The Spitsbergen-reindeer, also known as Svalbard-reindeer, has seen a lot of ups and downs since it came to Spitsbergen from the Russian Arctic thousands of years ago. It became a sub-species on its own which is not found anywhere outside Svalbard. Nevertheless, it was hunted almost to extinction until it was finally protected by the Norwegian government in 1925 – soon after the Spitsbergen Treaty had given Norway the power to do this. Estimates of the reindeer population from the early 20th century are a mere 1000 animals – for the whole Spitsbergen archipelago!
Spitsbergen-reindeer: two strong males. Straumsland, east Spitsbergen.
Spitsbergen reindeer can disperse, and while doing so, they can cross glaciers, solid fjord ice and even drifting sea ice. Otherwise, they would obviously never have made it to Spitsbergen in the first place. But as long as they are happy in a given area, they tend to stay where they are, so it can take many decades until they re-populise remote areas where they became extinct in the past.
The local populations are subject to strong dynamics. Weather extremes are an important factor: in bad years, when strong rainfall on snow-covered ground in the winter with subsequent freezing covers the tundra with a layer of ice, many reindeer can starve to death later when the fat reserves are used up and the vegetation is still under ice. This is especially the case when the population is actually already too big for the area. In Adventdalen near Longyearbyen, the population has doubled in the last 10 years.
Other reindeer may die during accidents in steep and slippery terrain after winter rainfall. In the winter of 2018-2019, several reindeer died in the vicinity of Longyearbyen, where strong rainfall occurred in December. Some had obviously fallen down steep slopes, while have probably starved to death later. In such cases, local populations may experience a significant decrease. If such episodes happen several times over subsequent years, it may even lead to local exctinction. The event of the 2018-19 did, however, not have significant consequences for the local population.
Dead Spitsbergen-reindeer at Operafjellet, east of Longyearbyen:
the exact cause of death is unknown, but either falling down from a steep, icy slope or starvation are likely.
On the other hand, the population may increase again quickly in good years. In spring 2017, for example, reindeer in Adventdalen increased quickly again in numbers due to favourable conditions.
Next to weather fluctuations, climate change is an important factor on a longer time scale, moving from months and single years (weather) up to decades (climate): an increasing frequency of strong winter rainfall may make life more difficult for reindeer, while more luxurious growth of tundra vegetation can provide more food, supporting a bigger population. Currently it seems as if Spitsbergen reindeer benefit from increased vegetation growth at least in some areas. On top of that comes the population recovery after the ban on hunting in 1925, a development that is probably still going on as reindeer continue to move back to areas where there were no reindeer in decades during the 20th century.
It becomes evident that reindeer population dynamics are a complex matter which is influenced by a number of factors. Reason enough to have a good look at the current population. Earlier estimates where rather fragmental in space and time. Now, a team of scientists made a proper census for the whole Svalbard archipelago. Proper counts where completed with distance sampling of transects where necessary to cover large and mostly rather inaccessible areas. The group around biologist Mathilde Le Moullec has now published their results in The Journal of Wildlife Management.
Unusually large group of reindeer in Krossfjord, an area where reindeer did not exist during decades or even centuries.
The key message: the total population of reindeer in Svalbard is now estimated at a good 22,000 animals. The “exact” number is 22,435, with a 95% confidence interval from 21,452 to 23,425. In 2009, the number was still estimated between 10,000 and 11,000. Today’s larger number may at least partly have to do with an actually increased population, including an increase in population because of recovery from past excessive hunting, as a consequence of protection in 1925, but the better quality and the more complete spatial approach are certainly also likely to be a significant factor influencing the now updated numbers.
Today, reindeer are even found again in remote areas as Kong Karls Land, where they did not occur over longer periods, although they existed there before Europeans started to frequent Spitsbergen in 1596, when Willem Barentsz discovered the islands.
The population density varies a lot between different areas. Vegetation is believed to be a key factor. In some areas, they may be up to 10 reindeer per square kilometre – locally, even more – while one animal will need the same area or more on its own to find enough food in sparsely vegetated areas such as the polar desert landscape of Nordaustland.
The recent study was published on 04 October: Mathilde Le Moullec et al (2019), A Century of Conservation: The Ongoing Recovery of Svalbard Reindeer. In: The Journal of Wildlife Management, Vol. 83, 1676-1686.