Most of us in the Northeast just see Florida as an escape from our cold winters. Yet, ecologically it’s a special place: 11% of all the vegetation consists of species that are endemic to the state. Scrub jays, whose 1-year old offspring help their mother raise new chicks, are found nowhere else. The same applies to 13 species of fish, amphibians, reptiles and mammals. But technology, wealth and the escape-perception have severely impacted these organisms and their ecosystems. And it has also made human residents there more vulnerable.
To make more land available for home building and agriculture, 19th and 20th century developers in Florida drained swamps and cut down forests. In addition, wetlands bordering bays, lakes, and rivers were filled in. To manage shorelines where much of the growing population concentrated, seawalls were built. From overuse, the state’s shallow aquifers have also become increasingly stressed, and the Everglades National Park, though protected from further development since 1947, receives insufficient water.
Luckily, there are active conservationists in the state. The Jupiter Inlet Lighthouse Outstanding Natural Area is part of the Bureau of Land Management’s 27-million acre National Landscape Conservation System. As we walked through the area, I noticed a few scattered animal trails as they scurried across the path before the trail’s concrete had a chance to set. It was comforting to see evidence of animals advertised at the park’s entrance. The rate at which concrete sets—a series of reactions in which calcium silicates get hydrated –—increases with temperature. So if these tracks are authentic, it reveals that the animals all crossed in less than 12 hours.
A few miles away, at the Jupiter Ridge Natural Area, I spotted a southern species of lichen, the powder-puff. (Cladina evansii) Lichens consist of a pair of mutualistic organisms, a sac fungus and an algae. The fungus secretes acids and dissolves minerals from its rocky or woody substrate. In return, the green algae provide carbohydrates. If nitrogen-fixing cyanobacteria partners up with the fungus, ammonium ion is also bartered. Florida’s powdery puffy lichen is not poisonous, like over 99.9% of the 20 000 lichen species. That does not imply that it is palatable. Unless you’re a reindeer whose four-chambered rumen harbors microorganisms and protists who can break down the lichen’s fiber and acids, you can’t eat it raw. You have to first treat it with bicarbonate or ashes, which are alkaline.
I was reminded that lichens are sensitive to pollution because of their structure—they essentially consist of a pair of fungus-networks that sandwich algal cells. There’s no tissue or wax acting as a barrier or buffer against environmental contaminants. Most students and teachers don’t realize that when they use litmus to test pH, they are in fact using lichen extracts.The United States Forest Service lists ways of using lichen to monitor sulfur dioxide, nitrogen oxides, acid deposition, ozone and a number of other pollutants.
To thrive, lichen need clean air, undisturbed surfaces and time. It’s also the prescription needed by Florida’s ecosystems.