Latest news with #BiologicalConservation
Miami Herald
11-06-2025
- Science
- Miami Herald
Invasive bullfrogs ‘eat everything' — including turtles — at Yosemite, study says
A study has found that removing invasive bullfrogs from Yosemite National Park ponds has generated a resurgence in the population of native pond turtles, experts said. When University of California, Davis, researchers first began studying four ponds at the park, they were overwhelmed by non-native American bullfrogs, a news release said. 'At night, you could look out over the pond and see a constellation of eyes blinking back at you,' said Sidney Woodruff, a UC Davis Ph.D. candidate and lead author of the study. 'Their honking noise is iconic, and it drowns out native species' calls.' The invasive frogs had decimated the native population of northwestern pond turtles, according to the study, published in the May issue of the journal Biological Conservation. Together with the southwestern pond turtle, northwestern pond turtles are the only native freshwater turtles in California, the university said. Northwestern pond turtles have vanished from over half their range, which stretches from Baja California to Washington state. At Yosemite, the only surviving turtles in the ponds surveyed were the ones that were too big for bullfrogs to eat, the study found. American bullfrogs are native to the eastern United States but don't belong in the West. 'One reason American bullfrogs are among the top worst globally introduced pests is because they eat everything — anything that fits into their mouth,' said senior author Brian Todd, a UC Davis professor in the Department of Wildlife, Fish and Conservation Biology. 'They've been causing declines to native species everywhere they're introduced, which is around the world.' The bullfrogs were introduced to Yosemite National Park in the 1950s and quickly spread throughout the park, researchers said. While their arrival was believed to be linked to the decline in pond turtles, it wasn't confirmed until the study took place, according to researchers. Between 2016 and 2022, researchers monitored four ponds at Yosemite, two with bullfrogs and two without, the study said. Turtles were 2 to 100 times more prevalent at the ponds where bullfrogs were absent, researchers said. When bullfrogs were removed from the other two ponds in 2019, researchers found juvenile pond turtles in them for the first time, the study said. 'As bullfrog presence declined, we started to hear other native frogs call and see native salamanders walking around,' Woodruff said. 'It's nice to be able to go back to these sites and hear a chorus of native frogs calling again that previously would not have been heard.' The Western Pond Turtle Range-wide Conservation Coalition, Yosemite Conservancy, U.S. Geological Survey and USDA National Institute of Food and Agriculture funded the study.
The Guardian
04-06-2025
- Climate
- The Guardian
Weatherwatch: How 60 species are just one cyclone away from extinction
Hurricane Dorian is thought to have been one of the worst natural disasters for the Bahamas, leaving at least 70,000 people homeless and causing more than $5bn (£3.7bn) in damage in 2019. But it wasn't just people who suffered. For one forest dwelling songbird – the Bahama nuthatch – this hurricane spelled the end. Now a new study reveals that a significant number of species that are endemic to a single island, like the Bahama nuthatch, are at increasing risk of extinction from severe tropical cyclones, with an estimated 60 species potentially one cyclone away from being wiped out. Researchers mapped all the severe cyclones (those with wind speeds above 200km/h) that have occurred since 1972 and worked out how many of these had hit biodiversity hotspots. To their surprise, they found three-quarters of severe cyclones struck biodiversity hotspots made up entirely of islands and 95% of these repeatedly pummelled the same five island regions: Japan, Polynesia-Micronesia, the Philippines, Madagascar and the Indian Ocean islands, and the Caribbean islands. Consulting the red list of most threatened species they report in the journal Biological Conservation there are 60 storm-threatened species that are present in a single location on a single island. Upping the conservation effort for these species is essential if we do not want the next severe tropical cyclone to be their last.
The Star
26-05-2025
- Science
- The Star
Lesser flamingos lose one of their only four African breeding sites to sewage
KIMBERLEY, South Africa (Reuters) -Until the last half-decade, the majestic lesser flamingo had four African breeding sites: two salt pans in Botswana and Namibia, a soda lake in Tanzania, and an artificial dam outside South Africa's historic diamond-mining town of Kimberley. Now it only has three. Years of raw sewage spilling into Kamfers Dam, the only South African water body where lesser flamingos congregated in large enough numbers to breed, have rendered the water so toxic that the distinctive pink birds have abandoned it, according to conservationists and a court judgment against the local council seen by Reuters. Lesser flamingos are currently considered near-threatened, rather than endangered, by the International Union for Conservation of Nature: there are 2-3 million left, four-fifths of them spread across Africa, the rest in a smaller area of South Asia. But they are in steep decline, and the poisoning of one of their last few breeding sites has worsened their plight dramatically. Tania Anderson, a conservation biologist specialising in flamingos, told Reuters the IUCN was about to increase its threat-level to "vulnerable", meaning "at high risk of extinction in the wild", owing largely to their shrinking habitats of salty estuaries or soda lakes shallow enough for them to wade through. "It's really very upsetting," Anderson said of the sewage spills in Kamfers Dam. "Flamingos play a pivotal role in maintaining the water ecosystems of our wetlands." A 2021 study in Biological Conservation found sewage threatens aquatic ecosystems across a vast area of the planet. Although 200 nations came together at the U.N. COP16 biodiversity summit in Colombia last year to tackle threats to wildlife, no agreement was reached. 'THEY JUST DISAPPEARED' Footage taken by the Wildlife and Environment Society of South Africa in May 2020 shows Kamfers Dam turned flamboyant pink with flamingos. When Reuters visited this month, there were none. A closer look at the water revealed a green sludge that bubbled and stank of human waste. "It was a sea of pink," Brenda Booth recalled, as she gazed over the bird-free lake located on the farm she owns, dotted with acacia trees and antelope. "They all just disappeared," said Booth, who last month secured the court order compelling the African National Congress-run municipality in charge of Kimberley, a city of 300,000, to fix the problem. Over the years, the treatment plant "became progressively dysfunctional to the point where ... approximately 36 megalitres a day of untreated sewage was being discharged into the dam," said Adrian Horwitz, the lawyer bringing the case in the High Court of South Africa, Northern Cape division. Municipality manager Thapelo Matlala told Reuters thieves had vandalised the plant and stolen equipment, grinding it to a halt. "We are working on a new strategy for ... repairing the damage," he said outside his office, adding that this needed 106 million rand ($5.92 million), money the council didn't have. Failure to deliver services was one of the main reasons the ANC lost its 30-year-strong majority in last year's elections. Lesser flamingos mostly eat spirulina, a blue-green algae - filtering it through their beaks. This limits them to alkaline water bodies, largely in East Africa's Rift Valley. They're fussy about where they breed, with just three sites in India alongside the remaining three in Africa. Flamingos began breeding at Kamfers Dam in 2006, said Ester van der Westhuizen-Coetzer, wetlands specialist for local diamond miner Ekapa Group, as she waded through grassland at the edge of another lake where she had spotted a flock. In 2020, there were 71,000 on the dam, with up to 5,000 new chicks each season. "They've missed three or four breeding seasons," she said, and many also died of botulism, a disease that flourishes in waste. Sewage has become a problem across South Africa, where few treatment plants are in working order, and if nothing is done, "the whole system will degrade and blow up," she said. "That will have a huge impact, and not only on flamingos." ($1 = 17.8903 rand) (Editing by Kirsten Donovan)
Yahoo
24-05-2025
- Science
- Yahoo
This invasive frog can fit baby turtles inside its mouth
Listening to frogs croak at night might sound like the perfect nature-focused getaway. But if those vocal amphibians are American bullfrogs and the place is in Yosemite National Park in California, that's not really a good thing. American bullfrogs (Lithobates catesbeianus) are large frogs originally from the eastern United States, meaning that in California, they're considered an invasive species. Humans introduced them in Yosemite in the 1950s, and within two decades they had become well established in the region. 'One reason American bullfrogs are among the top worst globally introduced pests is because they eat everything — anything that fits into their mouth,' Brian Todd, a professor at the University of California (UC), Davis' Department of Wildlife, Fish, and Conservation Biology, said in a statement. The problem is that a lot of things can fit into the frogs' mouths, from snakes and birds to rodents and baby turtles. 'They've been causing declines to native species everywhere they're introduced, which is around the world,' Todd added. Northwestern pond turtles (Actinemys marmorata) are one of only two native freshwater turtles in California, and they have seen a particularly dramatic population decline. Todd and colleagues thus decided to investigate whether this could also be linked to American bullfrogs. In a study published recently in the journal Biological Conservation, the team monitored four native turtle habitats in Yosemite National Park, two of which also hosted the bullfrog. They immediately saw that native turtles sharing their habitat with American bullfrogs were fewer, older, larger, and heavier than those in habitats without them. In other words, adult turtles that can't fit in the frog's mouth. 'The evidence so far suggests that bullfrogs are physically eating young western Pond turtles, which means the baby western pond turtles never grow up to become adults and the population will eventually disappear as adults are not replaced,' Todd tells Popular Science. The researchers started removing American bullfrogs to see how this might impact the native turtle populations. Low and behold, when the researchers had almost completely eliminated the invasive species from both sites, baby northwestern pond turtles made a comeback. [ Related: It's raining tiny toxic frogs. ] Furthermore, 'as bullfrog presence declined, we started to hear other native frogs call and see native salamanders walking around,' Sidney Woodruff, lead-author of the study and an ecology PhD student at UC Davis, explained in the statement. 'It's nice to be able to go back to these sites and hear a chorus of native frogs calling again that previously would not have been heard.' As such, the study suggests that this could be a winning approach for supporting pond turtle populations in priority conservation areas where non-native bullfrogs are unlikely to make an unwelcome comeback. 'The best reason to eradicate invasive species or to prevent them from establishing in the first place is because of how damaging they can be to native ecosystems,' Todd tells Popular Science. 'Invasive species can outcompete and eliminate desirable native species and cause declines in many endangered species. Invasive species can even damage human livelihoods by affecting crops or domesticated animals and they can spread diseases.'
The Hindu
08-05-2025
- Science
- The Hindu
Trace DNA left by large carnivores at livestock kill sites can be used to reliably identify individual predators: NCBS study
National Centre for Biological Sciences (NCBS) researchers in a recent study have stated that trace DNA left by large carnivores at livestock kill sites can be used to reliably identify individual predators. NCBS said that this approach offers a powerful tool to effectively manage human-wildlife conflict and understand predator behaviour and ecology. 'In communities that live in proximity to large carnivores, livestock depredation might cause conservation challenges. Systematic understanding of individuals involved in conflict is a critical first step towards a solution,' said Uma Ramakrishnan, senior author of the study which has been published in Biological Conservation. NCBS said that around the world, managing human-wildlife conflict often involves relocating or removing the suspected predator. 'Typically, forest departments rely on field signs like pugmarks, scat, or claw marks to identify the animal involved. However, these signs can be ambiguous, and removing the non-target individual may disturb carnivore populations and sometimes further intensify conflict situations. More reliable and robust genetic identification of predators could be an effective strategy for conflict resolution,' NCBS said. The researchers in collaboration with Panthera and the Madhya Pradesh Forest Department investigated 198 kill sites across two of Central India's key tiger habitats - Kanha and Bandhavgarh Tiger Reserves. At each site, researchers collected non-invasive genetic samples - saliva, scat, and shed hair as a potential source of predator DNA. Using genetic tools based on Single Nucleotide Polymorphisms (SNPs), they identified individual tigers present at these kill sites. Shed hair samples were the most effective for individual identification, followed closely by saliva and scat. Overall, tigers were successfully identified at 85% of the kill sites, with species-level identification exceeding 95% across all sample types. To assess each tiger's likely involvement in a kill, the team developed a classification framework based on the type and location of genetic evidence. Each case was categorised as a true predator (high confidence),circumstantial predator (medium confidence), or predator uncertain (low confidence). Out of the 198 cases studied, 72 were classified with high confidence, 34 with medium confidence, and 49 with low confidence. 'Genetic samples are often the only true evidence of a predation event and are therefore vital. While identification is possible, there remains some possibility of misidentification especially when multiple individuals are present at the kill site. That's why it's important to assign confidence levels in identification. We hope that such a classification scheme will help better represent the level of confidence provided by the genetic tools and further evidence-based conflict management,' said Himanshu Chhattani, lead author of the study.
