Western pond turtles gather on a log at Phoenix Lake in the Mount Tamalpais watershed on Tuesday, May 2, 2023. (Sherry LaVars/Marin Independent Journal)
Some plant and animal communities on Mount Tamalpais are thriving, while others are suffering, according to a new report.
The report, titled “Peak Health,” was produced by the One Tam Partnership, a program that includes 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 of a similar analysis from 2016.
The new report says that while most plant communities are doing well, many are declining due to the effects of climate change, invasive species, plant diseases and a lack of natural, controlled fires.
In terms of wildlife, the red-legged frog, foothills yellow-legged frog and northwest pond turtle have all benefited from restoration and restocking efforts, but coho salmon and steelhead populations are dangerously small and of great concern, the report says.
The report suggests that the Sleeping Lady’s overall health is fair, unchanged from the 2016 screening.
“The goal of One Tam is to better understand where we need to prioritize our efforts,” said Bill Merkle, a National Park Service ecologist and one of the report’s lead authors. “I think starting in 2016, we really identified a lot of data gaps, which we’ve filled in with this update.”
For example, some species, such as the threatened northern spotted owl, have been monitored for years, while monitoring of mammals has only just begun, he said. The report shows that the spotted owl population is healthy and stable.
Other groups, such as 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 critical to understanding the overall health of the mountain’s diverse plant and wildlife communities, Merkle said.
Overall, the report examines eight plant communities and 14 wildlife species and communities, calling them “indicators” of mountain health. The status of each indicator is rated as good, fair, poor or unknown. The report also indicates whether the indicator’s trend is improving, unchanged, decreasing or unknown.
Merkle said the seven years between reports was not enough time to see a difference.
The report shows that a class of rare plants called sterile serpentine endemics are in relatively good condition but declining. Oak forests, although in a cautious state, are holding up. No detectable changes have been seen in the health of redwood forests, the report says.
Bee studies began in 2017. Although the status and trend of the population are unknown, initial results show that there are healthy populations of special host plants and suitable nesting habitat.
Bat monitoring was launched the same year. From initial reports, there appears to be a diverse population of bat species.
Salamanders, while not federally listed, are considered of special concern by several organizations, the report said. These animals can be indicators of the health of forests, headwater streams and adjacent riparian areas, the report said. More research is needed to assess these 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 recent data and sets benchmarks,” said Bree Hardcastle, environmental scientist for California State Parks, during a presentation of the report last month.
Hardcastle said the report is not an official management document that supersedes policies set by individual partner agencies.
“The power of One Tam is that it really allows us to coordinate and share resources more effectively,” she said, as each respective agency sets priorities and actions for the area of land they manage.
Adriane Mertens, a spokeswoman for the Marin Municipal Water District, said the Peak Health report “demonstrates the true value of the One Tam collaboration and the commitment of the partner agencies involved, including Marin Water, to monitor, restore and protect the mountain’s biodiversity.”
Nona Dennis, president of the Marin Conservation League, said her organization’s members are still digesting the more than 600-page report but are supportive of the effort.
“For those of us, like the Marin Conservation League, who have been committed to being public advocates for One Tam since before its official founding in 2014, the Peak Health update is a remarkable realization of the collaborative promise of four public agencies with a nonprofit partner in mind,” she said. “The report brings together thousands of hours of teamwork by scientists inside and outside the member agencies into a highly readable report that measures the status of many ‘indicators’ of ecological health for wildlife.”
More information about the report is available online at bit.ly/3XS0XPv.
