What is an endangered species? - via Herp Digest

Date: January 17, 2020

Source: Michigan Technological University

Summary: What makes for an endangered species classification isn't always obvious.

Lions and leopards are endangered species. Robins and raccoons clearly are not. The distinction seems simple until one ponders a question such as: How many lions would there have to be and how many of their former haunts would they have to inhabit before we'd agree they are no longer endangered?

To put a fine point on it, what is an endangered species? The quick answer: An endangered species is at risk of extinction. Fine, except questions about risk always come in shades and degrees, more risk and less risk.

Extinction risk increases as a species is driven to extinction from portions of its natural range. Most mammal species have been driven to extinction from half or more of their historic range because of human activities.

The query "What is an endangered species?" is quickly transformed into a far tougher question: How much loss should a species endure before we agree that the species deserves special protections and concerted effort for its betterment? My colleagues and I put a very similar question to nearly 1,000 (representatively sampled) Americans after giving them the information in the previous paragraph. The results, "What is an endangered species?: judgments about acceptable risk," are published today in Environmental Research Letters.

Three-quarters of those surveyed said a species deserves special protections if it had been driven to extinction from any more than 30% of its historic range. Not everyone was in perfect agreement. Some were more accepting of losses. The survey results indicate that people more accepting of loss were less knowledgeable about the environment and self-identify as advocates for the rights of gun and land owners. Still, three-quarters of people from the group of people who were more accepting of loss thought special protections were warranted if a species had been lost from more than 41% of their former range.

These attitudes of the American public are aligned with the language of the U.S. Endangered Species Act -- the law for preventing species endangerment in the U.S. That law defines an endangered species as one that is "in danger of extinction throughout all or a significant portion of its range.”

But There Might Be A Problem

Government decision-makers have tended to agree with the scientists they consult in judging what counts as acceptable risk and loss. These scientists express the trigger point for endangerment in very different terms. They tend to say a species is endangered if its risk of total and complete extinction exceeds 5% over 100 years.

Before human activities began elevating extinction risk, a typical vertebrate species would have experienced an extinction risk of 1% over a 10,000-year period. The extinction risk that decision-makers and their consultant experts have tended to consider acceptable (5% over 100 years) corresponds to an extinction risk many times greater that the extinction risk we currently impose on biodiversity! Experts and decision-makers -- using a law designed to mitigate the biodiversity crisis -- tend to allow for stunningly high levels of risk. But the law and the general public seem accepting of only lower risk that would greatly mitigate the biodiversity crisis. What's going on?

One possibility is that experts and decision-makers are more accepting of the risks and losses because they believe greater protection would be impossibly expensive. If so, the American public may be getting it right, not the experts and decision-makers. Why? Because the law allows for two separate judgements. The first judgement is, is the species endangered and therefore deserving of protection? The second judgment is, can the American people afford that protection? Keeping those judgements separate is vital because making a case that more funding and effort is required to solve the biodiversity crisis is not helped by experts and decision-makers when they grossly understate the problem -- as they do when they judge endangerment to entail such extraordinarily high levels of risk and loss.

Facts and Values

Another possible explanation for the judgments of experts and decision-makers was uncovered in an earlier paper led by Jeremy Bruskotter of Ohio State University (also a collaborator on this paper). They showed that experts tended to offer judgments about grizzly bear endangerment -- based not so much their own independent expert judgement -- but on basis of what they think (rightly or wrongly) their peers' judgement would be.

Regardless of the explanation, a good answer to the question, "What an endangered species?" is an inescapable synthesis of facts and values. Experts on endangered species have a better handle on the facts than the general public. However, there is cause for concern when decision-makers do not reflect the broadly held values of their constituents. An important possible explanation for this discrepancy in values is the influence of special interests on decision-makers and experts charged with caring for biodiversity.

Getting the answer right is of grave importance. If we do not know well enough what an endangered species is, then we cannot know well enough what it means to conserve nature, because conserving nature is largely -- either directly or indirectly -- about giving special care to endangered species until they no longer deserve that label.

Story Source:

Materials provided by Michigan Technological University. Note: Content may be edited for style and length.

Journal Reference:

1. Tom Offer-Westort, Adam Feltz, Jeremy T Bruskotter, John A Vucetich. What is an endangered species?: judgments about acceptable risk. Environmental Research Letters, 2020; 15 (1): 014010 DOI: 10.1088/1748-9326/ab5cc8

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Michigan Technological University. "What is an endangered species?." ScienceDaily. ScienceDaily, 17 January 2020. <www.sciencedaily.com/releases/2020/01/200117162700.htm>.

Discovery of an endangered species in a well-known cave raises questions

SEPTEMBER 24, 2019

by Jim Steele, University of Alabama in Huntsville

You'd think there'd be no way someone could newly discover an endangered species hanging out in Fern Cave in the Paint Rock River valley of Jackson County, so close to Huntsville, home to thousands of spelunkers exploring every cave, nook and cranny.

But Matthew Niemiller and colleagues did.

In a discovery documented in a paper in the journal Subterranean Biology, Dr. Niemiller, an assistant professor of biological sciences at The University of Alabama in Huntsville (UAH), found a specimen of the Alabama Cave Shrimp Palaemonias alabamae while doing a biological survey of Fern Cave in summer 2018 as part of a team of four.

The endangered shrimp had previously only been discovered in six caves in four cave systems in Madison County.

"Fern Cave is the longest cave in Alabama, with at least 15 miles of mapped passage and five to seven distinct levels," Dr. Niemiller says. The cave features a 437-foot deep pit and exploring most of its lower levels is reserved only for the very fittest, since the trip involves an arduous journey including drops to be rappelled.

Dr. Niemiller and team's route to their discovery was no easy feat, either. The team entered the cave's bottom level via the Davidson Entrance at the base of Nat Mountain on the Fern Cave National Wildlife Refuge. The section of Fern Cave is only dry enough for exploration without scuba gear at the height of summer. Otherwise, it takes a dive to explore its flooded passages.

Read on

Invasive round gobies may be poised to decimate endangered French Creek mussels

APRIL 1, 2019

by Pennsylvania State University

The round goby—a small, extremely prolific, invasive fish from Europe—poses a threat to endangered freshwater mussels in northwestern Pennsylvania's French Creek, one of the last strongholds for two species of mussels, according to researchers.

French Creek flows from southwest New York state about 117 miles to the Allegheny River at Franklin, Pennsylvania. It is the most species-rich stream in Pennsylvania and is nationally recognized for its biodiversity, with more than 80 species of fish and 29 species of freshwater mussels.

Four of the mussels in French Creek are listed under the Endangered Species Act: northern riffleshell, snuffbox, clubshell and rayed bean. Northern riffleshell and clubshell mussels are considered critically imperiled and have lost 95 percent of their historic global range—but they appear to have stable populations in French Creek.

Continued

Why endangered species matter

 March 26, 2019 by Renee Cho, Earth Institute, Columbia University

The Endangered Species Act (ESA) was established in 1973 to protect "imperiled species and the ecosystems upon which they depend" and help them recover.

The Trump administration has put forth a number of proposals that would weaken the ESA. These include measures to allow for the consideration of economic impacts when enforcing the ESA, ending the practice of automatically giving threatened species the same protection as endangered species, and making it easier to remove species from the endangered list.

In a way, this is nothing new because the ESA has been under attack for decades from construction, development, logging, water management, fossil fuel extraction and other industries that contend the act stifles economic development. But between 2016 and 2018 alone, there were almost 150 attempts to undercut the ESA; and last year, from July 8 to 22, Republicans in Congress or the Trump administration introduced 24 such measures and spending bill riders.

These bills included efforts to remove the gray wolf's protected status in Wyoming and the western Great Lakes; a plan to remove from the endangered list the American burying beetle that lives on oil-rich land; and a strategy to roll back protection of the sage-grouse, which also inhabits oil-rich land in the West and whose numbers have declined 90 percent since the West was first settled. The Trump Administration recently opened up nine million acres of sage-grouse habitat to drilling and mining.

Endangered species, if not protected, could eventually become extinct—and extinction has a myriad of implications for our food, water, environment and even health.

Extinction rates are accelerating

Ninety-nine percent of all species that have ever lived have gone extinct over the course of five mass extinctions, which, in the past, were largely a result of natural causes such as volcano eruptions and asteroid impacts. Today, the rate of extinction is occurring 1,000 to 10,000 times faster because of human activity. The main modern causes of extinction are the loss and degradation of habitat (mainly deforestation), over exploitation (hunting, overfishing), invasive species, climate change, and nitrogen pollution.

Read more at: 

Bringing endangered species back from the brink

March 26, 2019, University of Oxford

A technique to produce eggs from ovarian tissue in the lab may offer hope for critically endangered species like the Northern White Rhino that have passed what is currently considered the point of no return.

A research team at the University of Oxford has begun work to find a new way of saving the Northern White Rhino by using tissue taken from animal ovaries to produce potentially large numbers of eggs in a laboratory setting.

Led by Dr. Suzannah Williams, researchers working on the Rhino Fertility Project will refine the method that she has successfully demonstrated in mice. Rhino tissue is scarce and precious—however, ovarian tissue has been obtained by Dr. Williams from a euthanased Southern White Rhino which provides the foundation for the work.

The research is being funded by Mr André Hoffmann, via Fondation Hoffmann.

The desperate plight of the Northern White Rhino has highlighted the precarious situation of many endangered species around the world. Previous breeding programmes had been successful in raising their numbers but the animals were destroyed by poachers. The world's last remaining male died in 2018 leaving just two female rhinos, Najin and her daughter Fatu, neither of which are capable of producing offspring naturally.

Although sperm has been saved by conservationists from male Northern White Rhinos, any successfully fertilised eggs would have to be raised in a surrogate mother – most likely a Southern White Rhino, one of their closest living relatives.

Read more at: 

In developing nations, national parks could save endangered species

Date:  March 7, 2019

Source:  Purdue University

The West African chimpanzee population has declined by nearly 80 percent in recent decades. Habitat loss is threatening their livelihoods across the continent, and especially in Senegal, where corporate mining has started eating up land in recent years.

The geographical distribution of West African chimps overlaps almost perfectly with gold and iron ore deposits, and unfortunately for the chimps, mining is a key piece of the country's development strategy, said Stacy Lindshield, a biological anthropologist at Purdue University.

Extractive industries are already improving people's livelihoods and promoting investment and infrastructure development, and researchers are trying to find a way to protect Senegal's chimps without surrendering these benefits. Many of Earth's animal species are now dying off at accelerated rates, but as human's closest living relatives, they tend to tug at our heart strings. Chimps are scientifically important, too -- because they participate in collective activities such as hunting and food-sharing, they're often studied by social science researchers.

A new study of animal populations inside and outside a protected area in Senegal, Niokolo-Koba National Park, shows that protecting such an area from human interaction and development preserves not only chimps but many other mammal species. The findings were published in the journal Folia Primatologica.

"We saw the same number of chimpanzee species inside and outside the park, but more species of carnivores and ungulates in the protected area," Lindshield said.

Continued

Britain's most endangered species identified for first time as Natural England launches 'Back from the Brink' campaign

Helena Horton 

1 FEBRUARY 2019 • 10:59PM

Britain's 20 most endangered species have been identified for the first time by a host of wildlife and woodland charities, as Natural England has launched a campaign to bring them back from the brink of extinction.

The charities, including the RSPB and the Woodland Trust, have been given over £7.7 million in funding from the National Lottery and other donors to work together to save the endangered animals and plants.

Since the ambitious project began a year ago, the charities have already managed to reintroduce of the Chequered Skipper butterfly to the Rockingham Forest area of Northamptonshire. It  had been extinct in England since 1976.

Now, the various charities are working together for the first time to safeguard the rest of the animals on the list.

The species include the pine marten, which used to be Britain's third most common predator until it was hunted almost to extinction for its beautiful pelt.

While the population is recovering in Scotland, they are scarce in England. By the conclusion of this project, it is hoped they begin to colonise in Northumberland and Cumbria.

Funding for the project will mean that nest boxes can be built for them in the woodland areas they thrive in, and that the current pairs can be tracked.

Continued

New mathematical model can help save endangered species

Date:  January 11, 2019

Source:  University of Southern Denmark

What does the blue whale have in common with the Bengal tiger and the green turtle? They share the risk of extinction and are classified as endangered species. There are multiple reasons for species to die out, and climate changes is among the main reasons.

The risk of extinction varies from species to species depending on how individuals in its populations reproduce and how long each animal survives. Understanding the dynamics of survival and reproduction can support management actions to improve a specie's chances of surviving.

Mathematical and statistical models have become powerful tools to help explain these dynamics. However, the quality of the information we use to construct such models is crucial to improve our chances of accurately predicting the fate of populations in nature.

"A model that over-simplifies survival and reproduction can give the illusion that a population is thriving when in reality it will go extinct.," says associate professor Fernando Colchero, author of new paper published in Ecology Letters.

Colchero's research focuses on mathematically recreating the population dynamics by better understanding the species's demography. He works on constructing and exploring stochastic population models that predict how a certain population (for example an endangered species) will change over time.

Continued  

Indonesia tsunami raises fears for endangered Javan rhino

December 28, 2018 

The latest killer tsunami in Indonesia has put pressure on conservationists to ramp up a longstanding plan to find a suitable secondary habitat for the Javan rhino

Indonesia's tsunami has raised fears that another deadly wave could wipe out the few dozen Javan rhinos still living in the wild, conservation authorities said Friday.

There are believed to be fewer than 70 of the critically endangered species in a national park not far from a rumbling volcano that triggered Saturday's killer wave.

None of the animals are believed to have been killed in the disaster—which left more than 400 people dead—but officials are warning that another deadly wave could slam into the stricken region.

That is putting pressure on conservationists at Ujung Kulon National Park, on the western tip of Indonesia's main island of Java, to ramp up a longstanding plan to find a suitable secondary habitat for the rhinos.

"It's become our duty to work harder to find a second habitat because the danger is real," national park chief Mamat Rahmat told AFP.

"We're lucky that the tsunami did not affect the Javan rhinos this time. But the threat is there and we need to act accordingly."

Widodo Ramono, head of the Rhino Conservation Foundation of Indonesia, added: "If you've only got one habitat and there's another tsunami, the rhinos could be wiped out completely."

Plans to find a second home for the species have been in the works for about eight years, with conservationists surveying areas all over Java and neighbouring Sumatra but so far without success, he said.

Read more at: 

'We're sounding the alarm': half of Canada's chinook salmon endangered

Prospects for species look dire as federal science body finds that only one of the country’s 16 populations is believed to be stable

Leyland Cecco in Toronto

Wed 5 Dec 2018 09.00 GMTLast modified on Wed 5 Dec 2018 09.02 GMT

Half of Canada’s chinook salmon are endangered, with nearly all other populations in precarious decline, according to a new report, confirming fears that prospects for the species remain dire.

The report by the Committee on the Status of Endangered Wildlife in Canada concluded that eight of the country’s 16 populations are considered endangered, four are threatened, one is of special concern and the health of two remain unknown.

Only one population, which spawns on the Thompson river in British Columbia, is believed to be stable.

“For those of us who have been working on recovering chinook salmon runs in British Columbia, we knew they were in terrible, terrible shape for quite a while now,” said Aaron Hill of Watershed Watch, an organisation that monitors ecosystem health. “It was actually good to see it finally recognised by this federally mandated science body, because this hopefully initiates more serious protection efforts from the government.”

Continued

Protecting adult female north atlantic right whales from injury and death key to recovery

Date:  November 7, 2018

Source:  NOAA Northeast Fisheries Science Center

Why is the endangered western North Atlantic right whale population growing far more slowly than those of southern right whales, a sister species also recovering from near extinction by commercial whaling?

NOAA Fisheries researchers and colleagues looked more closely at the question and have concluded that preserving the lives of adult females in the population is by far the most effective way to promote population growth and recovery. Most of these deaths are attributed to entanglement in fishing gear and collisions with ships. The findings are reported in Royal Society Open Science.

"Had North Atlantic right whales increased at the annual rate that we show they are capable of, the population number would be almost double what it is now and their current situation would not be so dire," said Peter Corkeron, who is lead author of the paper and heads the large whale research effort at NOAA Fisheries' Northeast Fisheries Science Center.

The North Atlantic right whale, Eubalaena glacialis, is one of three species of right whales. Of the three, it lives in the most industrialized habitat and migrates close to shore.

From 1970 to 2009, 80 percent of all North Atlantic right whale deaths (70 of 87) for which the cause is known were human-induced, mainly from entanglement in fishing gear and collisions with ships. By comparison, most deaths of southern right whales that have been observed were calves in their first year of life and very few were directly attributable to human activities.

Continued 

Frogs Are Disappearing, What Does That Mean? - via Herp Digest

For ages, they have been symbols in human culture — of fertility, gastronomy and now the alt-right movement. But these noble amphibians are declining in numbers.

Banded bullfrogs, native to Southeast Asia (and not yet endangered), on their thrones of chanterelle, lobster and shiitake mushrooms.

Photo Credit Photograph by Kyoko Hamada. Styled by Victoria Petro-Conroy

By Ligaya Mishan, 10/18/18, New York Times Style Magazine

THE DUSKY GOPHER FROG, once endemic to the longleaf pine savannas of Mississippi, Alabama and Louisiana — and now listed among the 100 most endangered species on earth — is tiny, dark and warty.

 

The creature is often described as both secretive and shockingly loud, with a rumbling, back-of-the-throat mating call that is uncannily close to the human snore. It hides from the sun almost its whole life, finding shelter in burned-out tree stumps. And although it’s armed against danger (its glands secrete poison), in the presence of a predator, the three-inch-long frog lifts its front legs to cover its eyes, like a child pretending to be invisible: You can’t see it if it can’t see you,

As of 2015, around 135 dusky gopher frogs were estimated to remain in the wild, mostly at a single pond in Mississippi, their breeding sites fragmented by new roads and the timber industry. The fate of the species may lie in the hands of the Supreme Court, which, as it begins a new term in October, will consider as its first case Weyerhaeuser Co. v. United States Fish and Wildlife Service. The lawsuit concerns the government’s designation of privately owned land in Louisiana as a critical habitat for the endangered frogs, setting property rights (and a potential $34 million loss in development value for the $27 billion Weyerhaeuser Company) against environmental conservation.

One study estimates that since the 1970s, around 200 frog species have disappeared, with a projected loss of hundreds more in the next century. Frogs are under threat on nearly every continent: from the French Pyrenees to the Central American rain forests to the Sierra Nevada in California. Some species, like the dusky gopher frog, have been depleted by human encroachment on their habitats. But the decimation that started 50 years ago was largely the work of the chytrid fungus Batrachochytrium dendrobatidis, which thickens a frog’s skin, hindering the animal’s ability to absorb water and oxygen and to maintain a balanced flow of electrolytes, leading to heart failure. Once infected, entire populations can collapse in a single season.

No one knows exactly how the disease spread, but it was likely carried unwittingly by humans from one country to the next, or by the female African clawed frogs that were shipped around the world for laboratory experiments and, until the early 1970s, hospital pregnancy tests. (In the test, a frog was injected with a woman’s urine, which, if she was pregnant, would contain an ovary-stimulating hormone that caused the frog to lay eggs.) Live frogs, potential carriers of the disease, continue to be moved across borders into nonnative habitats; in the first decade of the 21st century, the United States imported nearly 48 million pounds of them, some destined to become exotic pets, others winding up on dining tables.

More than three billion frogs are eaten worldwide each year, some 4,000 tons by the French and half that by Americans, who tend to prefer them patted with flour and sautéed in browned butter. These are mostly farmed frogs and thus not as vulnerable to extinction, but the circumstances in which they’re bred and exported may contribute to the spread of disease. And while in some parts of Asia the whole frog — minus the skin, which contains toxins — is submitted to the pot and boiled for soup, in many cases only the hind legs are used for food, meaning the bulk of the body goes into the garbage.

It’s an ignoble end for an animal that, despite its diminutive size, has held an exalted role over the ages in almost every culture. Frogs have been revered as emissaries of the divine (because of their regenerative powers) and feared as witches’ familiars, noxious and baleful. They have also been beloved as our stand-ins, infiltrating the stories we tell about ourselves, appearing as tricksters and fools, pompous kings and yearning commoners. Their value isn’t merely symbolic: Their croaks were the music in hundreds of early Japanese verses, until the 17th-century Japanese poet Matsuo Basho gave them physical presence — and comic power — in the famous 1686 haiku: “Old pond / Frog jumps in / Water-sound.” Their omnipresence in our fables speaks to their centrality in sustaining the world around us. In science class, they are our introduction to biology, dissected to reveal life’s inner mysteries. Toxins in their skin may yield new antibiotics and painkillers.

More fundamentally, frogs are linchpins in the ecosystem, both predator and prey. And they are our watchmen, keeping vigil over our ponds, marshes, lakes and streams, our meadows and our woods, the quality of our water and our air. “If they go silent, there could be bad stuff happening,” says Christopher J. Raxworthy, a herpetologist at the American Museum of Natural History in New York. Like honeybees, whose colonies began to collapse en masse across the United States a decade ago, frogs are portents of the greater ills that could befall our environment — and us.

AS AMPHIBIANS, frogs lead double lives, in water and on land, starting out as tadpoles equipped with gills and tails, which are reabsorbed into their bodies as they grow lungs and limbs. The seasonal emergence of frogs prophesies rain, essential for crops and survival, and their role in spring’s awakening may explain why early Christians used images of them to celebrate resurrection. In frogs’ prodigious fertility — they lay tens of thousands of eggs each mating season — the ancient Egyptians saw abundance; the goddess of fertility, Heqet, is often depicted as a frog-headed woman, and the hieroglyph for the numeral 100,000 was a tadpole. But too many frogs, and they become a plague.

It’s this duality that has ultimately endeared them to us, for these creatures hold out the promise of human transformation, the ability to shed an ugly skin and reveal a hidden self. Part of the appeal of Kermit the Frog is his status as an Everyman: small, far from powerful, but pure of heart. Even his latter-day counterpart Pepe the Frog was originally a good-natured slacker, first drawn in a 2005 comic strip by Matt Furie, before being co-opted as a symbol of the alt-right movement, whose members seem to have conflated Pepe with Kek, the frog-headed Egyptian god representing the darkness before the world was born. (Furie killed off Pepe last year to prevent further misappropriation.)

Another cultural invasion of frogs occurred last winter, when one of the most downloaded smartphone apps in Asia was Tabikaeru (Journey Frog), a game featuring an amphibian that spends much of its time reading in a cozy hut, then wanders off for an indeterminate amount of time, occasionally sending home snapshots. This unfolds without any human input; players do little more than pack food for the frog’s journeys and pine for the little nomad to come back — a comforting inevitability, as kaeru, the Japanese word for frog, sounds almost exactly like the word for return. Tabikaeru is particularly popular in China, where the characters for frog and child are both pronounced “wa” in Mandarin, with only a slight difference in tone.

BUT THESE VIRTUAL FROGS may soon be all we have left. The rate of decline is particularly startling given that, until now, amphibians have outlasted most of life on Earth. “They’re survivors,” says Jennifer B. Pramuk, a herpetologist and animal curator at the Woodland Park Zoo in Seattle, Wash. Their ancestors evolved some 350 million years ago, and they have persisted through three global mass extinctions, including the Permian extinction 251 million years ago, which is known among scientists as the Great Dying because of the number of species lost: an estimated 80 to 96 percent in the oceans and 70 percent on land. Frogs — which separated from salamanders and emerged as a distinct order, Anura, between 240 and 275 million years ago — have been resilient, but their permeable skins are highly sensitive to changes in water quality and temperature.

When we grieve over frogs’ loss and the global degradation it suggests, we’re also mourning a kind of strange, singular natural beauty. Among those now extinct is the golden toad, of which the males were orange-skinned and bright as flame, once prolific breeders in the Monteverde cloud forest of Costa Rica. In 1989, a single male was counted. The next year, there were none. The southern gastric brooding frog, indigenous to the mountains of Queensland in eastern Australia, thrilled herpetologists with its unusual reproductive system: Females swallowed their eggs, which hatched in the stomach, only to be vomited into the world as fully formed froglets. The creature’s final appearance was in 1981.

Conservation efforts have succeeded in reviving a few species. Not long after the Kihansi spray toad, sunny yellow and smaller than a postage stamp, lost its home in the misty wetlands of Tanzania to a hydroelectric dam in 2000, 499 of them were airlifted to the Bronx Zoo. Within three years, only two toads were left at the original Tanzanian site. But by 2010, the rescued toads had spawned a thriving 4,000-strong population at the Bronx Zoo and the Toledo Zoo in Ohio; 2,500 were reintroduced to Tanzania two years later. Zoos may be the key to frogs’ survival, not only nurturing but proselytizing for them, so that a charmed public recognizes their worth.

Without frogs as a predator, mosquitoes and other invertebrates, themselves carriers of disease, will multiply. “It’s another chink in the armor of the ecosystem,” Pramuk says. Gone, too, will be the spring choruses, frogs calling for their mates. Pramuk still remembers when she finally made it to the Costa Rican cloud forest in 1995, six years after the sighting of the last golden toad, one of her favorite species, which she’d studied only on paper. She had hope: Sometimes amphibians thought extinct have suddenly reappeared. “You always think, ‘Maybe it will show itself to me,’” she says. So she stood and waited, listening to the silence. Frogs are the heralds of dusk, their evening song laying the day to rest. Without them, it is only night.