Poaching has decimated rhino populations across Africa, but a new study finds that dehorning the animals, or surgically removing their horns, drastically reduces poaching.

The study focused on 11 reserves in the Greater Kruger ecosystem that sprawls across the border of South Africa and Mozambique. Poachers killed nearly 2,000 rhinos here, 6.5% of the reserves’ population, from 2017-2023, reducing populations of both black (Diceros bicornis) and white (Ceratotherium simum) rhinos, according to Tim Kuiper, study lead and conservation scientist at Nelson Mandela University.

Poachers target rhinos for their keratin horns, incorrectly believed in traditional Asian medicine to hold medicinal properties. To deter poachers, many African reserves have tried dehorning, a procedure where veterinarians tranquilize rhinos and saw off their horns, leaving only a stump behind.

In eight of the 11 reserves the study examined, park authorities and researchers (some involved in the study) have dehorned rhinos in batches since 2017. This allowed the researchers to compare the impact of dehorning on poaching rates over time, against the three reserves where rhinos weren’t dehorned, and against conventional measures implemented prior to dehorning.

The study found a 78% reduction in poaching rates in the parks after dehorning — and it was cost-effective, too.

From 2017-2023, the reserves spent $74 million on antipoaching measures, including rangers, tracking dogs, cameras, better fences and access control. But dehorning accounted for just 1.2% of the budget, the study found. “So, it’s very clear that our study demonstrated massive declines in poaching in response to dehorning,” Kuiper told Mongabay by email, adding that some dehorned rhinos are nevertheless still hunted for the remaining stump.

Conventional antipoaching methods led to the arrest of more than 700 poachers, but didn’t significantly reduce poaching. Kuiper said it was surprising that reserves with more dogs, helicopters and cameras didn’t have less poaching overall. He added that systemic problems like insider information and poor law enforcement likely compromised these approaches.

Philip Muruthi, conservation scientist at the NGO African Wildlife Foundation, who wasn’t involved with the study, told Mongabay the paper adds valuable understanding about threatened wildlife, but said rhino conservation should be more holistic, involving all stakeholders, including local communities, and addressing root causes like local poverty and corruption that drive poaching.

Jasper Eikelboom, a wildlife researcher at Wageningen University, Netherlands, not involved in the study, said more research is needed to reveal the underlying cause of local reductions in poaching of dehorned rhinos.

“To do this, the poaching rates of other reserves in southern Africa at the same moment in time need to be considered as well, to contrast potential displacements of poacher activity with reductions in poaching due to reduced rewards,” he told Mongabay by email. “Before this is known, it still remains to be seen what will happen with rhino poaching rates if all rhinos in southern Africa are dehorned.”

Banner image: A dehorned white rhino with her calf. Image courtesy of Tim Kuiper.

Founder’s Briefs: An occasional series where Mongabay founder Rhett Ayers Butler shares analysis, perspectives and story summaries.

In the summer of 2024, searing ocean temperatures devastated much of Mesoamerica’s corals. But in Honduras’s Tela Bay, a reef known as Cocalito remains improbably intact — dominated by elkhorn corals so robust they scrape the water’s surface.

The survival of this reef is baffling. Elkhorn coral (Acropora palmata), once common across the Caribbean, has declined by up to 98% in many areas due to warming seas, disease and pollution. Yet in Tela Bay, fed by a river heavy with fertilizer and waste, these corals not only endure, they flourish.

Scientists have taken notice, reports contributor Fritz Pinnow for Mongabay. A team from the University of Miami in the U.S., suspecting the corals harbor heat-resistant algae or unique genetic traits, collected samples to crossbreed with Florida’s nearly extinct elkhorns. Early findings suggest Cocalito’s coral hosts an unusually resilient symbiont. Still, results are preliminary, and other theories abound.

Some point to environmental quirks. Coastal currents may shield Cocalito from sedimentation and heat. Others cite human behavior: the reef’s shallow waters deter fishers, perhaps allowing a healthier ecological balance to persist.

Whatever the explanation, Cocalito’s persistence stands in stark contrast to the regional picture. Tela Bay’s other reefs were not spared from the global bleaching event, now affecting 84% of reefs worldwide. Local conservationists have long been working to mitigate stressors — fighting pollution, managing tourism and monitoring reef health — but even they are surprised by Cocalito’s resilience.

That surprise is now fueling action. With support from the Mesoamerican Reef Fund (MAR Fund), local NGOs are ramping up reef monitoring and protection. A documentary team is preparing to tell Cocalito’s story to the world.

The mystery remains unsolved. But in a year defined by coral loss, Cocalito offers something rare: A reason to keep looking for answers.

Read the full story by Fritz Pinnow here.

Banner image: Thriving elkhorn coral comprises most of the Cocalito reef. The species was once among the most dominant coral species in the Caribbean but is now endangered. Image by Fritz Pinnow for Mongabay.

GENEVA (AP) — Swiss authorities cleared a village in the country’s east over a potential rockslide, three weeks after a mudslide submerged a vacated village in the southwest.

Residents of Brienz/Brinzauls, about 40 kilometers (25 miles) southwest of Davos, were being barred from entering the village because a rock mass on a plateau overhead has “accelerated so rapidly that it threatens to collapse,” a statement from local officials said Monday.

Farm work in the area was also being halted, and livestock owners moved their animals out of nearby pastures due to early warning signs on Sunday.

Authorities said the region is closely monitored by early-warning systems in the town, which is no stranger to such evacuations: Villagers had been ordered out of Brienz/Brinzauls in November and in June two years ago — before a huge mass of rock tumbled down the mountain, narrowly missing the village.

The mountain and the rocks on it have been moving since the last Ice Age. While glacier melt has affected the precariousness of the rocks over millennia, local authorities say melting glaciers due to “man-made” climate change in recent decades hasn’t been a factor.

The centuries-old village straddles German- and Romansch-speaking parts of the eastern Graubünden region and sits at an altitude of about 1,150 meters (about 3,800 feet). Today, it has under 100 residents.

Banner image: View of the village Brienz and the “Brienzer Rutsch”, taken in Brienz-Brinzauls, Switzerland, May 12, 2023. (AP Photo/Arnd Wiegmann, File).

Brazil’s red-tailed amazon parrot is a rare success story for reviving a species heading toward extinction, Mongabay Brasil’s Xavier Bartaburu reports.

By the end of the 20th century, the population of the red-tailed amazon (Amazona brasiliensis) had dwindled to fewer than 5,000 individuals in Brazil’s Atlantic Forest, one of the most endangered biomes in the world. The birds depend on guanandi trees for their fruit and natural trunk hollows for nesting. However, along with 88% of the Atlantic Forest, many of the trees were cut down and harvested for their sturdy wood.

The red-tailed amazons themselves were, and still are, targeted for the illegal wildlife trade and local consumption. In remote areas such as Rasa Island, off the southern state of Paraná, locals put glue on trees to catch the parrots for sale or to eat, local fisherman Antonio da Luz dos Santos told Bartaburu.

The Society for Wildlife Research and Environmental Education (SPVS) identified Rasa Island as an ideal location for conservation as it hosts both resting and breeding habitat for the birds. However, SPVS was initially not welcome by many residents. “I was one of those against SPVS here on the island. I said that if they came here, I’d shoot,” said Eriel “Nininho” Mendes. His trees full of fruit were being eaten by the parrots, and many people didn’t want to be barred from hunting.

Nonetheless, SPVS began conservation efforts on the island, employing local people to address the limited number of guanandi by building artificial nests — wooden boxes placed in the tree canopy, Bartaburu reported. Locals like Antonio were tapped to help build the nests.

“Back then, people said it wouldn’t work. But one day, I went into the forest, and there was a chick inside the box,” said Antonio, who now works with SPVS staff.

They installed 15 nests in 2003, and the boxes were 100% occupied before the breeding season began, said SPVS wildlife project coordinator Elenise Sipinski. Because the artificial nests were custom-made for the birds, the entrance holes keep predators out. “We have camera trap footage showing a hawk trying to get into the nest, but it couldn’t,” Sipinski told Bartaburu. More than 100 nests were installed across the island, and several more in nearby areas.

Nininho, who first threatened to shoot SPVS workers, now plants fruit trees for the birds, which have attracted tourists who stay in his guesthouse. “Tourists come, spend the day here, eat our food, walk around the island, go in the mud to dig oysters with me,” he said. “Parrots are now a profit for me.”

Initially listed as endangered on the IUCN Red List, the parrots’ conservation status has improved to “near threatened” as the population has increased to some 9,000 individuals. It’s the only Brazilian species that’s increasing in population, Bartaburu reported.

Read the full report here.

Banner image of a red-tailed amazon in an artificial PVC nest installed by SPVS. Image courtesy of Zig Koch/SPVS.

Sarus cranes typically live most of their lives as a male-female duo, singing tightly coordinated duets. At a glance, the male and female, both standing 1.5-1.8 meters (5-6 feet) tall, are difficult to tell apart visually. They’re both gray-bodied with red necks and head. But researchers have found a way of distinguishing between the sexes through the notes they sing in their songs, reports Mongabay India’s Kartik Chandramouli.

Being able to accurately tell between a male and a female of a species, such as the sarus crane (Antigone antigone), a species considered vulnerable to extinction, is crucial for understanding several aspects of its life: from the sex ratio of its populations and the sex-specific roles the individuals play in the wild, to how human activities influence the two sexes, all of which can ultimately help inform conservation actions.

So, for more than six months, researcher Suhridham Roy spent his time in agricultural fields in the Indian states of Gujarat, Haryana and Uttar Pradesh, observing and recording 215 duets from 136 breeding bird pairs of sarus cranes.

Roy and his colleagues analyzed the recorded duets as graphs called spectrograms. Each duet consists of an introduction, trill and the main section. The analysis, published in a recent study, showed that the male and female portions within each section — cross-referenced with careful field observations — varied significantly and had distinct acoustic signatures. Male notes tended to be longer, lower-pitched, with wider modulation. Female notes were brief, higher-pitched, and sharper.

“Identifying sex is a bigger problem in non-breeding flocks that don’t perform duets but are constantly vocalizing and form 50-70% of a population in an area,” study co-author K.S. Gopi Sundar, Roy’s Ph.D. mentor who has studied these cranes since 1998, told Chandramouli. He added the study offers baseline data to train machine-learning models to identify sexes in non-breeding birds, currently a major research gap.

Ecologist John Grant, who studies sarus cranes in northern Australia, told Chandramouli the acoustic sexing method developed using Indian sarus cranes can be used for all the subspecies. Sarus cranes can be found in the wetlands of Pakistan, Nepal and Myanmar, as well as the forests of Southeast Asia and Australia.

Mongabay India previously reported in a podcast episode that every sarus crane pair’s duet is acoustically unique, and used to reinforce bonds and announce the boundaries of their territories to other crane pairs.

While sarus cranes are typically monogamous, Sundar, Roy and researcher Swati Kittur also found that sometimes sarus crane pairs bring in a third crane into their closely knit families, singing unison calls called a triet. The presence of triets in a landscape can indicate poor habitat quality, where the third crane is essentially a helping hand, invited in to increase the chicks’ survival.

Read the full story by Kartik Chandramouli here.

Banner image: A sarus crane pair sings a duet. Image by Ad031259 via Wikimedia Commons (CC BY 4.0).

Some coastal wolves in Alaska, U.S., have toxic levels of mercury in their bodies after shifting from a terrestrial diet of deer and moose to a marine diet heavy with sea otters, new research finds.

Mercury is a naturally occurring heavy metal found in the Earth’s crust. However, human activities like burning coal and fossil fuels release mercury into the atmosphere, where it can travel hundreds of miles from its source. When mercury enters aquatic ecosystems, it’s converted into methylmercury, a potent neurotoxin that “moves efficiently through a food web,” Ben Barst, study co-author and assistant professor with the University of Calgary, Canada, told Mongabay in a video call.

Methylmercury “biomagnifies,” accumulating in larger amounts higher up the food chain, making it dangerous for predators like wolves and sea otters. Large sea otters (Enhydra lutris) daily eat roughly 11 kilograms (25 pounds) of invertebrates like mussels, clams and sea urchins, all known to accumulate methylmercury.

Gretchen Roffler, the study’s lead author and a research biologist with the Alaska Department of Fish and Game, first learned of mercury poisoning in wolves (Canis lupus) when she investigated the death of an emaciated collared wolf from another study. Roffler’s tests revealed “unprecedented” levels of mercury in the animal’s liver. So, she sent samples to Barst’s lab for further testing.

The mercury concentration in those samples were so high, “at first we thought the instrument was malfunctioning,” Barst said.

Once mercury levels were confirmed — on par with those observed in polar bears, an apex marine predator — the researchers wanted to know how widespread mercury poisoning is in wolves and where the mercury came from.

They examined archived tissue samples starting from the year 2000, along with samples from recently trapped wolves and hair and blood samples from collared wolves.

They looked at two different wolf packs: one on Pleasant Island in coastal Alaksa and another a mile away on mainland Gustavus Forelands. The island pack moved there in 2013 and within a few years wiped out the island deer population. Instead of swimming back to the mainland they stayed and “switched to a very marine-heavy diet dominated by sea otters; up to about 70% of their diet is sea otters,” Roffler told Mongabay in a video call.

The mainland Gustavus pack, despite having access to deer and moose, also began eating more sea otters around the same time.

Roffler said she believes both packs likely made the switch because sea otters, which are easier and safer to kill than a large moose, have recently become very abundant. Once decimated by the fur trade, sea otter populations have rebounded, thanks to conservation efforts including protection under the Marine Mammal Protection Act. They are now “super abundant wolf prey,” Roffler said.

“We expect this to be a broader geographic trend across the former range of sea otters as they recolonize,” she said.

Banner image: of a wolf, courtesy of U.S. National Park Service.