In the American state of Florida , rancher Jim Strickland can see his cows at any time , day or night .
在美国佛罗里达州，牧场主吉姆·斯特里克兰无论白天黑夜，随时都能看到他的牛。
To do this , all he needs is his phone .
要做到这一点，他只需要一部手机。
Strickland uses virtual fencing to watch and control the movements of his animals .
斯特里克兰利用虚拟围栏来观察和控制牲畜的活动。
It can also help improve animal health .
它还有助于改善牲畜的健康。
Strickland has been using the system for about six months .
斯特里克兰使用这套系统已经大约六个月了。
“It has exceeded by far my expectations .”
“它远远超出了我的预期。”
Virtual fencing uses radio signals to make an invisible fence .
虚拟围栏利用无线电信号形成一道看不见的围栏。
This means you cannot see the fence .
也就是说，你看不见这道围栏。
This keeps animals within , or outside of , certain areas .
这样就能把牲畜留在某些区域之内，或挡在其外。
The signals come from nearby mobile phone towers .
信号来自附近的手机信号塔。
The signals can also come from base stations that can be moved using a small truck .
信号也可以来自用小卡车就能移动的基站。
Each animal wears a collar around its neck .
每头牲畜的脖子上都戴着一个项圈。
The collar has a radio signal receiver and a GPS device that shows the animal's location .
项圈上有一个无线电信号接收器和一个显示牲畜位置的GPS设备。
Ranchers train livestock to connect a sound with a small electric shock .
牧场主训练牲畜把一种声音和轻微的电击联系起来。
When an animal gets close to a virtual fence , its collar makes a warning sound .
当牲畜靠近虚拟围栏时，项圈会发出警告声。
If the animal moves even closer to the fence , it receives a shock .
如果牲畜继续靠近围栏，就会受到电击。
In this way , livestock quickly learn to stay away from the fence .
这样，牲畜很快就学会远离围栏。
Ranchers can change the virtual fence boundaries quickly by using a phone App or computer .
牧场主可以用手机应用或电脑迅速更改虚拟围栏的边界。
And livestock quickly learn the new boundaries .
牲畜也会很快熟悉新的边界。
Strickland and his coworkers can use their phones even while on horseback to move cattle from one area to another .
斯特里克兰和同事们甚至可以在骑马时用手机把牛从一个区域赶到另一个区域。
All they need to do is change the virtual fence lines .
他们只需要更改虚拟围栏的界线就行了。
“And every 30 minutes , that line will move down ; it will literally drive those cows down .”
“每隔30分钟，那条线就会往下移，真的就把那些牛往下赶。”
Physical fences take time , labor and money to build .
修建实体围栏需要时间、人力和金钱。
It can be difficult to put them in areas such as rocky and hilly land , wet areas , or places with thick vegetation .
在多岩石的丘陵地带、潮湿地区或植被茂密的地方，很难修建围栏。
Over time , fences need to be fixed or new ones need to be built .
时间一长，围栏就需要修补或重建。
When hurricane Ian hit Florida last year , it destroyed four houses and 45 kilometers of physical fence on the land where Strickland works .
去年飓风“伊恩”袭击佛罗里达时，摧毁了斯特里克兰工作的那片土地上的四栋房屋和45公里实体围栏。
But the cell towers for the virtual fence system kept working .
但虚拟围栏系统的信号塔仍在正常运作。
Physical fences can also harm wild animals by making it difficult for them to move within and to areas they need for survival .
实体围栏还可能伤害野生动物，让它们难以在生存所需的区域内活动或前往这些区域。
The Nature Conservancy (TNC ) is a U.S-based environmental non-profit organization .
大自然保护协会（TNC）是一家总部设在美国的非营利环保组织。
It has partnered with cattle ranches in the states of Kansas , New Mexico and Colorado to research the effects of virtual fencing .
该组织与堪萨斯州、新墨西哥州和科罗拉多州的养牛场合作，研究虚拟围栏的效果。
William Burnidge is Deputy Director of TNC's North America Regenerative Grazing Lands Strategy .
威廉·伯尼奇是大自然保护协会北美再生放牧地战略的副主任。
He said that by changing fence boundaries , the systems prevent animals from eating too much vegetation within one area .
他说，通过改变围栏边界，这套系统可以防止牲畜在同一区域吃掉过多植被。
This helps plants regenerate , or grow again .
这有助于植物再生，也就是重新生长。
He added that virtual fences could help protect rare plants and areas near rivers and streams .
他补充说，虚拟围栏可以帮助保护珍稀植物以及河流和溪流附近的区域。
They could also support conservation of wild animals , improve the health of animals and help ranch workers have a better quality of life .
它们还能支持野生动物保护，改善牲畜健康，并帮助牧场工人提高生活质量。
Strickland works with partners at Florida Conservation Group and the University of Florida .
斯特里克兰与佛罗里达保护组织和佛罗里达大学的伙伴们合作。
With virtual fences , they can carefully control grazing .
有了虚拟围栏，他们可以精细地控制放牧。
This helps them research the effects of grazing patterns on the growth of young cows , birth rates , and even the effects on nesting birds .
这有助于他们研究放牧模式对小牛生长、出生率，甚至对筑巢鸟类的影响。
They also plan to research how grazing can affect the release of carbon dioxide gas into the atmosphere .
他们还计划研究放牧会如何影响二氧化碳向大气中的排放。
In Florida and other places , fields are sometimes burned to prepare them for future grazing .
在佛罗里达和其他地方，人们有时会焚烧草场，为日后的放牧做准备。
The burning releases carbon .
焚烧会释放碳。
Virtual fences may help reduce burning by better controlling where and how long cattle graze .
虚拟围栏可以更好地控制牛在哪里吃草、吃多久，从而有助于减少焚烧。
Both Strickland and Burnidge note that , unlike physical fences , livestock cannot not get injured by a virtual fence .
斯特里克兰和伯尼奇都指出，与实体围栏不同，牲畜不会因虚拟围栏而受伤。
The GPS collars also let ranchers watch for animals that may be having problems .
GPS项圈还能让牧场主留意可能出了问题的牲畜。
For example , if the system shows that a cow has not moved for many hours , it may be sick or injured .
例如，如果系统显示一头牛好几个小时都没动过，它可能生病或受伤了。
Cattle can easily damage burned areas and the young plants that grow there .
牛很容易破坏焚烧过的区域以及那里新长出的幼苗。
The Oregon study showed that cows without virtual fence collars ate nearly 70 percent of the plants available to them in a burned area .
俄勒冈州的研究显示，没戴虚拟围栏项圈的牛吃掉了焚烧区内近百分之七十的可食植物。
However , cows with collars spent very little time in the burned area and ate less than three percent of the plants available to them .
然而，戴着项圈的牛在焚烧区内停留的时间很短，吃掉的植物不到百分之三。
Although virtual fencing systems have benefits , they can be costly .
虽然虚拟围栏系统有很多好处，但成本可能很高。
A collar for just one animal can cost around $50 each year or more .
仅一头牲畜的项圈每年就可能要花约50美元甚至更多。
And portable base stations cost $10,000 or more .
而便携式基站要1万美元或更多。
Researchers are looking for ways to lower costs and bring the technology to developing countries .
研究人员正在寻找降低成本的方法，把这项技术带到发展中国家。
Last year , the Bezos Earth Fund awarded $9.9 million to Cornell University's College of Agriculture and Life Sciences to develop low-cost virtual fencing .
去年，贝索斯地球基金向康奈尔大学农业与生命科学学院拨款990万美元，用于开发低成本虚拟围栏。
The university plans to test new systems in Kenya , Mongolia , Argentina , Brazil and Colombia .
该校计划在肯尼亚、蒙古、阿根廷、巴西和哥伦比亚测试新系统。
But in some areas , virtual fencing may not be the best solution , Burnidge said .
但伯尼奇说，在某些地区，虚拟围栏可能不是最佳解决方案。
When Burnidge visited Kenya , he saw many workers who closely follow and take care of livestock .
伯尼奇访问肯尼亚时，看到许多工人紧跟在牲畜身边照料它们。
Virtual fences could cause some of these workers to lose their jobs .
虚拟围栏可能会导致其中一些工人失业。
Still , Burnidge said , many people want to learn more about the technology .
尽管如此，伯尼奇说，很多人都想进一步了解这项技术。
And Strickland said they are already working on more ways virtual fencing can be used .
斯特里克兰说，他们已经在研究虚拟围栏的更多用途。
“Now we're seeing so many things .
“现在我们看到了很多东西。
Once you start down the road of new technology , then it starts expanding . . .
一旦你走上了新技术这条路，它就会不断扩展……
It's like , what can we do next ?” he said .
就像是，我们接下来还能做什么呢？”他说。