Horned Larks (Eremophila alpestris) were Likely an Abundant Bird during Ice Ages

Stadials, the coldest stages of Ice Ages, fostered an expansion of arid grassland habitat all across Eurasia, Beringia, and North America.  Droughts were frequent and low CO2 levels slowed plant growth.  Grass and conifers outcompeted broad-leafed trees in these conditions.  Arid environments favored grass-eating herbivores, and a variety of smaller animals that prefer wide open spaces.  The horned lark (Ermophila alpestris) is an example of a species that likely abounded in large numbers during stadials.  They inhabit environments consisting of sparse grass and bare ground.

Horned larks require a landscape consisting of bare ground and sparse grass. This type of environment was common during Ice Ages.

The horned lark nests on bare ground, laying their eggs next to a tuft of grass.  Like most ground-nesting birds, they will feign injury to lure a predator away, but they do wait longer than other species before taking this evasive action.  Today, horned larks breed and nest from northern Canada to as far south as Maryland.  They winter as far south as Georgia.  In the east they find the type of environment they like in salt marshes, beach dunes, and winter-fallow agricultural fields.  They are also known as shore larks.  During the Ice Ages much of their modern day American breeding grounds were under glacial ice, so it is likely they bred farther south in the steppe-like landscapes that occurred adjacent to the glacial boundary.

Pleistocene fossil evidence of horned larks is scant in the south, but specimens have been recovered from Cheek Bend Cave in middle Tennessee.  The lark specimens were found associated with bones of other northern bird species absent or uncommon in Tennessee today, including gray jays, boreal owls, saw-whet owls, purple finches, and prairie chickens.  Evidence of other bird species from the cave represent those still common in the region today–blue jay, red-bellied woodpecker, flicker, sparrows, meadowlark, and others.  (The eastern meadowlark (Sturnella magna) is not a true lark but instead is more closely related to blackbirds and starlings.  It too prefers open spaces.)  During winter horned larks join large nomadic flocks of sparrows, juncos, lapland longspurs, and snow buntings as they edge toward more southerly latitudes, though the larks are among the first to return north in the spring.  All of these birds were likely common on Ice Age plains.

Horned larks feed on insects and grass seeds, even foraging in horse manure for undigested seeds.   Horned larks and other birds scratching through mammoth and horse dung on frozen ground was probably a common sight during the Pleistocene. 

Chickens foraging for worms and undigested grain in horse manure.  Horned larks also like to forage through horse manure.  Horse manure would have been one of their important food sources during Ice Ages.  Just think about this next time you are sitting in front of a plate of fried chicken.

Horned larks belong to the Alaulidae family which includes 20 genera and 99 species, but they are the only true lark that managed to cross the Bering Landbridge.  All the other species are confined to Africa, Eurasia, and Australia.  The horned lark is a successful widespread species, living in both Eurasia, and North America.  At present they are still considered a common bird but in steep decline.  The conversion of open agricultural land to 2nd growth forest is eliminating their preferred habitat.

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Can Conservatives get any more Heartless and Hateful?

I try to keep this blog focused on natural history, but some times I become aware of an issue that compels me to stand on my soap box and shout my outrage to the world.

I’ve read a couple of excellent books this summer–Tortilla Curtain by T.C. Boyle (my favorite writer), and Hammer of the Gods: The Led Zeppelin Saga by Stephen Davis.  The former is a novel that delves into the plight of undocumented immigrants seeking a better life in this country, and the latter is a biography of Led Zeppelin.  There are many fascinating details about history’s Number 1 rock band in Hammer of the Gods, but a few incidents  during the group’s concert tours of the south in 1969 seem eerily similar to how conservatives view undocumented immigrants.  Of course, southern kids loved Led Zeppelin and were always the band’s most boisterous fans, but the adults did not treat these hippies with southern hospitality.  Police threatened to physically brutalize the band, forcing Atlantic Records to hire their own thugs for protection.  Waitresses refused to serve them, and some  old southern fried fucks literally spit on the band members.  Hotel owners told the band members not to swim in the hotel pool because they didn’t want them to spread disease.  This last nugget of ignorance is what rings a bell.

Thousands of young children from Central America are escaping the rampant gang violence of their home countries by crossing the U.S./Mexican border.  U.S. border patrol agents are arresting them and confining them in small holding cells, even cages.  OUR TAX MONEY IS BEING SPENT ON PUTTING INNOCENT CHILDREN IN CAGES.  This is outrageous.  To justify this inhumane treatment, stupid redneck politicians claim these children might spread diseases.  These hypocritical politicians don’t give a shit about children getting sick.  Conservatives invariably fight to weaken or overturn environmental laws that prevent children from getting sick.  All of a sudden, they are concerned with childhood sickness?  Well, I say innoculate these children and send them to elementary school.  Put them up for adoption.  We should welcome them, not put them in cages like unwanted cats and dogs.

The United States can’t even spare a bed for these poor kids?  What a disgrace.

Conservatives claim the cost is too high to care for the children.  These are the same people who oppose abortion.  They favor forcing women to have unwanted children, yet are unwilling to pay for the care of children after they are born.  Conservatives should look at it this way: the Central American refugees are the replacements for all the aborted fetuses for which these jerks shed their crocodile tears.  We should adopt them, educate them, and let them be the future generation that supports us in our old age.  Opposition to accepting Central American refugees on the basis of economics is selfish and short-sighted.  It may cost more money to care for them now, but in the long run they could potentially pay us back with tax revenue from future labor.  Tax revenue from immigrants is the best hope of saving Social Security.

 

 

 

 

 

 

 

This is all the technology required to defeat the racist wall politicians had built along our border with Mexico.  There is no wall across our border with Canada because most Canadians are white.  The wall costs billions to maintain, yet does not keep a single person out.

The fence along the U.S./Mexican border is a racist symbol.  It prevents no one from crossing the border because it is easily defeated with a low tech ladder.  It costs billions of dollars to maintain–money that would be better spent on the care and education of the children who want to live here.

Conservatives refer to these children as “illegal aliens.”  This dehumanizes them and makes them sound as if they are monsters from outer space.  The other day, I listened to a local radio talk show host, Austin Rhodes, constantly refer to them as “illegal aliens” in one of his recent rants.  What really had him upset was the possibility that a child of an undocumented immigrant might get an education in a public school at taxpayer’s expense.  Really?  A kid getting an education is a catastrophe?  His racism was obvious.  According to his point of view, “illegal aliens” were like something subhuman who didn’t belong in school with real people.  He considered them all “bad guys.”  His sanitized racism appeals to the same types of old fart racists who spit on Led Zeppelin 45 years ago.

Austin Rhodes–Augusta, Georgia’s hate radio propagandist.  His sanitized racism still has a great deal of appeal in the south.  He referred to “illegal aliens” as “bad guys.”  His beef?  The children of undocumented adults might get a free education.  Heaven forbid!  What a catastrophe!  A child might get a free education.  This coward is a total shmuck who once threatened to send men to my house to beat me up.  Why?  Because I merely repeated a fact published in The Metro Spirit–a paper that publishes his asinine weekly column.  His former producer, Troy, the Apeman, Bradley warned me I should “pray I never meet him in the street.”  I guarantee Bradley would do nothing to me, if I met him on the street.  He is also a cowardly bully.  Bradley was too afraid to even take or return my phone call when I called him after his macho boast.

Statue of Liberty

It is against American principles to keep poor oppressed people from living in this country.  We are a nation of immigrants.  Immigrants make the U.S.A. strong.  Undocumented immigrants are not all bad guys, as redneck conservative pundits claim.  They are simply seeking a better life for themselves and their families.  Conservatives need to pay a visit to the Statue of Liberty and read these words.

“Give me your tired, your poor,
Your huddled masses yearning to breathe free,
The wretched refuse of your teeming shore.
Send these, the homeless, tempest-tossed, to me:
I lift my lamp beside the golden door.” –Emma Lazarus

Mr. Claw

Scientists classify the common house cat (Felis cattus) as a different species than the Old World wildcat (Felis sylvestris), but they are the same animal and readily interbreed in areas where they overlap.  Like the dog (Canis familiaris), I believe this species adopted humans, rather than vice-versa.  Humans have lived with cats for at least 9500 years–evidence of the oldest association between the 2 was excavated from an archaeological site in Cypress, Greece.  Cats first started living closely with humans when we began storing grain.  The grain attracted rodents, which in turn attracted cats.  Kittens, left unattended by their mothers, easily bond with humans who treat them with kindness.  The cat is an amazing intelligent survivor.  Fossils of F. sylvestris are often found in European caves, and this species has been in existence for over 2 million years.  Cats were able to live in environments with wolves, bears, lions, and mammoths; yet they were able to adapt to new environments shaped by humans, while the larger, fiercer beasts disappeared.

My favorite cat died about a year ago.  While she was alive, we never had mice in our house.  As soon as she died, mice and other small animals began to plague us.  Both the house mouse (Mus musculus) and the field mouse (Peromyscus sp.) invited themselves into our house.  I don’t appreciate mouse turds in my food supply, so I poison-baited our home–not the ideal solution because a poisoned mouse can go outside and get eaten by a bird of prey, thus killing the raptor too.  Usually, the poisoned mouse would emerge from hiding in a partially paralyzed state, and I would be forced to whack it with dress shoes that I refer to as my “mafia” shoes.

Frogs, like one of the 12 plagues of Egypt, also frequent our house.  Green frogs (Rana clamitans) burrow into the soil, find their way into our septic tank, and swim up the pipes to the toilet bowl.  I don’t mind the frogs, but my wife suffers from ranidophobia, or fear of frogs.  Small tree frogs (Hyla cinerea) often hang out by the living room window and croak so loudly that my wife can’t hear the television.  On several occasions my wife has interrupted me while I was enjoying my favorite video of a nude woman doing housework (http://www.dailymotion.com/video/xl5lms_cleaning-house-naked_redband), by ordering me to go outside and scare the frog away from the window.  She ignores my complaints about the futility of such an endeavor.

To keep my wet dreams from being ruined by my wife’s hysterics, I decided to tame a feral cat ranging in the woods behind my house.  I reasoned the mere presence of a cat in the immediate proximity of my house would keep the small pests at bay.

I started putting out food for the cat and gradually moved the feeding spot closer and closer to the house.  I sat outside on the back steps while he fed to get him used to my presence.  Some say feral cats never make good pets, but there is contradictory evidence of this on the web, so I viewed this as an experiment.  This required a great deal of patience.  To fight off boredom, I sat on the back steps, drank chilled white wine, and listened to rhythm and blues on my Sony Walkman.  I can get drunk and listen to music for hours without getting bored.  The cat saw me in my most relaxed state, and this seemed to relax the cat.  One day, I placed the cat food down, and the cat started circling me.  The circle kept getting smaller and smaller until he was rubbing against my legs.  And he let me pet him.  I thought this was great because I had earned the cat’s trust.

Mr. Claw approaching me before he ever let me pet him.

While I’m relaxing and drinking chilled wine on the back steps, Mr. Claw is getting relaxed enough to creep closer and closer.

Now this once feral cat rubs up against my leg.  I’ve gained his trust, but now I don’t trust him.  The sneaky little fella likes to claw me, seemingly as a practical joke.  I also always wear shoes to protect my toes which have become irresistable targets.

This is why I went to the effort to tame a feral cat.  After my beloved cat died last summer, we had mice in our house for the first time ever.  The smell of a cat alone is enough to keep mice away.

 

 

 

 

 

 

My wife is terrified of frogs.  This species, the green frog (Rana clamitans), often burrows into the soil and lives in our septic tank.  They occasionally swim up the pipe and into the toilet, causing my wife to have a freekout until I catch it and take it outdoors.  Maybe the cat will reduce the population of green frogs in our yard.

Green tree frog (Hyla cinerea).  This species is common around my house.  Whenever they croak, my wife orders me to go outside, find the frog, and take it away.  How ridiculous!  This is annoying, especially when I’m in the middle of watching a stimulating video of a naked woman doing housework.  Cats like to eat little frogs like this.

A problem occurred when I was sitting on the back steps one evening while getting relaxed with wine and song.  The cat snuggled next to me, then suddenly clawed my arm and retreated a short distance.  It occurred to me that the cat was playing because my late aunt and uncle had a Siamese cat that engaged in similar behavior but with the neighbor’s dog.  Their neighbor had a German shepherd kept chained in the backyard.  My uncle’s cat would slowly creep toward the dog which would go crazy barking and pulling on the chain.  The cat would smack the dog on the nose and run away–obviously teasing the hell out of it.  Could this cat be teasing me?  In any case, this cat earned the name, Mr. Claw.  He later laid down in front of me with his paw pointed toward me–claws unsheathed!

Since then, this sneaky cat has clawed my toe and my ankle, and I no longer trust him.  A cat expert suggested playing with the cat to channel its aggressiveness, but Mr. Claw shows no interest in playing with conventional cat toys.  He prefers the claw and run tease.  The difference between Mr. Claw and my old deceased cat is like the cliche` night and day.  Mr. Claw is aggressive, unpredictable, and sneaky.  My old cat, Lone Ranger, was always gentle and docile.  Mr. Claw probably needs to be fixed, but I don’t want to pay for that.  Removing a cat’s testicles seems like the equivalent of giving a human a lobotomy.  The experiment continues…

Mt. Mitchell and Chimney Rock State Parks

For our family vacation this year, I wanted to visit St. Simon’s Island, so I could walk through an old growth live oak forest and also hunt for fossils in the lagoon behind the island.  However, my wife objected to the heat and expressed her desire to seek relief in the Blue Ridge Mountains.  We have a successful marriage, meaning we compromised by choosing her destination.

We went to Mount Mitchell State Park located 35 miles north of Asheville, North Carolina.  To get there, it’s necessary to travel along the Blue Ridge Parkway.  I was looking forward to this route but was unimpressed and very disappointed with the Blue Ridge Parkway National Park.  It’s simply a busy road through the woods, and I can’t believe this sorry stretch is part of the national park service.  There were gangs of motorcyclists and inconsiderate bicycle riders and even an 18-wheeled truck.  The road is narrow and winding with a speed limit of 35 mph.  The bicycle riders act as if they own the road–not a single one of those lazy assholes pulled off the road to let us pass.  The entire parkway is a no passing zone and around many of the bends visibility is too poor to safely pass the bicycle riding jerks.  The only wildlife I saw on the parkway was a woodchuck.  I didn’t even see a single bird or gray squirrel.  By the time I reached the road that leads to Mount Mitchell, I was in a foul mood.  My aggravation increased because I hated the endless, climbing, winding road that led to the top.

Note the line of dead trees halfway up this mountain.  This forest is dying.

See how open the terrain is?  If there were any large mammals in the park, they would be visible.  The population of large mammals in Mount Mitchell State Park is zero.  There aren’t even any white tail deer.

At 6578 feet Mount Mitchell is the highest elevated point east of the Mississippi.  Nevertheless, a visit here is not recommended.

Path through Craggy Gardens located off the Blue Ridge Parkway.  It’s a thicket of catawba rhododendron and stunted birch trees.  I saw a yellow-throated warbler here but little else in the way of wildlife.

Note how the roots of this birch tree are growing over a boulder.

The sign welcoming us to Mount Mitchell stated that it is a “World Biosphere Preserve.”  This is a joke.  The trees are all dead or dying and the whole park is nearly devoid of wildlife.  Woolly adelgids, an invasive insect, have killed all of the Frasier firs, and acid rain is in the process of killing the red spruce.  Mount Mitchell used to host an interesting boreal forest with flora and fauna more commonly found in the Canadian life zones.  Now it is practically dead.  The landscape is open so from the top of the mountain, it’s possible to see every large mammal for miles.  I did not see a single deer, elk, wild boar, or black bear.  The population of large mammals in Mount Mitchell State Park, aside from Homo sapiens, is zero.  There are supposed to be red squirrels here, but I did not see a single squirrel’s nest, let alone a squirrel.  Bird populations are also very low.  I saw a few sparrows and swallows and a gray bird that I could not identify despite combing through my field guides for 90 minutes when I returned home.

A restaurant exists on Mount Mitchell.  They charge extra money for the view.  For example they serve a hotdog for $9.  Mount Mitchell totally sucks.

Menu from the Mount Mitchell State Park restaurant.  9 bucks for a hotdog.  They suck.

 Chimney Rock State Park

The road to Chimney Rock State Park located about 30 miles south of Asheville doesn’t suck as bad as the Blue Ridge Parkway but I saw even less wildlife here.  The view of the cliffs is spectacular. 

View of Chimney Rock cliffs.

This tunnel was bored through 500 million year Cambrian-aged rock.  It leads to an elevator that ascends 26 stories in 30 seconds to the top of Chimney Rock.

View of Lake Lure from the top of Chimney Rock.

View of a cliff opposite Chimney Rock.

Chimney Rock.  To be honest, as soon as I was on top of Chimney Rock, I wanted to go back down to earth.  I’m not afraid of heights but they make me feel uneasy.

The cliffs here reminded me of an article I wrote about a year ago. https://markgelbart.wordpress.com/2013/05/19/piedmont-cliff-ecology/  Supposedly, peregrine falcons nest on the cliffs but the only bird I saw was a black vulture.  Surprisingly large birch and hickories grow on the rocky cliff faces along with many cedar trees.

Lake Lure

My daughter and I went for a walk around Lake Lure, a manmade body of water in the valley between the cliffs of Chimney Rock.  It was hot, and we were delighted to find a public swimming beach here.  The cool swim in the lake salvaged my mood.

View of cliffs from Lake Lure.

There’s a belted kingfisher nest in the mud bank on the shore of Lake Lure.  I saw more wildlife in the Lake Lure city park than on the Blue Ridge Parkway, Mt. Mitchell, and Chimney Rock combined.

Ah Hah!  There is a public swimming beach here.  This swim after a hot walk was the highlight of my vacation.  Note all the Canadian geese.  I told my daughter to make sure not to swallow the water.  With all the goose fecal matter, it’s probably contaminated with E. coli.

The restaurants in Asheville serve “home cooked” southern fare.  The food may be good but it is not as good as my own cooking.  The Moose Cafe near the Asheville Farmer’s Market serves excellent biscuits and corn bread but their entree’s were overseasoned with salt while their sides were underseasoned.  The local cuisine is nothing to get really excited about.

The Squirrel-Conifer-Fungi Connection

The evolutionary divergence of the northern flying squirrel (Glaucomys sabrinus) from the southern flying squirrel (G. volans) is an excellent example of speciation resulting from environmental change.  Genetic studies suggest both of these American species of flying squirrels diverged from Eurasian flying squirrels between 4-6 million years ago.  Eurasian flying squirrels are much more diverse and include 44 species, most of which live in southeast Asia–evidence this part of the world is where they originally evolved.  During the late Miocene about 5 million years ago, a forested landbridge connected Asia with America, explaining how the ancestor of both American species of flying squirrels colonized this continent.  Genetic evidence suggests the 2 American species of flying squirrels diverged from each other early during the Pleistocene between 1-2 million years ago when Ice Ages began to become more severe.  Boreal spruce forests expanded during Ice Ages, growing as far south as middle Georgia and Alabama.  In the middle south spruce forests grew in higher elevations while deciduous oak forests still occurred in adjacent lower elevation.  Oak forests are rich in mast such as acorns and nuts, but spruce forests offer less food for squirrels–seeds from spruce cones are only available for 2 months of the year.  However, underground fungi, also known as truffles, are available year round in spruce forests.  For most species of squirrels, fungi is a minor component of their diet, but truffles and other fungi make up 85% of the northern flying squirrel’s diet whereas southern flying squirrels eat more acorns, nuts, berries, and animal matter.  The ancestors of the northern flying squirrel were those individuals from the parent population best able to subsist on a diet of mostly fungi.  These individuals were able to colonize spruce forests, while the rest of the parent population remained in oak forests.  Eventually, this habitat partition resulted in a divergence between the 2 American species.

Northern flying squirrels eat mostly fungi which is a minor component in most squirrel’s diet.  The ability to subsist on a diet of mostly fungi enabled this species to colonize spruce forests.  Eventually, they evolved into a different species than southern flying squirrels because of this capability.

Elaphomyces or truffle–favorite food of the northern flying squirrel.

 

 

Red spruce (Picea rubens).  Red spruce, truffles, and northern flying squirrels are beneficial and interdependent to each other.

Fossils of both species of flying squirrels have been found at Ladds and Kingston Saltpeter Cave in Bartow County, Georgia.  This is evidence that patches of spruce forest grew near patches of oak forest in this region during some climatic stages of the Pleistocene.  Northern flying squirrels are confined to the former; southern flying squirrels require the latter.

There is an interesting ecological interdependence between northern flying squirrels, red spruce, and several species of fungi.  Truffles grow intertwined with the red spruce roots, and they exchange nutrients.  The squirrels eat the truffles and spread their spores throughout the forest in their droppings.  A healthy spruce forest requires an abudance of truffles.  Many red spruce forests have been logged, and without the squirrel’s help, trees such as oak, maple, beech, and cherry are replacing them.  In West Virginia the U.S. Forest Service has successfully re-established red spruce forests.  Foresters discovered that red spruce seedling grow best in ground ripped apart by bulldozers and strewn with woody debris.  Some of these young spruce forests are on land reclaimed from strip mining. 

 

Fox squirrel.  This species may play a role in distributing fungi in longleaf pine savannah. 

Rhizopogon nigrescens–a fungi common to longleaf pine savannahs and likely an item in the diet of the fox squirrel.

Virgin stand of longleaf pine (Pinus palustris) in east Texas (circa 1908).

Although fox squirrels (Scirius niger) have a much more varied diet than northern flying squirrels, they occasionally eat fungi and may play a role in the health of longleaf pine savannahs.  Certain kinds of fungi that grow in the soil of savannahs also exchange nutrients with longleaf pine trees, and fox squirrels spread these spores in their dung as well.  Fox squirrels and longleaf pine savannahs were formerly common in the south, particularly on the coastal plain, but today both are rare.  The changes man has wrought have really sickened the natural communites of the world.

Reference:

Arbogast, Brian

“A Brief History of the New World Flying Squirrel: Phylogeny, Biogeography, and Conservation Genetics”

Journal of Mammalogy 88 (4) 2008

Looking at Ice Age Georgia From Outer Space

 I have a great curiosity about the ecology of southeastern North America before man colonized the region and that has always been the main focus of this blog.  It’s a frustrating obsession because there is no way I can know the exact plant and animal compositions and their interrelationships, though I believe I’ve made good educated guesses.  I’m particularly interested in Marine Isotope Stage 3–an interstadial dating to between 60,000 BP-30,000 BP.  This was a time of great climatic fluctuations that likely caused a fascinating intermingling of northern and southern species in this region.  I even fantasize that I’ve time traveled to 36,000 BP, so I can live in a homestead there and study the ecology of this past environment.  Time travel is not feasible.  However, it occurred to me that images of Ice Age Georgia have not disappeared forever.  (I swear I wasn’t stoned when this thought occurred to me, although I may have been drunk.)

w49A, a star forming region on the opposite side of the Milky Way from earth, is 36,000 light years away.  A super advanced telescope located in this region could potentially see images of Ice Age Georgia.

View of earth from 22,000 miles away.

W49A is a star-forming region on the opposite side of the Milky Way galaxy from earth.  It contains an astonishing 100,000 stars in a space just 10 light years wide.  By contrast, there are only 10 stars within 10 light years of our sun.  W49A is 36,000 light years from earth.  This means that, theoretically, an alien life form looking through a super advanced telescope could be watching Georgia as it was 36,000 years ago. This alien could not see what was happening in dense forests, but they could be counting mammoths, bison, and ground sloths living in open grassland environments. SBW1 is a star located 20,000 light years from earth.  Astronomers believe it is about to become a supernova.  Theoretically, an alien from this vantage point could be observing earth as it was during the Last Glacial Maximum.

Modern telescopes made by man are incapable of directly observing planets in the closest star systems to ours, though it’s now possible to detect them indirectly.  However, Europeans are building the European Extremely Large Telescope (E-ELT) on top of a mountain in Chile.  It’s scheduled to be finished in 15 years.  This telescope will be able to see planets in neighboring star systems.  Telescope technology on earth is only about 500 years old.  Imagine an alien civilization that has been developing telescopes for 5000 years.  They could have images of earth as clear as our present day satellite images.  Some being could be seeing earth as it was tens of thousands of years ago, and they would know facts about Pleistocene ecology that we will never know.

Artist’s rendition of the European Extremely Large Telescope (E-ELT) to be constructed on top of a mountain in Chile.  It will be able to directly observe planets in other solar systems.  It’s supposed to be finished in 15 years.

Of course, humans alive today will never know whether intelligent life exists elsewhere in the universe.  Developing a super advanced telescope that can observe life on planets thousands of light years away may be possible, but traveling those distances within a realistic lifespan defies the known laws of physics.  If I had to bet whether life existed on other planets, I would wager that it does, simply because the universe is so vast.  But life is probably rare.  It would be really weird if earth was the only planet where biological life evolved.  Without biological life, nothing would be aware of the existence of the physical universe, so the physical universe itself would not exist…or it may as well not exist.  As Rene Descarte once wrote, if a tree falls in the forest, and no one is around to hear it, does it make a sound?

I am an agnostic.  I don’t know whether there is a God or not.  I think agnosticism is the most honest belief system.  The concept of and belief in a supreme being who can see everything we do seems very bizarre to me.  Yet, the way space and time are intertwined shows it is theoretically possible that a supreme being could witness everything we’ve ever done…as long as we did it outside in an open environment.  ATTENTION SINNERS!  This means that if there is a God, you should sin in doors, under a roof, where you can’t be seen by a supreme being who is observing the entire universe from some vantage point in space with his super duper telescope.

The Pre-historic Plant Composition of the Vero Beach, Florida Fossil Site

The Vero Beach Fossil Site in Florida has provided scientists with a remarkable treasure of data.  The initial excavation took place in 1915, and it sparked a controversy at the time because conventional wisdom assumed humans did not overlap in time with Ice Age megafauna in North America.  The discovery of human remains in the same strata here as mammoths, mastodons, and giant ground sloths debunked that conventional wisdom. (See: https://markgelbart.wordpress.com/2012/02/19/the-vero-beach-mammoth-engraving/) A few years ago James Kennedy found a megafaunal bone with an engraving of a mammoth on it here, re-igniting interest in the site.  James Adovasio of Mercyhurst University is conducting a re-excavation of the site before the city of Vero Beach eventually converts it to a concrete sewer drain.

Location of Vero Beach.  

Re-excavation of the Vero Beach Fossil Site.

In addition to the human remains and artifacts, the Vero Beach site has yielded the bones of mammoths, mastodons, giant ground sloths, pampatheres, bison, horse, tapir, deer, saber-tooth, jaguar, dire wolf, rabbit, cotton rat, round-tailed muskrat, shrew, and alligator.  Most people are more interested in the archaeological finds than anything else uncovered at this site, but I’m more fascinated with the paleoecology.  So I was delighted when I came across an old paper written in 1915 by Edwin Berry entitled “The Fossil Plants from Vero Beach, Florida.”  I knew scientists had recovered plant remains here, but I thought they’d all turned to dust after being exposed to the atmosphere.  Apparently, Edwin Berry was able to identify and describe some of the plant remains prior to their dissolution.

The plants identified by Berry are typical of the same species found in the area today, suggesting little change in central Florida’s floral environment since 14,000 years ago.  Oak was the most common tree growing alongside this now extinct river.  (During the Pleistocene it was a tributary of the St. Johns River.)  The most common species of oak was swamp laurel oak (Quercus laurifolia), an evergreen species commonly found on moist sites throughout the modern day southeast.  Other components of this primeval forest were live oak, Chapman’s oak, willow oak, loblolly pine, corkwood, red maple, magnolia, cypress, saw palmetto, sabal palm, myrtle, holly, and pawpaw.  Arrowleaf viburnum, cocklebur, and sedges grew in the understory.  Water lettuce, water lilly, and knotweed occupied aquatic habitats. 

Live oak in Jacksonville, Florida.  Wow!  What a tree.

Leaves and acorns of swamp laurel oak (Quercus laurifolia).  These were the most common plant remains found at the Vero Beach Fossil site..

Sabal Palm.

Berry includes Pinus caribaea in his list of plants found at the Vero Beach fossil site.  At first I was excited that an extralimital species such as Carribbean pine might have formerly ranged into central Florida.  However, he wrote that Pinus caribaea still ranged into Florida.  I believe he was either using an archaic synonym for a species other than Carribbean pine such as slash pine or pond pine; or he simply had it confused with another species.  I just can’t figure out which species he was referring to because range maps of Carribbean Pine show that it originally was confined to the Carribbean and Central America, though it has been widely transplanted worldwide.  As far as I can determine, it did not naturally occur in central Florida when Berry published his article.

Berry listed the jujube (Ziziphus celata) among the plant remains found at this site.  This species prefers open sunny conditions on dry sandy soils and is the 1 species that doesn’t fit in with the habitat preferences of the other species listed here.  Berry wrote that it no longer occurred in Florida, but he was wrong.  Jujubes were discovered growing in Florida in 1948.  (See: https://markgelbart.wordpress.com/2013/06/20/the-florida-jujube-ziziphus-celata-a-pleistocene-relic/)  This species was once more widespread.  The Florida population is a disjunct relic related to similar species found in the America southwest.

I did find 1 species on Berry’s list that no longer ranges into this part of Florida–the willow oak (Quercus phellos).  Berry used Q. brevifolia, an archaic synonym as the scientific name for this species.  Willow oak still occurs in south Georgia but is more common in the piedmont.  Warmer summer temperatures may have made it difficult for this species to compete with other species in central Florida.  Its range may be in the process of contracting north.

Reference:

Berry, Edwin

“The Fossil Plants from Vero Beach, Florida”

Smithsonian Institution publication 1915?

The Mystery of the Silver Bluff Shoreline

Scientists give names to prehistoric sea shorelines along the Atlantic Coast.  Logically, we know the oldest shorelines are the ones located farthest to the west because otherwise subsequent high sea stands would have obliterated them.  The location of the Georgia shoreline during part of the mid-Wisconsinian Interstadial (~46,000 calender years BP-~30,000 calender years BP) is called the Silver Bluff Shoreline, and it roughly corresponds with our modern day shoreline.  This correspondence puzzles scientists.  During the mid-Wisconsinian Interstadial, glaciers covered most of Canada about as far south as the Great Lakes, and therefore sea level should have fallen many miles to the east as it eventually did between ~29,000 BP-~7,000 BP.  The carbon dating of Silver Bluff organic material is consistent, eliminating the possibility that scientists have been misled by contaminated dates.  Some scientists suggest a tectonic explanation for why sea level was as high as today when it should have been much lower due to the glacial expansion.  There is some evidence of this–buried oyster beds in the St. Mary’s River have been found in sediment that dates to a time period when the ocean should have regressed far to the east.  However, I have a different hypothesis.

I believe sea level regression lagged behind glacial expansion.  Though more and more of earth’s moisture was becoming locked in glacial ice, there was still enough atmospheric precipitation and groundwater to keep the ocean filled with water comparable to modern levels until some critical threshold was reached.  Perhaps this threshold was the Great Lakes themselves.  As long as the Laurentide Glacier remained north of the Great Lakes, there was enough atmospheric moisture to keep sea levels high, but once this glacier advanced over the Great Lakes and froze all that water, sea levels dropped dramatically.  Sea levels remained low until 7,000 BP.  Then, enough water was released from melting glaciers for the sea  to rise to modern levels.

The Silver Bluff Shoreline is colored red.  The oldest shoreline is colored yellow and dates to the Pliocene (~2 million BP).

Scientists have taken numerous cores of sediment from several areas of St. Catherines Island, Georgia that date to this mid-Wisconsinian Interstadial when sea levels were as high as they are today despite cooler average annual temperatures.  The northern part of St. Catherines Island was part of the Pleistocene-aged Silver Bluff shoreline but currents are eroding into this part of the island, and this sediment is accreting on the southern side of the island.  (Most of Georgia’s barrier islands are of Pleistocene age on the north side and of Holocene age on the south side.  The Holocene side is built from eroded Pleistocene sediment.)  The pollen record from these cores reveal some interesting and unique environments that existed on St. Catherines Island during the interstadial.  The most unusual core sample was taken from Yellow Bank Bluff.  The pollen composition consisted of 41% composites (flowers from the aster family), 17% alder (a shrub related to birch), 10% grass, 5% ragweed, and with the presence of pine and hickory.  There is no natural community in the modern day south that even closely resembles this.  The closest modern analogue would be a midwestern tag alder wetland.  Just visualize an open grassy meadow covered in a variety of colorful wildflowers and thickets of alder shrubs and widely spaced trees.  Megafauna foraging likely had a great influence on this landscape.

Yellow Bank Bluff on St. Catherines Island.  This was a much larger hill well above sea level between ~29,000 BP-~7000 BP.  It was connected to Guale Island which didn’t become submerged below rising sea levels until as recently as 4000 years ago.  The most unusual core sample of ancient Pleistocene pollen was found here.

A tag alder wetland in Wisconsin.  An environment like this existed on St. Catherines Island, Georgia about 40,000 years ago.

Cores taken from other sites on St. Catherines Island reveal less unexpected environments.  The St. Catherines Shell Ring core shows that pine and oak were equally common in a diverse forest growing next to a salt marsh.  Pollen from this core also included hickory, sweetgum, tupelo, birch, elm, cypress, grass, ferns, and salt marsh chenopods.  Beech was a surprisingly common component here.  Beech no longer occurs on the Georgia coast.  Today, the nearest population of beech grows on north facing bluffs along the Savannah River.  An abundance of grape and aquatic plant pollen suggests a cypress swamp covered with grapevines.  The ample fern and grass pollen is evidence of a fire-influenced environment such as a freshwater “prairie”, not unlike those found in the modern day Okefenokee Swamp.  The core from the Cracker Tom Hammock indicated an environment similar to that from the Shell Ring Core.

Several sites from Skidaway Island have also been cored and analyzed for pollen composition.  They also show that southeastern coastal plain environments have long hosted a stable diverse composition of pine, oak, hickory, cypress, and sweetgum, but during the cooler interstadial northern species such as beech, alder, spruce, and even hemlock were present.

Scientists have recently investigated the Central Depression Savannah on St. Catherines Island.  This was a beautiful 5 square mile wet meadow with many freshwater springs.  This site is considered to be of unusual and unknown origin.  Unfortunately, it was drained during the 1930s.  Pollen analysis of Pleistocene aged sediment here revealed a forest consisting of myrtle, heaths (blueberry or rhododendron), pine, oak, sweetgum, and a significant presence of hemlock, though the latter pollen may have been windblown from the coastal plain.  All of these studies suggest the floral composition of this region has remained stable for tens of thousands of years, but northern species did colonize this area during cooler climatic stages.

See also https://markgelbart.wordpress.com/2013/03/25/pleistocene-fossils-found-on-the-georgia-bight/

Reference:

Rich, Fred; and Robert Booth

“Quaternary Vegetation and Depositional History of St. Catherines Island”

From Geoarcheology of St. Catherines Island, Georgia: Proceedings of 4th Caldwell conference 2009

Anthropological Papers of AMNH #94