Pinning it on the Polar Bear
It’s an image that is ubiquitous in the media when the words ‘climate change’ pop up. The lone polar bear, drifting through the sea on a single ice floe. It is an effective image, evoking emotions like pity, loneliness and general despair for the plight of what has become the flagship species of what seems like the entire Arctic. But is associating the health of an entire ecosystem with one species useful, or dangerous?
Arctic ecologists have been worried about the polar bear (Ursus maritimus) for quite a while now. In the 90s, the first primary research was published which suggested that a warming climate could lead to a decline in their populations. Polar bears are dependent on sea ice to hunt ringed and bearded seals, ice which is now breaking up earlier than ever before. The southernmost populations of polar bears historically fasted over the summer, as sea ice becomes sparse an unreliable. However as summers have extended, the period over which polar bears would need to fast becomes untenable. There have been direct links shown between the length of the ice-free period and polar bear weight the next. Researchers have predicted declines in the southernmost populations first, which will eventually extend further north in the polar bear’s historic range.
So yes, the polar bear could face population declines and a range constriction as the planet warms. Though they could also adapt, and maintain a stable population, although perhaps at lower numbers. This isn’t what has made them the poster-child for climate change in the Arctic though.
A flagship species is one that is used to raise concern about or funding for an ecosystem. This is the polar bear to a tee – they’ve come to represent the plight of the Arctic in the face of climate change. And since the Arctic is being affected by climate change at a faster rate than other parts of the world, they’ve come to represent the impact of climate change itself. Flagship species are generally charismatic. Charismatic species are often large and/or mammalian and/or carnivores, all of which fit the polar bear. In 2014, Jean-Michel Roberge showed that the polar bear was by far the most tweeted species, being shown or mentioned on Twitter almost 4 times as much as the next species (the American bison). The scene of the polar bear struggling to find prey among a pack of walruses in Attenborough’s Planet Earth was one of the series’ most iconic scenes (although BOY did the walruses get theirs in the second season).
But is linking the health of the Arctic to the persistence of the polar bear a good idea? We know that Arctic ecosystems are facing a multitude of challenges outside of sea ice break-up, both relating to the planet’s biodiversity and to a rising climate. Rising temperatures are forcing other species further north and throwing food webs into chaos. Overfishing and Arctic aquaculture industries continue to threaten biodiversity and fish sustainability. The thawing of permafrost could release massive amounts of carbon into the atmosphere, kicking off a negative feedback loop. Reindeer populations are facing increased losses as rain falls earlier in the year and freezes. The list goes on. The point is, that if polar bear populations do find a way to stabilise or adapt, there are still a cacophony of problems that the Arctic faces.
There IS actually a decent chance that the polar bear will persist, too. Several populations of polar bears have maintained productivity in the face of the adversity presented by the loss of sea ice, with many adapting to new food sources like whale carcasses and snow geese. Those populations seem to be doing ok, while populations that are still heavily dependent on seals seem to be facing declines. The gradual nature of climate change means that other populations may still have time to adapt their diet, though what that may mean for human/polar-bear interactions is also a potential problem.
The question then becomes – if the polar bear persists, does public concern for the Arctic wane? This is the problem with linking the health of the planet so closely to one species.
It’s a problem that the International Union for the Conservation of Nature is well aware of. In 2009 at the Copenhagen climate change conference, they proposed ten additional species to be used as flagship species to “share the polar bear’s burden”. Unfortunately, a year later there was no sign that any of them had been actively used for their intended purpose.
Ultimately this comes down to the same issue that we’ve talked about multiple times on Ecology for the Masses. That it’s hard to get people to care about an abstract concept like an ecosystem without a tangible, charismatic object to lock onto. Overcoming that hurdle requires an enormous shift in how we talk about conservation (and nature in general) to the public, away from single species and towards the concept of an ecological community. Until then we have to hope that a) the polar bear survives the effects of climate change, and b) that if it does, our efforts in halting the degradation of the Arctic landscape will not suffer because of it.
Effects of climate warming on polar bears: a review of the evidence by Stirling and Derocher, 2012.