Saturday, June 18, 2011

Massive winter die off

Well, it's late June, the snow's finally gone, all marmots have finally emerged and we're figuring out what happened last winter.  First approximations suggest that we had unprecedented mortality:  50% of the adults died and over 80% of the pups died since early September last year!  It was a remarkably long winter--one of the three heaviest snowfall years--very delayed snowmelt...not so good for marmots.  

To put this into perspective, your average adult female has a 10% chance of dieing each year and about 50% of the pups survive to be yearlings.

How will this affect our research?  Well, the population biology studies march on...these are natural data.  However, sample sizes are smaller for some of the experimental work this year.  With luck, the population will begin to grow again next year.  But, strange things can happen to small populations...a few too many road kills...some additional predator kills...a few females unable to find males to mate with...and the population could crash more.  Indeed, this sort of randomness that happens at small population sizes is one of the primary reasons why we need to maintain large populations if we're to ensure their survival.

Long term research has many surprises and going from the largest population size to the biggest population crash was certainly a surprise for me.

1 comment:

  1. I find this interesting as I have a cottage at LaCasa Resort in Kelowna and they are now considering killing off some of the Marmot population. They say the population has exploded this year and that they are just pests that eat the grass and people's bushes, plants,etc. We love watching them and even though they have eaten some of our plants, we are just furious that they are going to kill them and pay out $150.00 per marmot killed. What happens next year when we may have very few and the population dies off? It sickens me to know that because a few people consider them pests they are just destroyed.