Archive for November, 2018

Paynes Prairie State Park in Florida

November 26, 2018

My visit to Paynes Prairie State Park was a colossal disappointment.  Paynes Prairie is an area where the Florida aquifer (a gigantic underground river) comes close to the surface.  During periods of heavy rain it fills with water and becomes marshy, but during droughts the water level recedes and parts of it host grassy environments.  The fluctuating water levels prevent trees from becoming established, and it contributes to the open nature of the landscape.  A forest dominated by live oak, slash pine, palm, and red maple with an undergrowth of saw palmetto surrounds the prairie.  Supposedly, bison, cracker cattle, and Spanish horses roam the park; and guides claim it is 1 of the best bird-watching sites in the U.S.  I didn’t see any of the megafauna and only saw a paltry 4 species of birds–an egret, a turkey vulture, a red-shouldered hawk, and a small gray bird with a white tail that I have frustratingly been trying to identify for years.  I’ve seen this bird in Augusta, Georgia too, and it always seems to be hanging around water, but it doesn’t resemble any the pictures in my field guides.  I also heard chickadees and an eastern phoebe.

This egret was the only wading bird I saw in the park.

Fluctuating water levels create an open landscape at Paynes Prairie.  I took this photo from a watchtower that swayed in the wind.

I didn’t see the bison, cracker cattle, or horses.  I did find deer hoof prints.

Some of the live oaks were 6 feet thick in diameter.

I saw more wildlife in Florida outside the park than I did inside it.

Next to my hotel in an urban area of Bradenton, Florida I saw a flock of 13 white ibis.

I got an even better photo of an egret next to my hotel than I did in the park.

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The Page-Ladson Site in Northwest Florida

November 19, 2018

I wrote a new blog article about this last night, but then realized I’d already written an article about this subject. I’m re-running this article this week because I don’t have time to write another one before the holidays. Happy Thanksgiving.

GeorgiaBeforePeople

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…

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Ants, Flies, and Trillium

November 12, 2018

Woodland herbs in the trillium family have evolved interesting traits that lure insects into helping them reproduce.  The trillium family belongs to the lily plant order, and it includes 45 species and 5 hybrids found in North America and Asia.  More species live in North America and the center of trillium evolutionary origin is probably the southern Appalachians.  Species of trillium were likely widespread in the tropical to temperate forests that occurred across both continents during the Miocene over 5 million years ago.   This is likely when trillium evolved a dependent relationship with bees, ants, and flies.  Some species of trillium, such as the great white (Trillium grandiflorum) produce flowers that attract bees and wasps with a sweet smell.  But others, such as the inaptly named little sweet betsy (T. cunacateum), have flowers that smell like rotting meat, and the red color looks like flesh, so they attract flies.  These flying insects help pollinate the trillium plants.

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Little sweet betsy–more accurately known as bloody butcher because they smell like rotting meat. The flesh color and carrion smell of the flowers attract flies, and in turn the flies pollinate the flowers.

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By contrast the flowers of the great white trillium smell sweet and attract bees and wasps for pollination help.

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Ants disperse trillium seeds throughout the forest.  Aphaenogaster picca is an example of an ant species that mostly preys on termites but takes advantage of the passive trillium seeds when they have a chance.

Trillium produce a fruit with over a dozen fat covered seeds that attract ants.  This layer of fat is known as the elaiosome, and it surrounds a hard seed.  The ants carry the fat rich seeds back to their nest, but discard the hard seeds after consuming the nutritious coating.  This helps spread the species throughout the environment. Most of the species of ants that consume trillium seeds normally prey on termites, worms, and grubs–the trillium seeds are an easier meal that puts up no resistance.  Plants that depend upon ants to disperse their seeds are called myrmecochorous.

For years many scientists were mystified at how trillium and other plant species so rapidly recolonized land formerly covered by glaciers. This is known as Reid’s paradox defined as the unexplained mystery of how some plant species apparently recolonized post glacial habitats faster than their modern dispersal rates suggest.  It is mathematically impossible for ants to have dispersed trillium across New England and parts of Canada in less than 10,000 years. However, scientists recently discovered deer feces containing viable trillium seeds.  Apparently, white tail deer eat trillium fruit and spread the seeds into new territory.  This would answer Reid’s paradox.  However, high populations of white tail deer can be detrimental to trillium populations.  Trillium plants are perennials, capable of surviving from the same root for up to 25 years, but repeated deer consumption of the leaves can kill the plant.  Deer also choose to eat the largest trillium plants, thus selecting for smaller and less productive individual trillium plants.  I hypothesize extinct tapirs and possibly long-nosed peccaries also fed upon and dispersed trillium during the Pleistocene.

The relict trillium (T. reliquum) is known from just 50 sites along the fall line, mostly in Georgia. A genetic study determined this species survived in 2 different Pleistocene refuges during Ice Ages when much of the landscape became desert like.  There is actually greater genetic diversity on the eastern and western parts of its range rather than in the central part.

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The relict trillium, also known as the Confederate wake robin.  It is an ancient species that became rare because of Ice Ages.

References:

Gonzalez, E.; and J.L. Hamrick

“Distribution of Genetic Diversity among Disjunct Populations of the Rare Forest Understory T. reliquum”

Heredity 95 2005

Velland, Mark; et. al.

“Dispersal of Trillium Seeds by Deer: Implications for Long Distance Migration of Forrest Herbs”

Ecology 84 (4) 2003

ABC Bears

November 5, 2018

During the Ice Age the coast of southeast Alaska was studded with ice floes and perfect habitat for seals and polar bears.  The interior of Alaska was mostly grassy steppe, the preferred habitat of brown bears.  About 16,700 years ago the icy habitat along the southeast coast of Alaska began to melt and polar bear populations became stranded on Admiralty, Baranet, and Chichagof Islands; also known as the ABC islands.  Here, the habitat began to become more favorable for grizzly bears, and young males looking for new territory not already occupied by adult males colonized the islands.  A genetic study of 1 specimen from this island group determined these colonizing male brown bears mated with female polar bears, creating an hybrid population  (Ursus arctos x U. maritimus).  Gradually, the population of brown bears swamped the DNA of this region, so today polar bear DNA makes up just 6% of their X  chromosome (the female chromosome is XX; the male is normally XY).  Polar bear DNA has also been found in specimens of the extinct Irish brown bear.  DNA evidence suggests polar bears diverged from brown bears about 4 million years ago, but there has been periodic hybridization in regions where the 2 species overlap.

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Location of the ABC islands.

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Top 2 photos are polar bear/brown bear hybrids in captivity.  Bottom right is a polar bear; bottom left a brown bear.  The 2 species rarely do hybridize in the wild.

A few months ago, Discovery Channel aired a program about the ABC bears that I lambasted in this blog article https://markgelbart.wordpress.com/2018/06/04/the-fear-island-special-that-aired-on-animal-planet-last-night-was-full-of-shit/ .  Previously, Discovery Channel has aired programs about Bigfoot, mermaids, and the extant existence of a 60 foot long extinct species of shark.  I assumed this program was completely bad pseudo-science, but 1 of my readers alerted me to the scientific merits of this program and also informed me that I wrongly assumed the ABC islands were the same as the Kodiak islands.  The Kodiak islands are on the other side of the Gulf of Alaska, so I errored geographically by hundreds of miles.  And the expedition on this program did have scientific merit because they were seeking just the 2nd DNA sample from an ABC bear.  However, I still think this program was full of shit…just not as full of shit as I initially assumed.  Here is why I stand by my first opinion:

1. The participants acted as if they were the first researchers to ever obtain DNA evidence from a bear on the island, though a study of 1 specimen had already been published.  They already had a good idea what they were going to find, and it was not a great mystery as they promoted.

2. The Indian guide claimed he saw 6 bears ceremonially bury another dead bear.  What unscientific bull crap.

3. I don’t buy the size estimate claim.  It was based on an up close trail cam photo.  Weigh it or just shut up.

Reference:

Cahill, J; et. al.

“Genetic Evidence for Island Populations Conversion Resolves Conflicting Theories of Polar Bear Evolution”

PLOS Genetics 2013