Why are most Arctic species found nowhere else?
What is the impact of human activity in the Arctic on species that live there?
These are just some of the questions about polar biodiversity that came flooding into the Facebook Live event we hosted recently in Svalbard, for WWF’s #WWFVoices. We had viewers from Sri Lanka to Sierra Leone, tuning in to see the mystery and the majesty of Arctic wildlife which undoubtedly captivated audiences all around the world.
Capturing that mystery was what brought me to the Arctic – along with the magic of Arctic wildlife – and, as a conservation biologist, to work to share some lessons about Arctic biodiversity with #WWFVoices.
#WWFVoices (you can find out more by using #WWFVoices as a hashtag on your favorite social media channels, or as a web search) is a digital campaign for global conservation organization
First, let’s rewind and unpack what ‘biodiversity’ is. First and foremost it is a descriptor and a metric, or rather a series of metrics, which describe the variety of life in a given place. This is measured primarily along two axes – how many species you have, and how common those species are. So it is incredibly important scientifically and is often used to help makes the argument for conservation of a given area. The other key word here is ‘endemic’ – this simply means the species is found nowhere else in the world. A location that has high biodiversity and high endemism are usually considered of the highest value for conservation. However, for the Polar Regions, which for any given area, no matter how well preserved it is, struggle to score well on account of both terms, the metrics alone don’t tell the full story.
It should be said that the fact that any life survives here in the High Arctic is rather remarkable. NASA estimates that around 85 percent of the northern archipelago of Franz Josef Land is covered in ice, while in winter temperatures plummet as low as -40°C. Hostile conditions to life indeed. However, survive it does, albeit with the small caveat of the Latitudinal Diversity Gradient.
What is this? Well, the Latitudinal Diversity Gradient is one of the most fundamental rules of biogeography, a school of ecology that looks beyond individual species at the big pictures of biodiversity, sometimes all the way up to a global scale – so it’s incredibly crucial to conservation biology. What it says is that biodiversity is (roughly speaking) highest at the equator, in the tropics, and steadily decreases as you move towards the poles. A devilishly simple trend to identify, vexingly difficult to unpick.
Although they might have lots of suggestions – ranging from a reduction in energy from incoming solar radiation to recent theories of a pest-pressure hypothesis – scientists can’t definitively prove why the Latitudinal Diversity Gradient occurs. What we do know is that it does occur, and that it holds up pretty well to rigorous testing.
What this means in practice is that the biodiversity of the Arctic is comparatively rare. No raucous dawn chorus of the tropics, no canopy surveys where every second individual is a new species. No, here life is rare.
That is part of what makes this environment so special because of course, that doesn’t mean that the environment here is any less important. The species here are almost all specialists – a biological term that describes species adapted to fill a very particular niche, often correlating with inhabiting a particular environmental space. Think about a polar bear (Ursus maritimus) – adapted to live in one of the harshest environments on Earth, but would struggle immensely outside of its natural habitat (in say, the tropics, or a hot, arid climate). That means that many of the species found in the Arctic are found nowhere else in the world.
There are relatively few Arctic species, so the same species might be found in different locations (though with some notable exceptions, the real gems of the Arctic, which are rare outside of a specific location), for example in both Franz Josef Land and Svalbard, but many of them are rarely found outside of the Arctic as a whole. Think about any of the terrestrial Arctic species – like the Arctic fox (Vulpes lagopus), Arctic wolf (Canis lupus arctos), or Svalbard reindeer (Rangifer tarandus platyrhynchus) - and they are largely, or wholly, restricted to the Arctic. Endemism to a region or biome, rather than a specific location, if you will.
Specialist species tend to out-perform all others in the environments which they call home (which can seem hostile or extreme), but struggle with changes to the specific conditions they are so well adapted to. And, in the Arctic, those changes are all too real - and all too often come in the form of climate change.
Although Poseidon’s Expedition Team reported not having seen significant changes in Franz Josef Land – they’ve been coming this far north for three years now, building up a wealth of experience (experience that I would continuously rely on) in the process – those living in neighbouring Svalbard report having seen significant changes over their time there. Considering that those I was speaking to have resided in Svalbard for less than a decade, this is doubly concerning.
For those lucky enough to visit the Arctic, while the wildlife is rare, the sightings are uniquely memorable. It took days of searching to find a walrus (Odobenus rosmarus) haul-out - an area of land where these large pinnipeds gather in large numbers in the summer months. The experience of finally coming across the mass of rolling blubber and the sheer smell of so many walruses packed in along a narrow strip of land is something that will stay with everyone for a long time, even after the scent has faded from their clothes.
Humans are obsessed with measurements and calculations, and as scientists, we are arguably the very worst of the lot in that regard. Moreover, we tend to judge the biological value of environments using metrics and measurements. Those metrics are useful, but that doesn’t do full justice to the polar regions, where the Latitudinal Diversity Gradient holds true, and life is rare. Perhaps the Arctic reminds us that there is more to the remarkable value of life than can be measured or counted. That is something worth celebrating.-------------------------------------------------------------------------------------------------------------------------------------
Joshua Powell is a founding member of #WWFVoices. A Conservation Biologist and National Geographic Young Explorer from the UK, Josh’s research is interested in conservation strategy, including the management of human-wildlife conflict, anti-poaching capability for wildlife ranger forces, and transboundary conservation. Josh was a Thouron Scholar and Churchill Fellow, and in 2016 was named one of the St Gallen Symposium’s ‘Leaders of Tomorrow’ in Switzerland.