Southeastern Grasslands are of Great Antiquity

I enjoy watching a summer thunderstorm.  Lightning strikes offer a natural fireworks show that sometimes surpasses the manmade kind.  The furious wind and roaring thunder show the excited side of mother nature.  It’s the dangerous side of nature–a human could be vacuumed into the sky by a tornado, electrocuted by lightning, or clobbered by a hailstone or wind-strewn debris.  Nobody, not a king nor a baby, is immune to these hazards.

Natural fireworks.

Some anthropologists and a few old school ecologists wrongly believe most of the grasslands that occurred in southeastern North America when Columbus accidentally sailed into the Caribbean were the result of manmade fires.  Reed Noss dispels this notion in his book, Forgotten Grasslands of the South. The map below shows the frequency of lightning strikes in North America.  The south, and especially Florida, has more lightning strikes than any other region of the continent.  Dr. Noss believes the high frequency of lightning strikes can spark enough wild fires to maintain abundant grasslands without any human activity.

Map of average annual lighting strikes in North America between 1989-1999.  Lighting strikes were naturally common enough to have sparked grassland-creating wild fires long before humans arrived in North America.

A longleaf pine savannah on fire.  Longleaf pines are one of the few species of tree whose seedlings can survive fire.

Several lines of evidence support Dr. Noss’s conclusion that anthropogenic activity was not necessary to maintain grasslands.  Formerly, longleaf pine savannah covered most of the coastal plain region of the south.  There were even patches of pine savannah in the piedmont region, though oak and hickory dominated that area.  There are over 900 species of plants endemic (meaning they live nowhere else) to longleaf pine savannah compared to just 80 endemic species found on the grasslands of the Great Plains.  A high number of endemic species suggests an ecosystem of great antiquity and stability.  Because evolution is usually a slow process, it’s not likely that all of these endemic fire-dependent species could have evolved in just the last 12,000 years.  Longleaf pines require fire intervals of 1-10 years or hardwoods will crowd them out.  Longleaf pines grow slowly, taking decades to reach reproductive age.  A species that reproduces this slowly would have never been able to adapt quickly enough to survive a sudden change in fire regime caused by man.  These fire dependent species must have already been present before man colonized the region.

Many species of animals are also endemic to pine savannahs.  The gopher tortoise and the red cockaded woodpecker are perhaps the 2 most well known vertebrates dependent on this fire-influenced environment. Gopher tortoise fossils have been found that date to millions of years ago, while red cockaded woodpecker fossils come from deposits in the vicinity of 200,000 years old.  The presence of these species and many others in the fossil record long predate man’s entrance into the region.  This is obvious evidence that southern grasslands preceded man.

There was a lower frequency of lightning strikes during the coldest stages of the Ice Ages.  Evidence from most fossil sedimentary sites show little, if any charcoal, indicating reduced fire activity.  However, less precipitation combined with megafaunal grazing created grasslands during the colder climatic phases.  Following the megafaunal extinctions, fire activity spiked because so much vegetation was no longer being eaten and instead it became dry tinder.

During the Last Glacial Maximum, longleaf pine savannahs still occurred in refugium located in Florida, Louisiana, Texas, and probably along the continental shelf where sea levels regressed.  Paradoxically, these areas were warmer and wetter during Ice Ages because the Gulf Stream shut down and warm water that normally circulated north pooled around these lower latitudes.  Oak scrub and prairie, the result of aridity and megafauna foraging, predominated in the upper coastal plain.  Longleaf pine savannah didn’t recolonize the upper coastal plain until about 6,000 years ago, but the pollen record suggests this type of environment has waxed and waned cyclically for millions of years, becoming common and widespread during warm and wet climatic phases.

Wakulla Springs, Shellpoint Beach, and The St. Marks Wildlife Refuge

The drive from Augusta, Georgia to the Florida panhandle takes over 7 hours.  I chose a route of mostly back country highways that bisect farmland, abandoned farmland, and second growth forest.  I saw almost as many species of birds while traveling on these back roads as I did when I visited Wakulla Springs State Park the following day, but spotting birds while driving 60 mph is not as enjoyable as spying them on a leisurely boat ride.  We stayed at the Best Western Hotel in Medart–a beautiful, clean, and spacious base of operations for my natural history explorations.  I went for a swim after the exhausting hot drive and was excited to find a dead giant waterbug in the swimming pool.

Giant waterbug. (Lethocerus ? sp.).  They prey on tadpoles and minnows by grasping them with their front legs and sucking the life out of them.  They’re considered a delicacy in Asia. 

Courtyard of the Best Western Hotel in Medart.  It’s newer and nicer than the Wakulla Springs Lodge.

We went to Wakulla Springs State Park the next day, and the rich variety of wildlife quickly eliminated any doubt over my choice of vacation.  Even my wife and daughter were impressed, and they don’t share my love of nature.  The cost of admission is $6–a pittance compared to the value.  We saw 4 manatees and big schools of mullet right away before we even went on the boat ride.

Mastodon leg bone excavated from Wakulla Springs.  Most of the Pleistocene mammal fossils were collected between 1859-1930.  I doubt there are any left to find.  During the Ice Ages many rivers in Florida dried up and the river beds consisted of isolated springs instead.

Here’s a big school of mullet in the crystal clear waters of the spring.  I tried to take a photo of the manatees, but they weren’t at a good angle and they don’t show up clearly in the picture I took.

One of the flat-bottomed boats was handicapped accessible, so my wife was able to go with us.  Rides cost $8 per adult.  The captain serves as a guide and identifies all the plants and animals on the 45 minute journey.  A flat bottomed boat is necessary because the water is shallow, except where it bubbles up from a deep underground cavern.

Map of the springs underground.  Several roads are as much as 200 feet above the underground part of the springs.  Signs on the local roads let drivers know this fact.  I guess that’s so drivers won’t be surprised if the road collapses.

The bird life is spectacular.  I saw a cattle egret rookery, common egrets, a great blue heron, little blue herons, a green heron, a yellow crowned night heron, a white ibis, wood ducks, pied billed grebes, anhingas, ospreys, coots, prothonotory warblers, red-winged blackbirds, crows, mockingbirds, and blue jays.  I also heard a woodpecker.  This was the first time I’d ever seen 3 of these species–the yellow crowned night heron, the white ibis, and the prothonotory warblers.   I have seen ospreys before, but this was the first time I ever saw an osprey nest, though I saw one again the following day at Otter Lake.  The guide said just about every tree snag was home to a wood duck nest.

Cattle egret rookery.  I really need to get a telephoto lens.  Cattle egrets are common all across the rural countryside now where they hunt for insects stirred up by livestock and farm machinery.

White ibis.  This was the first time I’d ever seen this species.

If you enlarge the photo, you can see the wood duck in the middle of the picture.  Wood ducks are abundant here.

Alligators and large turtles known as Suwannee cooters were common.  We also saw a soft shelled turtle.

Alligator in the upper left hand corner.  The Suwannee cooters were too far away for me to get a photo.

The water was so clear I could see the bottom everywhere, even in the deepest part of the spring, despite the guide’s claim that the water wasn’t clear enough that day to see the bottom in the deepest part which is 90 feet.  Looking into the spring was like looking into an aquarium.  We could see all the fish.  Mullet swam in big schools and was by far the most abundant fish, but I saw several long-nosed gar, 3 black and white sunfish, a warmouth sunfish, and someone else saw a bowfin.  Little red crayfish crawled on the sandy bottom.  It’s easy to understand why native Americans inhabited the area around Wakulla Springs for 15,000 years.  Spear-fishing was a cinch.  They had such a great variety of easily obtainable animal and plant foods that they could remain well fed without agriculture.  Fish, duck, turtle, squirrel, manatee, and deer were available protein year round.  Duck potato (Sagitteria sp.), cattails, wild rice, nuts, and acorns provided the starches.

Originally, Wakulla Spring had a mostly sandy and limestone bottom, but invasive hydrilla now covers much of it and gives the water a greenish tint.  The water wells up from deep underground, and the chill surprised me when I went for a swim after the boat ride.  I saw cold blooded reptiles swimming in the water and mistakenly assumed the water would be warm, like a bathtub.  Instead, the water temperature was at least 20 degrees F cooler than the air temperature.  What a shock.

The woods around Wakulla Springs consist of white oak, live oak, hickory, sweetgum, cypress, red maple, ash, loblolly pine, pond pine, willow, dogwood, and wax myrtle.  The trees are large and much of the tract looks like it holds virgin timber.  The productive hickory supports an abundant population of gray squirrels.

Picnickers left their lunches unattended while they went swimming.  Crows and squirrels were in the process of looting their food.  I saw a crow fly off with half a sandwich.

Spanish moss covers this white oak in the parking lot.  It had unusual leaves for a white oak.

Hickory trees are abundant here.  This 3-pronged one is quite large.

This cypress tree is 5 feet in diameter.  Scientists cored it and found it to be 200 years old.  A cypress tree next to it is less than 1/2 this tree’s size in diameter, yet scientists found it was 600 (yes 600) years old.  It had s stunted growth due to nutrient deficiency.

Pickerel weed (the purple) and duck potato (Sagitteria) blooming.

Cypress wood is rot resistant.  The guide noted a leaning dead cypress snag in the middle of the channel that looked like it was about to fall over.  He said it looked that way when he first started working in the park…in 1957.  Pickerel weed and duck potato were blooming.  I saw 2 kinds of grape vines growing in the woods including muscadine and some type of bunch grape that had a lot of young grapes on it.  As we left the park, we saw a white tail deer feeding in the middle of the day.

Shellpoint Beach

We arrived at Shellpoint Beach about midmorning and had the whole beach to ourselves before other sunbathers joined us 30 minutes later.  I didn’t find any interesting sea shells.  Oyster shells were the only common ones here.  Shellpoint Beach juts into Apalachee Bay and is known more for fishing than swimming.  There are seasons for grouper, red snapper, sea trout, cobia, and scallop harvesting.  There are no waves over 8 inches and those are caused by boats.  Laughing gulls and boat-tailed grackles hang around the pavilion, hoping to share scraps with picnickers.

Nice pavilion at Shellpoint Beach, Florida.

Apalachee Bay, Florida.

St. Marks National Wildlife Refuge

This refuge sprawls all along the coast of Apalachee Bay.  I visited the northern half during the heat of midday which is the worst time for viewing wildlife.  Nevertheless, I saw a turkey as soon as I pulled into the refuge.  Near the lighthouse, several naive juvenile cotton rats foraged at the base of the palm.  They didn’t know they were supposed to be afraid of us.

St. Mark’s Lighthouse.  It’s 180 years old.  It’s not open to the public.  I assume park officials are worried about liability issues.  Too many suicides.

Young cotton rat (Sigmodon hispidus).  It didn’t know it was supposed to be afraid of us.  Herons eat these mammals.  I’ve seen these quite often in roadside dtiches but never close up.  I didn’t realize they are a cute animal, especially compared to invasive Norway rats.

A saltwater storm surge killed these loblolly pines in 2008, creating an open habitat.

A freshwater lilly pond within the wildlife refuge.  Home to alligators, largemouth bass, shellcracker bream, bullhead and channel catfish, and warmouth.

Later that evening, I went to the southern part of the St. Marks NWR to look for fox squirrels.  An article in The Eagle Eye, a pamphlet published by the refuge biologists, reported the presence of fox squirrels in a pine flatwoods near Otter Lake.  I didn’t see any fox squirrels, but I spotted a pair of endangered cockaded woodpeckers.

I saw  2 red cockaded woodpeckers in this vicinity.  I didn’t even bother trying to photograph them without a telephoto lens.  Refuge officials maintain this environment with fire which is evident from the abundance of burned wood on the ground.  Frequent signs say “We prevent wildfire with prescribed fire.”  Actually, prescribed fire is no more beneficial than wildfire.

This pine flatwoods hosts loblolly pine, live oak, southern red oak, runner oak, saw palmetto, grasses, and ferns.  The mosquitoes weren’t bad this time of year in Florida but a species of yellow-green horsefly or deerfly was bothersome.  They thought I tasted good.

There’s no swimming at Otter Lake.  The sign warns of alligators.  I heard sheep frogs here.

There’s an osprey nest in this snag.  Note the osprey at the top of the tree.

To top off my trip, while I was driving home through Emanuel County, Georgia, I saw some endangered wood storks foraging in a flooded ditch in a farmer’s field.  I was satisfied with seeing a white ibis and wood storks until I arrived home and read a vintage ornithology book written in the early 20th century.  That author saw 25,000 white ibis on a wet prairie in Florida and 5,000 wood storks at a rookery also in Florida.  The Florida of 1910 is gone forever.

Wakulla County Eats

We dined at 3 restaurants in Wakulla County during our stay.  I thought Barwick’s Seafood and Deli was the best,  I ate grilled mullet and it was excellent, though I suspect it was broiled or sauteed rather than grilled.  All the local family restaurants have $12 entrees and $9 sandwiches.  Popular items found at most of them include fried seafood of all kinds (mullet, shrimp, flounder, catfish), grilled grouper sandwiches,  and pulled pork barbeque smothered in an overly sweet sauce.  An interesting breakfast item on the menu at the Coastal Restaurant is mullet and eggs.  Mullet is really abundant in Florida.  Many of the locals order farm raised catfish instead.  Catfish is bland compared to mullet.  One stand offers smoked mullet dip.  Most of these restaurants could shave a few dollars off their prices, if they didn’t serve ridiculous oversize portions.  No wonder Americans are so fat.  I had 5 slices of mullet on my plate, plus a big pile of french fries and hushpuppies and a salad bar.  Do Americans really expect dinners this large?  I’m a member of the clean plate club and managed to finish my portion, but I exercise hard everyday.

The worst restaurant was Hamahocker’s Barbeque.  I ate their smoked brisket.  I’m pretty sure smoked brisket is supposed to be more tender than shoe leather.  The potato salad tasted like someone dumped a load of sugar on it.  I like my own cooking better than any restaurant, but I can’t cook when I’m staying in a hotel.

Fire Suppression = A Decline in Biodiversity (Part 2–The Animals of Longleaf Pine Savannahs)

Fox Squirrels come in several color phases–orange, black, and gray.  Some have white or gray masks as well.

Fox Squirrel–Sciurus niger

I love these big colorful squirrels.  I lived in Niles, Ohio until 1975, and our home was bordered by oak woods on 2 sides.  Big orange fox squirrels were the playful denizens there.  But since I’ve lived in Georgia, I’ve only seen one–a black masked fox squirrel foraging with a group of gray squirrels (Sciurus carolinensis) in a pecan orchard in Burke County.

This range map is bullshit.  No statewide survey of fox squirrels has been done in at least 50 years, if ever.  It’s likely an accurate range map would show a much patchier distribution.

Southern fox squirrels differ in their habitat requirements from northern fox squirrels, despite being the same species.  The former prefer mature longleaf pine savannahs with fingers of oak forests, while the latter thrive in oak/hickory woods.  Fox squirrels are declining in Georgia because longleaf pine savannahs were largely replaced with shorter rotation loblolly pine tree farms.  Lumber companies harvest loblolly pines every 50 years which is not enough time for trees to develop snags.  The Trees are also planted closely and fire is suppressed.  Gray squirrels are more abundant today in state because they’re well adapted to the dense young forests that have sprouted on abandoned agricultural lands.  Gray squirrels escape predation by jumping from tree top to tree top, while fox squirrels prefer to dash on the ground as far as they can before retreating to a tree.  Though clumsy in trees compared to their smaller cousins, their larger size allows them to put up more of a fight, if a predator catches up to them.  This difference in behavior explains why gray squirrels occur in closed canopy forests, and fox squirrels prefer open parkland forests.  For this reason I think fox squirrels were more abundant in this region during the Pleistocene when open environments were common.  Areas managed for red-cockaded woodpeckers should benefit fox squirrels.  Forest managers used longer rotations and fire to maintain the bird’s required habitat.

Red Cockaded Woodpecker–(Picoides borealis)

Photo of a red cockaded woodpecker from google images.  All the photos in this entry are borrowed from there.

Thirty years ago, this bird was on the verge of extinction, despite having formerly been common throughout the south.  Fire suppression and short forest management rotation nearly caused the death of this species.  Young pine trees never develop the soft rot that red cockaded woodpeckers need for boring nesting cavities.  As a defense mechanism, red cockaded woodpeckers constantly peck wells below their nesting cavities from which pine sap continously flows.  The pine resin repels rat snakes–their number one predator.  For this defense mechanism to work, live trees are a must.  And without fire hardwood understory reaches the level of the nesting cavity allowing flying squirrels, and other predators easy access.  Flying squirrels will decimate red cockaded woodpecker nests.

In a successful effort to save the birds, scientists identified habitat requirements and some suitable land was set aside and managed using prescribed burns and longer tree harvest rotations.  Birds were relocated to the best habitat, artificial nesting boxes were installed to supplement the shortage of good nesting trees, and flying squirrel exclusion devices were used.  In many protected areas red cockaded woodpecker family groups (family groups consist of 2-10 individuals) have increased dramatically to the point where it’s no longer necessary to provide artificial nests or to protect them from flying squirrels.  At SRS for example the population grew from 1 family group in 1987 to 30 by 2003.

Sandhill Crane–(Grus canadensis)

These impressive birds grow to 5 feet tall.  They prefer to nest in grassy marshes adjacent to prairies or savannahs.  The real life version of Sesame Street’s Big Bird used to be common, but since grasslands and wetlands have declined so have the birds.  Georgia’s population includes a permanent one consisting of small family groups, and large congregations of winter migrants.  They’re omnivorous feeding on insects, crayfish, mice, snakes, frogs, worms, acorns, fruit, roots, and farmer’s crops.

Bachman’s Sparrow–(Peucaea aestivalis)

Another inhabitant of open pine savannahs that is declining in abundance.  I heard this bird’s song on a youtube video and recognized it as one I’ve heard.  Evidentally, the sparrow still occurs in Augusta.

Indigo Snake–(Drymarchon corais)

This snake grows to 9 feet long, making it the longest serpent in North America.  They’re rare because their habitat has been fragmented, and they need large ranges.  They hunt during the day and retreat into gopher tortoise burrows at night.  A wide variety of prey is taken–other snakes including venemous ones, small mammals, birds, frogs, and fish.  Indigo snakes don’t kill by constriction or envenomation, but instead bite the head of their prey and thrash, breaking the spines of the small creatures.  Their metabolism is faster then that of most other snakes.

Gopher Tortoise–(Gopherus polyphenus)

 

Gopher tortoises depend on a frequent fire regime to spark the growth of the kinds of plant they eat.  They also like sandy soil that makes it easy for them to dig their elaborate tunnel systems.  They’re a keystone species–over 60 vertebrates and invertebrates depend on their burrows for shelter.  (See also my article–“The Giant Extinct Tortoise, Hesperotestudo crassicutata, must have been able to survive light frosts” from my April or March archives)

Popular game animals such as white tail deer, turkey, and quail thrive in longleaf pine savannahs.  Savannahs were a favored habitat of many extinct Pleistocene species as well including mammoth, long horned bison, horses, llamas, Harlan’s ground sloth, hog nosed skunks, giant tortoises, and others.