Changes in Vegetation Patterns Following Megafauna Extinctions

September 19, 2014

C.N. Johnson of James Cook University in Australia shares my fascination with how extinct megafauna influenced past ecosystems.  Not long ago, he published a paper about my favorite discussion topic entitled “Ecological Consequences  of Late Quaternary Megafauna Extinctions.”  He believes the extinctions of so many large mammal species led to 3 major changes in the environment.

1. The replacement of open woodlands and diverse habitat mosaics created by megafauna foraging with uniform closed canopy forests and zonal vegetation.

2. An increase in flammable plant material and thus an increased frequency of fire intervals because the plant biomass was no longer being eaten.

3. The decline of co-evolved plants such as large-seeded fruits dependent upon distribution by dung transport, and plants that put much of their energy into growing defensive thorns to deter herbivory.

Dr. Johnson relates an interesting hypothesis as to how Pleistocene ecosystems responded to megafauna foraging.  The feeding and trampling behavior of mammoths, bison, horses, and ground sloths suppressed woody regeneration.  Scrubby thickets dominated by thorny plants grew in place of highly shaded forests.  And patches of natural pastures grazed into short grass lawns impeded the fires that could potentially burn thickets.  When the thorny vegetation grew thick enough, megaherbivores avoided these locations, allowing shade intolerant species such as herbs, oaks, and hazelnuts to sprout and grow.  The widely spaced oaks and other deciduous trees would eventually shade out the thorny thickets. The megafauna would return to suppress the regeneration of the woodland as the trees aged and died, and the cycle would begin anew.  I can guess who the players were in this scenario here in southeastern North America.  Thorny greenbrier and blackberry vines along with hawthorne grew in areas temporarily left ungrazed.  The thick growth discouraged most animals larger than a rabbit from penetrating this space.  Sun-loving oaks, hazelnuts, persimmon and plum popped up.  Perhaps not coincidentally, hazelnut has a lesser distribution in North America now than it did during the Pleistocene.  A hazelnut was extracted from a mastodon coprolite found in Florida.  Hazelnuts no longer occur in Florida’s wild.

Thorny scrub habitat in south Texas.  The sharp spines of the yucca  could theoretically deter a species of large mammal from chewing on the tree or trampling it.  When the tree grows larger and older, it will shade out the spiny plants that originally protected it.

American Hazelnut Tree

American hazelnut (Corylus americana).  This species was more widespread and common in the south during the Pleistocene because the megafauna suppressed tall forest regeneration.  Hazelnut trees prefer sunny conditions and can’t grow in shade.

Hazelnut_CorylusLarge.jpg

Photo of the actual hazelnut extracted from a Florida mastodon coprolite dated to ~14,000 calender years BP.  Hazelnut no longer occurs in Florida.

Some pollen studies in Europe dating to the last interglacial, when megafauna was abundant and climate similar to that of today prevailed, contradict the above hypothesis.  Shady closed canopy forests dominated much of northern Europe.  However, other pollen studies from evidence collected in river bottomlands do show evidence of higher populations  of diverse sun-loving plant species, and this evidence is associated with  the abundant remains of dung beetles. This suggests patchy environments influenced by megafauna activities did occur near rivers.  This makes sense: large herds of megafauna likely occurred where water was an easily accessible resource.  If we were to go back in time and search for megafauna in Georgia, our best bet would be to travel along river corridors.  Large mammals were probably scarce or even absent in locations far from water.  The ancient environment of the southeast likely consisted of a mosaic of small and large grasslands, open woodlands, closed canopy forests away from where megafauna congregated, and thorny thickets.

The pollen record of southeastern North America does consistently show a large increase in shade tolerant beech approximately correlated with the timing of megafauna extinction.  This suggests forests became more close canopied when large mammals became extinct.

One study discussed in Dr. Johnson’s paper proposed that the extinct Irish elk (Megaloceros giganteus), the largest deer known to science, converted Ireland’s scrub habitat into grassland.  Megaloceros recolonized Ireland ~16,000 years ago when glaciers retreated and the land became habitable.  Willow scrub dominated the landscape initially, but Megaloceros favored browsing on shrubs for the phosphorus content.  Juniper and crowberry replaced the willow, then Ireland became mostly grassland because Megaloceros suppressed the growth of shrubs.  After Megaloceros became extinct here, willow scrub again became the primary type of environment in Ireland.

Scale drawing comparing the extinct Irish elk with a man.  This animal may have transformed Ireland from willow scrub to grassland about 16,000 years ago.

Reference:

Johnson, C.N.

“Ecological Consequences  of Late Quaternary Megafauna Extinctions.” 

Proceedings of the Royal Society of Biological Sciences 2009

Shame on the National Audubon Society for Masquerading Alarmist Propaganda as a Scientific Study

September 14, 2014

Every single species of North American bird alive today survived the Sangamonian Interglacial Period (~132,000 BP-~118,000 BP), a climate phase when average annual temperatures were as much as 7 degrees F warmer than those of today in the northern latitudes of the northern hemisphere.  This fact alone directly debunks the National Audubon Society’s Birds and Climate Change Report.  The report claims 314 out of the 588 species of birds that live in North America are in danger of extinction by the year 2080 due to global warming.  Their report was not published in a peer reviewed scientific journal.  Instead, it was published as a special issue in the National Audubon Society’s magazine–a periodical that is sent to members who donate to their organization.  In other words it is a propaganda magazine.  Yet, all the major media outlets covering their press release regurgitated their findings without asking a single critical question.   A google search reveals the findings of this report repeated uncritically by The New York Times, USA Today, and dozens of smaller newspapers across the country.  This demonstrates the unanimous scientific illiteracy of journalists who are quick to hop on the bandwagon of anything alarmist and headline-grabbing.  The National Audubon Society’s climate report is akin to the infamous DNA study of bigfoot that was not published in a peer-reviewed scientific journal, but instead was the only article ever published in a phony made-up journal.  Without peer review, the National Audubon Society can publish any kind of nonsense and get away with it.

I study scientific journal articles as a hobby and can recognize the difference between a legitimate scientific study and propaganda. So when I heard David Yarnold, the president of the National Audubon Society, answer questions on National Public Radio about this report, I immediately recognized the report for what it is: a public relations press release.  It’s a total fantasy, not based on real science, and it could not be published in a reputable scientific journal.

Cover of The National Audubon Society’s Propaganda Magazine.  It is not a peer-reviewed scientific journal.  They could put any kind of misleading data in this. The large media outlets regurgitated it without asking a single critical question.

David Yarnold, president and CEO (yes that’s right…a CEO) of the National Audubon Society.  I thought CEO’s were only found in businesses.  The title seems to suggest this so-called charity is actually a money-making business. $1 in every $200 donated to the National Audubon Society goes to this idiotic crook’s salary.

During the NPR interview David Yarnold made some comments that were grossly untrue.  He claimed that “climate is changing at a scale or pace never before seen.”  The below chart shows David Yarnold is completely ignorant of recent climatic history.  Following Dansgaard-Oeschger events (which occurred with frequency), average annual temperatures increased by as much as 14 degrees F within a decade.  Climate did not change slowly in the past over thousands of years as Yarnold falsely claimed.  We are currently enjoying a period of relative climatic stability compared to the past. Yet, all 588 North American birds species that are with us today survived the drastic and sudden climatic upheavals of the past.

Yarnold also confused climate with weather in his NPR interview. He lamented the failure of raptors to nest in southern California this year due to drought.  This drought event is a short term weather event.  It hasn’t occurred long enough to be considered a climatic trend.

 

Chart showing average annual temperatures as recorded from air bubbles in the Greenland Ice Core.  Note how we are now in a period of relative climatic stability.  This chart clearly shows the current rate of climate change in not unprecedented as Yarnold falsely and stupidly claimed on NPR last week.  A finer scaled chart would show even more clearly how drastic and sudden past climate changes were.

Yarnold makes $460,489 a year as CEO and President of the Audubon Society.  His salary is paid for by the 1 in every 200 dollars donated to the society.  I thought the Audubon Society was supposed to be a charity.  If it was a true charity, this crooked shmuck should work on its behalf for free.  This report is obviously a public relations ploy to increase donations to the Audubon Society, thereby leading to increases in his salary.  He is a greedy corrupt businessman, not a scientist or environmentalist.  Maybe journalists don’t question him because he’s the head of a bird society, and they assume birdwatchers are nice people.  They don’t want to look bad by asking hard questions of a supposed bird lover.

Gary Langham, the scientist behind the alarmist propaganda published by the National Audubon Society in order to solicit more donations that will go to Yarnold’s and his salary.  I can’t find what his salary is but I’m sure he makes 6 figures…far more than the average college professor with a phd in ornithology.

This so-called study used bird surveys and Christmas day bird counts to determine “climatic suitability” for all 588 North American bird species.  Then, they looked at climatic models based on “greenhouse gas emission scenarios,” and estimated where the birds could live in the future.  There are serious problems with each end of this study.  The areas where people find birds now can in no way accurately predict the parameters of where they could potentially live.  The adaptabality of the birds is entirely underestimated.  Climate models are already known to be deeply flawed.  I like to call climate models what they are…wild guesses.  And as I noted at the very start of this essay, these birds survived global warming exceeding that being predicted by these climate models.

Dr. Langham says global warming is a greater threat to birds than habitat loss.  The past climatic history of the earth proves he is wrong.  However, I do think habitat loss resulting from an increase in human development will lead to bird extinctions.  Birds will become extinct in the future but not because of global warming.

Tabloid cover about bigfoot,

The information in the National Audubon Society’s Birds and Climate Change Report is about as reliable as that found in the Weekly World News.

Reference:

Gornitz, Vivien

Encyclopedia of Paleoclimatology and Ancient Environments

Springer Science and Business 2007

The Paleoenvironment of the Georgia Bight when it was Above Sea Level (~80,000 BP-~7,000 BP)

September 12, 2014

A wonderful study led by Scott Harris of the College of Charleston was published in Geomorphology last year.   The authors of this study mapped and analyzed various underwater features on the continental shelf of an area known as the Georgia (or South Atlantic) Bight.  I realized Dr. Harris, an expert on the geology of this region, might have an answer to the mystery of the Silver Bluff Shoreline (See: http://markgelbart.wordpress.com/2014/06/01/the-mystery-of-the-silver-bluff-shoreline/).  This shoreline is thought by some to date to about 38,000 BP, a time when most of Canada was under glacial ice, and therefore the shoreline should have been many miles to the east.  Yet, the Silver Bluff Shoreline is near the modern shoreline.  I asked Dr. Harris about this anomaly.  He informed me that he doesn’t like the nomenclature used to delineate this paleo-shoreline.  More importantly, he’s dated this shoreline using optically stimulated luminescense, and he consistently gets dates of 80,000 BP.  These dates are before sea level fell significantly in response to glacial expansion.  In my opinion this mystery is solved: his dates make more sense, and what is known as the Silver Bluff Shoreline is much older than previous researchers estimated.  There is no anomaly.

figure 1

Map of the Georgia Bight.  The area shaded in light gray was above sea level between ~80,000 BP-~7,000 BP.  It hosted a variety of dry land environments.

The study I mentioned above and reference below has re-ignited my curiosity about the environments on the continental shelf when it was above sea level.  It was a vast extension of the coastal plain–dry land occurred as much as 90 miles east of the modern shoreline.  Dramatic climatic fluctuations influenced the composition of the various environments that existed here.  The time period between ~80,000 BP-~60,000 BP (Marine Isotope Stage 4) was a climate phase of rapid glacial expansion, causing the sudden fall in sea level that exposed the continental shelf.  The period between ~60,000 BP-~28,000 BP (Marine Isotope Stage 3) was an interstadial–perhaps the most intersting climate phase because of an alternating feedback cycle that occurred.  Sudden warming events known as Dansgaard-Oeschger Events caused average annual temperatures to increase by as much as 14 degees F within a decade.  There was increased seasonality as summers averaged 5-9 degrees F warmer than during stadials.  And precipitation increased because the warm summer temperatures melted glacial ice.  After a few thousand years, icebergs and great quantities of glacial meltwater would flood into the North Atlantic.  This is known as a Heinrich Event.  Eventually, all this cold freshwater would shut down the Gulf Stream, causing temperatures to plummet.  Ice would again accumulate into glaciers.  MIS-3 saw at least 5 sudden warm ups followed by 5 cold downturns.  Between ~28,000 BP-~15,000 BP (Marine Isotope Stage 2), temperatures mostly remained in the cold climate phase. After ~15,000 BP sea levels rose until they reached modern levels about 6,000 years ago.  I am interested in how these climatic fluctuations influenced the flora and fauna of the continental shelf.  Below is a review of the types of environments probably found on the continental shelf and how they responded to climate change.

Prairies

I believe prairies were the most common landscapes on the continental shelf during cold arid stadials.  The presence of 13-lined ground squirrels (Spermophilos tridecemlineatus) in the local fossil record supports my hypothesis.   13-lined ground squirrels prefer treeless plains and are found today in the tall grass and short grass prairie regions but are presently absent in the southeast.  The abundant fossils of mammoths, bison, and horses found near the coast and underwater all suggest the existence of extensive grasslands here.  Pine savannahs, open deciduous woods, and even closed canopy forests replaced most but not all of these prairies during warmer wetter interstadials.

image: Thirteen-Lined Ground Squirrel

13-lined ground squirrels.  The presence of this species in the local fossil record suggests the existence of extensive grasslands on the continental shelf.

Pine Savannahs

Savannahs are dependent upon lightning-ignited fires which increased in frequency during interstadials.  Scrub oak thickets with some pine replaced savannahs when fire intervals were reduced.

Open Oak Woodlands and Forests

A woodland is defined as a natural community that has 50%-80% canopy cover, while a forest has >80% canopy cover.  The arid climate of stadials relegated these environments to river bottomlands and other locally moist areas, but following Dansgaard-Oeschgher Events they expanded across the continental shelf.  Pollen records dating to interstadials show oak, hickory, pine, and grass dominated this region then.  Open woodlands, consisting of large mature trees growing far enough apart to allow for a grassy understory, predominated.  Fire and megafauna foraging shaped this landscape.  However, the pollen evidence indicates the low level presence of trees that are not fire resistent and have northern affinities–hemlock, spruce, beech, and basswood. (Though this pollen may have been blown in from northern latitudes.)  Some areas of the continental shelf may have had low incidence of fires and a cool moist climate during some phases. Deer, long-nosed peccary, tapir, and bears favored these habitats.

Oak Scrub with some Pine

Much of the continental shelf had sandy soils more suitable for desert-like vegetation.  Low incidence of fire during stadials increased the extent of this scrub habitat, and it likely replaced savannah.  It would have provided favorable habitat for flat-headed peccaries and rabbits.

Cypress Swamp

Stadials reduced cypress swamps to relic status.  Low poorly drained areas likely held these relic stands, providing the seed population that allowed cypress swamps to expand following Dansgaard-Oeschger Events.  Submerged cypress swamps have been found off the South Carolina coast.  Rising sea levels at the end of the Ice Age inundated these swamps.

Sand Dune Fields

Sand dunes originating from dry river beds rolled across the landscape during both MIS-2 and MIS-4.  Scrub vegetation covered and held them down during interstadials when they became good habitat for burrowing tortoises.

Carolina Bays and Freshwater Marshes

Wetlands occurred in some low lying areas but were scarce during stadials.  Many wetlands were ephemeral and may have frequently dried out before they could succeed to cypress swamps.  This is where mastodons and giant beavers congregated.

Braided Rivers

Paleomeanders prove that large rivers such as the Savannah and the Altamaha flowed through the continental shelf all the way to the ocean.  These paleomeander scars are still visible for about 60 miles of the continental shelf but strangely disappear on the last 30 miles of the outer shelf.  Dr. Harris believes rivers that flowed over the outer shelf were shallow and had a braided pattern.  When sea level rose, sediment filled the shallower incisions, explaining why these parts of the river scars are not visible.  It has occurred to me that these shallow intermittent parts of the rivers may have impeded some fish migrations.  They may have acted as natural fish traps that paleo-indians could have taken advantage of.

Paleomeander scar 60 feet below the ocean surface off the coast of South Carolina from a sonar image taken by College of Charleston researchers.  This is evidence of rivers flowing through the continental shelf when it was above sea level.

The Narrow Coastal Zone

Sandy beaches with some rocky outcrops, salt marshes, and tidal rivers provided varied habitat for marine life.  Some arctic sea birds along with seals and walruses inhabited this zone.  It was much narrower than the modern coastal zone.  Heinrich Events brought cold currents chilled by icebergs that may have drifted as far south as Florida. Evidence of iceberg draglines on the ocean bottom is abundant off the coast of South Carolina.

In a past blog entry about Pleistocene bears of southeastern North America, I didn’t list polar bears as a species that occurred in the region, but I may have been wrong.  Predators follow their prey anywhere.  In 1534 Jacques Cartier encountered a polar bear that swam 30 miles to feast upon the sea birds nesting upon Funk Island located off the Newfoundland coast.  Strange as it may seem, that means it’s quite possible polar bear stragglers did reach the continental shelf of what’s now Georgia during the Ice Age.  Bears have an amazing sense of smell.  Though Funk Island is named for the strong smell of the tens of thousands of birds that nest there, it’s still surprising that a bear could smell them from 30 miles away.

Colony of Murres on Funk Island off the coast of New Foundland.  It’s named for the funky smell of guano from tens of thousands of sea birds.  Colonies of sea birds like this may have existed on rocky outcrop islands near the shelf edge off the coast of the Carolinas and Georgia during the Wisconsinian Ice Age.

Greenly Island April 2011

Bulls Scarp, a rocky promontory off the coast of South Carolina, probably looked something like this when this region was above sea level.  This is Greenly Island located off the coast of Labrador, Canada.

Reference:

Harris, Scott; et. al.

“Continental Shelf Landscape of the Southeastern United States since the Last Interglacial”

Geomorphology 2013

Mastodons, not Giant Tortoises, were the Probable Dispersal Agent of Torreya Seeds

September 6, 2014

Shortly after posting my blog article yesterday, I realized that mastodons rather than giant tortoises were the more likely dispersal agent of torreya seeds during the Pleistocene.  Connie Barlow came to the conclusion that giant tortoises were the most important dispersal agent of this now relic species of tree, but several flaws in her reasoning occurred to me.

1. She thinks mammal teeth would destroy the torreya seeds and accordingly, the seeds would be more likely to survive tortoise consumption because tortoises have no teeth.  However, mastodon teeth have big ridges.  A tiny conifer seed could easily escape the grinding molars of these teeth and pass through to the alimentary canal.  Mastodon coprolites have been found with intact seeds such as acorns, hazelnuts, persimmon and wild squash.  Mastodons were not thorough chewers.

Mastodon Tooth

Mastodon tooth.  Note the large spaces between ridges.  A tiny conifer seed could easily pass through the teeth into the alimentary canal without getting crushed.

Torreya seed cone.  The seed inside this cone is small enough for a mastodon to swallow without chewing.

2. Ms. Barlow claims the turpene found in torreya cones is toxic to mammals but not to reptiles–further evidence that tortoises must have been their main disperser.  Turpene is found in all conifer needles.  It may be toxic to some mammals, but it obviously was not toxic to mastodons.  Although mastodons ate a wide variety of plant foods, conifer needles were usually the most common item in their diet.  Mastodon coprolites found in the midwest almost entirely consist of spruce needles.  Cypress needles along with buttonbush twigs were the most common item in mastodon coprolites found in Florida.

3. Healthy torreya trees grew to 60 feet tall.  A giant tortoise would not be tall enough to reach most of the cones.  A mastodon could easily reach most of them and tear down the tree to reach the ones at the top.  They probably injested some cones while feeding upon the needles.

4. The closest living relative of the extinct giant tortoise is the gopher tortoise, and it feeds upon succulent plants growing in open sunny savannahs and desert scrub habitats.  This is precisely the type of habitat where torreyas can not grow.  Giant tortoises were likely a denizen of these open habitats that were unsuitable for torreyas.

5.  The last torreya trees are found along rivers in protected environments.  Isotopic studies show that mastodons migrated seasonally up and down river system corridors.  This may explain why the torreya’s last stand is located by rivers.  It’s where they would have been most abundant, if they had depended upon mastodon transportation for dispersal.

The Torreya (Torreya taxifolia) is Missing its Megafaunal Disperser

September 5, 2014

The torreya (Torreya taxifolia), also known as the stinking cedar because its crushed needles give off a strong resin odor, is a relic species thought to have been more widespread during warm climatic phases of the Pleistocene.  It likely diverged from an ancestor that was even more widespread during the Miocene when warm moist forests occurred all across North America and Asia.  T. taxifolia  is an extremely rare species confined to just the east side of the Apalachicola and Flint Rivers, while a closely related sister species (T. californica) is native to California where it is found in several disjunct populations. 

Pleistocene Ice Ages fostered the spread of arid grassland environments that were unsuitable for torreyas.  Under these conditions the torreya retreated to moist refugia on steep ravines of the Apalachicola and Flint Rivers. Connie Barlow, author of the below referenced book, thinks the torreya  formerly expanded its range as far north as the southern Appalachians, following the end of Ice Ages.  They are better adapted to live in an Appalachian cove forest rather than the environments surrounding their current range.  She hypothesizes the torreya’s current rarity is the result of its disperser’s extinction.  She suspects the giant tortoises (Hesperotestudo crassicutata and H. incisa) ate the torreya cones and defecated the seeds intact.  As the climate warmed following the end of Ice Ages, the tortoise’s range expanded and torreya trees spread in correspondence with this range expansion.  She believes the tortoises were the torreya’s main disperser. Squirrels can disperse the seeds but they are more likely to eat and destroy them, and other mammals are all potentially more likely to destroy the seeds with their teeth when they consume the cones. Tortoises don’t have teeth.  Furthermore, torreya cones contain turpene which is toxic to mammals but not to reptiles.  Now that tortoises are extinct, the torreya is stuck within a tiny range where it is probably going to succomb to fungal diseases. 

Barlow’s hypothesis will be difficult to support with concrete evidence–plant macrofossil remains from warm climatic phases of the Pleistocene are rare in this region.

Connie Barlow and her husband with a very rare Torreya tree.  She hypothesizes that its rarity today is due to the extinction of its most probable disperser–the giant tortoise.

Torreya taxifolia range map.png

Torreya taxifolia range map.

Torreya trees grow in natural communities the late naturalist, Charles Wharton, referred to as “torreya ravines.”  These are cool moist micro-environments also known as steepheads, and they only occur on the east side of the rivers.  The dominant trees in a torreya ravine are red maple, southern sugar maple, beech, magnolia, basswood, elm, torreya, and sabal palm.  Most of these species have northern affinities and are more commonly found in Appalachian cove forests.  Other plants found in torreya ravines also represent species of northern affinities such as strawberry bush, hydrangea, and redbud.  Wharton found torreya growing with beech, sourwood, and plum in the Faceville Ravine on the Flint River.

Wharton catalogued Torreya Ravines in his book The Natural Environments of Georgia written in 1978.  A more recent updated version of that book (The Natural Communities of Georgia) written by several authors and published last year does not mention torreya ravines.  I fear this means torreya trees may already be extinct in Georgia.  Wild torreya trees can still be found in Torreya State Park in Florida.

Mature torreya trees grow to 60 feet tall, but today few wild torreyas exceed 6 feet before dying back due to fungal disease.  Torreya trees have been transplanted to the Biltmore Estate in Asheville, North Carolina where they are doing much better than the wild trees.  Torreya trees growing on the Biltmore Estate survived a freeze of -30 F.  This shows they are capable of surviving in more northerly latitudes, and this supports Barlow’s hypothesis.

References:

Barlow, Connie

The Ghosts of Evolution

Basic Books 2000

Wharton, Charles

The Natural Environments of Georgia

Georgia Department of Natural Resources 1978

Identifying the Species of Fish described by John Lawson in 1710 (part 2)

August 31, 2014

Lawson admitted his list of freshwater fishes left out many species because he had explored the inland regions of the Carolinas during winter, a season when the natives didn’t often fish.  He starts his list with the sturgeon.  During his time the sturgeon was so common that a person could see “several hundreds of them in one day.”  Sadly, the sturgeon is almost extinct in North Carolina today, and there is no breeding population there.  The fish Lawson refers to as a pike is known today as the chain pickerel.  He caught 300 of them one day in his fish trap on the Neuse River.  I believe there is no river in North America today that would yield 300 chain pickerel in one trap within a 24 hour period.  This shows just how depleted America’s rivers are compared to yesteryear.  Some estimate there are 1000 times less fish in our rivers than existed during pre-colonial times.  

Chain pickerel. (Esox niger)  Lawson pulled 300 of these from his fish trap in the Neuse River on one occasion.

The trout Lawson mentions is undoubtedly the brook trout–the only native eastern species.  The fish he called the “English pearch” was actually the yellow perch and it was not the same species as found in England as Lawson mistakenly believed.  Lawson referred to the largemouth bass as a “brown pearch or Welchman” and again it was not the same species as found in England.  The fish he called a “flat or mottled pearch” is known today as the crappie.  Bream or freshwater sunfish were known by Lawson as “round-robins.”

Lawson claimed carp lived in Carolina but he was wrong.  Carp were not introduced to North America until 1831.  Instead, he may have had them confused with a native buffalo fish (Ictiobus bubalus) which does range into the western parts of the Carolinas in places he never vistited.  He does mention the “sucking fish” (suckers) and “cat-fish”, though he was unware that these 2 families of fish include many different species.

The fish Lawson called the “roach,” an English species, was most likely a type of shiner as was the fish he refered to as a “grindal.”  The fish he knew as the “gudgeon” was some type of minnow.  The fish he called a “loach” is the killifish.  He listed the dace, probably the long-nosed (Rhynicthys cataracterae).

Lawson knew alewives as “old-wives.”  The alewife is a type of herring that lives in the ocean and spawns in freshwater lakes and the deep slow bends of rivers.  The Indians used to dry and smoke alewives.  I remember seeing dead alewives littering a beach on Lake Erie, Ohio when I was a kid.  I had always assumed they died from pollution but that’s not the case.  Alewives are not native to the Great Lakes but instead colonized them by swimming through man-made canals.  Predatory fish populations had been devastated by overfishing, pollution, and lamprey colonization.  This allowed the alewife population to explode and during summer heatwaves, alewives would die by the thousands and wash up on the shore.  Incidentally, southerners not familiar with the Great Lakes probably don’t realize these bodies of water have big waves, just like the ocean.

Alewives. (Alosa pseudoharengus)

I’m not sure of the identity of Lawson’s “fountain fish.”  He wrote that they breed in the clear Running Springs and Fountains of Water, where the “clearness thereof makes them difficult to be taken.”  Perhaps, this is the fish known today as the creek chub (Semotilus atrumaculatus).

I can’t figure out what Lawson’s “white Fish” is.  He described them as being 2.5 feet or more long and were found in the “Freshes of the Rivers.”  I doubt he meant the white fish (Coregonus clupeaformis) found today in the Great Lakes.

The fish he called “Barbout” and “Miller’s Thumbs” is the freshwater cod or burbot (Lota lota).  I don’t think he ever saw this fish in person.  Within historical times this species was not known to have occurred south of the Kentucky River, though during the Ice Age it may have lived farther south.

A burbot or freshwater cod (Lota lota).  This species prefers deep cold lakes and during Lawson’s time probably didn’t range farther south than the Kentucky River.

Identifying the Species of Fish Described by John Lawson in 1710 (Part 1)

August 27, 2014

John Lawson wrote the first American natural history book circa 1710 after settling in North Carolina.  (See:http://markgelbart.wordpress.com/2012/07/27/john-lawsons-voyage-to-carolina-1700-1711/)  I often consult his work to obtain insight about the early unmodified environments of the southeast.  His chapter on fish is particularly confusing because he uses arcane common names, no longer in usage.  He also mistakenly refers to some species as the same as those found in England.  This is not true of any species.  So I gave myself a little project and attempted to decipher which species he was referring to in each individual description.  I used descriptions typed into search engines and information found from the obscure book referenced below to identify almost all the species he catalogued.  It’s evident that he directly encountered some species, but only knew about others from hearsay.  I now offer the results of my study.

Lawson includes the whales with the fishes.  Like most people living during this time period, he never enjoyed the benefit of a biology class and was unaware that whales are mammals.  He wrote about 4 “sorts” of whales.  He did not know of the many more species that live off the coast of Carolina.  He reports 1 “sperma ceti” whale washed up on Currituck Inlet, and how the local beachcombers “profited” from it.  Apparently, there were people living along the coast then who made a living scavenging shipwrecks and dead whales.  His “sperma ceti” whale is obviously known today as just the sperm whale.  He was also aware of the bottle-nosed whale, a deep sea species that lives in underwater canyons where it feeds upon squid and fish.  Bottle-nosed whales can stay submerged for an astonishing 2 hours.

Bottle-nosed whale (Hyperoodon ampullatus).  Lawson was aware of this deep water species of whale.  He mistakenly classified whales as fish.

Lawson mistakenly refers to killer whales as 2 different species–the thrasher and the crampois.  He claimed bottle-nosed whales always washed ashore minus their tongues which were eaten by “thrashers” and swordfish.  Killer whales will attack and eat other whales but swordfish do not.  Lawson also knew dolphins as “bottle-noses.”

I could not identify 2 other whales Lawson catalogued.  I could find no whale matching the description of a “shovel-nosed” whale, and there is no whale that is 60 feet long but just 3 or 4 feet in diameter.  I assume he was just wrong about the measurements.

I was excited when I read Lawson’s account of porpoises being found in a freshwater lake in North Carolina.  I thought I had come across a unique curiosity.  However, large lakes on the North Carolina coastal plain are Carolina Bays with no outlet to the sea.  And the lake is described as being located in a “great sound” which would mean it was saltwater.  Therefore, I’ve concluded Lawson was mistaken again.  Instead, he may be referring to a bay in Maryland known as Porpoise Bay and the porpoises  it’s named after may have been dolphins.  Porpoises are a cold water species that differ from dolphins by having shorter snouts.  They do range as far south as North Carolina during winter, so it’s possible the place was named based on the correct animal.

Porpoise Pond is located in Assawoman Bay, Maryland.  Is this the body of water where Lawson claimed porpoises lived in freshwater?  I think he wrongly was told this was a freshwater body of water, but it is actually saltwater.

The manta ray was known then as the “divel fish” and still is in some archaic circles.  Lawson recounts a case when a “divel fish” got caught in a sloop’s anchor line and dragged it at least a mile against the tide.  A similar even occurred in 1933 off the coast of New Jersey.

Giant Devil Ray

This manta ray with a 20 foot wingspan almost sank a boat.  A Coast Guardsmen shot it 20 times to save the endangered men on board.  Happened off the coast of New Jersey in 1933.

Lawson includes 2 “sorts” of sharks on his list, but he called one a “Paracooda” that I interpet as a misspelling of barracuda which is not even a shark.  He later adds the dogfish to his list and correctly categorizes it as of the “shark kind.”

Many of the species in his catalogue were easy to identify because the names he used are still their common names–Spanish mackerel, mullets, swordfish, shad, stingray, thornback stingray, conger eels, eels, lamprey eels, red drum, black drum, sheepshead, flounder, trouts of saltwater, croaker, toadfish, ocean sunfish, and herring.  Others took just a little deciphering.  His name for menhadden was fat-back, an obscure name little used today.  His description of the “guard” indicates he probably misheard the locals as they referred to this fish as the gar.  Lawson classified the gar as a saltwater fish.  Although gars are common in brackish waters, they are considered a freshwater species. 

Cavallies was a little more difficult to decipher, but I learned this is an archaic term for crevalle jack (Caranx hippo). His bass, or rockfish, is the striped bass, still known as rockfish by many.  The fish he calls a “sea tench” is most likely the tautog (Tautoga onitis).  Boneto is a mispelling of bonita, a type of tuna.  His angelfish includes members of the Pomancanthidae family.

Crevalle jack (Caranx hippos).  Lawson called them Cavallies. He wrote they stayed sweet for twice as long as other fish.

 

 

 

 

 

 

Tautog-a wrasse that lives as far south as South Carolina.

Lawson lists smelts as a fish living in the region, but he probably was referring to a similar-looking fish known as the silverside (Meridia meridia).  Smelts do not live as far south as Carolina.  The fish he calls a “sea bream” is likely a porgy from the Caridae family.  I could not determine what fish he named the “taylor.”

The culinary properties of the fish he catalogued seemed to be the most important attribute in his descriptions.  This is not surprising–his diet mostly consisted of wild animals he could kill and vegetables he could grow.  He praised the good eating qualities of crevalle jacks, mackerel, drums, sea trout, and eels.  He liked sheepshead but wrote that it was no better than many other species of fish, despite its fine reputation.  He thought bluefish among the best of fishes, “full as good meat as salmon.”  Menhaden contained so much natural oil they could be fried directly in a pan without the addition of fat, and Lawson referred to them as “a very sweet food.”  Menhaden comes from the Indian word meaning fertilizer, and today this is the most common use for this species.  Early Settlers liked to eat menhaden as well as to use them to fertilize their crops.

North Carolina is famous for its bluefish (Pomatomus saltatrix).  Lawson said they were as good meat as salmon.

In my next entry, I’ll decipher Lawson’s descriptions of freshwater fish.

Refererences:

Lawson, John

A New Voyage to Carolina

North Carolina Press 1967

Smith, Hugh

The Fishes of North Carolina

Originally published in 1907, republished by Cornell University in 2009

There May Be 5 Species of Shoal Bass Previously Described as 1

August 23, 2014

New discoveries await those entering the field of biological research.  Scientists have uncovered volumes of knowledge, yet we still know so little.  Nevertheless, it’s surprising that in Georgia, in the midst of what most would consider an advanced civilization,  there may be as many as 5 distinct species of bass left undescribed by science.  Byron Freeman and other scientists are using anatomical and DNA comparisons to remedy this unlikely gap in ichthylogical classification.

 

Redeye bass.  There may be 5 different species of shoal bass wrongly considered the same species.

Shoal basses; along with largemouth bass, crappies, and sunfish; belong to the Centrarchidae family.  Shoal basses favor rocky stretches of river too warm for trout, yet too cool for largemouth bass, though there is some overlap on both ends.  Dr. Freeman discovered that various specimens of a species of shoal bass, known as the redeye bass (Micropterus coosae), differed strikingly, depending upon which river they came from.  By comparing 20 anatomical characteristics, Dr. Freeman was able to determine that shoal basses from the Coosa, Apalachicola, Chattahoochee, Savannah, and Altamaha rivers all differed from each other enough to be considered separate species.  Differences in shoal bass DNA sequencing supports his discovery. The scientific name, Micropterus bartrami, or Bartram’s bass, has been proposed for a species living in the Savannah River.

All of these species share a close evolutionary relationship.  It’s likely the founding population of shoal bass became geographically isolated due to stream capture events when the headwaters of 1 stream eroded backwards and captured the flow of another. For example a tributary of the Savannah River captured a tributary of the Chattahoochee, explaining how speciation occurred between shoal basses from these 2 rivers.  (See:http://markgelbart.wordpress.com/2014/02/06/tallulah-gorge/) Similar geological events probably explain the evolutionary divergence of other shoal basses.

All of these species hybridize with each other, showing the difference between species is a gray area.  Hybridization via backcrossing is another way new species can originate.  By introducing a species of shoal bass into another species of shoal bass’s range, man may inadvertently create a new species.  However, scientists are concerned that introductions of smallmouth bass into shoal bass habitat will result in the latter’s extinction.

See also: http://markgelbart.wordpress.com/2013/04/26/the-evolutionary-history-of-the-black-bass-genus-micropterus-sp/

Reference:

Freeman, Byron; et. al.

“Shoal Basses, a Clade of Cryptic Identity”

Black Bass Symposium 2013

Giant Leopard Moths and Red Wasps are Invading my Property

August 19, 2014

In some ways insects are more adaptable than large mammals.  Insects are capable of evolving in response to environmental change much more rapidly than large mammals because several generations can reproduce within the timespan of just 1 growing season, while some large mammals take decades to produce a single generation.  The presence of humans has obliterated 70% of North America’s large mammal species, but it hasn’t put a dent in insect populations.  I will never see a mammoth or saber-tooth in my backyard.  However, thousands of interesting species of insects invade my property, and they are active almost year round, though the coldest days of winter relegate most of them to dormancy.  Most of the insects I find on my property are likely the same species that inhabited this space during the Pleistocene.  Insects suffered few known extinctions at the end of the Ice Age but instead experienced shifts in range distributions. (See: http://markgelbart.wordpress.com/2012/07/18/using-fossil-beetle-assemblages-to-determine-temperature-ranges-during-the-late-pleistocene/).  Climate in my neighborhood (Augusta, Georgia) remained relatively stable during this transition, and the change in insect species composition has probably been minimal since then. Recently, I’ve encountered 2 species of insects that have occupied my homestead space for hundreds of thousands of years.  Maybe, I should change the title of this essay, and call it “humans invading moth and wasp territory.” 

Giant Leopard Moth, Ecpantheria scribonia

 

 

 

 

 

 

 

 

 

Giant Leopard Moth (Hypercompe scribonia)

This woolly bear caterpillar is the larval stage of the giant leopard moth.

The giant leopard moth (Hypercompe scribonia) is a large species with a wingspan of nearly 3 inches.  It has beautiful teardrop-shaped spots on its wings.  That is the description I googled to help me identify this species.  I found a dead specimen near my wildflower bed but didn’t take a photo. (I ripped off the above photos from google images.) It probably died after depositing fertilized eggs on 1 of the species of flowers growing in my garden.  Their larva are known as woolly bears (as are the larva of many other species of moths), and they feed on a wide variety of plants including but not restricted to violets, mustards, basil, trumpet vines, sunflowers, mulberry, magnolia, and locust.

 photo Daphnesdorm001_zps3665f00a.jpg

Red paper wasps (Polistes sp.) nesting between my screen door and side door.  It’s a door we never use, so I let them stay there.  Though manmade, it mimics a hollow tree stump or log in scarce supply in modern young forests.

A nest of red paper wasps (Polistes sp.) lives in the space between my side door and screened-in door.  There’s a hole in the screen, allowing access to this sheltered area.  Before humans built structures, paper wasps built their nests in hollow tree trunks, but there are few den trees in the young 2nd growth forests surrounding modern day suburbia.  I’m letting the wasps live in the doorway because: a) we never use the side door, b) they are not aggressive, unless defending their nest, and c) they are beneficial predators, destroying the kinds of caterpillars that like to eat their way through my garden.  Each cell of the wasp’s nest contains a wasp larva with a paralyzed caterpillar upon which it feeds.

There are 28 species of wasps in the Polistes genus that live in the southeast, and I’m not enough of an expert to identify the exact species to which my housemates belong.  I admire these little monsters–they invented paper millions of years before the 1st humans evolved.

 

 

 

Bulls Scarp

August 14, 2014

Bulls Scarp is an uneven rocky cliff located approximately 66 miles to the east of the South Carolina coast.  This sloping underwater feature is on the edge of the continental shelf, and it covers about 20 square miles.  Today, Bulls Scarp varies in depth from 42 yards to 220 yards beneath the surface of the sea, depending upon the height of its rocky outcroppings.  But during the last Ice Age between ~24,000 BP-~16,000 BP, it was above sea level because the Laurentide Glacier had advanced over all of eastern Canada, locking up a great quantity of earth’s atmospheric moisture.

Sonar image of Bulls Scarp, about 66 miles east of the South Carolina coast.  This image was taken by researchers from the College of Charleston.  20,000 years ago, this was a rocky location right at sea level and it probably hosted breeding colonies of walruses, seals, and sea birds.  Note how it stuck out into the ocean like a kind of natural pier.

Bulls Scarp fascinates me because it represented an environment that no longer exists anywhere in southeastern North America.  The closest above sea level cliffs today are in Maine.  Scientists from the College of Charleston believe Bulls Scarp would have provided favorable habitat for marine mammals such as seals and walruses.  Fossils of both have been found near Charleston.  (See: http://markgelbart.wordpress.com/2011/01/28/seals-and-walruses-off-southeastern-north-americas-pleistocene-coast/).  Puffins and other sea birds nested here as well, and oyster reefs attached to rocks would have been abundant.  Researchers think these resources may have attracted paleo-indians.  Bulls Scarp also offered rock shelters, stone for tool-making, and freshwater springs.  Herds of mammoths, bison, horses, and llamas likely wandered all the way to the coast, and Indians following this game may have discovered these seaside cliffs.  Most of the continental shelf that was above sea level during the last Ice Age has been eroded by currents and wave action, destroying potential archaeological sites, but Bulls Scarp may have lag deposits containing fossils and human artifacts because the rocky outcroppings served as an impediment that trapped sediment. Scientists have identified it as a likely site where Clovis artifacts may be found.

Walruses on rocky shore with mist, Arctic  Jupiterimages

Walruses on a rocky shore off the coast of Alaska.  Strange as it may seem, an area off the coast of what today is South Carolina likely had a scene just like this 20,000 years ago.

A great variety of environments existed on the exposed continental shelf between Bulls Scarp and what today is the modern shoreline.  The climate was on average cooler and drier, though not especially cold during winter, thanks to the nearby Gulf Stream.  Lightning-induced wildfires were infrequent while draughts were common.  These climatic conditions favored prairies and scrub oak thickets.  Pine savannahs and river bottomland forests were less common than they are today.  “Sand dune fields” and Carolina bays formed on the northeast side of the braided rivers flowing on the shelf.  Rivers didn’t meander during this time period, but instead were shallow and clogged with sandbars.  Grassy marshes occurred near springs, and cypress swamps were relict habitats on low poorly drained sites.

When the Ice Age ended,  the Laurentide Glacier melted rapidly, and sea levels rose at an astonishing rate—40 yards per year.  Ocean front condos would have been a really bad investment then.  Cypress tree stumps found 19 yards below modern sea level date to 11,500 BP.  The Atlantic Ocean inundated cypress swamps and all the other types of environments mentioned above within a few thousand years.  Modern sea level was reached about 6,000 years ago. 

We can study the ocean floor off the South Atlantic Bight and imagine what it used to be like, but for me it’s not nearly as satisfying as it would be to have actually seen it.  The paleo-indians didn’t enjoy our modern technological wonders, but they did get to see interesting pristine landscapes.

Reference:

Lepper, Brad

“Paleolandscapes of the South Atlantic Bight”

Mammoth Trumpet 29 (3) July 2014

 

 


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