When I first moved to my home in Raleigh nearly 15 years ago, I was impressed with how the City of Oaks managed to maintain a woodsy natural environment with tree-filled neighborhoods ringing the downtown area.
As anyone who has driven through the area now knows, it was only a matter of time before many of these pristine areas would be discovered as desirable sites for new homes, a trend that has escalated as the region shrugged off the economic recession and doubled down on development.
In all directions, older homes with roomy lots are being torn down to make way for larger homes on smaller parcels of property. That’s a good sign for our economy and a reasonable pattern of growth, considering the negative consequences of urban sprawl.
But as a gardener concerned with wildlife, I’ve started to wonder what will happen to the animals that also make their homes in the region – particularly amphibians and reptiles.
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I posed this question to Jeffrey Beane, herpetology manager at the N.C. Museum of Natural Sciences. He referred me to a paper he has co-written on this subject, appropriately titled “Reptiles and Amphibians in Your Backyard.”
The first thing that struck me was the sheer variety of herpetofauna (science-speak for amphibians and reptiles) that live in our area – more than 100 species. It’s one area where the Southeast is actually ahead of the rest of the nation.
The next revelation was just how vulnerable these creatures are to environmental changes.
Although herps have been around for more than 350 million years, many species are now in decline. While for many of us, reptiles and amphibians lack the charismatic appeal of some mammals, they play an important role in the animal kingdom as both predators and prey. They help control our insect population and, in turn, are eaten by birds, foxes and others.
Some even have been found to possess life-saving attributes, such as the Australian red-eyed tree frog, whose skin is used in a compound that fights HIV infections.
Because of their sensitive nature, the absence of amphibians and reptiles may signal problems in the overall environment.
As cold-blooded ectotherms, herps must manage their bodies’ own heating and cooling systems by adapting their behavior based on the environment. That may mean crawling atop a sun-soaked rock to warm up or or tunneling beneath a pile of leaves to escape the heat.
Three of the biggest threats to herps in a rapidly developing environment are traffic, water pollution and loss of of existing habitat, Beane said.
It stands to reason that heavier traffic and/or road construction brings a greater chance that snakes, frogs, lizards, turtles and other creatures will become roadkill as they move slowly from one area to another. A toad, for example, first emerges as a tadpole that needs water to survive, but later grows legs and starts looking to move to a dryer but still moist, shady neighborhood. When those two environments are bisected by a road or another type of barrier, the toad’s life becomes much more complicated – and dangerous.
As for pollution, the biggest culprits are sedimentation and toxins. North Carolina has a Sedimentation and Pollution Control Act intended to limit the amount of runoff that occurs on properties that are under development. But most folks in the Triangle region have seen what happens on a graded lot during a thunderstorm. Without grass, trees or shrubs to absorb it, the water washes tons of dirt and silt into the road, as well as other low-lying areas nearby.
One result, as Beane points out, is silt and dirt accumulating in ponds and streams, choking out the oxygen needed by insects and plants, which, in turn, are dietary necessities for amphibians and reptiles.
In addition to washing sediment into streams, rainwater also may wash toxins into waterways. These include certain fertilizers, herbicides, insecticides and petroleum products that can harm herps in several ways: by soaking into their bodies through their permeable skin or killing their food sources, such as insects.
While there’s little that a backyard gardener can do to stop the explosion of development – even if he or she wanted to – there’s a lot we can do to mitigate the damage by providing additional habitat options.
▪ Adding a pond or other small water feature can provide a safe spot for tadpoles and other amphibians to grow to adulthood.
▪ Plant native wildlife species to replace the diminishing natural landscape in which the species has evolved.
▪ Create shelter by allowing grass to grow taller, building a brush or rock pile.
Although they may not be as charismatic as some of our other woodland fauna, herps have still deserve a place in our neighborhood ecosystem.