Posts Tagged ‘megafauna’

The Fishbait Tree (Catalpa bignoniodes) may be an Anachronism

August 13, 2013

The bignonia family includes 700 species of mostly tropical distributions.  The calabash tree (Cresenctia cajeta) of South and Central America is a species of bignonia that some scientists consider anachronistic, meaning it seems out of time and place.  The calabash tree produces large fruits with hard rinds that no extant native animal can crack.  Thus, this species has a limited distribution because no native animal can spread its seed in their dung.  However, introduced horses can bite through the rind and spread the seed.  During the Pleistocene horses along with ground sloths and the mastodon-like gompotheres aided in this species dispersal.  Another species of bignonia, the sausage tree (Kigela africana) of Africa produces large fruit pods that are known to be dispersed in the alimentary canals of elephants, giraffes, hippos, and baboons.

Some species in the bignonia family do occur in temperate regions.  The trumpet vine (Campsis radicans) is perhaps the best known and widespread.  The 2 species of catalpa trees, like the calabash tree, may be examples of anachronisms because they had  limited distributions before man widely transplanted them, and they produce long seed pods that no modern animal disperses.  Before European settlement the northern catalpa tree (Catalpa speciousa) was limited to the Mississippi River Valley from Arkansas north to Indiana, while the southern catalpa (Catalpa bibnonioides) ranged from southern Mississippi to western Georgia and the Florida panhandle.  The limited range of both species suggests they weren’t being dispersed as readily following the end of the last Ice Age as they may have been, if the megafauna hadn’t become extinct.

Illustration of the southern catalpa.  It has big showy flowers, big leaves, and long seed pods.  It was probably more widespread during the Pleistocene when climatic conditions were favorable.

Proposed pre-settlement range of northern catalpa (Catalpa speciosa).  It has been widely transplanted.

File:Catalpa bignonioides range.jpg

Proposed pre-settlement range of southern catalpa (Catalpa bignoniodes).  No one knows for sure what its exact pre-settlement range was because it has been widely transplanted as an ornamental.

Between 60,000 BP-30,000 BP, forests and woodlands in southeastern North America hosted many diverse species, but the climate deteriorated rapidly after 30,000 BP, and the species rich woodlands were replaced with pine and oak dominated landscapes.  Catalpa trees and other less hardy species were restricted to small refuges such as ravines that were protected from the harsher climate.  When climatic conditions improved ~15,000 BP, animals such as mastodons and ground sloths were headed toward extinction and were no longer common enough to be  effective dispersal agents.  Catalpa trees prefer early successional moist woodlands and are intolerant of fire, ice storms, and shade.  The megafauna inadvertently shaped the ideal environment for catalpa trees.  The presence of megafauna reduced the intensity of fires because they consumed so much flammable material.  The megafauna also maintained open sunny woodlands by grazing, browsing, and trampling. Catalpa trees thrived in these primeval rich environments during warm interglacials and interstadials, but their ranges contracted during cold stadials when low CO2 levels, drought, cold, and ice storms proved problematic for this big leaved species.

I am unaware of any genetic studies comparing northern and southern catalpa trees.  All the species in the bignonia family found in North America are descended from tropical species that evolved to survive in temperate climates.  Northern and southern catalpa trees likely split from a common ancestor.  I’m curious whether the 2 species split early during the Pliocene ~5 million years ago when Ice Ages began to occur or if they are a recent divergence resulting from a more recent Ice Age.

The reason catalpas are called fishbait trees is because they are the sole host of the catalpa worm (Ceratomia catalpae).  It’s not actually a worm but rather the caterpillar stage of a brown sphinx moth.  According to fishermen who use them, catalpa worms are a fair bait, if used as is, but are an excellent bait when the head is pinched off and their body is pulled inside out.

Catalpa worm.  They feed on catalpa leaves and after consuming enough food burrow into the ground and pupate.  They  then emerge as adult moths to mate and lay eggs which hatch into caterpillars.

A catalpa tree is a mini-ecosystem in itself.  Heavy catalpa worm infestations attract a whole swarm of predators.  Tiny braconid wasps insert their eggs into the caterpillars, and the wasp larva eat their way through the unfortunate caterpillars.  Ants then prey on the wasp larva.  Tachnid flies also parasitize catalpa worms, and a species of snout-nosed beetle preys directly on the caterpillars .

At least 1 species of braconid wasp parasitizes catalpa worms.  Tachnid flies parasitize them too.

Wasp larva chewing up a catalpa worm.  It’s doomed.

Catalpa worms build up a chemical compound from their diet of catalpa leaves that makes them distasteful to most species of birds, but the yellow billed cuckoo is an exception.  Cuckoos enjoy a specialized diet of caterpillars, and they relish catalpa worms.

Yellow billed cuckoo (Coccyzus americanus).  These birds specialize in eating caterpillars.  They are supposedly common summer migrants in North America.  They winter in South America.  I’ve maybe seen 1 in my entire life.  I may plant a catalpa tree in my yard in the hopes of attracting this bird.

Catalpa trees are resilient and regenerate leaves within the same growing season following a heavy infestation of worms that completely defoliates them.  Most trees, especially older individuals, can survive repeated defoliations.  This is evidence they could also have withstood having their leaves heavily browsed by mastodons and ground sloths.  Catalpa seedpods were probably consumed along with their leaves in the fall and deposited in big nutritious manure piles.  Man began cultivating catalpa trees as ornamentals and for fishbait in 1726.  Man has replaced the megafauna as a disperal agent for catalpa trees.


Megafauna game trails, then Indian Trails, now State Highways

May 25, 2011

Last week, my quest to find the site of the 18th century Great Buffalo Lick took me on a journey along Highway 22.  Few people who travel Georgia’s state highways realize that many of these roads through the piedmont region closely follow the routes of old Indian trails.  And Indians were simply following ancient megafauna game trails.

Historical map of known Indian trails.  I think Highway 22 originally was a branch of the Pickens Trail.  According to the treaty signed with the Creek Indians in 1773, an Indian trail that closely mirrors modern day Highway 22 formed the western boundary of what was to become Wilkes County.

Recall that last week, I chased a turkey hen with my car up the gravel road that led to Kettle Creek Battlefield.  The turkey chose the path of least resistance and seemed reluctant to leave the road for the cover of the brush because it takes more energy to run though thick vegetation.  Animals don’t like to waste energy.  They need to retain as much body fat as they can so they can survive hard times when there is less food or when they can’t forage due to injury.  Therefore, animals tend to travel along paths already trodden down by other animals or created by man.

While driving on a state highway, it’s exciting to contemplate that I’m probably following a path of considerable antiquity.  The routes could be tens of thousands of years old.  Originally, a herd of mammoths or mastodons formed the trail, beating down the grass and brush, stomping flat the saplings, ripping off overhanging tree branches.  Herds of bison, horses, llamas, deer, and peccary used the trail, keeping the path an open avenue.

Photo of a game trail in Africa formed by elephants and followed by other animals.  Even though this part of Africa is open grasslands, animals prefer to travel along the same routes to avoid resistance from plants and terrain.  Photo from the book The Early Settlement of North America: The Clovis era by Gary Haynes.

The paleoIndians followed these game trails too which were more prevalent in the piedmont region for two reasons: Unlike in the coastal plain, rivers in the piedmont were rapid with lots of rocky shoals, precluding the ease of travel by boat.  And the piedmont was more forested, necessating a preference for clearly marked trails both for ease of travel and to keep from getting lost.  Indian trails in the piedmont followed high ridges and avoided frequent crossings of deep creeks or wide rivers.  When they did lead to river crossings, they converged at shallow rocky areas that were easy to ford.  A number of Indian trails converged at what’s now Augusta because there are rocky shoals here that make fording the river easy.  I’ve crossed them myself many years ago.  If it wasn’t for these shoals, Augusta would not exist.  Fort Moore was the predecessor to Augusta.  General Oglethorpe chose this site for a trading fort because many Indian trails converged here.  Because open pine savannahs and wide navigable rivers prevailed in the coastal plain, Indian trails were less common or necessary there.  State roads built after World War II no longer needed to follow these old trails because heavy machinery made it possible to flatten hills, grade uneven land, and construct large bridges.


Warning: I’m getting on my soap box about the complete destruction of Bartram’s magnificent forest.  I am bitter.

I wrote about an impressive old growth forest described by William Bartram in my April 11th blog entry.  On my expedition to find the Great Buffalo Lick, I also searched for remnants of this forest and found absolutely none. ( I assumed the state highway followed the old Indian trail.)   As I suspected, the entire forest, many square miles of “gigantic” black oaks, sycamore, sweetgum, and hickory must have been cleared by cotton farmers between 1790-1860.   Today, the area from Little River to Philomath consists almost entirely of dense stands of loblolly pine and sweetgum–a monotonous nearly dead ecosystem.  I saw only a few black oaks–none of them “gigantic.”  Instead of  a “thinly planted by nature” oak parkland, it’s practically a monocultured thickly planted tree farm.  I saw not a single tree more than a foot in diameter, whereas William Bartram traveled through 7 miles of trees that were 8-11 feet in diameter.  I estimated, based on the appearance of this loblolly pine and sweetgum second growth, that the area was one big cottonfield until about the 1930’s, perhaps reverting to field following the boll weevil infestation that broke the back of agriculture here.

I can’t believe the greedy bastards who first cleared this land for growing cotton couldn’t protect even a small park of this original forest.  We will never see how beautiful the original environment was in this area.  It was destroyed before photography was invented, and no 18th century artist chose to paint it.  Instead, these stupid, illiterate bullies used slave labor to cut every single tree down, remove every stump, burn every bit of lumber refuse, and they continued to plant cotton seed in the bare red earth until the once rich soil and landscape transmogrified into a worn out old hag of its former self.  The natural beauty of the original environment has gone with the wind.

This is one more disgraceful legacy of southern white people.  In addition to crimes against humanity (slavery and an insurrection that led to the deaths of millions) I charge them with crimes against the environment with their destruction of Bartram’s magnificent forest.  Neither did I see remnants of the Indian mounds Bartam mentions, so go ahead and consider white southerners guilty of crimes against archaeology as well. 

I condemn white southerners for their disgraceful history, and for their current political stances which are still overwhelmingly backward, racist, ignorant, and short-sighted.

Strawberry Fields are Not Forever

April 27, 2011

Photo of wild strawberries from google images.  In the southeast during the Pleistocene wild strawberries probably covered the plains for miles.  Prairies, savannahs, and meadows existed to a greater extent then due to a number of different atmospheric and ecological factors.  Even during the Holocene just 200 years ago, William Bartram found what he referred to as strawberry plains where strawberry plants covered the ground for miles. This natural environment is extinct, though relic patches still occur.

According to one opinion poll, the strawberry is rated America’s favorite fruit.  This surprises me because the vast majority of supermarket strawberries are a tasteless waste of money.  They’re bred to withstand shipping, the newer economical varieties being hard and completely devoid of flavor.  Man has improved the quality of most fruit through cultivation, but the wild strawberry is considered an exception, the uncultivated fruit well known to be superior in flavor.  Cultivated strawberries are big and red and attractive, proving the old adage that people eat with their eyes, and thus explaining their popularity.   Good tasting cultivated varieties can be had at local farmer’s markets, so be sure to buy locally grown strawberries.

The native North America strawberry that grows wild in southeastern North America is Fragaria virginiana. A Dutch horticulturist crossbred this with a Chilean strawberry (Fragaria chiloensis) to produce the modern strawberry (Fragaria ananensis) from which all cultivated varieties are derived.  The hybrids produced a bigger berry but are not better in flavor.

Scientists theorize strawberries first evolved during the Eocene in one of the only cool locations on the planet then–high elevations near what’s now the polar ice cap.  As the woldwide climate cooled, they invaded the lowlands and became widespread in North America, Asia, and Europe.

Fragrant wild strawberries (the word fragaria is Latin for fragrant) were probably common during the Pleistocene, though, like 95% of plant species, don’t produce enough pollen to show up in palynological testing.  William Bartram, while traveling through northwestern South Carolina and southeastern North Carolina in the 18th century, twice referred to “strawberry plains,” where wild strawberries grew in association with grass, Virginia plantain, burnet, avens, and ginseng.  One of these strawberry plains was two miles long.  He also crossed mountain meadows that consisted of hundreds of acres of wild strawberries.

Photo of Virginia plaintain (Plantago virginica) from google images.  This is one of the plants Bartram found growing in association with wild strawberries in vast “strawberry plains.”

Burnet (Sanguisorba sp.)–another species Bartram found in association with wild strawberries.

Avens (Guem sp.).  And another species associated with wild strawberries in this extinct environment.

Bartram’s horse’s hooves were “dyed red” from trodding on the fruits.  I’m certain that wild strawberry plains two miles in length no longer exist anywhere in the southeast today.  When John Lennon sang “Strawberry Fields Forever” (Link to song ), he was crooning a fantasy of an environment that no longer exists.  How sad.

Suburban development and fire supression have eliminated all but relics of the type of environments wild strawberries need to establish a plain of two miles in length.  Wild strawberries thrive in open sunny spaces created by unchecked wild fires of the kind that were common until the 20th century.  Birds, including turkeys and passenger pigeons, and megafauna such as deer, horse, bison, and mammoth spread the seeds in their manure, so that strawberries could grow amongst the grass and herbs of open plains which were common during the Pleistocene because the atmosphere consisted of lower concentrations of carbon dioxide which is more favorable to grass than to trees.  Once established, strawberries grow runners and can carpet the ground.

One can catalogue wild strawberry plains as another one of those extinct natural landscapes that is forgotten or unknown by most of today’s lazy ass, electronics-obsessed, couch potatoes but is to be mourned by nature lovers.