Algorithmic Analysis Leads to Efficient Approach for Plant Conservation

Pimm and Jenkins lead the conservation nonprofit Saving Species, which works with local communities and international agencies to purchase and protect threatened lands critical for biodiversity.

Joppa, who earned his Ph.D. in ecology from Duke in 2009, worked with his colleagues to use computer algorithms to identify the smallest set of regions worldwide that could contain the largest numbers of plant species. He took a few minutes to explain how that process worked.

“We used a combination of ‘greedy algorithms’ and ‘genetic algorithms’ to figure out how to fit as many species as possible into the smallest amount of area,” he says. “Our greedy algorithm worked by picking the region with the most number of species in the smallest area and then asking which region—when added to the one already chosen—increased the number of species the most while increasing the amount of total area the least.

“This is a fairly straightforward approach, but the results are often non-obvious. This is especially true for ‘endemic species,’ those species found in a region or a set of regions and nowhere else. Thus our algorithm was constantly trying to trade off picking small areas with just a few species—such as islands—where all the species are endemic only to that island, versus picking larger regions—such as the central Amazon—that have very many species, but proportionately not as many species found only within that region.”

That, however, can be a delicate undertaking.

“The reason it is tricky,” Joppa confirms, “is because if, after choosing that central Amazon region, you then choose the regions next to it, you might suddenly have most of the species endemic to that broad set of regions. How can you possibly know if that is going to be the case? Well, it is hard, and that is where the computation comes in. But it provides some fascinating insights into the way that biodiversity is distributed around the planet—what species are shared with what regions, for example, is one of ecology’s oldest questions.

“This approach allows us to take a different angle when asking the question and provides very practical biodiversity conservation insights, as well. We then used a different approach—genetic algorithms—to confirm that our solutions were indeed near-optimal.”

The researchers who collaborated on the study analyzed data on more than 100,000 flowering-plant species to identify which regions contain the highest concentrations of endemic species relative to their geographic size.

The species data had been compiled by the Royal Botanic Gardens, commonly known as Kew Gardens and located in southwest London. Its biodiversity databases are among the largest in the world and, Joppa says, were integral to the study.

“Absolutely critical,” he says. “Without the efforts of all the taxonomists and other scientists who have collected the data, scientifically described the species, and provided information on where they are from, we would be left with nothing.

“Even after all that work, though, it would have still been impossible if Kew and their associated partners hadn’t done such an incredible service by providing those data back to the scientific community via web-accessible data portals. Information technology is just as important for successful environmental research as it is for running successful corporations. In that regard, this was a job very well done by the botanical-gardens community, Kew Gardens in particular.”

Joppa and Visconti created and ran the complex algorithms to analyze the large spatial database. Jenkins, meanwhile, created a color-coded global map identifying high-priority regions for plant conservation, ranked by endemic-species density. That led to another interesting observation.

“We also mapped where the greatest numbers of small-ranged birds, mammals, and amphibians occur,” says Jenkins, a research scholar at North Carolina State, “and found that they are broadly in the same places we show to be priorities for plants. Preserving these lands for plants will benefit many animals, too.”

Joppa’s online biography begins with a simple statement—“I work to conserve ecological systems”—and recently, his work has been gaining increasing notice. He is serving as an Honorary Research Fellow at the University of Kent’s Durrell Institute for Conservation and Ecology, as an Honorary Conservation Fellow at the Zoological Society of London, and as an adviser on science and innovation to the United Nation Environment Programme’s World Conservation Monitoring Centre. This year, he received the Society for Conservation Biology’s Early Career Conservationist Award.

These are exciting times to pursue such research. As Pimm, Doris Duke Professor of Conservation Ecology at Duke’s Nicholas School of the Environment, observes, two of the most ambitious goals established by the 2010 Convention on Biological Diversity—protection of 60 percent of Earth’s plant species and 17 percent of its land surface—are within reach.

“To achieve these goals, we need to protect much more land, on average, than we currently do,” he says, “and much more in key places such as Madagascar, New Guinea, and Ecuador. Our study identifies regions of importance.”

For Joppa, the challenge in enticing.

“The obvious next step is to narrow in on these regions and identify the actual places that are most appropriate to locate new protected areas,” he says. “What we did in our study highlighted broad regions of the world that are important for the conservation community to focus on, but we can’t simply just protect an entire country. Instead, we have to use more nuanced data and insights within those places to figure out the optimal places to protect. This includes thinking about the current and future threats to an area’s biodiversity, the cost of conserving it, the probability of success, and the various conservation options available.

“These are all areas of research that I have been pursuing for my entire career. While next steps can often seem daunting, you can understand why I’m also hugely excited just thinking about the work remaining to be done.”