Climate Change              
                                     
 

Biologists have noticed an increasing "natural" mortality within the Porcupine Caribou herd. They are uncertain of the causes but climate change may be a contributing factor. The annual average temperature and summer temperatures in the north have shown a slight but significant increase in the last one hundred years.
Scientists also predict other changes to environmental conditions will occur as a result of climate change, including more snowfall in winter, faster snow melt in spring and a greater number of thaw days during spring migration periods. An increase in snow depth in winter means that the caribou will spend more time and energy digging craters to access food and less time eating in a day. Deeper snow also makes escaping from predators more difficult.
 
Rising temperatures result in an earlier green-up of vegetation which is helping newborn calves, but the earleir green-up means that vegetation dies earlier. If caribou cannot get enough nutrient rich food, they cannot build up enough energy to survive the winter. Increasing summer temperatures can also lead to higher levels of insect harassment, which can also lead to the caribou spending less time eating in a day.
 

Faster snow melt and a greater number of thaw days during spring change the structure of the snow making it more difficult for caribou to travel and feed.

    
Overall, the cumulative effects of climate change can work to reduce the amount of time available to the caribou for feeding and increase the amount of energy that the caribou must expend which can work to decrease the condition of the Porcupine Caribou herd.
     
Interesting Link: Porcupine Caribou Herd Population Model    
   
Group 8 : Brandi Smithson : Anthony Jjumba : Geog 351 : Fall 06