Crawfish boils are popular in the springtime. Crawfish are generally harvested from aquaculture operations. Photo credit: Libbie Johnson, UF IFAS Extension
“You get a line, I’ll get a pole, we’ll go down to the crawdad hole, honey, baby, mine“…there are lots of great zydeco songs singing the praises of crawfish (aka crayfish, crawdads, mudbugs). They are in season now, and while crawfish festivals all around the southeast are canceled due to concerns over COVID-19, they are still available and make for great eating. Most of us would recognize a cooked one alongside a feast of corn and potatoes, but would you know an actual crawfish hole if you came up on it?
Last fall, our office welcomed about 500 kids (over several days) to the 4-H camp in Barrineau Park for a field trip. I showed every single one of them a small muddy mound with an opening in the top, and asked if anyone could tell me what it was. Not a single kid knew! Now, I make sure I point crawfish mounds out to anyone I happen to be walking with, as they are fascinating little structures. Also referred to as crawfish chimneys due to their upright, open construction, they are built by a crawfish in a muddy area, often near a creek or other water source.
Crawfish mounds are constructed using small pellets of mud, and the opening connects down to a burrow. Photo credit: Carrie Stevenson, UF IFAS Extension
The industrious invertebrate uses its legs and mouth to create pellets of mud as it digs its burrow. It places mud up above the ground, using the mud balls like small bricks. Bricking up the entrance to its burrow (as opposed to placing discarded mud elsewhere) also protects a crawfish from exposure to predators on open soil. The crawfish chimneys can be 6 inches tall (or more!) and connect down to a burrow that may reach 3 feet deep, some straight down and others with side tunnels extending different directions.
Since the crawfish lives in wetland areas, it is theorized that these chimneys extending above the soil allow for better oxygen flow in the burrow. During a drought, crawfish will plug the opening of their mounds with mud, to keep water in the burrow from evaporating.
Crawfish in the wild are rarely harvested, although some folks do fish for them like the song referenced earlier. For the vast majority of crawfish harvested in commercial production, two species are the most popular–the white river crawfish (Procambarus zonangulus) and red swamp crawfish (Procambarus clarkii). They are typically farmed in coordination with rice, as both commodities thrive in flooded conditions. Most aquaculture operations are associated with Louisiana, but at least five other southern U.S. states farm crawfish. To learn more about this industry, check out LSU AgCenter’s informative video.
The Wacissa River offers paddlers the opportunity to see north Florida unfiltered.
Being off the beaten path has many advantages. In the case of a spring-fed river, it translates to less pressure from human use and a great opportunity for those who do visit to experience the “real Florida”.
The Wacissa River, located in the southern half of Jefferson County, Florida, is near the crossroads identified as the town of Wacissa. There is a blinking light, a post office, and two small convenience stores where beer, ice and snacks can be purchased.
Access to the river is about two miles south of the blinking light on Florida 59, just after the state road veers to the southwest. The blacktop spur quickly become a dirt parking lot after passing several canoe and kayak rental businesses.
A county maintained boat landing with pick-nic tables, a manmade beach, and a tiny diving platform with a rope swing are the only signs of civilization. The cold, clear water extends to a tree line several hundred yards south of the landing with the river moving to the southeast.
The river emerges crystal clear from multiple limestone springs along the first mile and a half of the 12 mile waterway. The adjacent land is flat and subject to being swampy, especially in wet years like 2018.
The river terrain stands in contrast to the Cody Scarp just a few miles to the north. This geologic feature is the remnants of an ancient marine terrace and is hilly, rising 100 feet above the river in some spots.
Cypress, oak, pine, and other trees cover the bottomlands adjacent to the river. The river quickly enters the Aucilla Wildlife Management Area which results in a wide variety of animals, birds, amphibians and reptiles.
The wildlife viewing varies by season. Many migratory birds use the river’s shelter and resources on their annual trips.
Canoeing and kayaking are popular in the gentle current. Powerboats and fan boats can use the area also, but must be on constant alert for shallow spots and hidden snags.
For the adventurous paddler who wants to follow the river’s course, there is a debarkation point at Goose Pasture Campgrounds and another near St. Marks after the Wacissa merges with the Aucilla.
Be prepared when taking this journey. This is the real Florida, no fast food restaurants or convenience stores. Only clear water, big trees and the calls of birds will be found here.
Red mangrove growing among black needlerush in Perdido Key. Photo credit: Carrie Stevenson, UF IFAS Extension
Discovering something new is possibly the most exciting thing a field biologist can do. As students, budding biologists imagine coming across something no one else has ever noticed before, maybe even getting the opportunity to name a new bird, fish, or plant after themselves.
Well, here in Pensacola, we are discovering something that, while already named and common in other places, is extraordinarily rare for us. What we have found are red mangroves. Mangroves are small to medium-sized trees that grow in brackish coastal marshes. There are three common kinds of mangroves, black (Avicennia germinans), white (Laguncularia racemosa), and red (Rhizophora mangle).
Black mangroves are typically the northernmost dwelling species, as they can tolerate occasional freezes. They have maintained a large population in south Louisiana’s Chandeleur Islands for many years. White and red mangroves, however, typically thrive in climates that are warmer year-round—think of a latitude near Cedar Key and south. The unique prop roots of a red mangrove (often called a “walking tree”) jut out of the water, forming a thick mat of difficult-to-walk-through habitat for coastal fish, birds, and mammals. In tropical and semi-tropical locations, they form a highly productive ecosystem for estuarine fish and invertebrates, including sea urchins, oysters, mangrove and mud crabs, snapper, snook, and shrimp.
Interestingly, botanists and ecologists have been observing an expansion in range for all mangroves in the past few years. A study published 3 years ago (Cavanaugh, 2014) documented mangroves moving north along a stretch of coastline near St. Augustine. There, the mangrove population doubled between 1984-2011. The working theory behind this expansion (observed worldwide) is not necessarily warming average temperatures, but fewer hard freezes in the winter. The handful of red mangroves we have identified in the Perdido Key area have been living among the needlerush and cordgrass-dominated salt marsh quite happily for at least a full year.
Key deer thrive in mangrove forests in south Florida. Photo credit: Carrie Stevenson, UF IFAS Extension
Two researchers from Dauphin Island Sea Lab are planning to expand a study published in 2014 to determine the extent of mangrove expansion in the northern Gulf Coast. After observing black mangroves growing on barrier islands in Mississippi and Alabama, we are working with them to start a citizen science initiative that may help locate more mangroves in the Florida panhandle.
So what does all of this mean? Are mangroves taking over our salt marshes? Where did they come from? Are they going to outcompete our salt marshes by shading them out, as they have elsewhere? Will this change the food web within the marshes? Will we start getting roseate spoonbills and frigate birds nesting in north Florida? Is this a fluke due to a single warm winter, and they will die off when we get a freeze below 25° F in January? These are the questions we, and our fellow ecologists, will be asking and researching. What we do know is that red mangrove propagules (seed pods) have been floating up to north Florida for many years, but never had the right conditions to take root and thrive. Mangroves are native, beneficial plants that stabilize and protect coastlines from storms and erosion and provide valuable food and habitat for wildlife. Only time will tell if they will become commonplace in our area.
If you are curious about mangroves or interested in volunteering as an observer for the upcoming study, please contact me at firstname.lastname@example.org. We enjoy hearing from our readers.
Birds, migration, and climate change. Mix them all together and intuitively, we can imagine an ecological train wreck in the making. Many migratory bird species have seen their numbers plummet over the past half-century – due not to climate change, but to habitat loss in the places they frequent as part of their jet-setting life history.
Migrating songbirds forage for insects in coastal scrub-shrub habitat. Photo credit: Erik Lovestrand, UF IFAS Extension
Now come climate simulation models forecasting more change to come. It will impact the strands of places migrants use as critical habitat. Critical because severe alteration of even one place in a strand can doom a migratory species to failure at completing its life cycle. So what aspect of climate change is now threatening these places, on top of habitat alteration by humans?
It’s the change in weather patterns and sea level that we’re already beginning to see, as the impacts of global warming on Earth’s ocean-atmosphere linkage shift our planetary climate system into higher gear.
For migratory birds, the journey itself is the most perilous link in the life history chain. A migratory songbird is up to 15 times more likely to die in migration than on its wintering or breeding grounds. Headwinds and storms can deplete its energy reserves. Stopover sites for resting and feeding are critical. And here’s where the Big Bend region of Florida figures prominently in the life history of many migratory birds.
According to a study published in March of this year (Lester et al., 2016), field research on St. George Island documented 57 transient species foraging there as they were migrating through in the spring. That number compares favorably with the number of species known to use similar habitat at stopover sites in Mississippi (East Ship Island, Horn Island) as well as other central and western Gulf Coast sites in Alabama, Louisiana, and Texas.
We now can point to published empirical evidence that the eastern Gulf Coast migratory route is used by as many species as other Gulf routes to our west. This confirmation makes conservation of our Big Bend stopover habitat all the more relevant.
The authors of the study observed 711 birds using high-canopy forest and scrub/shrub habitat on St. George Island. Birds were seeking energy replenishment from protein-rich insects, which were reported to be more abundant in those habitats than on primary dunes, or in freshwater marshes and meadows.
So now we know that specific places on our barrier islands that still harbor forests and scrub/shrub habitat are crucial. On privately-owned island property, prime foraging habitat may have been reduced to low-elevation mixed forest that is often too low and wet to be turned into dense clusters of beach houses.
Coastal slash pine forest is vulnerable to sea level rise. Photo credit: Erik Lovestrand, UF IFAS Extension
Think tall slash pines and mid-story oaks slightly ‘upslope’ of marsh and transitional meadow, but ‘downslope’ of the dune scrub that is often cleared for development.
“OK, I get it,” you say. “It’s as if restaurant seating has been reduced and the kitchen staff laid off. Somebody’s not going to get served.” Destruction of forested habitat on our Gulf Coast islands has significantly reduced the amount of critical stopover habitat for birds weary from flying up to 620 miles across the Gulf of Mexico since their last bite to eat.
But why the concern with climate change on top of this familiar story of coastal habitat lost to development? After all, we have conservation lands with natural habitat on St. Vincent, Little St. George, the east end of St. George, and parts of Dog Island and Alligator Point. Shouldn’t these islands be able to withstand the impacts of stronger and/or more frequent coastal storms, and higher seas – and their forested habitat still serve the stopover needs of migratory birds?
Let’s revisit the “low and wet” part of the equation. Coastal forested habitat that’s low and wet – either protected by conservation or too wet to be developed – is in the bull’s eye of sea level rise (SLR), and sooner rather than later.
Using what Lester et al. chose as a reasonably probable scenario within the range of SLR projections for this century – 32 inches, these low-elevation forests and associated freshwater marshes would shrink in extent by 45% before 2100. It could be less; it could be more. Conditions projected for a future date are usually expressed as probable ranges. Experience has proven them too conservative in some cases.
The year 2100 seems far away…but that’s when our kids or grandkids can hope to be enjoying retirement at the beach house we left them. Hmm.
Scientists CAN project with certainty that by the time SLR reaches two meters (six and a half feet) – in whatever future year that occurs, 98% of “low and wet” forested habitat will have transitioned to marsh, and then eroded to tidal flat.
But before we spool out the coming years to a future reality of SLR that has radically changed the coastline we knew, let’s consider where the crucial forested habitat might remain on the barrier islands of the next generation’s retirement years:
It could remain in the higher-elevation yard of your beach house, perhaps, if you saved what remnant of native habitat you could when building it. Or if you landscaped with native trees and shrubs, to restore a patch of natural habitat in your beach house yard.
Migratory songbird stopover habitat saved during beach house construction. Photo credit: Erik Lovestrand, UF IFAS Extension
We’ve all thought that doing these things must be important, but only now is it becoming clear just how important. Who would have thought, “My beach house yard: the island’s last foraging refuge for migratory songbirds!” even in our most apocalyptic imagination?
But what about coastal mainland habitat?
The authors of the March 2016 St. George Island study conclude that, “…adjacent inland forested habitats must be protected from development to increase the probability that forested stopover habitat will be available for migrants despite SLR.” Jim Cox with Tall Timbers Research Station says that, “birds stop at the first point of land they find under unfavorable weather conditions, but also continue to migrate inland when conditions are favorable.”
Migratory birds are fortunate that the St. Marks Refuge protects inland forested habitat just beyond coastal marshland. A longer flight will take them to the leading edge of salty tidal reach. There the beautifully sinuous forest edge lies up against the marsh. This edge – this trailing edge of inland forest – will succumb to tomorrow’s rising seas, however.
Sea level rise will convert coastal slash pine forest to salt marsh. Photo credit: Erik Lovestrand, UF IFAS Extension
As the salt boundary moves relentlessly inland, it will run through the Refuge’s coastal buffer of public lands, and eventually knock on the surveyor’s boundary with private lands. All the while adding flight miles to the migration journey.
In today’s climate, migrants exhausted from bucking adverse weather conditions over the Gulf may not have enough energy to fly farther inland in search of forested foraging habitat. Will tomorrow’s climate make adverse Gulf weather more prevalent, and migration more arduous?
Spring migration weather over the Gulf can be expected to change as ocean waters warm and more water vapor is held in a warmer atmosphere. But HOW it will change is difficult to model. Any specific, predictable change to the variability of weather patterns during spring migration is therefore much less certain than SLR.
What will await exhausted and hungry migrants in future decades? Our community decisions about land use should consider this question. Likewise, our personal decisions about private land management – including beach house landscaping. And it’s not too early to begin.
Erik Lovestrand, Sea Grant Agent and County Extension Director in Franklin County, co-authored this article.
The American Alligator is an icon in the state of Florida. Viewed on the program “Swamp People” and as the mascot of the University of Florida, most visitors to our state view this animal more on television than in the wild; but they are certainly there. In need of mates and calories from the lack of eating over the winter, alligators and other reptiles become more active this time of year. Visitors and residents alike should be a little more cautious.
Alligator basking on the Escambia River; photo: Molly O’Connor
Like most predators, alligators seek food that will provide them energy. Generally predators will target prey that will cost them very little energy to capture and kill. Obviously small alligators will feed on small prey but adult alligators feed on smaller prey than many think. Fish, turtles, snakes, small mammals and birds make up the bulk of their diet. If the opportunity presents itself, and they do not have to expend too much energy, alligators will certainly take larger mammals and birds.
For humans the bigger problem has been the loss of pets and livestock. Small dogs are certainly easier prey than a human, and with the loss of habitat encounters with humans and their pets have increased. Since 1948 FWC has estimated about 300 alligator attacks on humans directly, less than 10% of these were fatal. As more alligators are forced into suburban areas more encounters have occurred. In the last 10 years 16,000 nuisance alligator calls have been reported to the FWC. As with other wildlife, like coyotes, many of these animals are living in ditches and other watering holes where they seek fish and turtles. However if we visit such places, particularly with our pets, these animals may certainly make an attempt to grab them. If you feel an alligator is a nuisance and could be a potential problem you can call FWC at (866) FWC-GATOR; (866) 392-4286). Folks should be aware that FWC does not relocate nuisance alligators, they will be destroyed. Currently FWC issues about 7000 permits for alligator control across the state.
A couple of safety notes if you live near waterways with alligators.
- Do not swim in these locations at night; alligators are more active hunters between dusk and dawn
- Try to discard fish remains after cleaning in another location besides the water; if these locations have a few alligators they will certainly learn this habitat and hang around the boat ramp more.
- DO NOT FEED alligators; help us let visiting tourists know this and that it is illegal in our state. Alligators fed by humans will eventually lose their natural fear of us and this could bring on problems.
These are awesome animals. We should better understand their natural history so that we can exist with them. For more information on alligators in your area contact your county extension office.