Friday, March 16, 2007

WOLVES = TROUT

Trouts Best Friend In Yellowstone

..Straight from Southwest Florida comes insight into the "bizarre ecological labyrinth" in Yellowstone National Park. We found this one of the most able statements of our surroundings in recent memory. We quote at length from the article in Gulfshore Life.

From the 1890s through the 1920s, in an effort to increase the elk herds and "protect the wildlife," the park service went about the business of eradicating the wolf from Yellowstone. The last wolf pack was killed off in 1926.

For half a century things were fine. The elk herds, lacking the wolf packs that historically preyed upon them, rapidly expanded. When winter arrived, knowing they had nothing to fear, the herds elected to browse the readily obtainable young cottonwoods and willows that lined the trout streams and rivers of the park. Ecologists began to note that there were always plenty of sapling cottonwoods and any number of mature, 70-year-old trees, but nothing in between.

Then the trout started disappearing. Lacking the intermediate-sized trees and heavy underbrush that had been consumed due to the elk’s overgrazing, the exposed banks of the rivers were now washing away in the spring freshets and the summer thunderstorms. Those streams, once crystal clear, were now silted over and murky. The trout, being sight feeders, either starved or swam off in search of cleaner water. The fly-fishermen of the Lamar, Yellowstone and Firehole rivers were also disappearing, much to the frustration of the local outfitters and hotels.

In an effort to reduce the overgrazing, the National Park Service, amidst a storm of local controversy, decided to capture 14 wolves from the wilds of British Columbia and reintroduce them into Yellowstone in 1995. Eventually three separate wolf packs were established within the park. With the wolves keenly aware of the elks’ tendency to browse along the riverbanks during the deep snow-packed months of winter, the wolves were inadvertently standing guard over the young cottonwoods and willows. Once the wolf packs began to thin the elk in these river valleys, the juvenile cottonwoods soon returned, the trout streams cleared, and there you have it: wolves = trout.

..The elk along the Firehole River have also adopted a couple of other interesting feeding behaviors since the fires of '88. They submerge their heads to feed on potamogeton, (which concentrates arsenic,) and they eat charcoal, (which buffers the digestive system and allows the delay and/or denial of winter kill from bark stripping, and pine needle eating .)

.. Elk will eat a willow right down to the ground and kill it. Moose, on the other hand are gardeners. They eat the tender tips of branches and cause the willows to branch and proliferate. Interestingly there are few moose or willows along the Firehole. There were more in the 60's and 70's. We intend to have a post in the future about the vanished willows of the Firehole River.

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The fish are working The Madison River between the lakes. We've started the annotations on the map. Report when we get back.