Bacteria and fungi (真菌) might call to mind the images of diseases and spoiled food, but they also do a lot of good. The billions of microbes (微生物) in a handful of dead leaves, for example, act as nature’s recyclers and regenerate nutrients needed for the next generation of plants to grow.

“If it weren’t for bacteria and fungi, we’d be surrounded by masses of dead trees and plant matter. So they actually do a really important job.” said Sydney Glassman, an assistant professor of the University of California, Riverside.

While microbial communities are the engines driving the breakdown of dead plants and animals, little is known about whether they are equipped to handle big changes in climate. In a paper published in Proceedings of the National Academy of Sciences of the United States of America, Glassman and his colleagues examined what happens after microbial communities move into new climate conditions. The study is a first step toward understanding the vulnerability of these ecosystems to climate change.

To mimic (模仿) a warming planet, the researchers chose five study sites that differ in climate along the San Jacinto Mountains, three of which are in natural reserves operated by the University of California. “While we know that climate influences how fast microbes can recycle plant material, we don’t know how important the particular types of microbes are to recycling,” said Jennifer Martiny, co-author of the study.

To move the microbial communities around, the researchers contained the microbes in nylon containers with tiny holes. These “microbial cages” were filled with dead grass and live microbes sourced from each study site.The containers allowed water and nutrients—but not microbes—to move in and out. The amount of grass decayed by the caged microbes was measured at 6, 12, and 18 months.

The study confirmed previous results that sites with moderate climates saw the most rot and therefore were the most effective places for nutrient recycling. Quite surprisingly, however, the source of the microbes also affected the amount of rot. For example, when moved into the drier bushes, grassland-sourced microbes outperformed the bush residents by as much as 40 percent.

“We expected to see a ‘home-field advantage’ situation where every microbial community decomposed (分解) best at its own site, but that wasn’t the case,” Glassman said. “While we know that microbes decompose plants more slowly in hotter and drier environments, we are just now learning that specific microbial communities play an independent role in decomposition, and it is yet to be seen how these communities will be affected by climate change and desertification.”

Phil Wise’s heart raced as he opened one of the transport tubes. He and a team of scientists stepped back as a young Tasmanian devil(袋獾) named Oddity came out. Oddity took a cautious look around and then ran into the forest on Maria Island.

Wise is a wildlife biologist from the Save the Tasmanian Devil Program. The scientists working with this program study Tasmanian devils, monitor their health, and track the devils found in the wild. Because a rare disease is reducing the number of devils, Oddity and 14 others were raised on a preserve and then brought to Maria Island to be released into the wild.

Though they are raised in zoos all over the world, devils live wild only in Tasmania. They are important to the ecosystem because they eat dead animals they find, which helps clean up the environment. But a cancer called Devil Facial Tumor Disease (DFTD) is killing devils on mainland Tasmania, endangering the species. The goal of the scientists who released Oddity and the others was to create a population of disease-free Tasmanian devils on Maria Island. Oddity is a part of this “insurance population” of devils raised in zoos and wildlife preserves.

The scientists chose Maria Island for the release because there is no DFTD there. It is separated from mainland Tasmania by the ocean. Devils from the rest of Tasmania can’t get there, which prevents the facial disease from spreading.

Wise and his fellow scientists monitored Oddity and the 14 other Tasmanian devils. The animals did so well that 13 more devils were released. The 28 original Tasmanian devils have reproduced; there are now around 80 devils. Scientists are now figuring out their next move. According to Wise, the focus will soon shift to moving some of the healthy devils back to mainland Tasmania.

Wise says he is “extremely happy to know that animals are getting a chance to be free in the wild in an area that is free of DFTD. It is the ultimate aim of all who work to conserve threatened species.”

The cultivation of plants by ants is more widespread than previously realized, and has evolved on at least 15 separate occasions.

There are more than 200 species of ant in the Americas that farm fungi (真菌) for food, but this trait evolved just once sometime between 45 million and 65 million years ago. Biologists regard the cultivation of fungi by ants as true agriculture appearing earlier than human agriculture because it meets four criteria: the ants plant the fungus, care for it, harvest it and depend on it for food.

By contrast, while thousands of ant species are known to have a wide variety of interdependent relationships with plants, none were regarded as true agriculture. But in 2016, Guillaume Chomicki and Susanne Renner at the University of Munich, Germany, discovered that an ant in Fungi cultivates several plants in a way that meets the four criteria for true agriculture.

The ants collect the seeds of the plants and place them in cracks in the bark of trees. As the plants grow, they form hollow structures called domain that the ants nest in. The ants defecate (排便) at designated absorptive places in these domain, providing nutrients for the plant. In return, as well as shelter, the plant provides food in the form of fruit juice.

This discovery prompted Chomicki and others to review the literature on ant-plant relationships to see if there are other examples of plant cultivation that have been overlooked. “They have never really been looked at in the framework of agriculture,” says Chomicki, who is now at the University of Sheffield in the UK. “It’s definitely widespread.”

The team identified 37 examples of tree-living ants that cultivate plants that grow on trees, known as epiphytes (附生植物). By looking at the family trees of the ant species, the team was able to determine on how many occasions plant cultivation evolved and roughly when. Fifteen is a conservative estimate, says Campbell. All the systems evolved relatively recently, around 1million to 3 million years ago, she says.

Whether the 37 examples of plant cultivation identified by the team count as true agriculture depends on the definitions used. Not all of the species get food from the plants, but they do rely on them for shelter, which is crucial for ants living in trees, says Campbell. So the team thinks the definition of true agriculture should include shelter as well as food.