by It was a good idea at the time: to build metal bridges over busy roads and bats would confuse them with trees, it was said. They would then try to climb over the pylons and, having been tricked into flying higher than usual, would avoid being hit by lorries and buses traveling on the road below. A widespread wildlife problem for the UK would be easily solved.
It was a compelling vision, and to achieve it, a total of £2m was spent on 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 Cambridge University. “The bridges didn’t work.”
Conservation researchers discovered that bats – from tiny pipistrelles to common noctules – were not taken by the metal cranes they were supposed to confuse with trees. As a result, they continued to fly at unsafe altitudes on busy roads. “The trouble was that the plan was based on faith and not science,” Sutherland added.
It’s a question that’s still all too common in conservation today, he claimed. Evidence is collected too often or used ineffectively, a process that leads to faulty decision-making and wasted resources. His group has been set up to stop this trend and ensure that scientific evidence is properly used before attempting to boost biodiversity or protect endangered species. Good ideas need to be backed up by good evidence before they are widely accepted, it is said.
As an example of a sound, evidence-based approach to conservation, they point to the story of the great blue butterfly. Phengaris arion almost extinct in the UK by the end of the last century but has been successfully reintroduced using intensive care to assess the true causes of its decline.
The great blue relies on red ants to raise its young. Its larvae are parasitic and feed on red ant stings. “The key discovery – made by Oxford ecologist Jeremy Thomas – was that great blues were looking for only one species of red ant, Mirmica sabuletiand it was decreasing in number.
“However, by changing grazing practices on grasslands M sabuleti lived, his fortune and numbers were restored, and after that were the heads of the great blues. This was achieved by understanding the threat, testing solutions and then acting on the results.”
Sutherland cited the strict rules used to gather evidence before taking action in medicine, the aviation industry and building design. “In these areas, a strict set of procedures are followed – at the start of an operation or take off – before any action is taken. That is what we need to do in conservation before we launch a project or take action. We must be sure that our actions are effective.”
This last point was illustrated by a study in Finland that looked at 10 of the most common actions taken in recent years to protect European birds of prey such as the Montagu’s humpback and the white-tailed eagle. Six of these actions were found to be highly effective. Two of them had no effect. And two of them were actually harmful, Sutherland said.
Relocating the nests to fenced areas to protect young birds of prey, for example, has been very successful. In contrast, marking nests to warn bird watchers and others of the presence of birds was harmful because research showed high chick losses from these nests. “The harm done to birds of prey in the name of protecting them clearly demonstrates the need for evidence-based action that relies on strong background research.”
To provide such a service, the Cambridge team works by gathering all relevant evidence from journals on conservation projects to create a database containing more than 3,000 peer-reviewed articles. “If you want to know what to do about a conservation problem, you can just look at it and get an answer.
“If you had done that for bats and road crossings, for example, you would have found some much more promising solutions, including building underpasses and culverts.”
It is vital that conservation projects are seen to be 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 improving, but they still want scientists and doctors get more information and improve treatments.
“The same goes for conservation. They want things to get better. However, we need to ensure that we have decision-making processes that get the best possible results in terms of boosting biodiversity. Some organisations, such as the Woodland Trust, do it well, but others often don’t get it right.”
Future projects
Conservation scientists have identified a range of issues that will require careful, evidence-based responses in the coming years.
• earthworms play a central role in soil fertility and nutrient recycling. Studies suggest that their numbers are now in serious decline in the UK, and that populations need to be restored.
• Many plans have been put forward for use ocean absorb increased amounts of carbon dioxide, including plans to boost algal growth through the use of fertilizers. But their global impacts must be properly assessed.
• Incidents of wildfires and biomass burning they are expected to become more frequent as the world progresses. Dealing with the release of harmful aerosols will require careful planning.
•Turning on hydrogen as an alternative to burning fossil fuels it will greatly help the fight against climate change. However, leakage from hydrogen production plants can have a harmful effect.
