The days of Rudolph, Dancer and Prancer in recent decades, have been numbered and it’s possible that the threats from global landscape and climate change may force Santa Claus to find a new mode of transport in 2020. But what are the real reasons driving the decline of these majestic herd animals across North America and Canada? Do we have more to do with it than we want to admit… are we infringing on that naughty list after all?
Threats to the species bring a whole new meaning to the infamous ‘run Forest run’ quote
Starting with the large hoofed mammal in the room… it’s important to note that Caribou are actually the same species as reindeer, Rangifer tarandus. While there are some differences between populations living in different locations across the globe; Caribou are native to North America, whereas reindeer are native to northern Europe and Asia.
Their life span is around 15 years and for those populations of migratory caribou in North America, they spend most of their time on the move, displaying the longest terrestrial migrations anywhere on the planet. In northwest Alaska, some caribou travel up to 2,737 miles per year!
Most students sometimes struggle to identify with this amount of physical exercise, but try and put yourself in the mind of a caribou or King Julian for at least a few seconds. © Tenor Gifs
Migration makes sense. It’s a distinctive behavioural trait of caribou and appears to represent not only an effective strategy to escape predation but a clever means of making the most of abundant food sources. For example in summer abundant grasses and plants of the northern tundra are an excellent source of food for the caribou, especially for mothers feeding their new born calves. Then in winter its a journey south to feed on lichen and avoid the worst of the cold climate.
A global decline
Caribou and reindeer herds are declining across Earth’s north polar range, with thirty-four out of the forty-three main herds being monitored during the past decade, taking on rapid population decrease. The scary looking red figure below shows that overall herds have declined an average of 57% from historical population maxima… now imagine if that 57% eradication was in the human or dog population? Would we care a little more?
Red is hardly ever good… blood, death, decline? Well in this figure it brings a visual depiction of census data for the decreasing caribou herd size around the northern regions. Green regions represent herds where growth was observed and grey are populations which are data insufficient.
Why? It’s all up in the air… literally
As is turns out, these heard number declines coincide with increasing arctic temperatures and precipitation. Arctic surface air temperature which have warmed at twice the rate of anywhere else on Earth, now think as a caribou, for a temperature change to double in a period of only a few decades, you’d be quite confused wouldn’t you? Now accompany that air temperature rise with erratic increases in rain and higher frequencies of random yet extreme weather events, e.g. freezing rain. The environment these animals live in will dramatically change in response to the new climates. What does that mean for our courageous caribou? It means their food sources will be limited by those new environmental conditions. Brings the meaning of hangry to a whole new level!
Food is their fuel. And a car (especially one that travels a heck of a lot) can’t run without fuel.
Migratory species may experience seasonal limitations in good quality food and altered floral species composition (different mixes of foods) as a result of changing climates. This is what fundamentally drives their movements. However in response to rapidly changing climates, the timing of migration might be later or earlier than normal. Further afield, as they move north or south, there may not be enough of their food source as they were pushed into early or late migration at a time when the vegetation is not abundant in new locations. Because of the sheer rate at which these environmental conditions have been changing, the Caribou have not had time to adapt and within populations there starts to be heightened competition for resources like food. In Ecology this is what’s known as infraspecific competition. Competition and starving animals can mean one thing, deaths.
Ecosystems are Patchy
Another significant stress on the caribou population is landscape change. Namely forestry, mineral extraction and petroleum infrastructure have fragmented Caribou habitat and sealed off the narrow corridors which have been open to Caribou for centuries to move between calving and summer ranges in the north and winter range in the south.
It’s happened before, and it’s happening again
Caribou perform the last remaining large‐scale ungulate migration in the northern hemisphere and have remained long after human activities of the past like intensive hunting and habitat change have eradicated less resilient species such as bison (Bison bison) and saiga antelope (Saiga tatarica), in a similar geographical area. The same fate could lie with our beloved Rudolph and co. if we don’t start to address the driving force behind the causes of these declines.
Why should we care?
With conflict and urgent requirements of our own species to deal with, some might find it difficult to understand why Caribou population decline matters (add a personal level of exam and deadline stress to the mix and it seams even less so). But fundamentally the threat of extinction for this majestic species who have found such a home in the commercial and traditional culture of humans, symbolises a much larger theme. Over exploitation.
Is it our consumption killing the Caribou after all?