news
Grassroots
August 2017
Vol. 17, No. 3
wildebeests in the Serengeti exploit the habitat. “You can take one satellite image and you can sense the productivity — where the grass is greenest — based on reflectance patterns. And you can create a layer showing where all the wildebeests are, and see if they are tracking the productivity of the environment well.” Another overlay factors in the “landscape of risk,” he says — that is, a predator attack is more likely on the edge of a forest, or near one of the rock outcrops called kopjes, or at a watering hole. “Then you can ask how all that maps onto the migration corridor,” to understand the importance of protected areas, especially in the face of increasing human development. Over the years, McCauley’s team and collaborators at the University of Glasgow have tracked several dozen wildebeests using radio collars. “This year, we don’t want to track two more,” he says, “we want to track 200,000” via satellite.
McCauley describes the rapidly improving view from outer space as “a macroscope.” It should also be a major boost for dwindling conservation program budgets, because the data is often available at no cost — and at much less risk for the researchers. In a study of U.S. biologists killed during research or management work from 1937 to 2000, two-thirds died as a result of air accidents. “I don’t think we are ever going to get away from people in airplanes doing some biology,” says David Johnston. “But for things that are especially dangerous, like over the water,” or in remote polar regions, satellite images are at least as good.
So why haven’t more wildlife researchers rushed to take advantage of satellite data? Partly because of scientific fiefdoms, says Nathalie Pettorelli, of the Zoological Society of London. “Biological tradition is built on going outside and working with species. But the development of remote sensors and the use of satellite data have mainly happened in geography departments. Those two disciplines haven’t been used to working together. They don’t share common terminologies. A remote sensing expert will tell you about land cover, and a biologist will tell you about ecosystems. So you have to reconcile those viewpoints.”
“For the moment, a lot of biologists have no idea what remote sensing is, how to get the data, and how to use the data.” When Pettorelli first turned to satellite data to help determine how environmental change is affecting biodiversity and ecosystem services, biologists told her it was a bad idea. “There are people who don’t trust satellite data,” she says. They consider it “competition with ground data,” though in reality satellite and ground data often enhance each other, as happened with the Cape Cod seals. Meanwhile, the remote sensing experts “were telling me it’s too complex, you need to hire somebody. I didn’t have money to hire somebody, and I just learned more and more how to do it myself.”
Lack of training remains an obstacle to broader reliance on satellite data, she says, “particularly in developing countries where people could get the most out of it, where there is no money for large on-the-ground studies,” or for airplane surveys. “But for the moment a lot of biologists have no idea what remote sensing is, how to get the data, how to use the data.”
That lack of familiarity with the nuances of satellite data is also an impediment at the global level, says Pettorelli. Under the Convention on Biological Diversity, the 196 party nations have a series of targets to achieve by 2020 for the conservation of protected areas and the protection of plant and wildlife diversity. The only way to monitor progress in a timely and economical way is by satellite, says Pettorelli. But with just three years to go, participants still haven’t even agreed on which space-based indicators to rely on. Building trust in satellite data among her fellow biologists remains a painfully slow process.
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