Panda poop and eyes in the sky
The paper in Nature Ecology & Evolution is here: http://go.nature.com/2xu6Q9N
Scrambling up the steep slope was hard work. The vegetation was thick, the elevation high enough to notice and, yes, I hated to admit it, I wasn’t as young as I once was. Finally, struggling through a dense stand of bamboo, I found why we were there, with no explanation from my companions.
There was what they charmingly call “panda poops” lying in piles in an opening where the bamboos had been flattened down. They weren’t smelly, indeed, smelled of fresh bamboo, and were neat packets of what looked like the barely digested grass. We’d missed the panda, but not by long.
The giant panda is the most iconic endangered species. Not all endangered species are hard to find, but pandas are. They are cryptic and live at low densities in some of the most spectacular mountains on Earth. All this makes counting them extremely hard. Unless we can count them, we won’t know whether conservation efforts are improving their status.
What those who survey pandas usually find are the obvious and very recognisable droppings that we had stumbled upon. The standard way to count pandas is measuring these droppings and distinguishing individual pandas by their different sizes of the mouthfuls of bamboos they digest.
All this makes estimating the changes in panda numbers over time and over their entire geographical range a considerable challenge. So my Chinese colleagues and I analysed four decades of satellite imagery to understand how the changes in land use. One change was obvious just from when I first visited these areas with them in 2002 and the situation today: there are more and better roads. That makes travelling a lot easier, but it fragments the habitats.
The Chinese authorities have protected much more of the panda habitat in recent years. (And, in doing so, they are protecting many other species that are endemic to the part of China — see Li BV, Pimm SL. (2016) China’s endemic vertebrates sheltering under the protective umbrella of the giant panda. Conservation Biology. 30:329-339.) They also stopped the forestry that until 1999 was a major cause of habitat loss. But while our study showed improvements, they also confirmed that the fragmentation of the habitat has increased substantially.
There’s one major solution to that — to create habitat corridors whenever possible. Many pandas now live in small, isolated populations, where their long-term viability is unlikely. It’s what my group and I have been doing elsewhere in the world through the non-profit I direct — SavingSpecies (www.savingspecies.org).
Using remote sensing and GIS to aid assessments of threatened species is not new, but its use is now expanding rapidly. A recent study we completed on birds worldwide showed that substantially more species are likely to be at risk of extinction, when one examines remote sensing to estimate how much habitat remains (see Ocampo-Peñuela N, Jenkins CN, Vijay V, Li BV, Pimm SL. Incorporating explicit geospatial data shows more species at risk of extinction than the current Red List. Science Advances (2016);2(11):e1601367).
Of course, remote sensing doesn’t replace the hard slog of foot surveys. But it does provide vital insights into how our world — and the panda’s world — is changing.
Stuart Pimm is the Doris Duke Professor of Conservation at Duke University and President of SavingSpecies.
Photographs are the author’s except panda, reproduced with permission of Dr. Binbin Li.