Sharks and their relatives are some of the most threatened vertebrates (脊椎动物) on Earth. Coral reefs (珊瑚礁) provide homes for countless fish species that are vital for fisheries and are therefore an especially important ecosystem for humans — and one where the decline of shark populations seems to be especially sharp.

The study by Simpfendorfer with his team is the result of an act of worldwide cooperation called the Global FinPrint Project. The data analyzed include more than 20,000 hours of standardized underwater video taken at nearly 400 reefs in 67 countries around the world. It reveals declines of 60 to 73% of once-abundant coral reef shark species at reefs around the world. The global conservation status of sharks and rays (鳐鱼) is worse than a decade ago and is even more concerning for some groups of sharks.

However, the findings of Simpfendorfer with his team include signs of hope and a clear path forward. Their result s show that although shark populations in many reefs had declined, some health y reef shark populations remained. The reefs with healthier shark population s had some important similarities: they tended to be in the waters of high-income countries with stronger natural resource management laws and rules. Unfortunately, such countries were relatively rare, and lower-income countries tended to have fewer resources for eco-friendly management.

The most unexpected result of the study is that a decline or complete loss of shark species in one reef was not always associated with similar changes in nearby reefs. They found that one reef could be overfished so badly that a once-common reef shark species was totally gone, but another reef a short distance away could have healthy populations of that same species.

The problem is clear -animals that provide ecosystem services that are vital for human food security and livelihoods are disappearing at an alarming rate. The loss of sharks and the ecosystem services they provide represents an ecological disaster that can cause substantial harm to humans.

Even plant can run a fever， especially when they're under attack by insects or disease． But unlike human， plants can have their temperature taken from 3，000 feet away straight up． A decade ago， adopting the infrared（红外线） scanning technology developed for military purposes and other satellites， physicist Stephen Paley came up with a quick way to take the temperature of crops to determine which ones are under stress． The goal was to let farmers precisely（精确的） target pesticide（杀虫剂） spraying rather than rain poison on a whole field， which always includes plants that don't have pest problems．

Even better， Paley's Remote Scanning Services Company could detect crop problems before they became visible to the eye． Fixed on a plane flown at 3，000 feet at night， an infrared scanner measured the heat sent out by crops． The data were transformed into a color﹣coded map showing where plants were running "fevers"． Farmers could then spot﹣spray， using 50 to 70 percent less pesticide that they otherwise would．

The bad news is that Paley's company closed down in 1984， after only three years． Farmers resisted the new technology and long﹣term supporters were hard to find． But with the renewed concern about pesticides on produce and refinements（改进） in infrared scanning， Paley hopes to get back into operation． Agriculture experts have no doubt that the technology works． "This technique can be used on 75 percent of agricultural land in the United States，" says George Oerther of Texas A& M， who recently retired from the Department of Agriculture， thinks remote infrared crop scanning could be adopted by the end of the decade． But only if Paley finds the financial support which he failed to obtain 10years ago．

Wildlife corridors are like safe highways for animals. These untouched areas let species move about freely to feed, breed, and migrate (迁徙) without disturbance from humans. The Vital Ground Foundation and Yellowstone to Yukon Conservation Initiative (Y2Y) bought 80 acres in northwestern Montana. The area was bought from a landowner committed to protecting open spaces over development. The area will be used to maintain wildlife habitats for species throughout the state’s northwestern corner and is particularly important for grizzly bears.

“In 2015, new science on grizzly bear connectivity identified this area as one of a few remaining connection points for grizzly bears in northwest Montana,” says Grossman, U.S. program manager for Y2Y. “Last year, the opportunity became available to work with the landowner in the area. With the rapid development of the real estate (房地产) market, we knew we needed to act quickly.”

“At the local area, this project conserves open spaces for wildlife movement,” Grossman says. She points out that grizzly bears are an umbrella species. This means that if they are doing well, most other wildlife in the ecosystem is also doing well. Bears can help us conserve habitats for a full range of plants and animals that make a functioning ecosystem that all of us need to survive. That is why this project focuses on the needs of bears.

It often becomes more difficult to preserve wildlife corridors like these. In Montana where this land has been purchased, property values have increased and land has been sold and developed quickly. Once development happens, it’s harder to conserve land and keep areas connected. “However, this change in the real estate market has led to some landowners reflecting on their values and vision for the community. In this way, it creates an opportunity for us to be able to work with people who want to see these areas remain high quality wildlife habitats, rural and undeveloped,” Grossman says.