Mastodons and Wild Plum Thickets

I found this thicket of wild Chickasaw plums in south Richmond County, Georgia.  The thicket covers at least 2 acres.

Wild plum thickets abound over much of North America.  They’re a pioneer species, growing extensively in old overgrown fields before other trees eventually shade and thereby outcompete them.  The lifespan of a plum tree seldom exceeds 20 years anyway, which is the length of time a plum thicket lasts during its stage of forest succession.  Plum thickets are a common site along roadsides in Georgia and other southeastern states.  For various reasons highway crews often clear corridors on the sides of roadways, and plums thrive in the sunny locations when overstory trees ares stripped or removed.  Today, birds and small mammals such as oppossums, raccoons, and gray foxes eat the fruit and spread the seeds in their feces.  American Indians also extensively planted plums around their settlements.  The variety of plum in the above photograph is known as the Chickasaw plum (Prunus angustifolia), and it is believed to have been originally cultivated by the Chickasaw Indians.  They spread the variety east from their early settlements.

There are 3 species of wild plums that range into Georgia, including south Richmond County where I found the plum thicket pictured above.  I used photographs from google images to compare and distinguish between the 3 and determined that the ones I found were probably Chickasaw plums, though I’m not a trained botanist, so I don’t know for sure.  The other 2 species are the American plum (Prunus americana) and the hog plum (Prunus umbellata).  I harvested a pint of the Chickasaw plums (I could’ve collected bushels.)  They are as sweet and  tasty as the best quality cultivated plums one can buy at a supermarket.  The only drawback is the small size–they’re a little smaller than cultivated cherries and the fruit to pit ratio is even smaller.

Picture of mastodons from google images.

Photo of Mastodon dung recovered from the Aucilla River.

Scientists examining 14,000 year old mastodon dung from the Aucilla River in north Florida found plum pits.  Chemical tests of fossil mastodon bones found at the site determined that mastodons wandered back and forth from north Florida to central Georgia.  These wide-ranging behemoths spread fruit and seeds of many plant species far and wide.  Most of the seeds that went through their alimentary tracts were not only still viable, but they had the added bonus of being encased in fertilizer when excreted.  (See also my blog entry “Paw Paw: Favored Fruit of the Mastodon” which I think is either in my May 2010 or April 2010 archives.)

The dynamic landscape of the Pleistocene included natural environments in all stages of forest succession.  Disturbances and atmospheric conditions such as fires, storms, megafauna foraging, insect damage, disease, floods, beaver activities, drought, and low CO2 levels contributed to frequent formation of meadows, prairies, and savannahs–all suitable environments for plum thickets.  With mastodons (and giant ground sloths) facilitating their spread, plum thickets must have been just as common then as now, if not more so.

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This is an addendum to my last week’s rant about the environmental destruction that white slave-owners inflicted upon Georgia in the early 19th century.  My favorite poem is the lyrics to the rock group, Rush’s song “The Trees.”  Rush is a fantastic group, if you can get past the high voice of the lead singer.  It’s amazing that just 3 people can put out the amount of sound they do.  Anyway, here are the lyrics.

“The Trees” by Rush.

There is unrest in the forest

There is trouble with the trees

For the maples want more sunlight

and the oaks ignore their pleas

The trouble with the maples

(and they’re quite convinced they’re right)

They say the oaks are just too high

and they take up all the light

But the oaks can’t help their feeling

if they like the way they’re made

and they wonder why the maples can’t be happy in their shade

There is trouble in the forest

and the creatures all have fled

as the maples scream “oppression!”

and the oaks just shake their heads

So the maples formed a union

and demanded equal rights

“The oaks are just to greedy; we will make them give us light”

Now there’s no more oak suppression

for they passed a noble law

and the trees are kept all equal by hatchet, axe, and saw

The Geological and Ecological History of the Okefenokee Swamp (part three)

Common and Interesting Plants Found in the Okefenokee Swamp

Most of the aquatic  plants that dominate the present day landscape of the Okefenokee Swamp were restricted to small scale marshes alongside the reduced number of rivers and streams that still incised the Okefenokee basin during the arid milleniums of the Ice Age when the water table fell and the swamp dried up between 36,000 BP and 7,000 BP.  The rest of the basin during this time period probably consisted of grassy pine savannah and scrub oak.  Nevertheless, these relic aquatic remnants provided the nucleus of the population that eventually re-established itself as the primary vegetation of the region.  Here are some interesting floral components of this environment.

Bald Cypress (Taxodium distichum)–Eight-hundred year old giants still stand in a few coastal swamps near Georgia’s coast.  One-hundred years ago, when loggers decimated much of these ancient bottomland forests, they skipped over the biggest cypress trees because they were too large and hollow, and therefore too much trouble to economically harvest.  One of these gigantic cypress trees is located in the Townsend Wildlife Management Area in McIntosh County.  It’s 44 feet in circumference.  Imagine 7 men, all at least 6 feet tall, laying end-to-end in a circle around the tree and they still wouldn’t completely encircle it.  It’s understandable but not generally known that cypress trees are relatives of the famous Californian redwoods.  They sure have great size and long life in common.

For more about Georgia’s big cypress trees see this following link  http://savannahnow.com/news/2010-08-30/700-year-old-cypress-tell-story-survival

I took this photo of a cypress tree in autumn foilage at Phinizy Swamp in Augusta, Georgia.  Unlike most coniferous trees, cypress trees lose their foilage in the winter, like deciduous broad-leafed trees.

Unlike most coniferous trees, cypress trees are not evergreen, and they shed their needles in the winter.  They usually live in flooded swamps. They have mysterious knees–wooden knobs that grow above water.  Scientists are uncertain whether these aid in respiration or simply balance the trees in the watery muck where they grow.

Water tupelo (Nyssa aquatica)–Cypress trees hollow out and provide roosting habitat for bats and homes for other animals, but tupelo trees become hollow more frequently.  Matt Clement, a grad student at UGA, found 97 roosts of Rafinesque’s bats along the Altamaha River, and most of them were in hollow tupelo trees.

Water shield or dollar pad (Brasenia schreberi), Floating Heart (Nymphoides sp.), and White Water Lilly (Nymphaea odorata)–These are three completely unrelated plants, but their leaves look similar.  In fact, I can’t really tell their leaves apart.  It’s an example of convergent evolution when different species evolve similar structures to solve the same ecological problems.  All three are what people think of as the lilly pads so commonly seen floating on the surface of the open water habitats in the Okefenokee Swamp that are often confusingly referred to as prairie because they’re treeless.  All three species have round floating leaves attached via long stems to underwater roots.

Panic grass (Panicum sp.) Saber-tooths and jaguars lurked hidden in patches of this tall cane-like grass, stalking the long-horned bison and horses that fed upon it during the Pleistocene.  The large fauna are gone but the flora remains.

Photo of some panic grass also known as maiden cane that I took at Phinzy Swamp, Augusta, Georgia.  There was another patch on the other side of the path that was 12 feet tall.  I wish I would’ve taken a photo of that.

Spanish Moss (Tillandsia usneoides)–Oddly enough, Spanish Moss is related to pineapple–both are Bromeliads or air plants.  Wind and birds spread seeds and fragments.  The seeds and fragments of the Spanish Moss lodge in other tree branches.  The Spanish Moss then grows (both from seed and vegetatively).  The plant survives by extracting nutrients from air and rain water, not from the trees upon which they land, thus they’re considered epiphytes, not parasites.  Birds, bats, spiders, and snakes live in and about the moss.

Spanish Moss hanging from either a water or laurel oak at Phinizy Swamp, Augusta, Georgia.  Spanish Moss is quite common in the lowlands of the Augusta area, but I’ve never seen any in hilly sections.

Bladderwort (Utricularia sp.)–Like strange creatures from a low budget horror film, carnivorous plants thrive in the Okefenokee Swamp.  Bladderwort is an underwater plant with no roots.  The bladder-shaped structure on the plant works like a trap door, a suction-on-contact action captures fish fry, mosquito larvae, tadpoles, and protozoa.

Pitcher plants (Sarracenia flava, Sarracenia mino, Sarracenia psittacaea)–There are three species of pitcher plants found in the Okefenokee–the hooded, the parrot, and the golden.  A sweet rotten odor emanating from the plants attracts insects which get trapped in tubular stems.  Backward hairs block insects from being able to escape, and eventually, they tire and fall into the toxic water at the bottom of the tube.  Bacteria in the water digests the insects, releasing nitrogen that the pitcher plant is able to absorb.

Round-leafed Sundew (Drosera rotundifolia)–The sticky hairs on this plant work just like flypaper, trapping hapless insects.

Burreed (Sparanium sp.)–Fossil mastodon dung discovered in the Aucilla River, Florida contains many types of aquatic plants, including most discussed here.  Cypress was the most common item in their diet, but the beasts ate nympoides, nymphaea, and this one–burreed.  Burreed is an important plant in the second stage of forest succession that occurs when islands develop within the swamp.

The five stages of forest succession in the Okefenokee Swamp

1.  Sphagnum moss floats to the surface of open water and soil begins to accumulate on it forming an island.  Beakrush takes root.

2. Burreed, panic grass, and redroot are the second stage of plants to colonize the island.

3. Sedges take over.

4. Bushes and saplings colonize the island.

5. Trees such as cypress, tupelo, water oak, and pond pine form the final components of island forest succession in the Okefenokee Swamp.

The Paisley Cave Pre-Clovis Site

For this week’s blog entry I’m going to step away from southeastern North America and discuss a fascinating site in south central Oregon.  The Paisley Cave site collectively includes 8 different caves and rock shelters created when waves from an ancient Pleistocene Lake (Lake Chewaucan) eroded hollows into the upland bedrock about 17,000 years ago.  By 14,500 years ago weather patterns changed, becoming drier, and the lake receded away from the caves for a distance of about a mile.  But the climate here was still wetter than that of today, and the environment consisted of conifer woodland, meadow, and lakeside marsh; unlike the sagebrush desert which is now the primary type of ecotone at this location.  The caves were ideal shelters for Paleo-Indians, and the surrounding area provided abundant rock (obsidian) for tool-making, and a plentiful supply of big game, small game, waterfowl, fish, and edible wild plant foods.

Most of the caves contain evidence of early Holocene (~9,000o BP)occupation–charcoal from human-lit fires, basketry, and interesting tools such as wooden pegs and sagebrush rope.  But a cave known as Cave number 5 yielded evidence of pre-Clovis material including obsidian projectile points, debitage (the leftover flakes from stone tool processing), and scrapers, all associated with bones of megafauna–a camel ankle bone, the jaw bone of an extinct goat (Harrington’s Mountain goat? Oreamnos harringtoni), bison bones, and two long bones that looked like they were broken for the marrow.  There is one spot in this cave that’s been interpeted as a possible hearth, a  “a bowl-shaped depression with a rock lined base,” where a burned horse bone was discovered.  Moreover, very old processed grass fiber and muscle sinew were found in the cave.  Most importantly, however, was the fossilized human feces carbon dated to 14,290 calender years BP which predates the Clovis era (13,200-12,500 BP).

DNA testing of the feces indicates these people descended from Siberians, meaning they were Asiatic, like native Americans.  An analysis of their fecal content showed they ate bison, dog, squirrel, bird, fish, wild sunflower seeds, and grass.

The Topper site near Allendale, South Carolina (which I visited a couple of years ago) yields tools in soils dating to before Clovis also.

Archaeologists and crew excavating the pre-Clovis trench at the Topper Site in Allendale, South Carolina.  The people there were very nice to me when I visited two years ago.

Tools found in the Aucilla River in Florida also date to slightly before the Clovis era.  I theorize small bands of humans began crossing Beringia and migrating across North America before the LGM (28,000-15,000 BP) when glaciers would’ve blocked their passage.  The reason evidence is lacking is because they were so few in number and so scattered they left little proof.

References:

Pinson, Ariane

“Paisley Caves: What’s the scoop on the poop?”

Mammoth Trumpet 23 (4)  October 2010

www.uoregon.edu/-ftrock/paisley_caves_description.php