With the only giant pandas, Yang Guang and Tian Tian, in the United Kingdom set to return to China from Scotland’s Edinburgh Zoo, crowds have been gathering around the panda enclosure(围栏) to bid them farewell.

The Royal Zoological Society of Scotland, the conservation charity that owns and manages Edinburgh Zoo, said that the pandas will leave for China, but the exact date and time of departure will not be announced because of safety and security reasons.

Yang Guang, whose name means sunshine, and Tian Tian, whose name translates to sweetie, arrived at the Edinburgh Zoo in December 2011 as part of a 10-year agreement between the zoological society in Scotland and the China Wildlife Conservation Association. The agreement was later extended by two years because of the pandemic.

Since their arrival, Yang Guang and Tian Tian have accumulated a great deal of public interest, and the BBC billed the panda enclosure as a “rock star” attraction that has been at the top of the must-see list of more than 600,000 visitors to the zoo each year. Vanessa Moreland-Strange and Andrew Strange, a couple living near Edinburgh, brought their two children to the zoo recently to say goodbye to the pandas. The family told China Daily they had visited the panda enclosure 28 times since 2018 and “every time was the best time”.

To bid farewell to Yang Guang and Tian Tian, the Royal Zoological Society of Scotland has been holding a series of events since January that have proved extremely popular. Activities priced between 30 and 500 pounds ($38 and $630) included a one-hour guided tour and behind-the-scenes experience to help the keepers feed Yang Guang. The tickets sold out in just 90 minutes. The zoological society members said the sales raised more than $53,280 and the money will be used by the charity to help save wildlife from extinction.

In a recent study, researchers at Germany’s Technical University of Munich（TUM）find that trees in cities can grow up 25% faster than their country cousins. This is believed to be a direct result of the heat island effect, which is a situation where the temperature of the city is higher than the nearby rural areas. It’s mostly caused by the fact that buildings, roads, and many other things in the city take in a lot of sunlight and send out the sun’s heat more than natural landscapes such as forests and water bodies. A secondary cause is waste heat produced by heavy uses of energy.

For the study, TUM researchers studied 1,400 trees in 10 cities around the world, which were found in both city centers and nearby rural areas. Based on tree ring study, researchers found that city trees are growing faster than their rural cousins. But before the 1960s, both city and rural trees grew at about the same speed.“We can show that city trees of the same age are generally larger than rural trees because they grow faster. While the difference is about a quarter at the age of 50, it is still just under 20% at a hundred years of age,” lead author Hanz Pretzch says.

Researchers from TUM also found that in some cities, higher-than-normal temperatures have led to growing seasons that are more than eight days longer than the norm. This sounds like a good thing. But while fast -growing city trees are busy taking in CO₂and providing relief from the heat, they’ re also aging and dying at a faster speed than rural trees. As a result, these trees need to be replaced and replanted more frequently.

Considering the valuable “ecosystem services” that city trees provide, planning and management should follow to make a change with today’s tree growth speed. Pretzch and his team set out to perform the study largely in response to United Nation’s report that the world’s cities will experience population growth of more than 60% by 2030. And with such fast growth comes a great need for city trees that make these cities better places to live in.

From 1990 to 2000, fishermen trying to get swordfish (剑鱼) off the coast of California accidentally caught and killed over 100 sea turtles (海龟), and injured many more. In 2001, the government set up the Pacific Leatherback Conservation Area (PLCA), an area off the coast of California where fishing boats are not allowed to enter from August to November. Since then, the number of turtles killed by mistake has fallen rapidly, but a small number of animals still die from being caught in fishing nets each year. And at the same time, the once $15 million swordfish industry has become a $ 2 million industry.

Scientists are hoping to find a way to not only protect sea turtles and other endangered creatures but also help fishermen make a living. For this, many scientists are looking at dynamic ocean management to help fishing boats meet fish where they are and avoid catching other creatures by mistake.

The first paper to suggest that the fish living in the open ocean should be guarded with fluid, ever-changing zones of protection, came out in 2000. Larry Crowder, a professor at Hopkins Marine Station, remembers reading it and thinking, “Cool idea, but it will never work.” In 2000, scientists didn’t have the computer power to cheaply test statistical models or deal with satellite data quickly. They didn’t have enough data dealing with fish or satellite data on ocean conditions, either.

Now scientists can download satellite data of oceans in minutes and attach satellite archival tag to sea animals to track their movements. They first collect data by marking the creatures, collecting reports from fishing boats, or other tracking ways. Then they compare that data with weather conditions, the time of year, and any other data that can be sensed. Finally, they can predict where fish probably are.

Crowder and his workmates used the data to develop a tool called EcoCast during the 2012 and 2015 fishing seasons, they could have fished in at least 125,000 square miles, without high risk of hunting turtles.