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中国科技网4月21日报道（张微 编译）环境科学家说，澳大利亚的城市可以防止他们呆萌的考拉因交通事故而香消玉殒——如果他们正确地规划他们的道路。
环境决策中心澳大利亚研究委员会的一项最新研究表明，在现有公路上加设防护措施，而不是修建新的道路，是降低日益拥堵的交通与不断增加的城市考拉数量的最好方式。 研究团队开发了世界首个数学模型，有助于开发出最具成本效益的方式来保护生活在马路附近的野生动物种群，如安装防护网，建地下或地上通道，通过有限的基金给这些动物最好的保护。 “随着城市的不断扩张，公路对野生动物的影响越来越大，”昆士兰大学CEED中心的乔纳森 罗兹博士说。“世界各地的动物，包括哺乳动物、鸟类、爬行动物和青蛙，正遭受越来越大的交通流量的危险。” 罗兹博士解释说，这些影响包括栖息地的丧失，人类活动的干扰和动物横穿马路时的交通事故。“以考拉为例，在1997年-2008年的昆士兰地区，就有超过3800只考拉被汽车撞倒，其中的85%死亡。 “虽然考拉的大部分时光都消磨在树上，但是它们也需要到地面上寻找食物和配偶。减少公路惨案发生的关键是，当我们扩张城市时，应该更加细致地设计公路网。 科学家们研究了当它们穿过交通流量大的大型道路，或是许多交通流量小的小路时，哪里的劫难少。他们发现，在大多数情况下，比起少数的几条大型道路，数量众多的小马路对考拉的杀伤力更大。 他们还发现雄性考拉比雌性考拉被容易被车辆撞到，这是因为雄性有较大的活动范围而且移动的距离更长，尤其是在繁殖季节，罗兹博士说。 “它们穿越的马路越多，被车辆撞到的几率就越大，”他说。“如果我们保持较大的交通流量，我们依然有机会保护我们的考拉。加设道路防护比新建马路的方式更有效。” 昆士兰大学CEED中心的塔尔 波拉克女士领导的另一项研究中，研究人员开发了一个数学公式，减少现有道路对附近野生动物种群的影响。 “既然我们不能重建或改变建有道路，就需要用不同的方法来保护生活在公路附近的动物，”波拉克女士说。“这包括修建防护网让它们远离公路，以及修建地下或地上通道让它们安全地过马路。 “但直到现在我们也没有找到最具成本效益的方式来解决问题，因此我们开发了一个数学模型，保证动物的安全同时也把每一个美元都花在刀刃上。” 该模型包含的信息，如野生动物种群规模，附近道路的大小和交通流量，动物安全过马路的机会。然后模型显示出建设防护网、野生动物通道或不用对道路采取措施的性价比最高的方式，以及建设保护措施的最佳地点。 以考拉种群作为一个案例进行研究，研究人员发现，简单地建造更多的地上通道不是最好的解决方法。波拉克女士说。“举个例子，如果它的种群数量小，那么建设防护网而不是地上通道才是更有效的方式。在这种情况下，更重要的是要保护好我们所拥有的珍稀动物，而不是让它们冒着生命危险过马路。 研究人员说，司机也需要在保护野生动物方面发挥自己的作用。“超速行驶是考拉的一大杀手，特别是在黎明和黄昏的时间里，这时候是考拉最活跃的时候，”罗兹博士说。“我们应该严格遵守限速规定，黄昏或夜晚在路上行驶时要留心观察野生动物。” How smart roads can help koalas beat traffic Australian cities can keep their precious koalas from ending up as road kill – if they plan their roads properly, environmental scientists say. A new study at the ARC Centre of Excellence for Environmental Decisions (CEED) reveals that expanding existing highways, instead of building new roads, is the best way to minimise the impact of increasing traffic and growing cities on koalas. The team also developed a world-first mathematical model that helps determine the most cost-effective way to shield wildlife populations that live near roads – such as where to build fences, and over- or underpasses, to give these animals the best protection on limited conservation funds. "The impact of roads on wildlife is growing rapidly as we continue to expand our cities," says Dr Jonathan Rhodes from CEED and The University of Queensland (UQ). "Animals worldwide, including mammals, birds, reptiles and frogs, are increasingly threatened by high traffic volumes." Dr Rhodes explains that the effects include the loss of habitat, disturbances from human activities, and traffic accidents as the animals cross the road. "Take koalas for example – more than 3800 of them have been hit by cars between 1997 and 2008 in Queensland, and 85 per cent of these victims die. "While koalas spend most of their time up trees, they also need to travel along the ground to find food and mates. The key to minimise the number that get killed on roads as we expand our cities is more careful design of our road networks." The scientists studied whether koalas fare better when they have to cross a few large roads with more traffic, or many smaller roads with less traffic. They found that in most cases, having a large number of small roads results in significantly higher koala death rates than does having fewer larger roads. They also found that male koalas are more susceptible to getting hit by cars than females, as males have larger home ranges and move greater distances, especially during the breeding season, Dr Rhodes says. "The more roads they have to cross, the greater their chances of being hit by cars," he says. "If we want to accommodate higher traffic volumes and still have a chance of keeping our koalas, it's better to expand existing roads instead of building new ones." In another study, led by Ms Tal Polak of CEED and UQ, the researchers developed a mathematical formula to minimise the impact of existing roads on nearby wildlife populations. "Since we can't rebuild or change existing roads, various ways are used to protect animals that live close by," says Ms Polak. "This includes building fences to keep them off the road, and under- or overpasses that allow them to cross the road safely. "But up until now we didn't have a way to work out the most cost-effective way to do this. So we developed a mathematical model to work out how to ensure that the animals gain the most benefit per dollar spent." The model combines information such as the size of the wildlife population, the size and traffic volume of nearby roads, and the chances of the animal crossing the road safely. It then shows the cost-effectiveness of building a fence, a fence with a wildlife passage or leaving the road as is with no mitigation – as well as the best places to do so. Using a threatened koala population as a case study, the researchers found that simply building more overpasses isn't the best solution, Ms Polak says. "For example, if it's a small population, it's better to build a fence instead of an overpass. In these cases, it's more important to keep what we have instead of letting them risk their lives on the road." The researchers say motorists must also play their part in protecting wildlife. "Speeding is a major killer of koalas, especially at dawn and dusk, when they're the most active," says Dr Rhodes. "We should all stick to speed limits and be on the lookout for wildlife that is out on the roads at twilight or at night." |
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