extinctions we cause will have less of an overall impact on the planet’s diversity.

A third lesson is that we should not introduce species to other habitats (such as the African Clawed Frog) because there is always the potential for unintended harm. Species introductions have caused damage to numerous species and are in important factor in endangerment of many species. The chitryd and the frogs may be the most extreme example of a single introduction leading to extinction of 10’s to 100’s of species, but the lesson is an important one. These lessons still seem to me to be small comfort in the face of the loss of hundreds of frog species from our planet.

Extinction

Dealing with extinction is difficult. All this was written because of my despair over the extinction of the frogs at El Valle, yet most of the writing dances around the actual issue. As the second trip approached, my dread at seeing Rio Maria without frogs increased. As a scientist the response is often to study the problem. Take for example cancer researchers that start a career because someone close to them is affected. Describing the science is like working harder to avoid thinking about the death of a loved one, it is ducking the fact that the frogs will never been seen in nature by people again.

The harsh reality, to me, is that most people do not care much about extinction of other species. In my introduction to biology course I ask a class of 80 students about this issue. I describe a local species that is going extinct, a small fish that is spiny and non-descript (the Topeka Shiner). I ask the class to raise their hand if they think the fish should be saved. Most of the class puts their hand up. Then I tell them to leave their hand up if saving the fish would be worth it if it required some personal expense to them. Over half the people in the class put their hand down.

A man has a business that removes gravel from some of the streams where Topeka Shiners still remain. He argues, in public hearings, that he is strongly against listing the species as endangered. He thinks that his right to make a living one particular way is greater than the right of that species to exist. He asks the crowded room, “what is more important, people or fish?” Many in the room nod in agreement with his arguments.

How willing are people to actually pay to save species? Is the life of a single person more important than the existence of an entire species? Is there a monetary value to a species? In a recent paper I wrote with my students we attempted to answer this question. The US requires recovery plans to be filed when species are listed as endangered. The average recovery cost was $732,000 per year. Some species cost much more to replace. Tens of millions of dollars have been spent on recovery of the black footed ferret. Total costs of recovery for the California Condor are in excess of $35 million over the last half century. Clearly some species are thought to be very valuable. However, putting a monetary value on species is dangerous. This sets up a situation where somebody could simply pay to be allowed to do an activity that threatens or causes extinction of a species.

Evolution is slow and mutation is random so that once a species has gone extinct, there is essentially zero probability it will ever return. The potential exception to this in the future is the technology for sequencing and synthesizing DNA is growing so rapidly that we might be able to completely recreate a species if the sequence of its entire genome is known. Scientists have already done this for bacteria. It is possible because bacteria have very simple genomes. It is not completely impossible that a complete genome could be synthesized and inserted into an egg of a similar species, allowing for recreation of an entire species. That is not possible for most species now, and probably for decades it will not be possible. For now, extinction is forever.

Current rates of extinction are thousands of times greater than rates of evolution of new species. It has taken 3.5 billion years for life to reach its current level of complexity. Over half the existing species are predicted to be gone in most of our lifetimes. Extinction is one of the major global environmental trends occurring during our lifetimes. We are living in unusual times where one species, us, can influence the entire planet. For the majority of species, we are a disaster. The reasons for this global trend and others are described more fully in my book, “Humanity’s Footprint”.

The fate of most species is to go extinct. As a scientist, I know that 99% of all species that ever existed on earth do not exist now. That fact does not make me feel better about humans destroying over half of all species on earth now.

In Douglas Adams’s science fiction novel “Hitchhiker’s Guide to the Galaxy” the planet Earth is destroyed to make way for an intergalactic bypass. The lead character escapes right before the destruction. He laments the loss of his entire planet but nobody from other planets seems to care much. The lack of interest by most people in extinction is similar; people who care about the plants and animals of the earth and are educated as to what is actually happening to them have a difficult time conveying the urgency of saving species. So many issues are deemed more important by most people, that preserving species ends up very low on the list.

I have dedicated my entire scientific career to studying ecology because I have always been fascinated by the natural world. I am a tree hugger. It is deeply saddening, both intellectually and emotionally, to know these losses are occurring.

It is curious to think about why people grieve. When a close loved one is lost, the feeling is physical. It is such intense emotion that it sweeps all else away. Yet, we know that people are dying all the time around the world, of hunger, disease, violence, and it has almost no emotional effect on most people. I think grief has deep evolutionary roots and leads to people protecting those who are related to them. That is why grief is so physical.

Little evolutionary advantage has existed for our species to protecting other species from extinction, just as there has been little evolutionary advantage to protect people we do not know well. Grief over loss of other species is intellectually driven emotion. Still, it is grief.

Utilitarian arguments for conserving diversity are good ones; species are the glue that holds ecosystems together. The next cure for cancer or some other disease may be found in an exotic organism or in the mold that grows in the dirt under your feet. Still, someday we could cure cancer some other way or find replacement species to keep ecosystems working in ways that provide benefits to humans. The ability to engineer ecological systems to perform functions for humanity does not, in my mind, make the extinctions acceptable.

The nitty gritty of science between trips

Now that Matt had secured funding for a second research trip, we had a lot of preparation to do. One of the most pressing issues was the need to analyze the results from the first experiment. This work required analysis of thousands of samples. Many hours of work to be done included the tedious processing, grinding and weighing of samples. Samples needed to be submitted for analysis and when the results were received, the data entered. Once the data were entered, we need to use the computer models I had created to calculate the results. Given the fact that I am not the world’s best modeler, the calculations were time consuming and required a good bit of data manipulation. The results of this complex modeling would tell us the flux rates of nitrogen through the ecosystem before the tadpoles were extinct.

We needed to finish this modeling and analysis in order to be able to conduct the second large experiment correctly. A romantic picture of field biologists who spend all their time tramping about exotic locales is not accurate for many of us. The reality is that we spend more hours behind computer screens than we do outdoors. The further along the career of an academic, the more time spent writing and administering. A horrible fate, being a department head or, God forbid, a dean, will suck the life out of a research career and eliminate research trips to the field for serious science.

Understanding how nitrogen moves through ecosystems provides one avenue to understanding the way the stream works to support the life that is found there, and how it influences the rivers and oceans downstream. Many scientists had originally considered streams as gutters that simply transport everything that enters them downstream. The research that I have been involved with disputes that view. The science demonstrates that it does matter what happens in the stream with respect to what moves downstream. This understanding has assumed great importance in the US because nitrogen transported out of the Mississippi River into the Gulf of Mexico is causing major environmental problems.

This nitrogen pollution that originates in runoff from cropland moves through the streams and fertilizes the waters of the Gulf. The fertilizer stimulates growth of the microscopic plants that live in the surface waters where there is light. These microscopic algae photosynthesize, grow, and eventually die and sink to deeper, darker waters. When they reach this area, the bacteria that live there decompose the sunken microscopic corpses, and in the process use up the oxygen that is dissolved in the water. Most animals absolutely require abundant dissolved oxygen to survive. Fishes can swim away from the low-oxygen water, but the invertebrates that serve as food to the fishes do not swim so well will die in the low oxygen waters. The pollution is thought to cause substantial economic damage.

Stream ecologists such as myself, Bob Hall and a group of others have determined that what happens in the small streams determines how much of the nitrogen makes it down into the Gulf of Mexico. We, therefore, need to account for how much nitrogen is held back in each stream. This is part of the reason that the methods we were using in Panama were developed.

The second reason is that the way the nitrogen is used in the system alters the ability of different animals to exist in the food webs found in the streams. Thus, nitrogen allows us to characterize properties of the stream relevant to conservation of stream organisms. This conservation has the goal of maintaining the biotic integrity of the stream. Again, the methods developed in general would be useful in the specific case of the Panama streams.

I wrote a computer model to analyze the data. Matt and Bob checked it, and Piet started running it on the data we had. He had lots of questions about the model, and some of them were related to errors he found. After hours of re-programming and discussions with Piet and Matt about how to use the model, Piet was finally able to get some results. A true picture of the importance of the tadpoles in the stream began emerging. Piet’s work with the modeling confirmed that the tadpoles were central to how the ecosystem of Rio Maria functioned. The open question was what would happen once the frogs were gone.

Now Matt had funding and the group’s preparations needed to begin for our next trip to El Valle and Rio Maria. Matt made the arrangements to fly, ordered materials, and Edgardo started working on local arrangements. Matt needed to find some new students to replace the ones who had graduated. The ball was rolling toward the next trip.

Hustling for funds to get back to Panama

The frog extinctions were starting to generate professional and public interest. Matt published results from his Panama studies done on the trips before ours in a very high profile, non-technical, ecological journal (the publicity magazine for the Ecological Society of America) and other more specialized papers from the group were coming out in the peer reviewed literature. Meanwhile Karen and Matt were receiving numerous invitations to speak at universities across the country where they would tell the story of the disappearing frogs of Panama and how the effects of these extinctions were reverberating through the ecosystems.

The research group also continued to make presentations at scientific meetings. Such meetings are great places to share scientific ideas and results with hundreds of others who are working on related issues. They provide the one time where scientific specialists are not the oddballs; nerd talk is the norm.

Matt and I attend a meeting of stream scientists every year and room together. Rooming with me may not be the most pleasant experience, but it is one way we could both use our grant money more efficiently. The day starts at 8:00 with scientific presentations till 5:00. Dinner is followed by a boisterous mixer in the meeting hall with hundreds of people discussing and arguing science. As with any large group of talking people, the volume increases to a roar. This makes for a long day, and after this Matt and I would lie in our beds and talk about science, our colleagues, and the state of the world.

Often our conversations would turn to the frogs in Panama. We kept trying to think of ways to strengthen the research. As in all science, every experiment leads to more experiments. In addition, the impending extinction of the frogs was something to worry about, even if we could do nothing to stop it. One thing we learned early on from rooming together at meetings, earplugs are essential.

One of the gaps in our research after our trip to Panama, and an issue Matt and the rest of us worried about for the next proposal, was measuring how much nitrogen is excreted by tadpoles. The tadpoles could be what we refer to as “ecosystem engineers”. Ecosystem engineers are organisms that have a disproportionately large effect on the environment and this effect cascades to the other species. Beavers that fill valleys with their dams, hippopotami grazing in fields and bringing nutrients they excrete back to the water, alligators digging water holes in the Everglades that last through the dry season, and bison eating dead grass and recycling the nutrients locked up in the grass available for the new growth of grass, are all examples of ecosystem engineers.

The tadpoles at El Valle were abundant and active enough that they could be major nutrient contributors to their streams. We were concerned with what happens when these potential ecosystem engineers in streams are lost. Some species of the tadpoles break down the organic material that falls into the stream in the form of leaves, and others clean the algae off the rocks. An interesting feedback is that the leaves become better to eat and the algae grow better when supplied with nitrogen. The tadpoles excrete nitrogen, and it actually stimulates production of their food. This excretion may also stimulate the microbes that serve as the food source for many of the tadpoles, insect larvae, shrimps, and fish in the stream. There were so many tadpoles in the streams that their effect had to be large, but how large was what we wanted to know.

Nitrogen excretion measurements were made while we were in the field with live tadpoles collected directly from the stream. The animals were placed in test tubes and then removed and released back into the stream. The amount of ammonia (the form of nitrogen excreted by the tadpoles) left after the tadpoles were removed was used to estimate the rate of their excretion. We did quite a few of these experiments streamside on the first trip with the samples returned to our rooms in Hotel Campestre for late night analyses. Our initial experiments indicated the rates of excretion were very high over the first few minutes and then decreased over time.

Bob argued that the tadpoles quit eating when they were placed in the experimental tubes and their excretion rates were slowing after a few minutes because of that. Alex and I thought that maybe stress was causing them to excrete more at the beginning of the experiment. Matt, being the diplomatic group leader, and a fine scientist to boot, suggested experiments were needed to settle the argument. This is the scientific processes. Our speculations formed hypotheses and now we needed the experiments to test them.

These discussions led Matt and Alex to run a series of experiments on tadpoles from the Midwestern US that are taxonomically-related to the tadpoles dominant at Rio Maria. These experiments proved that the higher excretion rates at the beginning were from the stress of being handled and put into a tube. Excretion rates from later in the experiment were more applicable to what the tadpoles were doing in the stream. Matt and Alex proved that handling tadpoles and putting them in large test tubes literally scared the piss out of them. These results were written up and submitted for publication in the scientific literature. They also strengthened the next proposal and would guide our experiments if we got funded to go back to Panama.

Another five months went by and the proposal was rejected again. This was extremely disheartening because once again, the reviews were fabulous. Matt called the program officers at the National Science Foundation to try to figure out how to get the proposal funded. The funding situation was getting dire because Piet’s and several graduate students’ salary depended upon continued funding.

We had agreed to fund the follow-up experiments in Panama out of our own pockets if need be, but we could not expect post-doctoral researchers or graduate students already living on poverty-level salaries to do the same. Luckily the program directors at the National Science Foundation agreed to some stop-gap funding to keep the project going and allow Matt time to apply for funding in the next round. One of the investigators on the grant actually paid Piet’s salary out of her personal funds for awhile. Scientists generally don’t enter the field of ecology to get rich, and many are quite generous with their time and resources, but this was exceptional. There is a long tradition of using personal funds for research; Charles Darwin had to pay his own way as naturalist on the Beagle.

Scientists through the years have had to scrape for external funding and we were no exception. Matt and the rest of us had to strategize on how to make the proposal sexy, compelling, and stress how imperative it was to fund the research immediately. We needed to write the proposal so well that the agency simply could not justify declining to fund it. Matt worked with the group on the best way to sell the research, and the proposal was submitted yet again.

The third time was a charm. I received an email from Matt telling me to plan to travel to Panama the following February. This was very good news and just in the nick of time. Matt had scouted out one site not far from the other side of Panama City where there were still frogs and additional experiments could be conducted as part of this new grant. If the disease spread much further into Panama the work would be finished for good. The remote Darien rainforest between Panama City and Columbia presumably contains the last areas the disease has not reached, but the eastern part of it is inhabited by drug runners and rebels and is not a safe place to work without an entire protective army. Going to the Darien was out of the question; we had a hard enough time getting funding, but getting support for a private protective army was out of the realm of possibility.