The African Continent has various habitat types, but savanna (热带草原) ecosystems cover approximately half. And where there is savanna, there is fire. "It's an important part of the ecology of the system," says University of Liverpool ecologist James R Probert. Burning allows grasses to take the lead by keeping taller bushes from occupying the land, Loss of grasses could push out species such as wildebeest (牛 羚 ), which are famous for their splendid annual migration.

A decade ago researchers put decreasing fires within Tanzania's Serengeti National Park down to the recovery of wildebeest population following an epidemic of rinderpest, a viral disease. When millions of wildebeest feed on grass, they remove fuel from the land, making fire less frequent and less severe.

But Probert and his colleagues found that even after wildebeest populations had stabilized by the mid-1990s, fires continued to decrease in the same area. Their analysis of satellite data showed that the region experienced a 40 percent reduction in wildfires between 2001 and 2014- in line with dramatic increases in farm animals in the area.

If you have lots of farm animals eating the grass, then you have less fire. That’s well known Probert says. "But I don’t think anybody had realized the degree of the decline in fire and linked it to farm animals before.”

This is a really interesting pattern, "says University of Guelph biologist John Fryxell, who was not involved in the study. He cautions, however, that 15 years' worth of data is still a fairly small amount of information from which to draw final conclusions. "What a short-term connection like that suggests is that there's something interesting here that could provide the grounds for a deeper experimental analysis, "he adds. That research could include artificially controlling fire frequency or grazing intensity (放牧强度) in certain areas and then monitoring the land's response over time.

We found him a few weeks ago when we were walking along the country road. He was jumping around between cars. We thought maybe his family was camping somewhere nearby, so we passed him by. A few hours later, on our return trip, he was still there, trying to get someone to stop for him.

We stopped and took a good look at him. He had no collar (项圈) and he was really thin. We guessed that he was abandoned (遗弃). He was clearly on the road for some time. He was covered with scars and new wounds. We thought that some of them were from fights with wild dogs or other wild animals.

So we took him home, cleaned him and fed him a lot over the next two weeks. He gained over 10 pounds. Then we took him to the vet, who said he appeared to be in good health. The vet said the dog was about two or three years of age, according to the condition of his teeth. And the vet gave him all the required shots.

We really loved this dog. He had obviously been mistreated but he was still so sweet. He had no manners, but he was a quick learner. He no longer tried to get on the bed, but he liked sitting in the chair. We thought he wanted to avoid being underfoot when our daughter was dancing, which she did often. She had stepped on him a few times. When that happened, he simply moved. He did not growl (狂吠) or bare his teeth.

Since then, he had become a member of our family.

Taylor grew up on the coast of New South Wales, Australia and swimming in the ocean was part of everyday life. She began spear fishing and worked her way up in her early 20s to become one of very few women who were professional spear fishers and was named the Australian Ladies National Champion.

However, as she spent more time underwater, especially with the sharks, she had a change of heart. “I learned straight away that sharks are nowhere near as dangerous as the media would have us believe. And I learned that they all have different personalities-there’s the shy guy, the cross guy, and the aggressive guy; they’re all different.” From that point on, she decided, along with her late husband and world spear fishing champion, Ron Taylor, to hang up her spear and to only shoot them with her camera.

As a pioneering shark conservationist, Taylor succeeded in many firsts throughout her life’s work. She was the first person to dive with sharks cageless. The first person to test the power of a shark bite; she hand-fed a Great White and petted it. There’s nothing she wouldn’t do to help correct the false image that sharks are dangerous, man-eating beasts. Her research has become the basis for much of what we know about sharks today and she succeeded in becoming the first person to get Grey Nurse sharks protected in a specific area, the first shark species in the world to receive protected status.

When asked about what could be done to help save the sharks, and the oceans, Taylor said she was quite pessimistic about the whole thing. “Change has to come from the government level.”But she also recommended, “The thing that works the best is to get a good story and then get it on camera. Then go on television and speak to the public. Say it to the mothers, “Wouldn’t you like your child. . . when they’re old enough, to be able to see this wonderful, friendly shark?””