It was a lifesaving task as thrilling as any in the months-long battle against the wildfires that have torn through the Australian bush. But instead of a race to save humans or animals, a specialized team of Australian firefighters was bent on saving invaluable plant life: hidden groves (树林) of the Wollemi pine, a prehistoric tree species.

Wollemi pines peaked in abundance 34 million to 65 million years ago, before a steady decline. Today, only 200 of the trees exist in their natural environment. The trees are so rare that they were thought to die out until 1994. That’s the year when David Noble, an officer with the New South Wales National Parks and Wildlife Service, came across a grove of large trees he didn’t recognize.

Noble brought back a few branches and showed them to other biologists and botanists. A month later, Noble returned to the grove with some scientists. It was then that they realized what they had found: “a prehistoric tree species that has outlived the dinosaurs.” the American Scientist explains. So when Australia’s wildfires started burning toward Wollemi National Park in recent weeks, firefighters from the parks and wildlife service put a carefully planned operation into action.

Large air tankers dropped fire retardant (阻燃剂) around the pines. Firefighters set up an irrigation (灌溉) system around the trees to keep them wet. “If the fire did go through, we wanted it to be a cool burn as opposed to a hot burn to give them the best chance of survival,” Kean said. The fire did sweep through the groves where these trees have somehow survived for millions of years. For a few days, the smoke was so thick that it wasn’t clear whether the plan had worked. At last the smoke eased off. A few trees had been burned by the flames, and two died. But the efforts had paid off. “Finally,” Kean said, “we were able to get in there and see that, thank goodness, the trees were saved.”

The world’s insects are hurtling down the path to extinction, threatening a “catastrophic collapse of nature’s ecosystems”, according to the first global scientific review. More than 40% of insect species are declining and a third are endangered, the analysis found. The rate of extinction is eight times faster than that of mammals, birds and reptiles.

“It should be of huge concern to all of us, for insects are at the heart of every food web,   they pollinate the large majority of plant species, keep the soil healthy, recycle nutrients, control pests, and much more. Love them or loathe them, we humans cannot survive without insects, ” said Prof Dave Goulson at the University of Sussex in the UK.

The analysis, published in the journal Biological Conservation, says intensive agriculture is the main driver of the declines, particularly the heavy use of pesticides. Urbanization   and climate change are also significant factors.

One of the biggest impacts of insect loss is on the many birds, reptiles, amphibians and fish that eat insects. A small number of adaptable species are increasing in number, but not nearly enough to outweigh the big losses.

Matt Shardlow, at the conservation charity Buglife, said: “It is gravely sobering to see this collation of evidence that demonstrates the pitiful state of the world’s insect populations. It is increasingly obvious that the planet’s ecology is breaking and there is a need for an intense and global effort to stop and reverse these dreadful trends.”

Scientists have discovered the world’s largest known field of sea grass. They did it using videos shot by some unusual helpers: tiger sharks. The work should help protect the sea grass, and also shows off a powerful way to explore the ocean.

Sea grasses are flowering plants that normally grow in shallow waters near coasts. They grow in thick fields，known as meadows(草地). Sea grass meadows help clean the ocean’s water, and provide food and shelter for many sea creatures. Sea grasses store huge amounts of carbon—the harmful pollution that’s making global warming worse. Damaging these sea grass meadows can release this pollution again,so it’s important to protect them.

From above, the meadows can be hard to spot, either because the water is too deep or not clear enough. And the ocean is so huge that it’s simply not possible to study it all by diving. So a team of scientists decided to have sharks help with the research. Tiger sharks are huge, strong, and deadly. But they also live underwater, are fast swimmers, and spend a lot of time in sea grass meadows. Between 2016 and 2020, a team of researchers attached cameras and other trackers to the fins (鳍) of seven tiger sharks. After catching the sharks, the scientists worked quickly to attach the equipment, and then let them go again.

The scientists have learned that the waters around the Bahamas are home to the largest sea grass meadow ever discovered and that the world has roughly 40% more sea grass meadows than they previously thought.

The programme shows how useful large underwater animals can be in helping to learn more about life under the sea. Oliver Ship ley is a scientist at Beneath the Waves,which led the work. He says animals like tiger sharks “...are going to take us to new places that we didn’t know existed.”