By Staff
With another deer season now underway many deer hunters are again griping about the lack of deer. With the obscene deer populations we had in the late 90s we all grew accustomed to seeing a lot of deer. Even the most avid hunters agreed there were too many. Now that things are getting back in hand we're going through a bit of withdrawal. However, in many places we still have too many deer.
We all know there is a maximum number of deer a given piece of habitat can support. What most of us don't realize is there's a big difference between CAN support and SHOULD support. The goal from the earliest days of deer management has been to have the most deer possible without going over that tenuous boundary into winter starvation and big population swings. We are now discovering, though, that this maximum population approach is devastating the ecosystem. Over browsing by deer has changed the entire structure of much of our forests.
Until the 1960s or so there just weren't many deer around. Surely many of you remember when it was a big deal just to see a deer. Long term studies comparing all the plants growing in deer habitat prior to the big deer boom and those remaining now show that in average deer habitat 20 percent of the original plant species are now gone. In some cases it's much more. We're finding this is largely due to excessive deer browsing.
Deer browse on all manner of young trees, forest plants and wildflowers throughout the year. Unlike grasses, when the top of a tree or plant is nipped off its health and growth is severely retarded. It's unlikely such an injured plant will make the difficult journey through the overhead canopy to find sunlight, mature and develop seed. Areas of states like Michigan and Wisconsin are rapidly losing important species such as hemlock and white cedar largely as a result of deer browsing. Between 1950 and 2000 A study area at Lake Gogebic in the U.P. had lost 75 percent of its plant species almost entirely due to over browsing.
Recently a botanist was strolling the Pennsylvania woods. He came across a number of rock outcroppings and decided to scale them. At the tops of the outcroppings that deer could not access he found the most diverse and lush mini-ecosystems. Young trees were healthy and thriving, a wide variety of plants and wildflowers were robust with huge blooms. On adjacent outcroppings that deer could access the mini-ecosystems were quite different. There was little undergrowth and what was there was anemic. The saplings were just stubs with shoots sprouting out the sides and the dismal display of flowers and other plants were stunted and frail. He determined that on the deer proof sites the vegetation was three times as dense, 30 percent larger and sported 40 times more blooms. It was a startling example of the effects of deer browsing.
To sum it up, too many deer simplify a forest. A forest may look intact but it has lost its diversity. This has far reaching consequences. Ground dwelling birds no longer find the berries, insects and shelter they need and their numbers are drastically declining. Deer mice and other small mammals that depend on acorns also eat gypsy moth pupae. With all the acorns in deer's bellies the mice disappear and gypsy moths flourish to further devastate the forests.
These simplified forests do function to a degree and their openness even looks appealing. Its obvious they CAN support the amount of deer they do, at least in the short term, but SHOULD they? Not if we want the everlasting, diverse, healthy ecosystem that mother nature intended. The great Aldo Leopold pointed this out over a half century ago when he wrote, "Just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer." Carpe diem.
Larry Lyons writes a weekly outdoor column. Reach him at larrylyons@beanstalk.net