Last Saturday, I graduated from the Florida Master Naturalist program. That means I successfully completed 3 modules (Freshwater wetlands, Upland Ecosystems, and Coastal Ecosystems) of 40 contact hours each. Each class component involved classroom work, field work, and a final project. For the Wetlands course I developed a powerpoint presentation (exciting!) on Wetland birds and Coastal Warming. I delivered the talk at Green Cay Nature Center‘s Migration Day celebration last October. That day was the one and only day in my life that I actually had laryngitis. Despite my underwhelming vocal apparatus, Don Campbell, the manager of the nature center, invited my back this year for another lecture.
So this Saturday, I’ll present a modified version of the talk I just developed for the Coastal Ecosystems class, dealing with shorebirds and sea-level rise. You see, the issues here are pretty crucial for a low-lying state like Florida:
All of the ecosystems of south Florida arose during the Holocene period–yesterday, geologically speaking (geologists refer to this period as having begun .01 million years before present). Such newness might explain Florida’s relative lack of shorebird fauna despite seemingly perfect habitat: 1350 miles of coastline with sandy beaches, dunes, tidal flats, and estuaries galore. Many species have been migrating enormous distances for tens to hundreds of thousands of years. They’re professionals. Their genes tell them that, even though that peninsula down there might look tempting, it’s a sucker’s bet to put down roots there, because to them, it’s still underwater. And you know what? They’re probably right. But many shorter-distance migrants have found Florida in the last 5000 years, and it has become a refuge for important populations of wintering shorebirds willing to roll the dice on the continued existence of the peninsula above the waters of the Atlantic Ocean and Gulf of Mexico.
Coastal birds in Florida and around the world face multiple conservation challenges from human-induced changes to their environment: habitat destruction, disease, increased predation pressure, and changes in food supplies. One of the greatest threats in Florida, though, comes from rising sea level. Higher stands of sea level increase beach erosion, reducing the available habitat for both migrating and wintering species. And the birds’ adaptation strategies have evolved to deal with this threat. However, now these birds, which have survived for so long in a naturally fluctuating landscape (the Florida peninsula has been alternately submergent and emergent dozens of times in the last 10 million years alone), face a new threat: human efforts to combat sea-level rise through hardening the coastline in search of some “permanent” (at least in human time frames) solution to the problem of beach erosion. Such hardening simply increases the built footprint on our coasts, while completely failing to halt either sea-level rise (can you hold back the sea?) or the associated erosion.
Heavy coastal development in Florida is a result of our love of the beach and our desire to live as close to it as possible. In this, we’re very much like the shorebirds. Unlike them, though, we’re loving our beaches to death. Because we live in some cases literally on top of the dunes, property owners are threatened with losses by normal storm tides and wind events. Add a higher stand of sea level into the mix and you get an even greater sense of urgency to “protect” the beach. All too often the methods chosen do little to stop erosion, though, and in most cases they actually increase it. Such is the case with almost all “hardening” of coastal property. Seawalls, revetments, groins, and jetties interfere with longshore drift, increase erosion down the beach and offshore, and reduce the diversity and abundance of macroinvertebrates on which shorebirds and other wildlife depend.
While we might not be able to hold back the advancing seas, we can and should shape our response to them in ways that allow for all species to continue to love Florida’s shores.
Compare the natural shoreline on the left to the altered shoreline on the right:
If we want to protect our inland development from inundation, at some point we’re going to have to stop the insane continuation of developing our coasts. Barrier islands and beaches are simply going to disappear.
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