|The Drowned Lands of the
Wallkill supported a vast array of species, and were part of the migration
paths for them. Fossil evidence here
is helping study the progression of species and the enigma of why some
species died out.
|Scientist Guy Robinson
studies these remains for evidence:
|Summary of Robinson
|Paleoecologist Guy Robinson
of Fordham University has studied evidence of mammoth and other big game
hunts in the Black Dirt area. He says
that the evidence points to the idea that over hunting was a major cause of their
extinction at the end of the Pleistocene era. Prior theories postulated that
the extinction was due to climate change, that the warming of the earth
caused this extinction., but now some scientists believe a major contributing
factor was the action of man.
| Radiocarbon dating is not
precise, but the fact that these extinctions occurred around the time that
the first spear points are being found in North America; recent data has made
it clear the last of the mammoths and other ‘megafauna’ had disappeared
before the heat wave that ended the Pleistocene.
| Robinson believes that by tracking the arrival of the humans and
studying the evidence of climate change, it can clarify why they
disappeared. He works with ancient
pollen and flecks of charcoal he digs up in the Black Dirt. Fossil spores of a fungus that grows on the
dung of large herbivores shows that they disappear from the sedimentary
record just before charcoal marks of large fires—which he contends were set
|He has found the stomach
contents of some mastodons from orange county and using his microscope, he
can tell what kinds of plants grew near Lake Fairchild thousands of years
ago, like alder pollen. Studying the preserved pollen, he can learn about
long extinct ecosystems and the shifting patterns of plant communities.
| He has found two dramatic shifts in the microfossil record. First, the dung fungus disappears, then
within a few hundred years, landscape fires increase tenfold. In this Robinson sees that local
populations of large grazing animals crashed when the first people arrive and
found them to be easy prey. Without
the huge herbivores, fuel sources built up and fires lit by lightning and
people burned larger and hotter than ever before. There is no pollen shift during this time
period, disproving the theory of climate change.