ecology news and archives — 8

critical predator species
Return of wolves:

“According to numerous biologists and wolf-watchers, the willows have grown because the elk, worried about staying too long in open streambeds, no longer gorge on the nutritious plants. Since the reintroduction of wolves in 1995, the elk have been increasingly itinerant and drawn up out of the wetlands to high rocky areas where they eat more grass. As hunters, soldiers, and elk all know, streambeds and valleys are dangerous. Attackers can scout from up high and pounce.”
—
“ Willows help the park's northern Lamar Valley, which was beggared of the plant before the wolves returned, in several ways. For one, they provide a decent nesting and migratory stopover site for many birds. According to Roger Pasquier, an ornithologist with Environmental Defense, several bird species that nest in the park could particularly benefit, including the yellow warbler, warbling vireo, and the tellingly named willow flycatcher.

“Perhaps more important, beavers thrive on willows and those waddling creatures have recently returned to the Lamar Valley after a long absence.”

related material
web of life collapse on 1% extraction of killer whales?

the web address for this article is
https://www.abelard.org/news/ecology8.htm#ecology121003

12.10.2003

related material
web of life collapse on 1% extraction of killer whales?

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an adventurous ship receives a useful home—capitalising on junk

“In three years it will be teeming with fish and coral," said Cesar Navas, a deeply tanned scuba diving instructor who convinced Venezuelan authorities that the ship would be better off lying 98-feet under water.

“Instead of dying as a rat-infested piece of junk, we are turning it into a beautiful artificial reef which will shelter sea life and also will be a divers' playground," he said as he prepared to sink the boat in the waters off Aragua state, about 110 miles west of Caracas.”

the web address for this article is
https://www.abelard.org/news/ecology8.htm#ecology111003

rehabilitating the dead sea

“Known as the Dead Sea because nothing can live in it, the world's saltiest body of water has fallen from 1,280 feet to 1,368 feet below sea level in the last 50 years.

“The drop has accelerated to three feet a year recently, erasing a third of its ancient 366-square-mile size.”

the web address for this article is
https://www.abelard.org/news/ecology8.htm#ecology071003

variation in sun intensity has predictable effects on climate during recent times

“Emerging geochemical and biological evidence from Alaskan lake sediment suggests that slight variations in the sun's intensity have affected sub-polar climate and ecosystems in a predictable fashion during the last 12,000 years.

“Researchers at six institutions report the findings in the Sept. 26 issue of the journal Science. The data, they say, help to explain past changes on land and in freshwater ecosystems in northern latitudes and may provide information to help project the future.

“The scientists identified cycles lasting 200, 435, 590 and 950 years during the Holocene Epoch, said principal investigator Feng Sheng Hu of the University of Illinois at Urbana-Champaign. The pattern of environmental variations they found also matches nicely with cyclic changes in solar irradiance and the extent of sea ice in the North Atlantic.”

Holocene (Also called Recent.)

of or relating to the most recent epoch of the Quaternary period with
evidence of human development and intervention, and the extinction of
large mammals.

the web address for this article is
https://www.abelard.org/news/ecology8.htm#ecology021003

web of life collapse on 1% extraction of killer whales?

“Coming at the issue from both the beginning with the rapid spread of commercial whaling after WWII, and the end, with drastic declines of kelp forests today, Springer, Estes and their six co-authors present a domino theory of major ecosystem impacts and restructuring.

“It started with the capture of hundreds of thousands of great whales from the North Pacific Ocean from 1946 to 1979. The paper's eight authors argue that this removal of prey forced some killer whales to seek alternative sources of food. Beginning with harbor seals (populations collapsed early 70's - early 80's) then fur seals (mid 70's - mid 80's), sea lions (late 70's - 90 's) and finally sea otters (90's - today), the killer whales targeted populations of small, coastal marine mammals.

“The authors surmise that killer whales may have preferred harbor seals and fur seals to sea lions because of the higher nutritional value of harbor seals and because seals are less aggressive and easier to catch.

“As the pinnipeds became comparatively rare, some killer whales expanded their diet to include the calorically least profitable mammals - the sea otters - with rippling ecosystem effects. By the late 1990's low numbers of sea otters allowed an explosion of sea urchins and decimation of the kelp forests due to the sea urchins' over grazing.

“ "The point of this story is not to vilify whaling and exonerate overfishing," says Estes. "In principle we think that when any species is exploited to excess - be it pollock, halibut or whales - it may trigger a broad and devastating 'domino effect,' and the ecosystem impacts are significant." ”

the web address for this article is
https://www.abelard.org/news/ecology8.htm#ecology270903

global warming accused [26.09.2003]

This article has been transfered to Arctic melting ice,sea levels

the web address for this article is
https://www.abelard.org/news/ecology8.htm#ecology260903

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© abelard, 2003, 26 september


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