August 1, 2016

The Habitat You Drive Through

By Danica Melone, Marketing Intern

I find it curious that I never before considered how and why I saw animals running through roadways, often becoming roadkill. To some extent I could sense it was partly from human encroachment on lands where the animals once thrived without limitations. However, this consideration came full circle while listening to one of our naturalists speak about opossums and how the species have been using highways as a habitat for some time. Well, sort of.

It all begins with the advent of the automobile. At that time, meager roadways existed for steam-powered trolleys and other such transportation, but there was nothing like the main arterial highways of today. As the automobile picked up in popularity, the need for roads led to development of newly constructed highway systems. These highways, and other roadways, became attractive to animals such as opossums for a slew of reasons. On the edges, roads offer minimal vegetation, almost field-like (picture the unkempt lawn-length grass that small rodents and animals can hide in and scavenge for seeds.) For many New England highways, just past the long grasses is usually the forest wall. This is where, on the edge of the forest and beside the highway, that animals like the opossum have found a fitting habitat where they’re able to find food sources: berries and seeds, insects, saplings, and the herbivores like meadow voles or white footed mice, who feed on this vegetation. Unfortunately, we often find the animals living here as roadkill.

The opossum, an omnivorous scavenger also facing human encroachment in its habitat, began moving north after the advent of the automobile, into southern and central New Hampshire. Though not all of the New Hampshire opossum population resides next to a highway, many opossum find it a rewarding habitat for the food supply, forest shelters, and living space. So why haven’t opossums continued moving north and over the White Mountains? Looking at photos of an opossum, you may notice that their protection from the cold and wind is rather limited. The exposed ears, tail, and feet of opossums are threatened by the cold temperatures and are susceptible to frostbite even in the southern part of the state. It’s clear that opossums, North America’s only marsupial species (like a koala or kangaroo), are not well-suited to the climate in New Hampshire and thus hints at the concept of this species utilizing roadway systems as a habitat over the past century.

For me, a commuter driving the highways of New Hampshire for over an hour in total each day, I began noticing the breadth and frequency of species near the highway - both alive and deceased. I noted that besides the opossums, I saw other wildlife near the roadway usually for one presumable purpose: food. For instance, the raptors circling above I had initially assumed may be there for the hot air rising from the pavement, but I soon began questioning “well, why this hot air mass over that hot air mass?” Further down the highway I watched as two vultures tugged a white-tailed deer from the break-down lane into the drainage ditch. This was my answer; there’s a constant food supply here for everyone sharing the habitat. From the driver’s seat in my hatchback I could watch butterflies and other insects buzzing around a laurel bush positioned in the median of the highway; squirrels scurrying out of sight with their seeds; white-tailed deer grazing in the tall grasses; and two crows pulling unrecognizable carrion from a rumble strip.

Remarkably, these animals are able to accommodate changes to their habitat, accepting that fast moving cars are a part of daily life whether it is noise, pollution, or the moments when our cars become top-of-the-food-chain predators, running down these critters. Though it may be too late to reverse the industrial revolution, or for that matter, reverse the damage the industrial revolution brought unto our environment and society, it is not too late to consider the future. I find it both intriguing and humbling to consider this during my long commutes: the impact on the future generations of these species that are adapting to their highway habitat.

Here are some interesting topics to think about if you also have a long commute:
  • Did you see a live animal? Wonder: does it seem to be living nearby, or running for its life to never come back? Does it have babies? Could it have babies? What’s the lifespan of the animal (and possible babies) if it’s using a highway habitat? At what rate is it ingesting chemicals from cars and air pollution (like windshield washer fluid)? And the list goes on…. 
  • Did you see a dead animal? Wonder: If it’s an opossum, which have pouches for their newborns, could it have babies that were also killed? How does the death of an adult and/or baby opossums affect the opossum population? How does its/their death affect the ecosystem where it once lived?
Feel free to leave any questions or comments at the bottom and I’ll answer as soon as I can, and as well I can!

Night-time driving tip: When watching for animals at night, chances are when they hear your car they’ll turn their head towards the noise. This gives you the opportunity of catching the split second they are looking into your headlights, and the light is bouncing off their tapetums. The tapetum is a reflective sheet covering the back of the eyeball in most animals, like a dog when you take their picture. The reason we can’t see this reflection during the day time is because tapetums exist to help animals see better at night by amplifying the light source. Ultimately when that picture of your dog or cat is developed and he has red eyes, this is because the flash, combined with the effects of the tapetum, illuminated blood vessels in his eyes. Therefore, watching for the flash of your high beams off an animal’s tapetums is a great way of identifying if an animal is up ahead before it’s too late.

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