4 ways climate change is killing the caribou

By Carl Young

April 29, 2019

Caribou populations have declined by more than half in the last 20 years, and climate change is one of the significant factors influencing their rapid decline. Mother nature can work in mysterious ways, here's how warmer temperatures are affecting caribou:

1. Vegetation

When spring arrives earlier than caribou internal clocks dictate, it negatively impacts their migration habits and hinders their foraging capabilities. Caribou migration patterns are in tune with the availability of their food sources. Earlier seasons means that vegetation has passed it's nutritional peak by the time caribou arrive to their spring and summer ranges, which requires more energy spent foraging for the same amount of nutritional intake. 

In addition, warmer temperatures also leads to a change of vegetation. “Warming means other, taller vegetation is growing and the lichen are being out-competed.”, says Howard Epstein, an environmental scientist from the University of Virginia who worked on the 2018 Arctic Report Card from the NOAA.


2. Parasites

Higher temperatures also cause longer parasitic seasons, especially warble and bot flies which lay eggs in caribou skin. This prolonged contact harms caribou by decreasing their feeding time, increasing their energy expenditure and lowering their ability to store fat.


While parasitic exposure is a nuisance and somewhat dangerous to adult caribou, it is incredibly harmful to calves who are much less tolerant to the invasion.  


3. Rain-on-snow

As caribou go into winter, increased temperatures continue to escalate the situation by melting top layers of snow into ice preventing caribou from digging through the snow easily to find food. This essentially strips away their only energy source that is not based on dwindling fat from the previous summer.


Unfortunately for caribou, especially young calves, insufficient levels of stored fat combined with difficulty finding food makes it incredibly difficult for them to survive the harshness of winter.


4. Disappearing sea ice

As with polar bears, the caribou are yet another species that depend on sea ice for their expansive migration routes. The instability of sea ice on historic routes disrupts the cycle of migration from summer range to winter range to spring calving grounds, and limits access to the resources they rely on to battle the severe conditions of the Arctic.

The change in climate resulting in higher temperature averages are greatly impacting caribou survival and contributing to the rapid decline of caribou populations. With your help through financial contributions, our goal is to create an extensive caribou conservation plan through thorough research to address the challenges facing caribou and map the way for survival of this incredible species in their natural habitats.



NOAA; www.arctic.noaa.gov; "2018 Arctic Report Card; Migratory Tundra Caribou and Wild Reindeer'; D. E. Russell, A. Gunn, S. Kutz, 2018