Above: Pleistocene fossils. Below: a modern glacier. The glaciers never reached Florida, but the climate there was still much cooler and drier than it is today.
Students were impressed with the scenery on the way to Ichetucknee Springs State Park. Such clear water…such COLD water. East Aiken arrived on January 21, 2000.
Despite a wintry chill, several hearty souls went for a quick dip in the river. It wasn’t so much the water temperature that got to them as the air temperature. After all, the spring water emerging from deep underground is a relatively constant 70°F no matter what time of year.
Even in a short dive one student noticed a neat find on the bottom—a black bone. An Ice Age fossil!
The most recent Ice Age was part of a geological time period, or epoch, known as the Pleistocene epoch that extended from about 2 million years ago until 10,000 years ago. Fossils similar to those that East Aiken kids saw on the bottom of the Ichetucknee River are evidence of the ecology of that time period—mastodons, wooly mammoths, ancient horses, camels, tapirs, giant armadillos—to name but a few. What an unbelievable landscape it was only a short time ago!
During the Pleistocene there were repeated advances and retreats of great ice sheets, or glaciers, across the continents. During some periods more of the Earth’s water was contained in those glaciers, resulting in sea levels that were as much as 400 feet lower than sea levels today. Glaciers today cover only about one-third of the area that was covered at the Pleistocene glacial maximum.
Glaciers did not reach Florida, but this is not to say that the Pleistocene was no different than today. The ocean alternately flooded and retreated from the land. Many of the present-day springs, lakes and rivers were formed during the Pleistocene. At times of maximum glaciation (i.e., lowest water level) Florida was much larger, and extended almost 100 miles farther west into the Gulf of Mexico.
Much of the unglaciated Southeast probably experienced a much colder, drier climate than the climate today. Scientists who study plant pollen discovered that many northern species of plants actually lived in the South during Pleistocene times. Pleistocene Florida probably looked somewhat like a grass savanna in Africa does today.
Of course, when glaciers melted, as they did several times during the Pleistocene, sea levels would rise during the interglacial periods. During these times much of Florida was flooded, and central Florida was a chain of islands. These sea level rises and falls from long ago still play a role in where plants and animals are found today.
Growing up to be a ... Herpetologist?!?
by Alison L. Whitlock, Wildlife Biologist, National Wildlife Refuge System USFWS NE Regional Office
Weighing a turtle
As I leaned forward ever so slowly, I heard a large dog growl and a deep gruff voice say, "You know you’re trespassing." These sudden and loud threats came from the road 10 feet behind me. But I was not on the road. I was precariously balanced between two large sedge tussocks, trying to avoid stepping into an unknown depth of muck, and trying to be as quiet as I could; I was sneaking up on some basking spotted turtles, and I was close. Until my new friends startled me. I slipped waist-deep into the mud, the turtles dove off into the water, and the dog lunged toward me. It was now time to haul myself out and convince both dog and landowner I was no threat. I knew I’d be spending the next hour explaining my research, saying "yes, I know how deep the mud is," and "yes, I know there are snapping turtles in there."
I am a herpetologist. I specialize in turtles. When I was a small girl the boys would suddenly present bullfrogs close to my face to scare me. But I kissed the frogs’ noses instead. Or I took the frog (or lizard, or snake) from the boys and and released the harmless herp (our common name for all reptiles and amphibians) back to the wild. I would collect frog eggs every spring from a garden reflecting pool when the maintenance men would come to drain and clean it. The eggs would hatch in the 20 buckets I had on my porch and when the pool was refilled, I would release the surviving tadpoles to the pool. Many of them died under my care because, while I meant to help, I did not know how to properly care for them.
A muddy Alison
I grew up loving wild animals and by 12 wanted to be a veterinarian and by 17 knew that I wanted to be a wildlife biologist. Early on in my college education I found out that, while we heard about sea turtles in the news quite often, no one really heard much about the freshwater turtles in our own neighborhoods. And until very recently, no one heard about how many species in the wild are rapidly declining in numbers. Part of the problem is that their habitat is being destroyed so we humans can keep spreading our houses and stores across the landscape. And part of the problem is that there are many people, adults and kids, who, like me at 8 years old, pick these animals up and take them home because we like them and want to help them.
Measuring a turtle
My interest in wildlife conservation has taken me to many places to study many animals, such as birds and finback whales. I went to graduate school to look at the threats of road development on reptiles in New England for my Master’s degree, and to study the ecology of bog turtles for my Ph.D. I have spent untold numbers of hours in the mud trying to determine whether wild populations of turtles are surviving or not. We try to tell this by figuring out how many there are in a population, if they are producing young, and if they can live to a healthy old age. What we’re learning is that turtles need every one of their number to make a healthy, or "viable" population. That means we have to help by reducing the chances that they will be run over by cars, or being picked up and taken for pets. We need to protect them by allowing them to stay safe in their own wild habitats.
I spend a lot of time going to schools and giving talks. It seems people will be more likely to believe that reptiles need protection and that even snapping turtles are not evil if a woman can hold them without fear. I am now a wildlife biologist for the U.S. Fish and Wildlife Service, and part of my job is to make land protection plans and help buy important wildlife habitat for preservation. And you can bet that if that land has muck, tussocks, and turtles, I’ll do everything I can to protect it.