Native plant’s growth baffles scientists | TahoeDailyTribune.com

Native plant’s growth baffles scientists

Gregory Crofton, Tahoe Daily Tribune

Figuring out what makes the Tahoe yellow cress flourish may be as much of a challenge as determining what exactly is causing Lake Tahoe’s clear waters to cloud.

The lake and the Tahoe yellow cress likely developed in tandem over millions of years. The delicate, flowering plant exists nowhere else in the world. Its growth fluctuates with the varying level of the lake, thriving when the level of Lake Tahoe drops — but no one knows why.

Botanists and U.S. Forest Service employees on Monday crouched under blue skies inside a fenced area at Baldwin Beach to begin a long-term study to unlock the plant’s mysterious growing habitats. Yellow cress can survive underwater or in the middle of a dry, coarse-grained beach.

The plant is listed as endangered in California and Nevada, and it is considered by the federal government to be a candidate for the endangered list. If botanists discover better ways to protect yellow cress, it would likely eliminate the possibility of laws being adopted that could limit recreation or any activity in its habit.

“We are here to keep the population viable,” said Gail Durham, a U.S. Forest Service botanist. “We are committed to try and conserve this species.”

Botanists from BMP Ecosciences, of San Francisco and South Lake Tahoe, are leading the study, which will likely last 10 years. On Monday, the study began with 600 nursery grown yellow cress going in near the mouth of Taylor Creek.

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Each plant was nestled next to a color-code flag. It indicates to the scientists the genetic leaning of the plant so its success or failure can be tracked. This week, 1,500 yellow cress will be planted on South and East shores of Lake Tahoe. Next year, that number could double.

“Everything you see here is our best first attempt,” said Bruce Pavlik, of BMP Ecosciences. “It’s a full blown experiment.”

In the 1980s, a group of scientists transplanted yellow cress from nursery to sand. Some of it took, but the experiment lacked any scientific framework.

“It was more an effort to garden than a study,” Pavlik said. “I think at that time the whole science of doing this type of restoration really wasn’t developed.”

Durham said fences will stay up all summer to protect test plots at Sand Harbor, near Zephyr Cove and Emerald Bay.

According to Durham, the largest number of yellow cress test plants are being planted near Taylor Creek because the area provides the broadest variety of growing conditions. Yellow cress is more prone to grow at South Shore near the mouth of the Upper Truckee River.

“Fourteen thousand of 20,000 (plants) are there,” Durham said. “It’s the main mother site.”

Botanists will check back on their plants in two weeks. After that, they’ll go back every month to check them. The yellow cress experiment, which will cost $35,000 this year, is funded by the Forest Service and the California and Nevada state parks.

A conservation strategy for the plant, more than a year in the making, was released last year. It calls for public and private groups to work together to protect the rare plant.

— Gregory Crofton can be reached at (530) 542-8045 or by e-mail at gcrofton@tahoedailytribune.com

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