Valley Floor

The Valley Floor’s ecological health is improving, according to town officials and the scientific community. But still, it will take some time to reverse 100 years of human-caused impacts. (File photo)

A century of mining and agriculture has left its mark on the Valley Floor, but since the land was acquired by the town and placed in a conservation easement, the approximately 540-acre tract is bouncing back.

Members of Telluride’s Open Space Commission recently received an update from the Mountain Studies Institute’s (MSI) Rory Cowrie, PhD, the organization’s research director and hydrologist. MSI maintains a weather station and a series of groundwater wells and other test areas scattered throughout the Valley Floor that provide data and information that town officials, including the Open Space Commission, use to guide management decisions.

In a nutshell, the Valley Floor’s ecosystem is responding well to its care under the conservation easement.

“It’s behaving the way it wants to behave naturally,” Cowrie said. “The community has removed its human-influenced disturbances.”

By that, Cowrie means no more mining and grazing, and the prohibition of dogs.

Open Space vice chair, Nancy Craft, echoed Cowrie’s assessment following the MSI presentation to the commission.

“We’re seeing so much more diversity (on the Valley Floor),” she said. “This is what it’s all about — restoring the land.”

Both Cowrie and Craft agree that when it comes to land stewardship, it is important to take a long view and carefully monitor the data over the years.

“We’re letting the land be our guide,” Craft said. “MSI is doing a great job.”

Rechanneling the San Miguel River to a more natural course has proven beneficial, as it has allowed the river to meander, instead of coursing down a straight channel.

MSI collects data on groundwater and at its weather station, monitors air and ground temperature and snow cover.

“It’s important to monitor the micro-climate,” Cowrie said, noting that most local weather data comes form the airport, which is a much different micro-climate than that on the Valley Floor.

Another encouraging observation is the healthy presence of beavers doing what beavers do — dam and lodge-building. Several colonies are thriving and adding robustness to the riparian environment.

“The natural ecosystem is always evolving,” Cowrie said. “Native wildlife has been able to use the natural landscape. The river rechanneling allows for the expansion of wetlands and the riparian habitat.”

Measuring groundwater, Cowrie said, is a way to “measure quantitative changes” on the Valley Floor. He noted that the new river channel should help elevate groundwater levels, which, in turn, will help species like willows thrive. “It will impact vegetation,” he said.

Another aspect of management practices as undertaken by town officials is the control of invasive weeds. Craft said the culprits the town seeks to control are Canada and musk thistle, toadflax (butter and eggs) and oxeye daisies. Commission members received a report detailing new methods of weed control using insects instead of spraying. There is nothing in the Valley Floor management plan that forbids spraying, but Craft said the commission is keen to try other, less impactful methods of control.

In the introduction of its report to the commission, participating scientists explained how insects from the Palisade Insectary were brought in to do battle with the toadflax.

“The Palisade Insectary has implemented biological control and post-release monitoring for yellow toadflax and Canada thistleon the Telluride Valley Floor,” the report reads. “The Insectary has also released the weevil Trichosirocalus horridus for use against musk thistle on the Valley Floor.

“We lacked effective agents for use against Canada thistle and yellow toadflax until eight years ago (yellow toadflax) and five years ago (Canada thistle). With the recent availability of new agents the Palisade Insectary has sought partners willing to forego chemical controls in areas dedicated to biological control, and also willing to allow monitoring of post-release control of these two highly invasive weeds. The Telluride Valley Floor is an ideal location for tracking post-release efficacy of these two biological controls.”

The weevils appear to be effective, though researchers noted last summer’s drought may have impacted the test site, as well.

“The number of toadflax stems and the estimated percentage of toadflax cover were both down considerably from 2017, when we first set up the monitoring plot.,” the report reads. “This may have been partially or even completely due to the weevil presence, but it is difficult to know if this was due in some part to drought conditions. Future monitoring will tell us more. Monitoring is planned to continue until 2020.”

The introduction of rust spores on the Canada thistle test sites also seemed to indicate some success, though continued monitoring will take place. And, Katrina Blair founder of Bee Happy Lands, has been contracted since 2016 to employ non-chemical methods of weed control on the oxeye daisy invasion. Test areas have been treated by a combination of harvesting seed heads, mechanically taking plants up by the roots, reseeding with a town-approved seed mix and applying  a “bio-weed remedy (homeo-dynamic process) composed of ash from roots and water at specific dilution, and succussed to achieve potency,” according to the report.

“It’s like homeopathy,” Craft explained.

Not included in this month’s presentation to the commission, but of interest to local naturalists, is the answer to what happened to the Gunnison’s prairie dogs. The colony apparently collapsed and the absence of its large population was noted by both scientists and casual observers this spring. Town officials asked experts from Colorado Parks and Wildlife to investigate, but findings were inconclusive.

Amy Seglund is CPW’s area species conservation coordinator.

“We were able to collect fleas from the Telluride colony and the fleas we tested were negative for plague,” she wrote in an email to the Daily Planet. “Within the colony the majority of burrows were collapsed, making me think the prairie dogs died off in the fall or over the winter.

“So if the reason for the die-off was plague that occurred prior to the spring, it would be difficult to detect the disease and therefore the plague cannot be totally ruled out. If the die-off was due solely to a hard winter, I would have expected a few survivors. Thus, we are not certain why the colony collapsed.”

Of the commission’s work in reviewing data collected by MSI and other experts in the field, Craft said she and other commission members took pride in their work.

“We operate on the question of ‘What’s best for the land,’” she said. “That strips away a lot of things. It’s a huge responsibility — we take it seriously.”

A few prairie dogs have been anecdotally observed on the Valley Floor. Perhaps, as a part of the Valley Floor’s intricate eco-system, they, too, will rebound.