Sunday, July 10, 2005

HUMAN IMPACT STATEMENT

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Once again, on the world stage, America's leader repudiated science and the planet and basically said, we won't change a thing, we don't care if this destroys the planet, we will pollute.

This week there is a stark reminder of human climate change. From the National Geographic:
Humans first reached Australia around 60,000 years ago and changed the landscape forever, scientists have concluded.

Roughly 60 species of the continent's large mammals and some bird species became extinct around 45,000 to 50,000 years, as a result of a change in the ecosystem brought on by massive fires set by the early settlers.

The exact purpose of the fires is unclear; the settlers may have been clearing land, signaling other tribes, or hunting. What is clear is that the fires changed the landscape from a mosaic of forests and grasses to the fire-adapted shrubs and spinifix (a grass) found today.

Climate change is often thought to have caused extinctions in other parts of the world. The researchers were able to eliminate this possibility by studying the carbon isotopes of the eggshells of emus and the teeth of wombats going back 140,000 years. There were many large climate shifts during that period that did not induce a change in the ecosystem. In addition, evidence from dust in marine sediments off the coast of Australia suggests that the climate was relatively stable 45,000 to 50,000 years ago.

However, the evidence showed a clear shift in the diet of many animals 45,000 years ago.
All living things try to alter their surroundings to be more pleasing. Most do this accidentally, like savannah grazers which eat saplings thus preventing forests from growing or bees pollinating trees and flowers turning them into colorful wonders.

Then there are termites which build huge nests and denude the grounds around them or beavers who spend many hours building complex dams turning waterflowing streams into ponds which then silt up and turn into meadows.

The biggest changers are humans. With cunning foresight, we manipulate nature. This isn't new. In fact, our impact upon living systems has been huge even when all we had were some stones and fire.
Before 50,000 years ago, the emu ate a wide range of foods. The isotopic evidence suggests they lived on the abundant nutritious grasses available during wet years, and on shrubs and trees in drier years.

After 45,000 years ago, however, there was a major disruption in the range of food sources, and the plants available were largely inedible and low in nutrition. The carbon isotopes in wombat teeth reflect a similar change in diet.
One of the problems with humans is desertfication. We tend to tip systems over into that mode.
The timing of the abrupt change in diet, and the extinction of up to 50 giant marsupial species, coincides with the arrival of humans.

Many of the extinct marsupial megafauna were large, herbivorous browsers, some weighing several tons. The emu, with its wide range of food sources, was able to adapt and survived the changes to the ecosystem. Animals like the Genyornis, which had a more specialized diet, did not.
Perhaps the large grey kangaroo survived the fires that suddenly swept their environment due their high speed and jumping abilities. Like jack rabbits that tear through the desert, they can outrun nearly anything including humans.

The natives of America used slash/burn techniques. They also altered the flora and fauna of the Americas. From Eco Composite:
Fire management was an essential and important tool of the native people (Lewis 1973; Biswell 1989; Anderson 1993). Selected areas were burned regularly at different seasons and frequencies to improve hunting, facilitate harvesting, and to produce desired materials (i.e. numerous straight willow shoots for weaving). Burning might be done in the Spring, Fall, Spring and Fall, or on an annual, 5, 10, or 20 year rotation. These "fire stick" management practices were pervasive and lasted until long after the missions were established. The settlers in California, who failed to understand the use of fire, were tormented by them, and edicts from the Governor were periodically issued to stop them -- beginning in 1793! The elimination of periodic burning (often on a 2 to 4 year return frequency) contributed to dramatic changes in plant communities. In Ponderosa forests in the Southwest for example, stem counts increased from 23 to more than 800 trees per acre in some areas (Covington and Moore, 1992). Coastal California was once much more grassland and oak savannas and has now been invaded by brush.
This burning of the weeds and lower stories of plants to replentish the soil and clear the ground for grasses and other things we savannah refugees adore so much was actually a wise way to do things in California's wet/dry cycle climate. The flora and fauna we call "Californian" today are actually artificial, brought about by human intervention.
Discussion with the Tohono O'odham (Papago) revealed that the knowledge of individual trees was striking, but this is not surprising after a little reflection. Trees near the settlements were known by sweetness, flavor, and time of ripening. Imagine these trees and plants as the restaurants in your neighborhood--and how quickly a knowledge of their dishes is learned by direct observation and by word-of-mouth and it makes sense.
I lived with the Tohono O'odham who own Kitt Peak, which is leased from them. Not only did they know all the trees and cacti, the important ones had names and not only names but a spirit that was appeased or they protected or cooperated with the tree/saguaro. If the wind was blowing in the afternoon, one could hear the noble saguaro whispering. The paloverde trees sigh and the mesquite rattles its seeds like a medicine healer.
Many of the biological "problems" posed by the Torrey Pine can also be explained as the result of human intervention. Native people traveled extensively and moved plant material over large areas. Studies of relatively intact cultures in the Amazon have found they were shaping the forests to provide better living conditions and improve resource availability (Posey, 1985; Balee, 1987). These "primitive" forest dwellers were found to be selecting, transporting, planting and managing plant materials from an area as large as western Europe. It is likely that California was no different, and that plant resources were selected and gathered from an equally large area. One of the closest relatives of the Torrey Pine is found in southern Mexico (Pinus psuedostrobus) (Anon, 1993; Perry, 1991), and is easy to imagine an early plant explorer returned with a few of these flavorful (one of the best pine nuts) and nutritious seeds to San Diego and the Channel Islands.
Indeed, I would suggest much of this planet has been hopelessly altered by human intervention, not all of it is bad. Indeed, despite the extinction of many species, others benefitted greatly. Horses, for example, nearly went extinct until humans adopted them. The same goes for dogs and cats.

Time to revisit the story of Prometheus: From messagenet.com
Zeus had many plans for the reshaping of creation. After the fall of Kronos and his confinement in Tartaros, Zeus took no interest in the mortal race of men on the bountiful earth, he intended for them to live as primitives until they died off. Zeus said that knowledge and divine gifts would only bring misery to the mortals and he insisted that Prometheus not interfere with his plans.

Dispite Zeus’ warning, Prometheus took pity on the primitive mortals and again, he deceived Zeus. Prometheus gave the mortals all sorts of gifts: brickwork, woodworking, telling the seasons by the stars, numbers, the alphabet (for remembering things), yoked oxen, carriages, saddles, ships and sails. He also gave other gifts: healing drugs, seercraft, signs in the sky, the mining of precious metals, animal sacrifice and all art.

To compound his crime, Prometheus had stolen fire from Zeus and given it to the mortals in their dark caves. The gift of divine fire unleashed a flood of inventiveness, productivity and, most of all, respect for the immortal gods in the rapidly developing mortals. Within no time (by Immortal standards), culture, art, and literacy permeated the land around Mount Olympos (Olympus). When Zeus realized the deception that Prometheus had fostered, he was furious. He had Hephaistos (Hephaestus) shackle Prometheus to the side of a crag, high in the Caucasus mountains. There Prometheus would hang until the fury of Zeus subsided.

Each day, Prometheus would be tormented by Zeus’ eagle as it tore at his immortal flesh and tried to devour his liver. Each night, as the frost bit it’s way into his sleep, the torn flesh would mend so the eagle could begin anew at the first touch of Eos (the Dawn).

Zeus’ anger did not stop there. He intended to give the mortals one more gift and undo all the good Prometheus had done. He fashioned a hateful thing in the shape of a young girl and called her Pandora. Her name means, ‘giver of all’ or ‘all endowed’. Her body was made by Hephaistos, he gave her form and voice. Athene (Athena) gave her dexterity and inventiveness. Aphrodite (goddess of Love) put a spell of enchantment around her head and Hermes put pettiness in her tiny brain. She was ready for the world.
Of course, the males writing this stuff long ago had to despise Pandora. She was truly a human. Note that she was an inventor and creator. As we can see today, many inventors and creators can't resist making mischievious things that cause endless woes. They can't help it.
Zeus gave Pandora to Ephemetheus (brother of Prometheus). Ephemetheus knew better than to trust Zeus and he had been warned by Prometheus never to accept gifts from the Olympians, especially Zeus. One look at Pandora and Ephemetheus was rendered helpless. He could not resist her, he accepted her willingly. When the gift was ‘opened’, evil and despair entered into this world. Mistrust and disease spread over the wide earth. After Pandora was emptied of her curse, only Hope was left inside. Unreasonable, groundless Hope that makes the curse of life into a blessing.
And that is what we have and need most: hope.

I hope people relearn simple lessons and learn the names of all the trees and good things around us all and cherish them and listen to them.

Hope for the best.

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