Claire Asher

Large hydroelectric dams are not worth the environmental and societal costs, and their benefits will continue to dwindle further as the climate changes, analysts argue. Dams have been linked to habitat degradation, harm to biodiversity and migrating aquatic species, and to negative changes in river ecology. More problems: dams rarely live up to promoter pledges. Costs are often underestimated, and once built, big dams rarely generate the huge energy amounts promised.

Thirty years after the construction of a dam in southern Thailand, bamboo and vines have replaced the local rainforest, and forest-loving birds have vanished. The damming of the Khlong Phrasaeng River in 1986 flooded 165 square kilometres of forest and created about 100 islands in the dam’s reservoir. To investigate the dam’s impact, Gregory Irving at King Mongkut’s University of Technology Thonburi in Bangkok and his colleagues tallied bird species on land around the dam’s reservoir and on...

Impressive past reductions in the rate of Amazon biome deforestation in Brazil have been counteracted by major increases in deforestation and native vegetation loss in the neighboring Cerrado savanna biome, according to a study recently published in the Journal of Geographical Sciences.

A high-resolution satellite can detect signs of whales splashing and pooping in the oceans — and can even pick out a humpback whale’s long flippers.
Previous studies have used satellite data to count whales, but the WorldView-3 satellite, which was launched in 2014, captures images in much higher resolution than its predecessors. Hannah Cubaynes and her colleagues at the British Antarctic Survey in Cambridge, UK, searched WorldView-3 images of waters off the coasts of Italy, Mexico, Hawaii an...

More than 200 million cattle live and graze in Brazil, bringing US $123 billion into the country’s economy annually. However, 80 percent of new deforestation in the Brazilian Amazon is caused by the conversion of forest to cattle pasture. While international beef retailers have worked to decouple their markets from cattle-driven deforestation, a recent report shows that a lack of traceability and transparency of the cattle supply chain continues to thwart their efforts.

A group of ground beetles known as bombardier beetles are famous for shooting a boiling-hot, noxious liquid at would-be attackers, but despite their formidable defense, they prefer not to shelter alone, according to a study publishing October 31 in the open-access journal PLOS ONE by Jason Schaller and colleagues from the University of Arizona in Tucson, USA.

Bombardier beetles in the genus Brachinus are nocturnal predators that shelter during the day in dark, moist crevices on the banks of r...

Horns have evolved independently multiple times in scarab beetles, but distantly related species have made use of the same genetic toolkit to grow these prominent structures, according to a study publishing October 4, 2018 in the open-access journal PLOS Genetics by Teruyuki Niimi at the National Institute for Basic Biology in Okazaki, Japan, and colleagues.

A vast aspen grove that is renowned as one of the world’s biggest living organisms is shrinking as a result of human activity and browsing deer.

One aspen tree can sprout thousands of genetically identical trunks to form a single, sprawling clone known as a ‘forest of one tree’. The biggest known clone is the Pando, a quaking aspen (Populus tremuloides) in Utah that covers 43 hectares and is thought to have survived for thousands of years.

Centuries-old cesspits reveal that residents of a bustling port in medieval Germany were infested with a diverse range of parasitic worms — suggesting that trade helped to carry the worms far and wide. Intestinal parasites such as tapeworms and roundworms were common in Europe before the advent of modern sanitation. Adrian Smith at the University of Oxford, UK, and his colleagues extracted DNA from parasite eggs in soil samples...

A virus that can inflict feather loss and severe beak deformities on infected parrots is widespread in the wild. Infections with beak and feather disease virus, which can cause lethal illness, are common in captive cockatoos, parakeets and other types of parrot. But how far the virus, which originated in Australasia, has spread in wild bird populations has been a mystery.

Sharks are notorious carnivores, but one small hammerhead shark also feels the need to eat its greens. Bonnethead sharks (Sphyrna tiburo) live in seagrass meadows in the shallow waters off the coasts of the Americas. In addition to consuming invertebrates such as squid, they have been observed eating large amounts of seagrass. But whether the animals digest this dietary plant matter has been a mystery. Samantha Leigh at the University of California, Irvine, and her colleagues fed five captive...

A new genetic analysis shows that rivers in northeast South America rarely give rise to new bird species, but are important in maintaining existing biodiversity. Researchers found that 86 pairs of the more than 400 endemic bird species in the Rio Negro basin have range boundaries that meet but never overlap, many of them coinciding with either the Rio Negro or the Rio Branco. Amazonian rivers, they conclude, can play two distinct roles in species evolution: their formation may separate popula...

Testosterone has been extracted from the hair of Siberian woolly mammoths, including two females whose hormone levels suggest that they may have been pregnant.
The remains of mammoths are often found embedded in ice and permafrost, which preserves the extinct animals’ DNA so well that scientists can sequence it. To investigate whether chilled remains could yield other important molecules, Lee Koren at Bar Ilan University in Ramat Gan, Israel, and her colleagues set out to extract testosterone...

Bees around the globe are in trouble, and many scientists worry that a common pesticide bears some blame. Now, scientists have shown that a chemical hailed as a potential replacement has similar harmful effects, reducing the number of new queens and males in bumblebee colonies. The finding could force farmers to seek alternative solutions to reduce crop damage from insect pests.