Monday, May 27, 2013
Milder winters, warmer summers spell trouble for the gentle comeback kid of our boreal forests.
Not long ago, it was a cool, new thing to see a moose track here in the woods of the Monadnock highlands.
Around here, it was in the late ‘80s and early ‘90s. I’d stand over those tracks and think about the moose’s remarkable comeback, the resilience of our forests and our fortune of sharing wild places with this big and gentle mammal.
It was a reminder that our forests are connected to something bigger, like the northern Appalachians and the great boreal forest that stretches across the top of North America.
It was a reminder that wildlife – like our forests – can be resilient. While moose were once abundant here, their numbers crashed with agricultural clearing in the 18th and 19th centuries. By 1898, only 13 moose remained in New Hampshire. But as forests returned, eventually moose did, too, with their numbers really picking up in the 1970s, generally moving north to south.
By 1988, New Hampshire had enough moose to sustain its first modern, scientifically managed moose hunt, with 75 permits drawn by lottery. By 2006 and 2007, permits peaked at 675 statewide.
That’s when the slow decline started. Not because of the hunt, but because of greater, more complex forces at play. In 2012, reflecting the moose’s downward population trend, the N.H. Fish and Game Department issued 275 permits. In 2014, the department is likely to issue fewer permits.
Now, the sight of moose tracks here in our Monadnock hills is a remarkable sight again, but for different reasons than years ago. Now, it’s a sign of vulnerability, a reminder that we’re connected to something far greater than the great boreal forest.
Moose across North America are in trouble. And though the reasons are complex, biologists pin the blame on warming winters and summers – if not climate change in general.
The Triple Whammy
Moose are getting whacked from all directions. And it’s not good.
In the past few years, the warming trends in both winter and summer have contributed to New Hampshire’s moose numbers declining in every part of the state, except in the far northern area of Pittsburg. Some regions, like the White Mountains and central part where moose once held strong numbers, have seen precipitous declines.
The first whammy comes with our well-documented warming summers. When temperatures get high, moose seek shady shelter and settle down; they don’t feed. And by not feeding, their well-being declines, and they become susceptible to disease and parasites. Female moose (cows) affected by this weight loss are less likely to give birth to twin calves – as usual for healthy cows – and more likely to have one calf or none at all.
The second whammy comes as warmer winters actually help deer numbers. White-tailed deer are a vector for brain worm, though they survive brain worm just fine. Moose aren’t so lucky. Brain worm is fatal for moose; and more deer means more brain worm.
The final whammy is even uglier: ticks. Specifically a species called winter tick. A single moose can host tens of thousands of winter ticks, feeding on the moose’s blood and engorging until they drop, usually in April. If those ticks drop on snow, they’re far less likely to survive to their next life cycle. If they drop on snow-less ground, they’re more likely to survive, reproduce and find their next moose host. And increasingly, our Aprils are snowless.
Moose with tick infestations – 30,000 to 150,000 on a single moose! – can lose their winter coats and encounter hypothermia. Tick-infested moose can also suffer from anemia and can ultimately succumb. Research by the University of New Hampshire and N.H. Fish and Game Department has documented the extent of winter ticks on moose and their impact. The research has found that over a five-year period beginning in 2001, tick infestations accounted for 41 percent of the state’s moose mortality.
Keep in mind that moose are near the southern end of their range in New Hampshire.
So, environmental impacts like weather are more likely to affect moose here at their margins than say, in the heart of their northern habitats.
This Is Climate Change
How bad is it? The combination of factors in this triple whammy is dropping moose numbers throughout the state. In Minnesota, wildlife officials recently called off the state’s moose 2013 hunting season, citing a 35 percent drop of moose numbers from the previous season and a 65 percent decline since 2008. They stressed that moose-hunting is not the cause of this precipitous decline.
Eric Orff is a retired N.H. Fish and Game wildlife biologist who now works for the National Wildlife Federation and is now a member of the state’s Fish and Game Commission. Little more than a decade ago, the 11-member N.H. Fish and Game Commission openly pooh-poohed and scoffed at climate change and its impacts on wildlife.
Not so anymore. As a member of the governor-appointed commission, Orff is publicly making the case through speaking appearances, op-ed pieces and blogs that climate change is harming New Hampshire’s fish and wildlife, including its poster-child comeback kid, the moose.
So, the next time you see a moose track around here, think about it. How long are we going to be so lucky to share our world with moose? And what are we going to do to save them?
Eric Aldrich writes from his home in Hancock.