IIt seemed like a good idea at the time: build metal bridges over busy roads and bats would mistake them for trees, it was argued. They would then attempt to soar over the masts and, having been tricked into flying higher than normal, would avoid being hit by trucks and buses traveling on the road below. A widespread wildlife problem for the UK will be solved in one fell swoop.
It was a compelling vision, and to realize it, a total of £2 million was spent building 15 bat bridges across Britain, from Cumbria to Cornwall. “However, there was one problem,” said Professor William Sutherland of the Conservation Science Group at the University of Cambridge. “The bridges didn’t work.”
Conservation researchers found that bats – from tiny pipistrelles to common noctules – were not impressed by the metal portals they were supposed to mistake for trees. As a result, they continued to fly over busy roads at low, unsafe altitudes. “The problem was that the plan was based on faith and not on science,” Sutherland added.
It’s an issue that’s still all too common in conservation today, he argues. Evidence is either collected too little or used inefficiently, a process that leads to faulty decision-making and wasted resources. His group was founded to reverse this trend and ensure that scientific evidence is properly used before attempting to promote biodiversity or protect an endangered species. Good ideas need to be backed up by good evidence before they are widely adopted, it is argued.
As an example of proper, evidence-based approaches to conservation, they point to the story of the big blue butterfly. Phengaris arion was practically extinct in the United Kingdom by the end of the last century, but has been successfully reintroduced with the aid of careful care to determine the real causes of its decline.
The big blue relies on red ants to raise its young. Its larva is parasitic and feeds on red ants. “The crucial discovery – made by Oxford ecologist Jeremy Thomas – was that great blues sought out only one species of red ant, Myrmica sabuletiand it decreased in numbers.
“However, by changing grazing practices on grasslands where M sabuleti lived, his fortunes and numbers were restored, and in turn so were those of the great blue. This was achieved by understanding the threat, testing solutions and then acting on the results.”
Sutherland pointed to the strict rules used to gather evidence before taking action in medicine, the aerospace industry and building design. “In these fields, a strict set of procedures – at the start of an operation or at take-off – is followed before any action is taken. This is what we must do in conservation before we launch a project or take action. We must be sure that our actions are effective.”
This last point was demonstrated by a Finnish study that looked at 10 of the most common actions taken in recent years to control European birds of prey such as the Montagu’s harrier and the white-tailed eagle. Six of those actions were found to be very effective. Two of them had no effect. And two of them were actually harmful, Sutherland said.
The relocation of nests to fenced areas has been very successful in protecting young raptors, for example. In contrast, marking nests to warn birders and others that they contain young is harmful because research has shown that it results in high losses of chicks from nests. “The fact that raptors have been harmed in the name of protecting them clearly illustrates the need to take action that is evidence-based and relies on strong background research.”
To provide such a service, the Cambridge team works by collecting all relevant evidence on conservation projects from journals to create a database containing more than 3,000 review articles. “If you want to know what to do about a conservation problem, you can just look it up and get an answer.
“If you had done this for bats and road crossings, for example, you would have found a number of much more promising solutions, including building culverts and culverts.”
It is crucial that conservation projects are seen as effective, Sutherland added. “People support conservation in the same way that they give money to cancer research – in the latter case, because they know that cancer practice is good and getting better, but they still want scientists and doctors to find out more and improve treatments.
“The same goes for conservation. They want things to get better. However, we need to make sure that we have decision-making processes that get the best results we can in terms of promoting biodiversity. Some organisations, such as the Woodland Trust, do this well, but too often it is not done properly by others.”
Future projects
Conservation scientists have identified a range of issues that will require careful evidence-based responses in the coming years.
Earthworms play a key role in soil fertility and nutrient recycling. Studies suggest that their numbers are now in dramatic decline in the UK, and populations need to be restored.
Numerous plans have been suggested to use oceans absorb increased amounts of carbon dioxide, including plans to boost algae growth by using fertilizers. But their global impact needs to be properly assessed.
Incidents of wildfires and biomass burning expected to become more frequent as the world warms. Dealing with the release of harmful aerosols will require careful planning.
