Grizzly bears, which may grow to about 2.5m long and weigh over 400kg, occupy a conflicted corner of the American psyche-we revere(敬畏) them even as they give us frightening dreams. Ask the tourists from around the world that flood into Yellowstone National Park what they most hope to see, and the iranswer is often the same: a grizzly bear.
"Grizzly bears are re-occupying large areas of their former range," says bear biologist Chris Servheen. As grizzly bears expand their range into places where they haven't been seen in a century or more, they're increasingly being sighted by humans.
The western half of the U.S. was full of grizzlies when Europeans came, with a rough number of 50,000 or more living alongside Native Americans. By the early 1970s, after centuries of cruel and continuous hunting by settlers, 600 to 800 grizzlies remained on a mere 2 percent of their former range in the Northern Rockies. In 1975, grizzlies were listed under the Endangered Species Act.
Today, there are about 2,000 or more grizzly bears in the U.S. Their recovery has been so successful that the U.S. Fish and Wildlife Service has twice attempted to de-list grizzlies, which would loosen legal protections and allow them to be hunted. Both efforts were overturned due to lawsuits from conservation groups. For now, grizzlies remain listed.
Obviously, if precautions(预防) aren't taken, grizzlies can become troublesome, sometimes killing farm animals or walking through yards in search of food. If people remove food and attractants from their yards and campsites, grizzlies will typically pass by without trouble. Putting electric fencing around chicken houses and other farm animal quarters is also highly effective at getting grizzlies away. "Our hope is to have a clean, attractant-free place where bears can pass through without learning bad habits," says James Jonkel, longtime biologist who manages bears in and around Missoula.
If you want to tell the history of the whole world, a history that does not privilege one part of humanity, you cannot do it through texts alone, because only some of the world has ever had texts, while most of the world, for most of the time, has not. Writing is one of humanity's later achievements, and until fairly recently even many literate (有文字的) societies recorded their concerns not only in writing but in things.
Ideally a history would bring together texts and objects, and some chapters of this book are able to do just that, but in many cases we simply can't. The clearest example of this between literate and non-literate history is perhaps the first conflict, at Botany Bay, between Captain Cook's voyage and the Australian Aboriginals. From the English side, we have scientific reports and the captain's record of that terrible day. From the Australian side, we have only a wooden shield (盾) dropped by a man in flight after his first experience of gunshot. If we want to reconstruct what was actually going on that day, the shield must be questioned and interpreted as deeply and strictly as the written reports.
In addition to the problem of miscomprehension from both sides, there are victories accidentally or deliberately twisted, especially when only the victors know how to write. Those who are on the losing side often have only their things to tell their stories. The Caribbean Taino, the Australian Aboriginals, the African people of Benin and the Incas, all of whom appear in this book, can speak to us now of their past achievements most powerfully through the objects they made: a history told through things gives them back a voice. When we consider contact (联系) between literate and non-literate societies such as these, all our first-hand accounts are necessarily twisted, only one half of a dialogue. If we are to find the other half of that conversation, we have to read not just the texts, but the objects.
On March 7, 1907, the English statistician Francis Galton published a paper which illustrated what has come to be known as the "wisdom of crowds" effect. The experiment of estimation he conducted showed that in some cases, the average of a large number of independent estimates could be quite accurate.
This effect capitalizes on the fact that when people make errors, those errors aren't always the same. Some people will tend to overestimate, and some to underestimate. When enough of these errors are averaged together, they cancel each other out, resulting in a more accurate estimate. If people are similar and tend to make the same errors, then their errors won't cancel each other out. In more technical terms, the wisdom of crowds requires that people's estimates be independent. If for whatever reasons, people's errors become correlated or dependent, the accuracy of the estimate will go down.
But a new study led by Joaquin Navajas offered an interesting twist (转折) on this classic phenomenon. The key finding of the study was that when crowds were further divided into smaller groups that were allowed to have a discussion, the averages from these groups were more accurate than those from an equal number of independent individuals. For instance, the average obtained from the estimates of four discussion groups of five was significantly more accurate than the average obtained from 20 independent individuals.
In a follow-up study with 100 university students, the researchers tried to get a better sense of what the group members actually did in their discussion. Did they tend to go with those most confident about their estimates? Did they follow those least willing to change their minds? This happened some of the time, but it wasn't the dominant response. Most frequently, the groups reported that they "shared arguments and reasoned together." Somehow, these arguments and reasoning resulted in a global reduction in error. Although the studies led by Navajas have limitations and many questions remain, the potential implications for group discussion and decision-making are enormous.
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As cities balloon with growth, access to nature for people living in urban areas is becoming harder to find. If you're lucky, there might be a pocket park near where you live, but it's unusual to find places in a city that are relatively wild.
Past research has found health and wellness benefits of nature for humans, but a new study shows that wildness in urban areas is extremely important for human well-being.
The research team focused on a large urban park. They surveyed several hundred park-goers, asking them to submit a written summary online of a meaningful interaction they had with nature in the park. The researchers then examined these submissions, coding (编码) experiences into different categories. For example, one participant's experience of "We sat and listened to the waves at the beach for a while" was assigned the categories "sitting at beach" and "listening to waves."
Across the 320 submissions, a pattern of categories the researchers call a "nature language" began to emerge. After the coding of all submissions, half a dozen categories were noted most often as important to visitors. These include encountering wildlife, walking along the edge of water, and following an established trail.
Naming each nature experience creates a usable language, which helps people recognize and take part in the activities that are most satisfying and meaningful to them. For example, the experience of walking along the edge of water might be satisfying for a young professional on a weekend hike in the park. Back downtown during a workday, they can enjoy a more domestic form of this interaction by walking along a fountain on their lunch break.
"We're trying to generate a language that helps bring the human-nature interactions back into our daily lives. And for that to happen, we also need to protect nature so that we can interact with it," said Peter Kahn, a senior author of the study.
According to the Solar Energy Industry Association, the number of solar panels installed(安装)has grown rapidly in the past decade, and it has to grow even faster to meet climate goals. But all of that growth will take up a lot of space, and though more and more people accept the concept of solar energy, few like large solar panels to be installed near them.
Solar developers want to put up panels as quickly and cheaply as possible, so they haven't given much thought to what they put under them. Often, they'll end up filling the area with small stones and using chemicals to control weeds. The result is that many communities, especially in farming regions, see solar farms as destroyers of the soil.
"Solar projects need to be good neighbors," says Jordan Macknick, the head of the Innovative Site Preparation and Impact Reductions on the Environment(InSPIRE)project. "They need to be protectors of the land and contribute to the agricultural economy." InSPIRE is investigating practical approaches to "low-impact" solar development, which focuses on establishing and operating solar farms in a way that is kinder to the land. One of the easiest low-impact solar strategies is providing habitat for pollinators(传粉昆虫).
Habitat loss, pesticide use, and climate change have caused dramatic declines in pollinator populations over the past couple of decades, which has damaged the U.S. agricultural economy. Over 28 states have passed laws related to pollinator habitat protection and pesticide use. Conservation organizations put out pollinator-friendliness guidelines for home gardens, businesses, schools, cities—and now there are guidelines for solar farms.
Over the past few years, many solar farm developers have transformed the space under their solar panels into a shelter for various kinds of pollinators, resulting in soil improvement and carbon reduction. "These pollinator-friendly solar farms can have a valuable impact on everything that's going on in the landscape," says Macknick.
