Archive for April, 2015

The Pleistocene Ridge and Valley Reptile Corridor

April 28, 2015

The composition of reptile and amphibian species living in present day Georgia is almost the same as it was during the late Pleistocene.  This suggests climate change in southeastern North America has been much more moderate compared to the rest of the continent.  There are 2 excellent late Pleistocene fossil sites in the ridge and valley region of Georgia that yield the remains of reptiles and amphibians–Ladds Quarry and Kingston Saltpeter Cave.  Over 40 species of reptiles and amphibians (aka herpetofauna) were excavated from Kingston Saltpeter Cave, and all but 1 (wood turtle) still live in the region.  Most of the herpetofaunal remains recovered from Ladds also still live in Georgia, but there are a few exceptions, leading to some interesting paleoecological implications for this time period.

Map of sites sampled in the Valley and Ridge of Alabama and Georgia to assess responses of fish, invertebrates, and algae to urbanization.

Map of the ridge and valley region of Georgia and Alabama.  This region provided a corridor where reptiles and amphibians with northern affinities could mingle with those that preferred a warmer climate.

Fox snakes (Elaphe vulpine) and wood turtles (Glyptemys insculpta) lived in the ridge and valley region of Georgia about 13,000 years ago.  These 2 species no longer live this far south, implying summers were cooler here then.  However, the extinct giant tortoise (Hesperotestudo crassicutata), red bellied turtles (Pseudemys nelsoni), and southern toads (Bufo terrestris) ranged into the ridge and valley region as well.  Researchers assume giant tortoises required frost free winters, while red bellied turtles no longer occur north of the Okefenokee Swamp.  Aside from a disjunct population, southern toads are restricted to the coastal plain.  The presence of these 3 species implies a climate phase of warmer winters than those of the present.  There is an astronomical explanation for the strange co-existence of species with northern affinities alongside those of warmer preferences.

The fossil remains that accumulated at both Ladds and the Kingston Cave date to the Boling-Alerod Interstadial when average annual temperatures spiked from Ice Age lows to nearly modern day warm temperatures. (Pundits who claim today’s rate of global warming is “unprecedented” are ignorant of this climate phase.)  The Boling-Alerod lasted from 15,000 BP-12,900 BP.  This warm pulse led to rapid melting of the glaciers covering Canada then.  Although average annual temperatures were similar to those of today, they were not distributed in the same way.  Summer highs were lower on average than they are today, but winter low temperatures in this region probably did not go far below freezing.  During the Boling-Alerod Interstadial, the earth tilted to a lesser degree than it does today, resulting in reduced seasonality. It’s fascinating how small changes in astronomy can be tied to changes in the distribution of small animals.

I disagree with scientists who believe the ridge and valley was entirely frost free then.  I hypothesize the extinct giant tortoise was able to survive light frosts by digging burrows or by using burrows dug by ground sloths and pampatheres. (See: https://markgelbart.wordpress.com/2011/04/15/the-extinct-pleistocene-giant-tortoise-hesperotestudo-crassicutata-must-have-been-able-to-survive-light-frosts/)  Moreover, red bellied turtles and southern toads do live in regions that experience light frosts every winter.  Instead, the ridge and valley region probably had winters similar to those of modern day south Georgia and north Florida.  Florida muskrats (Neofiber alleni) have a similar range as red-bellied turtles, and their fossil remains have also been found at Ladds.  The presence of Florida muskrats this far north during the Boling-Alerod indicates year round green vegetation and does suggest a longer growing season but does not preclude the possibility of winter frosts.

Wood Turtle

Wood turtle.  This species lived in north Georgia during the Pleistocene but no longer occurs this far south.

Florida red-bellied turtle.  This species lived in north Georgia during the Pleistocene but no longer occurs this far north.

The ridge and valley region provided a corridor for the migration of species that expanded their range according to varying climate phases.  Species not well adapted to living at higher elevations could utilize river valleys and move south to north or vice versa.  Species that preferred higher elevations could travel along the ridges, also along a north-south axis.  The Appalachicola river is thought to be another corridor that facilitated north-south  migrations of species, correlating with changes in climate phases.  I think the 2 corridors are close enough to have some connection.  Some species expanding their range up and down the Appalachicola River corridor reached the ridge and valley region and expanded their range through there as well.

The region between these 2 corridors includes Talbot, Taylor, Schley, and Marion Counties in southwest central Georgia.  Researchers recently discovered this region is a diverse herpetofaunal hotspot. In just 1 week, 25 people surveyed this region and counted 62 species of reptiles and amphibians, greater than any other region in North America north of Mexico.  This includes more reptiles than are found in Big Bend National Park, and more amphibians than are found in the Great Smoky Mountains National Park.  This region is the southernmost range limit of the wood frog (Rana sylvatica) and the spring salamander (Gyrinophata poryphactos), yet it is the most inland northern range limit for coastal plain species such as the gopher frog (Rana areolata), striped newt (Notophthalmus perstiratus)), and diamond back rattlesnake (Crotalus adamenteus).  They also found an endangered alligator snapping turtle (Macroclemys temmincki), and gopher tortoises (Gopherus polyphemus).

The southern toad has a curious disjunct population in upper South Carolina.  The scientific literature is silent as to their preferred habitat, other than their preference for sandy soils.  Most of their modern day range was formerly open pine savannah, so I assume this is their favored habitat.  This suggests at least some savannahs occurred well into the northern parts of South Carolina and Georgia.  Indians maintained extensive grassy savannahs in upstate South Carolina by setting frequent fires.  William Bartram did travel through miles of “strawberry plains” in this area circa 1777.  The extinct giant tortoise favored savannah habitat as well.  The presence of these 2 species at Ladds indicates some savannahs occurred in the ridge and valley region during the late Pleistocene.  There is a disjunct population of longleaf pine (Pinus palustris) in the ridge and valley region at Berry College.  At least some areas of longleaf pine savannah have occurred in this region since at least the Boling-Alerod Interstadial. Apparently, lightning-induced fires were frequent enough to maintain this environment, even before man began setting fires here.

Bufo terrestris

Range map for southern toad.  Note the disjunct population in northwestern Georgia and northeastern South Carolina.  Fossils of this species have been found in the ridge and valley region at Ladds, located west of this disjunct population.

Incidentally, it should not be a great surprise if fossil evidence of alligator and gopher tortoise, dating to the late Pleistocene, is some day found in the ridge and valley region.  The herpetofauna biodiversity of this region during the Boling-Alerod Interstadial likely surpassed that of any present day region of North America north of Mexico.

References:

Holman, Alan

“Paleoclimatic Implications of Pleistocene Herpetofauna of Eastern and Central North America”

National Geographic Research

Graham, Sean; et. al.

“An Overlooked Hotspot: Rapid Biodiversity Assessment Reveals a Region of Exceptional Herpetofaunal Richness in Southeastern North America”

Southeastern Naturalist 9(1) 2010

 

 

 

 

 

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The Pinckney Island National Wildlife Refuge and Other Stops on a 27 Hour Overnight Trip

April 23, 2015

 

For the 8th anniversary of my 45th birthday, my wife suggested we go on a nature excursion.  I chose to visit Pinckney Island National Wildlife Refuge and Spring Island, an upscale development.  Pinckney Island was a worthwhile destination.  The trail on this island is wide and surfaced with hard-packed gravel.  I was able to push my wife’s wheelchair on the trail, so I didn’t have to leave her behind in the car.  The trail goes through maritime forest and salt marsh.  The maritime forest here consists of live oak, Carolina palmetto, and loblolly pine with an undergrowth of saw palmetto.  Quacks sell an extract made from saw palmetto berries that is supposed to reduce the size of enlarged prostate glands, but 2 large trial studies found no evidence it works beyond a placebo effect.  However, the berries are good food for wildlife, and the Indians ate them too.  Cordgrass dominates the salt marsh.  I saw fiddler crabs (Uca sp.) crawling around the mud flats during low tide.

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Maritime forest of live oak, Carolina palmetto, and loblolly pine.

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Saw palmetto.  Quacks use an extract from the berries to treat enlarged prostates.

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Young Carolina or Sable palmetto.

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Salt marsh with a maritime forest hammock in the distance.

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Fiddler crabs.  Click on the photo to enlarge.

We went to the Ibis Pond about 1 mile from the parking lot.  It’s a freshwater pond covered with green algae, fertilized by abundant bird guano.  Egrets and herons nest in the willow trees growing in the pond.  I saw great egrets, snowy egrets, cattle egrets, yellow-crowned night herons, black crowned night herons, and little blue herons. Some had fledgling young in the nests.  I also saw an unusually large boat-tailed grackle, and there were coots swimming in the water.  One bird stymied my attempts at identification, and I saw this bird on the following day at the Savanna River NWR.  It had brownish-orange wings and a striped belly.  The closest match in my bird guide was a Louisiana water thrush, but I’m not sure what it was.  We were about to go back to the car, and I remarked that we hadn’t seen any ibis at the Ibis Pond.  As soon as I said this, a flock of about 15-20 white ibis flew overhead and landed in the trees, but they were too far away to photograph.  A person could spend a whole day on trails here, but the evening winds were too chilly for my wife, and it was past suppertime.  We went back to the car.  I was impressed anyway.

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White ibis pond.  I saw 3 species of egrets, 3 species of herons, and white ibis here.  It’s an impressive rookery and worth a visit.

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Yellow crowned night heron and nest.  Click on the photo to enlarge.

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The boat-tailed grackle in the middle of the photo was bigger than a large crow.  I didn’t know they got this big.

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View of the waterway that separates Pinckney Island from the mainland.

Spring Island Fox Squirrels

Reportedly, Spring Island, South Carolina has the densest fox squirrel population in the southeast.  The paper referenced below estimates a population of 187 fox squirrels per square mile on Spring Island compared to 98 fox squirrels per square mile in areas of the coastal plain where they still exist.  (I converted the figures from the square kilometers given in the paper.)  Fox squirrels are nearly absent from the piedmont and mountain regions.  This species prefers mature open woodlands with widely spaced trees and grassy understories, while gray squirrels prefer young dense forests with woody understories.  Fox squirrels were formerly more common in the south because Indians set fire to the woods every few years, creating their favored habitat.  However, researchers discovered that conditions on Spring Island favor gray squirrels, yet fox squirrels are common here.  They believe frequently mowed golf courses, and a field planted in wheat on the island have helped maintain this large population of fox squirrels.  I wanted to see this population because I hypothesize fox squirrels were also common during the Pleistocene when their habitat was shaped by foraging activities of now extinct megafauna. (See: https://markgelbart.wordpress.com/2012/07/05/colorful-fox-squirrels-were-they-the-more-common-squirrel-in-the-southeast-during-the-Pleistocene/)

I suspected Spring Island might be a gated community, and my suspicions proved to be accurate.  I thought I’d con my way on the island.  I told the security guard I was interested in purchasing a property on the island, hoping they would just let me drive on the island.  She referred me to a real estate agent in an office located next to the gate.  The agent was willing to show me the island in his car, but I didn’t want to get stuck with a boring salesman, so I declined the opportunity.  There are lots available on the island for as little as $10,000, but to become a Spring Island property owner requires an initiation fee of $15,000, plus annual dues for country club crap.  I’m a working class dude, not a country club kind of guy.

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A black fox squirrel on Callasawatchie Drive about 100 yards before the entrance to Spring Island.  Spring Island is a gated community.  I couldn’t con my way inside without being accompanied by a boring real estate agent, so I couldn’t investigate the densest population of this species in the south.  Click on the photo to enlarge.

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Black vultures on Chechessee Road, near Spring Island.  I saw more black vultures on this trip than any other species of bird.

I did see a beautiful black fox squirrel on Callasawatchie Drive about 100 yards from the security gate.  It wasn’t a completely wasted trip, but we had an hour before lunch.  I decided to revisit the

Savannah River NWR.

This refuge consists of abandoned rice fields left fallow since the end of the Civil War.  I’ve been here before, and some day I’m going to visit during winter when migrant ducks flock here.  On this visit I walked on an old dike and immediately saw a marsh hawk hovering low over the ground looking and listening for rodents.  Red-winged blackbirds and boat-tailed grackles nest in the high grass.  These are the birds that migrate in huge flocks during early winter.  FYI, the rice dikes are pock-marked with fire ant mounds, and I stumbled over several while looking in the air for birds.  In addition to the 3 birds species already mentioned, I saw red-shouldered hawk, osprey,  black vulture, great blue heron, smaller unidentified herons, great egret, cattle egret, anhinga, cormorant, wood stork, coot, a cardinal, and maybe a Louisiana water thrush.  Near the Savannah River that I think is part of this refuge, I saw several terns.  Reptiles seen included several alligators and young soft-shelled turtles.

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Muddy alligator sunning itself at the Savannah River NWR.

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I saw a greater variety of birds at the Savannah River NWR than anywhere else on this trip. Various species of blackbirds nest in these grassy wet prairies.

Eats

Monday evening we ate supper at Captain Woody’s in Blufton, South Carolina.  They offer signature fish sandwiches on their menu–$13.99 for grouper, $11.99 for triggerfish, and $9.99 for fish of the day.  Their fish of the day was tilapia, a fish I can get anytime.  I picked the triggerfish because I’ve never even seen it on a menu before.  It was delicious, like the best filet of sole.

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Captain Woody’s in Blufton, South Carolina.

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I ate a giant triggerfish sandwich.  It was delicious.

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Anita had a shrimpburger. Even though it had bell pepper in it, she didn’t get sick.

On the way home Tuesday, we stopped by the Schnitzel Shack in Rincon, Georgia.  They offer a menu that is half Thai and half German.  It’s a bit overpriced…I payed $13.95 for what basically were a couple of big fat hotdogs.  The décor consists of mostly Marilyn Monroe memorabilia.  The waitress looked like Marilyn Monroe but without the blonde hair and with piercings and tattoos.  All the best looking young ladies I saw on this trip had tattoos.  If I was a young man, I’d have to reconsider my rule against dating women with tattoos.  I think tattoos are stupid but could learn to overlook them on a woman with a buxom build.

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The Schnitzel Shack in Rincon, Georgia.

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The menu is half Thai, half German. It’s a bit overpriced.

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I ate knockwurst, red cabbage, and German potato salad.  Too bad I had to drive.  Beer would have been great with this.

Reference:

Lee, James; David Osborn and Karl Miller

“Habitat Use by a Dense Population of Southern Fox Squirrels”

Southeastern Naturalist 8 (1) 2009

My 5 Favorite and 5 Most Disappointing Wildlife Destinations

April 18, 2015

I fantasize about living during the Pleistocene  because I would love to live in a world where I could open my front door and see a mammoth or saber-tooth cat, not just occasionally but often.  The thought of being surrounded by wilderness never fails to relax me. True wilderness no longer exists on earth, but there are still a few places in the world where a man can see an abundance of large wild animals. However, they are far away, and I despise traveling.  I would like to see Wood Buffalo National Park in Canada and observe wolves hunting bison, but it would take a week just to drive there from my house, and I refuse to fly on an airline until they stop ordering perverts to feel up all the passengers before they’re allowed on the aircraft.  So that trip will never happen for me.  I have made the effort to see regional wildlife attractions.  Here’s a list of my favorite and my most disappointing wildlife attractions.

Favorites

1. Wakulla Springs, Florida–This is the only location where I’ve ever seen manatees.  I was also thrilled to see bird species I’d previously known only from books such as white ibis, yellow crowned night herons, wood ducks, and prothonotory warblers.  There are lots of turtles, alligators, and deer here, and the crystal clear waters reveal many types of fish–schools of mullet, black and white sunfish, and gar.

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The boat ride at Wakulla Springs made the 7 hour drive from my house worth the trouble.

2. Harbor Island, South Carolina–My parents used to own condos here when the island was first being developed by real estate companies.  There were noisy heron and egret colonies on the island, and alligators swam in the brackish lagoons beneath the rookeries.  Pelicans and black skimmers flew over the shallow ocean water, while sandpipers and sea gulls scurried ahead of human beachcombers.  Sharks and dolphins hunted in the surf.  The species of sharks I saw hunting were probably either Atlantic sharp-nosed or sand, but I did once see a dead blue shark washed up on shore.  Loggerhead sea turtles buried their eggs in the sand.  I never saw a live individual, but did come across a dead specimen.  I witnessed large tarpon spawning in the shallow water.  I caught mullet with a cast net and captured blue crabs in traps.  A large colony of cottontail rabbits lived on this bushy island with few trees.  The adjacent more heavily wooded Hunting Island carries lots of deer and raccoon.

3. Berry College Campus, Georgia–Bald eagles nest here, and I have also seen a peregrine falcon and a swan on campus.  But deer are the most impressive attraction.  Great herds of does take refuge on campus during hunting season.  They must know it’s a safe zone–the campus is adjacent to the largest wildlife management area in the state of Georgia.  Flocks of turkeys abound here too.

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Berry College is the only place I’ve ever seen a swan.  Don’t know whether it’s a natural occurrence or an introduction, but swans were widespread in North America during the Pleistocene.

4. Land Between the Lakes, Kentucky–We drove by a herd of bison and saw turkeys and cattle egrets as well.  Deer roam throughout this vast forest of oaks, hickories, and black walnut, but on the day I visited it was hot and I didn’t get to see the elk that must have been hiding in the deep shade.

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Up close with a herd of bison at Land between the Lakes.

5. Congaree National Park, South Carolina–I’ve been here twice.  I took a 5 hour hike on my first visit.  Deer and a milk snake crossed my path, and I must have ducked under 10,000 spider webs.  Barred owls hoot during the day and pileated woodpeckers are common in the park.  The splendor of the spectacular old growth trees makes a visit here worth the trip.

Most Disappointing

5. Mount Mitchell, North Carolina–The brochure claims red squirrels and black bears live on the mountain.  I don’t believe it.  I saw not a single mammal and just a couple songbirds.  The forest here is dying.

4. Blue Ridge Parkway, North Carolina–This is a busy road through a boring stretch of woods. I saw 1 woodchuck.  I can’t believe this crap is part of the National Park Service.  It totally sucks!

3. Oaky Woods Wildlife Management Area, Georgia–This holds the last population of black bears in the entire piedmont region of southeastern North America.  Hunters stopped a planned development, so they could continue to enjoy killing the bears, though this population is probably way too low to support sustainable hunting.  I didn’t see a single bird or mammal in the part I hiked.  It was a boring stand of 2nd growth dominated by pine with few oaks, despite the name.

2. Okefenokee Swamp Wildlife Refuge–I expected to see lots of wading birds.  I didn’t see a single wading bird or alligator.  I visited during a drought, so there was no water, and no wildlife at all.  Nothing!

1. Great Smoky Mountains National Park–This overcrowded joke is completely devoid of wildlife.  I saw absolutely nothing, except for thousands of Homo sapiens.  There are 2 areas of this park that are allegedly rich in wildlife–Cades Cove and the Canaloochee.  When I visited, the road to Cades Cove was closed.  A visit to the Canaloochee requires a drive up a steep narrow winding road.  I got tired of driving up this shitty road and turned back.  Wildlife habitat in this park would be greatly improved with selective logging and regular burning.  The do-gooders in charge will never do this.  Having more wildlife would cause more work and conflicts than they want to handle.

Sadistic Hunters Saved what Pitiful Wilderness Still Exists

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In 1909 Theodore Roosevelt and his party  went on a safari and killed 44,900 mammals in just 11 months.  He founded the National Park Service so future sadists could continue to enjoy slaughtering animals.  That’s the only reason there is any wilderness left…so humans can continue to enjoy killing the animals that live there.

We can thank sadistic hunters for most of the wild lands that are left.  Theodore Roosevelt founded our National Park Service.  This bloodthirsty sadist went on safaris in Africa and slaughtered thousands of animals for the simple joy of killing.  All of North America’s magnificent animals would be extinct, if it wasn’t for sadists like him.  It’s a testament to the avarice of mankind that the only reason humans let other large wild mammals exist is so sadists can continue to enjoy killing them.

In a recent Facebook discussion I pointed out this ironic historical fact to Rob Pavey, the outdoor editor of the Augusta Chronicle, an extremely conservative publication.  He claimed I was “catastrophically misinformed,” then ended the discussion by barring me from posting any additional comments.  (I think he unfriended me.  Facebook is just silly.)  One has to marvel at the chutzpah of someone who declares they are smarter than you and refuses to continue the discussion.  I asked him to explain how I was misinformed, but he could not.  When someone comes across as misinformed to me, I am more than happy to inform them. I never bar anyone from discussion on my blog.  He seemed particularly defensive about hunting, even before I referred to hunters as sadists.  I doubt most hunters even admit to themselves why they enjoy killing animals. I’m not against killing animals for food, safety, or even to protect valuable property. But I’m convinced there are many hunters who kill animals because they enjoy the killing, yet won’t admit it.  I like to eat wild game meats, but there are many hunters who don’t even like to eat what they kill.  Anthony Bourdain, host of various cable channel travel and cooking series, once went duck hunting with regular duck hunters who admitted they didn’t like the taste of wild duck.  What is the purpose for them killing the birds, if they don’t want to eat them?  Do they just like to blow birds out of the sky for the hell of it?  No wonder Pavey was so defensive, and I might add intolerant of my inquiry.

Blue Crabs (Callinectes sapidus) in Freshwater Springs

April 14, 2015

Marjorie Rawlings owned an orange grove in north central Florida from 1928-1941.  She was not a native southerner but used inheritance money to purchase the property.  Many of the characters she created in her short stories and novels were based on the people she met while she lived here.  Her most famous work is The Yearling, a novel later adapted for the big screen.  I think her most interesting book is her memoir of the 13 years she lived in a farm house next to her orange grove.  The title of this memoir is Cross Creek.  The relationships she developed with the “colored help” and the white “crackers” are entertaining reading.  Though progressive for her time, she clearly viewed black people as 2nd class citizens.  On 1 occasion she spent a week long hunting trip with her visiting brother.  When she returned to the farm she was outraged to discover the live-in “colored” help had spent the week enjoying a drunken orgy (literally…2 men and 1 woman in the same bed) and not a single chore had been completed.  Her brother joined her in chasing the help off the property at the point of a shotgun.  In my opinion Rawlings was at fault for being out hunting instead of supervising.  Moreover, today, her actions would be considered an illegal eviction, and she and her brother could be jailed for making terroristic threats.  However, if I could journey to 1930s Florida in a time machine and suggest this, all the white people there would think I was out of my mind.  How times have changed.

Marjorie Kinnan Rawlings with her dog - Cross Creek, Florida

Marjorie Rawlings, author of the famous novel–The Yearling.  This dog was accidentally poisoned.  She accused her neighbor of deliberately poisoning her dog, a charge he vehemently denied.  They feuded for a year before reconciling.

My favorite chapter in Cross Creek chronicled the local cuisine.  Bread here meant cornbread, cornpone, hoecakes, hushpuppies, or biscuits.  Meat meant salt pork, known here as “white bacon.”  Pork in 1930s America was much fattier than modern day pork.  White bacon was soaked in water, floured and fried.  The grease rendered from frying the fatty pork was used to season biscuits, cornpone, sweet potatoes, black-eyed peas, green beans, and greens.  These were the staple dishes but hunting and fishing supplemented the local diet with many exotic sources of protein such as alligator, rattlesnake, turtles and their eggs, limpkin, blackbirds, bear, and squirrel.  Rawlings accompanied men who went crabbing at night.  They caught crabs from a freshwater spring that flowed into the St. John’s River.  The men stood on boats and located crabs by shining lights into the clear water.  They used 12 foot poles with iron jaws on the end to snatch the crabs.

Crab

Blue Crab in Crystal River Spring, Florida. It’s probably a male.  The females stay in brackish water and migrate to waters with high salinity to release their eggs.

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Blue crab life cycle.

I was surprised to learn that blue crabs inhabit freshwater.  Apparently, during spring male blue crabs migrate in enormous numbers to brackish and fresh water.  During mating season the 2 sexes meet in brackish water to mate, and the females carry their fertilized eggs back to the saltier depths.  The larval stage of the blue crab is known as a zoeal.  As the zoeal grows, they shed their shells 7 times in a process known as molting.  Their bodies absorb calcium from the sea water and swell, and this extra calcium forms a hard exoskeleton.  Blue crabs are called megalops during the next stage of their life when  they move into water with lower salinity where they eventually transform into adult crabs.

Blue crabs outcompete and drive away crayfish in the freshwater springs they inhabit.  Both species eat the same foods, scavenging and actively hunting plant and animal material.  Blue crab larva can’t survive in freshwater.  If this species ever evolved that ability, they would eventually colonize freshwater creeks and rivers, causing a decline in crayfish abundance and diversity.  Fossil remains of the Callinectes genus date to about 15 million years ago, and Pleistocene-aged blue crab shells have been found from Massachusetts to the Caribbean and Texas.  It is an incredibly successful species.

Asian Elephants (Elephas maximus) and Horses (Equus ferus caballus) Refused to Eat Pawpaws in a Controlled Experiment

April 10, 2015

Some scientists have hypothesized certain fruiting plants were dependent upon now extinct megafauna for distribution.  They believe the fruits were eaten and the still viable seeds were scattered across the landscape in beneficial piles of manure.  The extinction of large mammals that ate the fruits of pawpaw (Asimina triloba) and osage orange (Maclura pomifera) explains why these plant species today have such a patchy distribution.  They are considered anachronistic fruits.  Members of the Hendrix College Biology Department in Arkansas recently tested this hypothesis by feeding these fruits to species closely related to extinct Pleistocene megafauna.  They then planted the defecated seeds to determine viability.  Oddly enough, they also included persimmon (Diospyros virginiana) in their experiment. Persimmon is a common tree, not patchy in distribution, and the seeds are known to maintain viability after passing through a raccoon’s (Procyon lotor) alimentary tract.  I don’t consider persimmon an anachronistic fruit for those reasons.

Asian elephant.  In an experiment they readily ate persimmons and did try osage orange but absolutely refused to eat pawpaws.  This does not convince me that mastodons didn’t eat pawpaws.

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Horse eating osage orange.  The experiment suggests horses were not a distributor of osage orange seeds.  No viable seeds survived the horses digestive tract.

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Horses and elephants loved eating persimmons.  Viable seeds survived elephant digestive tracts but not the horse’s.

Pawpaw Fruit

Scientists were surprised that elephants and horses didn’t eat pawpaws, a nutritious sugary fruit.  This doesn’t mean mastodons didn’t eat pawpaws.  Mastodons were not the same species as the Asian elephant and evolved in the same region as this fruit. I believe they did eat them.

Asian elephants are closely related to extinct mammoths and distantly related to extinct mastodons (27 million years of evolution separate them from the latter proboscidean).  Modern horses are arguably the same animal as 1 of the species of North American horses of the Pleistocene.  The scientists involved in the study fed persimmons, osage orange, and pawpaws to Asian elephants and horses to gauge how effective they would be as seed dispersers.  Persimmons seeds sprouted and grew well in elephant dung but failed to survive horse digestion.  One elephant ate osage oranges but refused to retry them given a 2nd helping.  Some osage orange seeds sprouted and grew in elephant dung.  But again, none survived horse digestion, though horses really liked this fruit.  Elephants and horses surprisingly refused pawpaws.  At first the horses tasted them but spit them out and visibly grimaced (known as a Flehman response) as if they tasted bad.  Pawpaws are sweet and nutritious, so it is puzzling why neither species ate them.

The results of this study suggest mastodons and mammoths could have been effective dispersers of fruit seeds, while Pleistocene horses were not.  The study doesn’t prove mastodons didn’t eat pawpaws.  Though related, mastodons are not the same species as Asian elephants and likely had different tastes.  Mastodons evolved in North America for  millions of years alongside pawpaws, and I suspect some time during that span of time the species learned to like pawpaws. Persimmons grow in Asia but pawpaws do not.  Perhaps this explains why Asian elephants were so willing to eat persimmons but not pawpaws.  It is a fruit that occurs in the region from where they evolved.

The Hendrix College Biology Department should expand their study to include other close relatives of extinct Pleistocene megafauna such as tapirs, pigs, peccaries, llamas, and tree sloths.

Reference:

Boone, Madison; et. al.

“A Test of Potential Pleistocene Mammal Seed Dispersal in Anachronistic Fruits Using Extant Ecological and Physiological Analogs”

Southeastern Naturalist 14 (1) 2015

Cloudland Canyon State Park in Dade County, Georgia

April 8, 2015

The intersection of 2 creeks eroding through sedimentary rock formed the spectacular Cloudland Canyon located in the northwest corner of Georgia.  For tens of millions of years Bear Creek and Daniel Creek cut through layers of shale and sandstone.  Both of these types of sedimentary rock formed here during the Pennsylvanian Age (320 million BP-286 million years BP) when this region was sandy shoreline and muddy shallow sea.  Sand buried under pressure conglomerated into sandstone, while shale is simply fossilized mud.  A continental collision caused the uplifting of the Appalachian Mountains raising the elevation of this area with its layers of sedimentary rock.  Shale is a soft rock and easily eroded, but sandstone is more resistant to erosion.  The creeks have eroded through the shale causing the overlying sandstone to collapse into the valley.  This ongoing process has been continuously widening this canyon.

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View of the eastside of Cloudland Canyon from the west rim.  There are at least 4 waterfalls on that side of the canyon.

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The canyon walls consist of layers of erosion resistant sandstone on top of layers of shale.  As the shale erodes, overlying sandstone shelves collapse into the canyon, widening it.

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Lookout Valley is beyond Cloudland Canyon.  Sand Mountain can be seen in the distance.

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All the rock in this location dates to the Pennsylvanian Age when this locality was at the bottom of a shallow sea.  It was then uplifted by the collision of continental plates.  There’s reportedly fossilized wood in some of these rocks, but I didn’t see any.

I walked along the overlook part of the West Rim Trail.  By far the most common trees were rock chestnut oak (Quercus montana) and Virginia pine (Pinus virginiana).  White pine, shortleaf pine, red cedar, southern red oak, post oak, sand hickory, rhododendron, and mountain laurel are also present.  Reportedly, serviceberry grows here.  I’ve never had a chance to try this blueberry-like fruit, but it doesn’t ripen until June.  There are 3 types of natural communities in Cloudland Canyon State Park–acidic oak/pine forest, acidic cliffs, and calcareous cliffs.

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Black vultures soaring. Click to enlarge. Cliff ledges make excellent nesting sites for vultures, eagles, falcons, swallows, and other smaller birds.

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Another view of the rounded peak.

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Trees are hiding this waterfall.  The intersection of 2 creeks–Bear and Daniel–created Cloudland Canyon.

Most cliffs are pristine environments because there is little industrial use for them, and they’ve been left unmodified by man.  Cliffs are fascinating environments (See: https://markgelbart.wordpress.com/2013/05/19/piedmont-cliff-ecology/).  They provide nesting habitat for many species of birds.  During the Pleistocene teratorns, California condors, golden eagles, the extinct Grinnell’s crested eagle, and ravens probably nested on the cliffs in the above photographs.

 

 

Kennesaw Mountain National Battlefield Park

April 6, 2015

William Sherman’s advance across a broad front through Georgia was a strategy borrowed from Napoleon.  I don’t understand why Napoleon is considered a great general–he lost 3 entire armies.  He lost an army to the plague in Egypt, wasted another army while campaigning during a Russian winter, then was finally outmaneuvered at Waterloo.  Nevertheless, Napoleon’s strategy was effective against outnumbered troops, and Sherman had 100,000 troops vs. 65,000 Confederates on this front.  If the rebels made a stand, the numerically superior Union forces merely had to outflank their line, threatening to surround them.  The Confederate forces were continuously forced to retreat to avoid encirclement, a scenario that would have led to the surrender of the entire army group.  Joe Johnston, the Confederate general, had no choice but to form a defensive position on Kennesaw Mountain during June of 1864, even though he was aware of Sherman’s strategy.  He did send a force to outflank Sherman’s flanking maneuver, but it ran into a fixed Union position, and the Confederates lost 1000 men.

Sherman decided to take a chance at Kennesaw Mountain and ordered the only frontal attack of his campaign through Georgia.  He believed it was worth the risk because a) a change in tactics from flanking maneuvers to a frontal assault could surprise the Confederates, b) by pressing the Confederates he could prevent them from dispatching troops to the Virginia front where Grant was struggling to defeat Lee, and c) a breakthrough at Kennesaw Mountain would split the Confederate forces in half and lead to the immediate capture of their supply depot.  However, the 2 pronged attack by 3 divisions of U.S. federal troops failed with a loss of 2500 men.  The Confederates lost 800, mostly to artillery bombardment.  Sherman wisely rejected his subordinate officer’s plans to renew the frontal assault.  Instead, he resumed his flanking actions forcing the Confederates to retreat to the Chattahoochee River on July 2nd.  Jefferson Davis unfairly fired Joe Johnston soon after this battle.  He was replaced by the inferior reckless Hood who also could not stop the inevitable Union advance.

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View of metro Atlanta from the top of Kennesaw Mountain.

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Confederate cannon.  There was a hell of an artillery duel at Kennesaw Mountain.

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Path to the top of Kennesaw Mountain.  The park also protects an oak/hickory forest that is much like the original environment here.

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View of Little Kennesaw Mountain from the main Kennesaw Mountain.  The Confederates cut a path through the woods and hoisted artillery to the top of this mountain, using rope.

Though I’m interested in military history, I really visited Kennesaw Mountain to enjoy the natural history of the park.  Kennesaw Mountain is a rare natural area located within the sprawl of metro Atlanta.  Almost 3000 acres of protected forest, field, and wetland are surrounded by heavily wooded suburbs, providing habitat for 538 species of plants and 175 species of birds.  There are 3 types of forest land in the park–oak/hickory, rocky slopes, and rocky outcrops.  The oak/hickory forests are dominated by white oak, southern red oak, mountain chestnut oak, and post oak, along with 3 species of hickories.  Beech, sweetgum, and tulip trees are also present.  The shrub layer consists of dogwood, hackberry, beauty berry, holly, black cherry, blueberry, honeysuckle, and several other species.  Trees and shrubs found on rocky slopes include hickory, American plum, blackjack oak chestnut oak, blackberry, blueberry, and others.  Shortleaf pine, American plum, blackjack oak, chestnut oak, elm, blackberry, and blueberry grow around rocky outcrops.  Wetlands within the park host buttonbush, grass, sedge, rushes, cattails, and arrowleaf.  There are also a few swamps where red maple, buttonbush, basswood, dogwood, tupelo, willow, and ferns grow.

I was excited to see a chipmunk (Tamias striatus) in Kennesaw Park.  Chipmunks don’t live in my hometown of Augusta, just 180 miles southeast of this locality.  Kennesaw Mountain provides ideal habitat for chipmunks, and I predicted I might see 1 here.  Chipmunks like to live in crevices under boulders and rock piles.  Rocky forest lands, their favored habitat, cover most of the mountain.

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The chipmunk I saw at Kennesaw Mountain scurried away too quickly for me to photograph it, but I did see several playing around this pile of old wood in my mother-in-law’s backyard the following day.  She lives in Lafayette and has a view of Pigeon Mountain from her backyard.  Click on the picture to enlarge, and 2 sitting together can be seen.

Due to the elevation Kennesaw Mountain was likely the 1st locality to host spruce trees at this latitude during the Ice Ages.  Following the end of Ice Ages, this locality was probably the last at this latitude where spruce trees grew more abundantly than oaks and hickories.

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Note all the granite and granitic gneiss.  It is resistant to erosion.  Kennesaw Mountain is composed of this granite, explaining why it hasn’t eroded like the surrounding region.

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Lichen-covered granite boulder.

Kennesaw Mountain is a monadnock–an isolated erosional remnant standing 700 feet above the surrounding terrain.  It is 1808 feet above sea level. The granite and granitic gneiss that compose the mountain are resistant to erosion.  Granite is common in the Atlanta area, but much of it is fractured.  Kennesaw Mountain and Stone Mountain are solid and less fractured and therefore stand by themselves.  The mountain consists of a  mixture of igneous and metamorphic rocks.  Some was directly spewed by volcanic action, while others were transformed deep under the earth and uplifted.  Gray migmatite is a common mineral found here.  It has alternating light and dark bands.  The light bands are composed of quartz and feldspar, while the dark bands are made of bratite and hornblende.

References:

Gore, Pamela; and William Witherspoon

Roadside Geology of Georgia

Mountain Press Publishing 2013

Hart, Liddell

Sherman: Soldier, Realist, American

De Capo Press 1993

Zomlefer, Wendy; David Giannasi, and S. Lee Echols

“Vascular Plant Flora of Kennesaw Mountain National Battlefield Park, Cobb County, Georgia”

Southeastern Naturalist 9 (1) 2010