Posts Tagged ‘sporormiella’

Florida Cracker Cattle (Bos taurus)

May 23, 2018

Even if there were no historical accounts, modern scientists could determine when European livestock were introduced to the Americas.  Scientists can take cores of sediment, radio-carbon date it, and measure the amount of sporomiella in each dated layer.  Sporomiella is a dung fungus spore found in the excrement of large mammals and is used as a proxy to estimate megafauna populations.  Scientists know when Pleistocene megafauna populations collapsed in some regions based on the amount of sporomiella in sediment, and they also can determine when European livestock were introduced using the same method.  Following the introduction of cows, horses, and pigs; the amount of sporormiella in the environment spiked to levels often equivalent to those of the pre-late Pleistocene extinctions.

Introduced livestock frequently outlasted the initial expeditions that brought them.  Early Spanish explorers of the 16th and 17th centuries perished with regularity in the harsh New World environments, so far from their accustomed European civilization, and some were massacred by Indians, but the cattle, pigs, and horses they brought with them ran wild.  The Europeans and their livestock carried contagious infections that decimated Indian populations with primitive immune systems as well, and feral livestock thrived in environments with low numbers of people.  The husbandry practices of early European settlers facilitated the increase of feral livestock populations.  Busy missionaries and homesteaders let their animals forage in the woods and fields, and the beasts often escaped and joined their free cousins.  Local environmental conditions shaped the evolution of feral livestock, weeding out those not adapted to living wild under each region’s unique conditions.  New breeds were born.

The Florida cracker cattle, also known as the piney woods cattle, rapidly evolved to thrive in the open pine savannahs of Florida and south Georgia.  They are related to the better known Texas longhorn cattle and also descend from cattle brought by the earliest of Spanish explorers.  They were already adapted to the warm climate of Spain, but in Florida the breed evolved tolerance for the humidity and local parasites. The tough cattle readily produced many calves on the low quality grasslands of the region, and their ferocity helped them fend off cougars, wolves, and bears.   Florida cracker cattle may be the “buffalo” that William Oglethorpe, the man who founded the state of Georgia, hunted during the early 18th century.  Colonial Europeans used the term “buffalo” interchangeably for both bison and feral cattle.  William Bartram saw great mixed herds of Florida cracker cattle, horses, and deer when he traveled through Florida in 1776.

Image result for Florida cracker cattle

Florida cracker cattle.  They are small–bulls weigh between 800 pounds to 1200 pounds.  Most are brown or partly brown and white but they come in a variety of coat colors.  The name cracker comes from the British settlers, known as crackers, because they cracked whips when they drove livestock on the road.

Florida cracker cattle were the best breed of cattle able to survive in the deep south until Brahman bulls from India were introduced during the 1930s.  Then, scientists invented antibiotics and medicines to treat parasites, and farmers were able to raise more productive breeds of cattle which they crossbred with the native cattle.  The Florida state legislature passed a law in 1949 outlawing free ranging cattle because farmers wanted to prevent the transmission of diseases from wild cattle to their preferred domestic breeds.  The Florida cracker cattle population plummeted.  Now, there is an effort to save the breed.  38 people still raise Florida cracker cattle, and herds are maintained at the Tallahassee Agricultural Complex, Withlacoochee State Park, Lake Kissimmee State Park, Payne’s Prairie National Wildlife Refuge, and Dudley Farm.  Customers who like free-roaming grass fed beef pay top dollar for meat butchered from the breed.

The Page-Ladson Site in Northwest Florida

June 5, 2016

During the late Pleistocene sea level contracted because much of earth’s atmosphere was locked in glacial ice.  The land area of what today is Florida doubled in size, and shorelines extended 50-100 miles west into the Gulf of Mexico.  The water table fell and many present day small rivers did not yet exist.  Instead, the land was pockmarked with many spring-fed ponds that attracted herds of megafauna and other wildlife.  The basal chemistry of these waters preserved bones and organic matter, and later when water tables rose, the Aucilla River began flowing and it covered these ponds with sediment.  The Aucilla River flows over 4 known Pleistocene pond sites–Page-Ladson, Latvis-Simpson, Sloth Hole, and Little River Quarry.  These sites contain deep layers of mastodon dung deposits.  Bones and artifacts are often mixed with the ancient piles of turds, and tracks are also visible where mastodons stepped on their own shit.  Scientists studied the dung and identified the plants mastodons ate.  Their favorite foods in Florida were cypress and buttonbush twigs and cones, but they also fed heavily on aquatic plants, oak leaves and acorns, and fruit including persimmon, plum, crabapple, grape, pokeberry, and wild squash.  At Latvis-Simpson a female mastodon skeleton with a fetus was excavated from a dung deposit.  Other dung deposits contain stone and ivory tools made by humans.

Aucillarivermap.png

Location of the Aucilla River. This river didn’t exist until about ~13,000 years ago.  It cuts through the site of spring-fed ponds that attracted megafauna, and eventually humans for thousands of years.

Tusk under Water.

A mastodon tusk.  Cut marks on a mastodon tusk found at Page-Ladson suggests humans butchered it for a fatty chunk of meat.

 

 

 

 

 

 

 

Radiocarbon dating of dung deposits at the Latvis-Simpson site indicated the oldest layer goes back to 32,000 BP.  The Page-Ladson site is not as old, but deposits there show man overlapped with megafauna as early as 14,550 years ago, predating the Clovis era.  The list of species remains found at the Page-Ladson site (just some of the fauna that overlapped with man) includes 2 species of gar, 2 species of pickerel, 5 species of catfish, 2 species of suckerfish, 7 species of bream, largemouth bass, black crappie, 3 species of frog, amphiuma, siren, Fowler’s toad, snapping turtle, an extinct subspecies of box turtle, gopher tortoise, an extinct species of giant tortoise, rattlesnake, alligator, great blue heron, pied-billed grebe, cormorant, Canada goose, duck, bald eagle, an extinct species of eagle, California condor, an extinct species of stork, red-shouldered hawk, red-tailed hawk, mourning dove, opossum, beautiful armadillo, pampathere, Jefferson’s ground sloth, Harlan’s ground sloth, raccoon, black bear, river otter, margay cat, bobcat, dire wolf, domestic dog, fox squirrel, beaver, muskrat, Florida muskrat, porcupine, capybara, mastodon, mammoth, bison, large-headed llama, stout-legged llama, white-tailed deer, long-nosed peccary, flat-headed peccary, horse, and tapir.  Remains of the extinct Florida spectacled bear have been collected from other Aucilla River sites, and large carnivores such as saber-tooths and jaguars left remains throughout much of the state’s other fossil sites.  Mastodon remains outnumber mammoth remains by a ratio of 4 to 1 at Aucilla River sites.  The former preferred aquatic wooded habitats, while the latter liked grassy open plains.  Remains thought to be of domestic dog may actually be coyote bones because the 2 species are difficult to distinguish from just skeletal remains.

My Georgia Before People blog was in part inspired by information gathered by the scientists who excavated the Aucilla River fossil sites.  So of course, I must highlight a new study of the Page-Ladson site.  Radio-carbon dates of organic material associated with human artifacts have long yielded dates in excess of 14,000 calendar years.  Many archaeologists dismissed these dates…they assumed error in the dating.  This new study was exhaustive–the scientists took 71 radiocarbon dates using the most modern methods–and they determined humans began frequenting the pond 14,550 years ago.  They confirmed that a mastodon tusk found here showed clear evidence of human butchery.  There are 2 additional examples of human butchering megafauna from Aucilla River sites.  Humans likely used these water sources opportunistically to specifically hunt big mammals.

The study also looked at sporormiella volumes.  Sporormiella is a fungus that grows on dung, and it can be used as a proxy for megafauna abundance.  Sporormiella volume spiked 13,700 years ago but then declined, and apparently the local megafauna became extirpated from the region by 12,600 years ago. This is within the accepted terminal extinction dates for Pleistocene megafauna.  Sporormiella volume briefly increased again about 10,000 years ago.  Researchers attribute this to a temporary migration of bison into the region, though this is based on the assumption that other species of megafauna were extinct by then.  I don’t agree with this assumption and believe local populations of now extinct Pleistocene megafauna persisted until the early Holocene but at levels so low they are difficult to detect in the fossil record.

The sporormiella spike at 13,700 is about 800 years after the first appearance of man in the region.  The entrance of man is also associated with an increase in charcoal from man made fires, and I might add, a change in climate to more frequent lightning storms.  I propose anthropogenic fires improved habitat for megafauna leading to an initial increase in megafauna populations.  But man eventually hunted these species to extinction.  As Gary Haynes proposes, the long term drought that occurred during the Younger Dryas cold snap likely concentrated megafauna around dwindling water sources, making them more vulnerable to human overhunting.

References:

Halligan, Jessi; et. al.

“Pre-Clovis Occupation 14,450 Years Ago at the Page-Ladson Site, Florida and the Peopling of America”

Science Advances May 2016

http://advances.sciencemag.org/content/2/5/e1600375

Webb, David (editor)

The First Floridians and the Last Mastodons: the Page-Ladson Site in the Aucilla River

Springer 2006

Lynch’s Crater

May 6, 2015

Long ago, a volcano collapsed, creating an 80 yard deep crater.  Lynch’s Crater, located in northeastern Australia, has since become half-filled with 230,000 years worth of lake and marsh sediment. This sedimentary deposit has preserved pollen evidence spanning 2 complete glacial/interglacial cycles.  From this evidence scientists know a wet rain forest prevailed in this region until man arrived here about 40,000 years ago.  The actions of Australian aborigines converted the rain forest to a dry woods dominated by fire-adapted trees such as eucalyptus.  This environmental change was not associated with any shift in glacial cycle.  Instead, man overhunted the megafauna into extinction and began setting frequent fires.  The large biomass of megaherbivores was no longer consuming vast amounts of vegetation, leaving lots of flammable material for men to burn.  Grazers and browsers were no longer suppressing plant growth, facilitating seed dispersal, and recycling nutrients in their dung.  Species of fungi, dependent upon megaherbivore dung for reproduction, declined in abundance.  Scientists use the measurable quantity of dung fungus spores in dated cores as a proxy for the former biomass of large herbivores.  Dung fungus is actually a  more reliable indicator of former megaherbivore presence than the fossil remains of these beasts because bones are rarely preserved.  Scientists have used this clue to study ancient megafaunal populations in North America, Europe, Madagascar, and Australia.  However, some researchers have noted some problems with using dung fungus spores as a proxy for megafaunal populations.  Chris Johnson, an Australian zoologist, along with other scientists, have addressed these concerns by implementing solutions in a study of data collected from Lynch’s Crater.

Location of Lynch’s Crater.  Sediment within the crater provide a 230,000 pollen record, illustrating how plant and animal communities changed over time.

 

Lynch's Crater (facing south)

Photo of Lynch’s Crater.  For over 100,000 years it was a lake but over the past 50,000 years it has been a marsh.

Some researchers have noted that dung fungus spores disperse over short distances, and their abundance can be effected by drought.  This can cause a variability in spore abundance unrelated to the abundance of megeherbivores.  Another problem is the variation in the amount of pollen produced by plants.  Because dung fungus is numerically expressed as a value relative to pollen counts, it can be difficult to compare fungus proxy values between studies.  Dr. Johnson and his colleagues executed 3 solutions to these problems.

1. They took core samples from different locations within the study area to minimize local effects.

2. They expressed dung fungus abundance independently from pollen counts.  They found interpretations of spore counts when expressed as a percent of pollen were not influenced by changes in vegetation type.

3. They compared trends in the quantity of dung fungus spores with spores from fungi that don’t rely on megaherbivore dung for reproduction.

Sordaria

 

 

 

 

Sordaria humana.  This species of dung fungus prefers human and dog shit.  While other species of dung fungus declined in abundance following the extinction of the megafauna, the abundance of this species remained strong and even increased after humans colonized Australia.

This study counted the volume of spores from 5 genera of fungi extracted from dated cores.  Sporormiella and podospora depend upon megaherbivore dung for reproduction.  Sordaria, coniochaeta, and cerophora spores occasionally land on megaherbivore dung, but these are generalist genera not as dependent upon megaherbivore dung for reproduction. There was a significant difference in decline between fungi dependent upon megaherbivore dung and generalist fungi.  Sordaria humana is a species of fungus that reproduces readily on human and dog feces.  Sordaria spores remained steady in abundance after 40,000 BP when sporormiella and podospora declined.

This study found that the volume of dung fungus spores in Australia prior to 40,000 BP was similar to numbers from studies conducted of Pleistocene North America, Pleistocene Europe, late Holocene Madagascar, and modern livestock producing regions.  This suggests the biomass of megaherbivores in pristine environments was close to what modern pastures can support.  Data from this study also show the extinction of Australia’s megafauna is closely associated with the initial presence of man.  It appears as if man hunted these animals into extinction within a 1000 year time span.  The transformation of wet tropical forest to dry fire-adapted woods occurred after the megafauna became extinct, precluding the possibility that climate change was a factor in the extinction of Australia’s megafauna.

Reference:

Johnson, Chris; et. al.

“Using Dung Fungi to Interpret Decline and Extinction of Megaherbivores: problems and solutions”

Quaternary Science Reviews Feb 2015

 

 

 

 

Gary Haynes Speculates Pleistocene Megafauna populations Suffered 3 Stages of Shock Before their Eventual Extinctions

January 24, 2013

Many old school anthropologists and paleontologists reject the hypothesis that man overhunted the Pleistocene megafauna to extinction.  Some of their arguments against the overkill hypothesis are so illogical they leave me astonished.  For example 1 argument against the overkill hypothesis used to be that there was no archaeological evidence that paleo-Indians ever killed giant ground sloths, camels, horses, llamas, peccaries, glyptodonts, giant beavers, etc.  Since that argument was made, evidence that paleo-Indians killed giant ground sloths, camels, and horses has been found.  Nevertheless, in my opinion it is an unreasonable expectation to find such evidence.  Large regions of the North American continent are almost completely devoid of Pleistocene fossils, let alone ones that show obvious evidence they were killed and butchered by humans.  The odds against finding such evidence are astronomical.   Most recent paleoecological studies of the late Pleistocene are consistent with the overkill hypothesis.  Climate change models of extinction for this time period are becoming less tenable when all of the latest data are considered.  One old school anthropologist who has not ignored the latest paleoecological data is Gary Haynes, a professor at the University of Nevada, Reno.  Dr. Haynes uses the new data to speculate how man managed to wipe out most of the large American mammal species over a time period of a few thousand years.  He suggests the megafauna suffered 3 stages of shock before man chased them into oblivion.

Man entered North America from Asia ~15,000 calender years BP (at the latest).  A human turd found in an Oregon cave is the oldest definitive evidence of man in North America, and it dates to a few hundred years after the probable entrance date.  Dr. Haynes refers to the initial contact between man and megafauna as the foreshock stage.  When humans first encountered the megafauna, the hunters killed them opportunistically, and this fragmented the animal populations, eliminating some species from some areas.  Humans likely followed big game trails and river valleys for the same reason the animals did–they were easier to traverse than hills and swamps.  Because they followed the same paths, humans were more likely to encounter megafauna than not.  Even low levels of hunting had a big impact on megafauna species with slow rates of reproduction.  The foreshock stage may well be represented from studies of dung fungus spore abundance in 4 New York bogs and 1 kettle lake in Indiana.  Below is an in depth explanation.

Scientists from Fordham University took cores of sediment from 4 ancient bogs in southeastern New York where fossils of mastodons and stag-moose had been found.  They analyzed the sediment for pollen and charcoal content and carbon-dated the samples.  Dung fungus spores, also known as sporormiella, live in the guts of megaherbivores.  The abundance of sporormiella is used as a proxy for the presence of megaherbivores in the environment.  When sporormiella levels fall below 2%, it means megafauna is absent in the local environment.  The scientists found that megafaunal populations collapsed between 14,800 BP-13,700 BP.  This time span is known as the Boling-Alerod warm phase.  The composition of flora remained unchanged within this time span, so this finding rules out climate change as the cause of the initial population collapse.  Moreover, the megafauna populations at each lake collapsed at different times, indicating humans wiped out all the game in 1 area, then moved on to the next location and extirpated them there later.   A second study, this time of a kettle lake in Indiana, got similar results.

Appelman Lake, Indiana.  This is a kettle lake formed when a partially buried piece of a glacier melted.  A study of dung fungus spore abundance suggests megafaunal populations around this lake collapsed between 14,800 BP-13,700 BP.

Sporormiella–a dung fungus spore. Sporormiella levels rose to Pleistocene levels when Europeans introduced livestock to America.

Pollen graph from Appelman Lake.  Sporormiella abundance is represented by the blue.  Note how charcoal amounts increased after the megafauna populations collapsed.  Forests replaced savannah environments after the megafauna were killed off.  Forest fires increased in frequency because megaherbivores were no longer eating flammable material.

Dr. Haynes believes the megafauna suffered the main shock in the few centuries before and after the Younger Dryas cold phase which struck suddenly ~12,900 BP.  Megafaunal populations had already collapsed, but they persisted in fragmented local refuges.  Clovis hunters and their successors deliberately targeted these remaining populations.  The Younger Dryas was an arid cold climate stage that caused water sources to shrink.  Megafauna concentrated around the shrinking water holes where they were easy to ambush.

Dr. Haynes thinks the Pleistocene megafauna extinctions occurred during an extended aftershock when the last of the beasts were subject to many difficulties resulting from human activities.  Humans continued hunting the now rare and declining populations; isolated populations were weakened by inbreeding; an ecology long dependent upon interdependence between different megafauna species was now completely disrupted as some species disappeared; and fire frequency changed as humans set fires at unusual times of the year.  Humans didn’t have to kill every last individual of a species to render it extinct.  Instead, anthropogenic changes, including hunting, raised the mortality rate above the reproductive capacity of each individual species.

There is no way of knowing exactly when each species became extinct.  The latest terminal date for the mastodon is from a specimen found in Rochester, Indiana.  It died ~10,032 BP.  The last mastodon likely died centuries after this but didn’t become fossilized.  SedaDNA in Alaska permafrost suggests horses didn’t become extinct there until 7600 BP.  It’s probable that by 7500 BP humans had discovered and annihilated every population of Pleistocene megafauna in America.

Growth rings on  mastodon tusks are another line of evidence consistent with overkill theories of extinction rather than climate models of extinction.  Dan Fisher analyzed the growth rings from 10 mastodon specimens that date to close to the time of extinction.  The growth rings on the mastodon tusks were similar to those from African elephants that had plenty of food but were under pressure from overhunting.

References:

Fisher, Dan

“Paleobiology and Extinction of Proboscideans in the Great Lakes Region of North America”

American Megafaunal Extinctions at the End of the Pleistocene 2009

Gill, Jacquelyn; et. al.

“Pleistocene Megafaunal Collapse, Novel Plant Communities, and Evidence of Fire Regimes in North America”

Science 326 November 2009

Haynes, Gary

“Extinctions in North America’s Late Glacial Landscape”

Quaternary International 2010

http://www.unr.edu/Documents/liberal-arts/anthropology/gary-haynes/Haynes_QI%20Extinctions2012Reprint.pdf

Robinson, Guy; Lida Burney, and David Burney

“Landscape Paleoecology and Megafaunal Extinction in Southwestern New York State”

Geological Monographs 75 (3) Jan 2005