The Big Sandy Mountaineer -

Drought harms more than just the landscape

 

January 3, 2018



Drought impacts wildlife, too.

As we enter the season of complaining about the snow and cold, reminders of this summer’s drought remain in the form of haystacks, cows and pocketbooks that are all far too thin. The same is true for deer and other wildlife species. Some impacts of the drought were immediate, like low chick survival for pheasants and sharptails. Lack of moisture meant low numbers of beetles and other bugs that provide protein critical for chicks to grow during the first couple weeks of life. Poor chick production equates to disappointed hunters, since young-of-the-year birds typically comprise over 75% of the harvest.

Other impacts will take longer to notice. For deer, every winter is a test of endurance. They rely on stored fat reserves to make up the difference between their daily energy expenditures and what few calories they can consume. Most of their winter diet consists of woody browse. This year’s drought has left many deer in poorer-than-average condition. Fawns are noticeably smaller than normal. Even slight deficits in stored fat reserves can have big impacts. “Almost” doesn’t count if you’re a deer desperately trying to make it to spring green-up. Of course, a lot will depend on what winter brings. Mild so far, but deep snows or bitterly cold temperatures cause deer to use up precious energy at a faster rate.

Even in the absence of hunting, normal overwinter mortality is around 25% for deer (and we expect that figure may be higher this year)—that’s why we say hunting mortality is “compensatory”—it doesn’t impact population levels. In fact, heavier harvest during times like this is a good thing. You reduce the number of mouths on the landscape. You split those critical and limited winter resources between fewer deer. The result is higher overwinter survival. Fewer fetal resorptions and abortions (starvation is the #1 cause of both), and more fawns hit the ground in the spring. Does in good body condition produce more and better-quality milk, and stronger fawns more capable of surviving the following winter. It’s somewhat counterintuitive, but by harvesting heavier in the fall, you can actually end up with more deer on the landscape the following year. It’s similar to a rancher cutting numbers. If you have 150 cows but only hay enough for 100, it makes sense to sell off 50 rather than risk your whole herd starving or not producing healthy calves in the spring.

Vegetation is not only important for nutrition, but also for cover. In years like this when vegetation production is low, utilization is high. We saw emergency haying and grazing of CRP, folks cutting anything and everything possible for hay - all necessary things to help ranchers stay alive in this tough year, but all things that reduce cover for wildlife. We all know that cover is critical for upland game birds through all walks of life. Game birds and eggs are tasty, but without adequate cover they are vulnerable to both ground-based and aerial predators. Newborn deer, elk and antelope fawns in the ‘hider’ stage rely on holding still in heavy cover to avoid predation. Cover also has thermal benefits, protecting wildlife from wind and blowing snow.

This year’s drought will no doubt benefit coyotes, as it will be easier to find a meal this winter and coming spring, but the negative impacts to game species will continue. With any luck, next year will be a wet one—with lots of complaints about rain and mud.

 
 

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