Report: Mount Tamalpais ecosystem in “fair” health

Some of Mount Tamalpais’ plant and wildlife communities are thriving, while others are suffering, a new report says.

The report, titled “Peak Health,” was produced by the One Tam Partnership, a program that consists of the National Park Service, California State Parks, the Marin Municipal Water District, Marin County Parks and the Golden Gate National Parks Conservancy. The report is an update from a similar 2016 analysis.

The new report says that while most plant communities are doing well, many are waning from the effects of climate change, invasive species, plant disease and lack of natural and prescribed fires.

As for wildlife, the red-legged frog, the foothill yellow-legged frog and the northwestern pond turtle have all benefited from restoration and restocking efforts, but coho salmon and steelhead trout populations are dangerously small and of great concern, the report says.

The report suggests the overall health of the Sleeping Lady is fair, unchanged from the 2016 screening.

“The whole vision behind One Tam is better understanding where to prioritize our efforts,” said Bill Merkle, a National Park Service ecologist who is one of the lead authors of the report. “I think from 2016, we’ve really identified a lot of data gaps, which we stepped into with this update.”

For example, some species such as the threatened northern spotted owl have been monitored for years, whereas mammal monitoring is just now underway, he said. The report shows that the spotted owl population is in good, stable condition.

Other groups, like invertebrates, have never been systematically inventoried or monitored on the mountain, he said.

The new report includes updated vegetation maps and new monitoring data on bees, bats and the California giant salamander, which have been identified as essential to understanding the overall health of the diverse plant and wildlife communities on the mountain, Merkle said.

Overall, the report looks at eight vegetation communities and 14 wildlife species and communities, labeling them as “indicators” of the mountain’s health. The condition of each indicator is rated as good, fair, poor or unknown. The report also notes whether the indicator trend is improving, unchanged, declining or unknown.

Merkle said the seven years between reports wasn’t enough time to see a difference.

The report shows that a class of rare plants called serpentine barren endemics are in fair condition but declining. Oak woodlands, while in cautionary status, are holding steady. There has been no detectable change in redwood forest health, the report says.

Bee studies began in 2017. So while the condition and trend of the population is unknown, early findings show that there are healthy populations of special host plants and suitable nesting habitat.

Bat monitoring was initiated in the same year. Based on early reporting, there appears to be a diverse population of bat species.

Salamanders, although not federally listed, are considered to be of concern by several organizations, the report says. The animals can can be indicators of the health of forests, headwater streams and adjacent riparian areas, the report says. More investigation is needed to assess the creatures.

“It’s important to note that as partners, the way we interact with Peak Health is as a key reference that brings together the most current data and establishes benchmarks,” Bree Hardcastle, an environmental scientist for California State Parks, said during a presentation of the report last month.

Hardcastle said the report is not an official management document that supersedes policies set by the individual partner agencies.

“The power of One Tam is that it really allows us to coordinate and share resources more effectively,” she said, while each respective agency sets the priorities and actions for the area of land they manage.

Adriane Mertens, spokesperson for the Marin Municipal Water District, said the Peak Health report “demonstrates the true value of the One Tam collaborative and the commitment of the involved partner agencies, including Marin Water, to monitor, restore and protect the mountain’s biodiversity,”

Nona Dennis, president of the Marin Conservation League, said members of her organization are still digesting the 600-plus page report, but they support the effort.

“For those of us, such as in Marin Conservation League, who have been engaged as public advocates in One Tam since even before it’s official founding in 2014, the Peak Health update is a remarkable fulfillment of the collaborative promise of four public agencies together with a nonprofit partner in the lead,” she said. “The report brings together thousands of hours of team work by scientists both inside and outside the member agencies in a very readable report that measures the condition of many plant and wildlife ‘indicators’ of ecological health.”

More information on the report is online at bit.ly/3XS0XPv.