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Recent extinctions
The mammoth extinction discussion got me to look at the B. bison thing.
It may have been that the array of super bears, cats and wolves on the
plains used to keep bison numbers in check until those carnivores went extinct.
Then the new predators, the early plains indians, may have done the same. As
you recall, the introduction of Eurodiseases into the Americas devastated
the aboriginal populations. The absence of any predation among the
r-strategist bison may have led to their population quickly ballooning to the
tens of
millions. But by the late 1700s early 1800s plains Indian numbers were
rebounding, and they got horses and then firearms. They may have been
suppressing
bison numbers by the mid 1800s. Now, when I was a kid we learned about how
the obtuse early frontiersmen called the western plains "The Great American
Desert" -- how silly of them we were taught. Actually, it was a desert at
the time because of a mid 1800s superdrought that probably drastically reduced
the bison pop. Then rains leading up to the early 1860s brought back their
numbers somewhat.
Westward migration from the east slowed when the southern traitors who
wished to keep folks in terror based bondage revolted against these United
States. After the war many of those disaffected traitors headed into the
southwest, as portrayed in the best western/Wayne film of all, The Searchers
that
costarred the future Captain Pike of the USS Enterprise. This is why the SW
was as virulently Jim Crow as the SE well into the 1900s. Also, the US
government paid the rail companies to lay down the transcon railroad. So
massive
migration to the west resumed across the northern and southern plains, as did
the cattle industry on the open range, leading to the cowboy culture that
consisted of minimum wage workers hitting the new towns to drink, gamble and
hit the brothels. Also having a good time in town were the buffalo hunters.
In twenty years commercial hunting reduced the bison to a few hundred. It
was almost entirely for the skins. The Feds were all for this. To eliminate
competition for the cattle ranchers. To keep the damn buffalo off the
railroad tracks (especially in the winter when bison herds used the cleared
tracks
to move along, holding up trains for days -- it was very annoying). And to
drive as our beloved Declaration of Independence calls the merciless Indian
savages (it's always a cringe factor when they get to that part of the NPR
recitation every 4th) to the reservations. Buffalo Bill got concerned. But
prez Grant refused to sign a bision protection bill. By the mid 1880s the bison
would have been extinct if a few had not been kept for old times sake (I
think most at Yellowstone Park). That was as the open range was just beginning
to be fenced up by them dang homesteaders, so habitat destruction had
little to do with it.
That the bison were so quickly eliminated from a large part of a continent
negates the cited argument concerning the difficulty of killing off Cape
buffalo. It is not a great analogy for Paleoindians hunting the megafauna to
extinction. Also irrelevant in the difficulty of wiping out roos. They are
modest sized r-strategist weed taxa.
Someone brought up the passenger pigeon. There is an argument that their
populations were not as colossal pre 1492 as they were in later colonial
times. PP were big mast eaters - acorns, chestnuts, etc. So were Indians who
developed a protoagriculture based on mast trees across the continent. Used
fire
to suppress nonmast trees, the latter dominated the Yosemite Valley floor
when the whites arrived for instance. PPs populations remained modest. A line
of evidence for this is that even though PPs make good eating, their bones
are rare in Amerindian middens which would be all the more odd if they were
superabundant and as easy to kill as they were in the 1800s, and the Indians
sure knew how to kill and eat critters. Then the Eurodiseaes wiped out most
natives and the mast forests went wild, and the theory is that the
delighted PPs had all the nuts they could eat and their populations soared to
abno
rmal levels. So when the Brits showed up in the 1600s is looked like a near
human empty wilderness of oaks, chestnuts with abnormally huge PP flocks
flying about. Continued disease pressures kept Amerindian populations west of
the
Appalachians low until the early 1800s, keeping the PPs happy as doves.
Then the Euros flooded into the midwest in the early 1800s as per Tom Sawyer,
cutting down almost all the mast trees to accomodate the inefficient farming
of the time (there was a lot more farmland in 1900 than there is now). And
everyone was eating the tasty, nutty flavored PPs. So their population
quickly crashed.
As I pointed out in DA, this was a good thing. We would not want huge
masses of doves, would be worse than the starling and crow flocks we have to
put
up with. They would be pest birds, pooping all over everything. An icky
health hazard. And the PPs probably could not breed in small flocks. So it was
either them or us. What I miss is the ivory bill. The last documented
population was wiped out in WW II because Roosevelt refused to ban the logging
of
the last river bottom virgin woods the woodpeckers lived in for war needs. So
we can blame FDR and Hitler for that one. Whooping cranes and California
condors were remnant post Pliestocence populations when Euros arrived. They do
not harm and are worth saving.
The highly specialized woolly mammoth evolved late in the Pleistocene and
may have been vulnerable to natural loss during interglacials. But that is
just one species. Just a few years ago geotime wise there was a spectacular
megafauna in the Americas including multiple genera and species of mammoths
and mastodonts, super sloths, super bears, cats, and wolves, super bisons,
super beavers, etc living in all sorts of habitats from subpolar to tropical.
Of course there was constant faunal change during the Pleistocene. But
nothing like the Ameroextinction around 10K years ago. Or the Australian
extinction somewhat earlier and only after arboriginals got there. That these
extreme
extinctions occured at pretty much the same time those pesky humans showed
up without the latter playing a major role is a real coincidence stretch.
Probably the people factor was a combo of hunting and habitat modification,
including setting large scale fires. The latter, and further habitat changes
due to the loss of the megafauna, may have impacted the minifauna.
Africa has the most intact megafauna because the elephants, rhinos, hippos,
giraffes, lions, hyenas, etc evolved in the presence of evolving humans.
Basically the big animals learned to flee and ask questions later when people
were about. The Eurasia fauna also co-evolved with later protohumans. The
Ameomegafauna would have had no idea what the protein hungry paleoindians were
up to when they suddenly showed up with unprecedented long reach weapons.
Same for the poor Aussie megafauna.
GSPaul
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