Along the east coast of Florida, the ridge down the center of the state, and the Big Bend and Panhandle, we find the “scrub country,” meaning that it includes among its beaches, orange groves, sand- and phosphate-mining pits and fishing camps the remnants of a huge semi-arid scrub habitat that reached all the way around the Gulf coast to northern Mexico a couple of million years ago. The contiguity of the habitat has long since been interrupted by rising sea levels that produced, among other things, the bayou country. What remains are islands of similar plants and animals that have been separated from their brethren for a long time. The independent changes that have occurred in the fragmented plant and animal species are of tremendous interest to biologists and zoologists, and the information about mutations and short-term evolutionary changes could (and does) fill numerous books.
[Example: a species of jay called the Scrub Jay that’s genetically identical to its relatives elsewhere, but whose courting rituals have changed to a point of no longer facilitating breeding with birds from outside its own area. They could make babies, but instead ignore each other’s courting displays. Basically, they just don’t get the “come on”. This discovery alone has altered the definition of “species” throughout zoology.]
Well, unfortunately for the scrub in central Florida and along the east coast where another isolated stretch occurs, it’s not exactly prepossessing real estate. The predominant trees are dwarfed and shriveled-looking scrub oaks, some pines that tend to grow close to the ground and lean a lot, and pignut hickory. Beneath those are found some truly vicious cacti called “prickly pears” that sport four-inch thorns like needles, equipped with microscopic barbs that take a couple of cc’s of your flesh along with them when they’re pulled out. (Trust me on that.) In between the patches of cacti are scrub rosemary and all sorts of less noticeable plants. Dominant animal species tend to be exciting things like gopher tortoises (who eat the prickly pears) odd-looking striped lizards, the aforementioned jays, and numerous insects and other small critters. Foxes, cottontail rabbits and bobcats occasionally visit from surrounding lowlands. Essentially, it’s a pretty useless-looking place.
However, the scrub is home to more rare and endangered plants and animals in one area than most anywhere else in the continental US. These include the tortoises, lizards and–among the plants–the only known flowering plant in the world that spends its entire life underground, facilitated by the translucent quartz sand that allows light to penetrate the few centimeters to where the plant lives. Only the blossom of the tiny plant protrudes above the surface for a short time each year to allow pollination.
Historically, the well-drained and geologically stable scrub regions have been seen as prime locations for orange groves, highway and railroad rights-of-way, industrial areas, quartz sand mines and similar intrusions. Arid habitats are fragile, and despite the average 50 inches of annual rainfall in that part of Florida, the scrub is dry most of the time. Plants adapted to such environments grow slowly. A set of tire tracks from a model T Ford, laid down in the 1920’s, might still be visible in the disturbed ground cover. Once the system has been completely disrupted by–say–an orange grove, it will never exist again in its original form regardless of efforts to achieve that end.
Another issue is the need for fire. The smaller plants and trees of the scrub, including the sand pines and oaks that help to stabilize the soil, are adapted to periodic burning (usually caused by lightning strikes in this, the thunderstorm capital of the world.) The seeds of the sand pines won’t even germinate unless they’ve been subjected to high heat. Generally speaking, fires in areas of orange groves and housing developments are frowned upon. Thus the necessary periodic burns are rarely permitted to happen. As much as that bodes ill for survival of the ecosystem, it gets even worse. Vines and bushes, unburned, get too big, grow up too far on the trees, create too much easily-burnable undergrowth, and when the inevitable fires finally do occur they burn so hot and high that they permanently kill the plants they ought to be helping. And once an arid or semi-arid habitat is gone, whether Florida scrub or Tibetan high desert, it’s simply gone. Finis. Never to return.
Why is this important? Simple. We find uses every day for plants and animals that were never dreamed of previously–not the uses, and often not even the organisms. Who knows what is being destroyed in the scrub? A cure for cancer? The answer to questions about genetics and heredity that might lead to valuable knowledge about human behavior? An ability observed in one of those highly specialized lizards that might lead to our being able to live on (or in) the arid surface of Mars? We never know from what source the next discovery will spring. In the case of the scrub habitats some discoveries will never be made. Others are at risk. So are thousands of undiscovered species and their undiscovered benefits elsewhere around the world, from the rain forests of Indonesia and the Amazon to the windy deserts high on the slopes of the Himalaya and Alaska Ranges. We evolved on this planet. It’s only logical that many of the living things we evolved with could be of use to us, if we knew about them. If we ever know about them.