Save the Amazon rainforests. Save the whales. Save the giant pandas.
The conservation movement has historically focused on protecting a specific species or its habitat, but there are a lot of species and habitats to save—far too many to make slogans for them all. As humanity’s footprint continues to expand, the list continues to grow, spurring scientists to find a more sophisticated—though less glamorous — way to protect biodiversity. According to a new study, we may only need to protect a little more land to preserve a significantly greater amount of biodiversity.
The paper by Laura Pollock, Wilfried Thuiller, and Walter Jetz argues that strategies for more efficiently conserving biodiversity can pinpoint areas that could be significant contributors to global diversity–more specifically, that a 5% expansion of protected land could as much as triple the amount of protected biodiversity.
In the past, conservation often meant rounding up endangered species and building a fence around them. But biologists know it’s not that simple.
For one, there’s more than one type of biodiversity. For a long time, scientists primarily considered only the number of species in a protected area. But now studies like this latest one also consider phylogenetic diversity, or the degree to which the tree of life is well represented, as well as functional diversity, such as the variety of diets or body sizes, present in an ecosystem.
Scientists also have to balance preserving high densities of biodiversity at the local level and wide ranges of biodiversity at a global level. It’s a matter of choosing between whether “we want to capture every little piece of biodiversity” or try to maximize biodiversity in certain areas, said Pollock, a postdoc at University of Grenoble in France.
Pollock and her colleagues’ paper maps out which unprotected parts of the globe, if protected, would maximize each of these three facets of biodiversity—species, phylogenetic, and functional—for both mammals and birds. While other papers have looked at each of these aspects before, none have applied as broad a scope as Pollock’s. “What’s novel is the application to a global scale,” said Marc Cadotte, an associate professor researching conservation, ecology, and evolution at University of Toronto-Scarborough who did not contribute to this paper. “It’s nice to see this all coming together to a global view of conservation.”
Conservation by Big Data
Such in-depth, large-scale analyses require a finely organized library of data and a wealth of processing power. Jetz said that this paper was six to eight years in the making—four to six years of organizing genetic data into a reasonable approximation of the tree of life, followed by two years of analyzing the data, including running algorithms that search for the most efficient ways to conserve biodiversity. “It’s computationally quite tricky to run these,” he said.
Before, simpler analyses assumed that conserving the most diverse areas would protect the most biodiversity. When deciding whether to protect an area, biologists would only consider whether this or other areas contained more biodiversity. In their analysis, Pollock and her team didn’t assume that the most diverse areas are the most important. Instead, they checked all of the possible combinations of areas to see which protect the most biodiversity as a whole. It’s not unlike IBM’s computer Deep Blue’s strategy for defeating Grandmaster Garry Kasparov in chess, in which the computer assessed almost all possible moves for each of its turns.
The benefit of these cumbersome analyses is that they do a much better job of conserving biodiversity than traditional methods, according to the study. Pollock and her team found that their algorithms expanded protected land by just 5% but included over 1,500 more bird species than simply prioritizing diverse areas. “We were able to much more efficiently—that is, over much less space and with much less resources—conserve more of the tree of life and functional diversity,” Jetz said.
It’s not a universal solution, though. Local and global conservation require two very different strategies. The end goal “matters a lot in terms of which areas you would protect,” Pollock said.
Her study also found that strategies for conserving phylogenetic and species diversity were more similar than strategies for saving functional diversity. In other words, if you’re trying to protect large chunks of the tree of life, you’ll probably succeed in conserving a lot of different species. But you might omit important functions in the ecosystem, perhaps cutting out a key link in the food chain, for example.
Improving efficiency is a priority for conservation biologists because so much biodiversity is either poorly protected or not protected at all. According to the paper, 13% of the bird tree of life and 23% of the mammal tree of life are unprotected. Even in protected areas, diversity has suffered. Pollock said that around a quarter of all species worldwide are absent from any protected area, a fact she finds “alarming.” And even diversity currently well-contained could be lost in the future. There continue to be problems worldwide with underfunded and poorly managed conservation sites, Cadotte said, as well as sites ravaged by poachers, leaving species that are theoretically protected still vulnerable to extinction.
Pollock and her colleagues intend to replicate and refine their methods. Future iterations of the study could use more data about each species’ role in the ecosystem, Jetz said, particularly for tropical species. They could also include a more detailed mammalian tree of life, as well as more finely grained spatial maps.
To him, improvements will come not from improved methods but from expanded data sets, saying that progress will “require good old-fashioned observations from the field.” Scientists only began collecting phylogenetic and functional data in the last 20 years, a relatively short time ago compared with other data. Pollock said that more work also needs to be done linking their methods to specific conservation goals, such as determining which approaches are better for global priorities than local priorities or which conserve a greater swath of the tree of life over ecosystem functions.
The authors hope their approach will be useful both for policy makers and non-governmental organizations. Pollock sees the study not so much as rewriting the rulebook for conservation as simply shifting a perspective. “We need to start taking a broader look at these other metrics at the same time because we do not want to miss really important species,” she said.
Interactive maps of global biodiversity distributions could help groups trying to shape public policy, Jetz said, pointing out that policy makers take notice when their country sticks out on conservation maps as a global priority.
While the plans ultimately will be carried out by local governments and organizations, the global approach shouldn’t be forgotten, Pollock said. “Conservation is very narrowly focused…we very rarely look at a broader scale,” she said. “Taking a step back and keeping that larger perspective in mind when doing local conservation would be an ideal way forward.”