Measuring the health of Mt. Tam

Maintaining a healthy, vibrant and diverse Mt. Tam begins with understanding how key ecological resources are faring, and how we can better care for this iconic and beloved place.

One Tam partners and Bay Area scientists have come together to try to answer the question: How healthy are Mt. Tam's natural resources?

Current and Past Natural Resource Management

Stewardship and management activities of varying scales have been underway for decades within the One Tam area of focus. The summary of current and past activities listed below is by no means a comprehensive list, but is intended to provide a sense of the type and scale of work that has been undertaken to monitor, protect, and restore important health indicators.

Where helpful for clarity, the responsible parties have been indicated below as follows: MMWD = Marin Municipal Water District; NPS = National Park Service; State Parks = California State Parks; MCP = Marin County Parks; USGS = US Geological Survey; Point Blue = Point Blue Conservation Science; SPAWN = Salmon Protection and Watershed Network. Other acronyms include: SOD = Sudden Oak Death; UC = University of California.

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Plants

Wildlife

Plants

Overarching Vegetation Management and Monitoring Efforts

Several large-scale programs manage or track plant communities and species on Mt. Tam.

Weed Monitoring, Surveying, and Management

One Tam staff and partner agencies survey roads, trails, facilities, and recently disturbed sites for priority invasive plant species. Although surveys are conducted year round, most occur between March and September. Survey areas are prioritized based on their rates of human use and on habitat health, with a goal of surveying all roads and trails every three to five years.

NPS surveys began in 2008, with other land managers launching their programs in subsequent years. One Tam initiated surveys in 2016 to add capacity to partner agency efforts.

Large-Scale Weed Management Program

One Tam partner agencies commit significant resources to mapping, monitoring, and managing invasive vegetation on their lands. Full-time and seasonal staff, as well as interns, are dedicated to providing volunteer management and leading these stewardship activities

Land managers also rely on contract labor to map and control targeted invasive plant populations. Wide Area Fuelbreak projects on both MMWD and MCP lands are implemented by contractors for both fuels management and resource enhancement. In 2012, NPS and State Parks staff launched comprehensive watershed-wide target invasive plant management in the Redwood Creek Watershed with the help of staff, contractors, and volunteers.

Rare Plant Monitoring

Mt. Tam supports more than 40 rare, threatened, and endangered plant species. Location and population data is available for many of these species through field surveys conducted by One Tam land managers and partners including the California Native Plant Society (Marin Chapter).

The scale of each monitoring program varies based on staff and volunteer resources. For example, NPS staff conducts annual rare plant monitoring, with individual populations visited once every three to five years; however, MMWD staff are in the process of re-inventorying their rare plant populations and have updated data on approximately 80% of the over 400 individual patches on watershed lands within the past five years.

Plant Community Monitoring

NPS staff monitors the structure and composition of redwood forest and coastal scrub plant communities at Bolinas Ridge, Muir Woods, and Green Gulch. This long-term monitoring program began in 2015, and randomly located, permanent vegetation plots will be revisited once every four years. Periodic trend analyses will help reveal community dynamics (succession, temporal variability, etc.), and examine correlations between climate change, land use, and biological interactions.

Coast Redwood Forests

Old Growth:

  • Muir Woods and Steep Ravine:

(1) Ongoing, systematic invasive plant mapping and management on varying scales at Muir Woods for over three decades, and invasive species management and increasing Early Detection and Rapid Response work in Steep Ravine—target species include yellow star thistle, and Scotch and French brooms, cape ivy, pampas grass, licorice plant, and panic veldt grass; (2) Expansion of this program in 2012 through NPS-supported crews working Redwood Creek Watershed-wide, and One Tam crews focusing on detection and treatment work at Steep Ravine

  • Muir Woods:

(1) Installed more than 14,000 native plants to revitalize disturbed and compacted redwood understory habitat; (2) Converted asphalt trails to raised boardwalks to reduce compaction and guide visitor access; (3) Established boot-washing stations to reduce the risk of Phytophthora spread; (4) Conducted an inventory to assess canopy health and species richness; (5) Reduced the entrance parking lot size and converted part of it to a plaza; (6) Raised the Hillside Trail in Muir Woods above the fragile redwood root system; (7) Collected LiDAR data to create topographic, stream channel, and tree canopy maps of Muir Woods and Kent Canyon which will help track changes to the forest over time

Second-growth:

  • Invasive Plant Management: Regular invasive plant detection and response surveys along roads and trails that border and traverse redwood habitat (MMWD)
  • The Resilient Forest Project: A series of forest treatment trials to identify ways to improve forest function and strengthen areas with high levels of SOD-related hardwood mortality, including approximately 20 acres of redwood-tanoak forest initiated in 2015 and scheduled to continue for at least five years (MMWD and UC Davis)

Sargent Cypress

  • Mapping and Inventories: Periodic vegetation community mapping and ongoing Early Detection and Rapid Response (MMWD)

Open-canopy Oak Woodlands

  • Restoration: (1) Succession management: Volunteer restoration workdays held to pull broom and cut encroaching Douglas-fir saplings in some areas, with additional conifer removal done by staff and contractors; (2) Wide Area Fuelbreak project at Pine Point: A joint project by MMWD and Youth2Work that removed Douglas-fir and non-native pine invading oak woodlands and grasslands and replaced Douglas-fir with native SOD-resistant oaks to meet both ecosystem and fuels reduction goals
  • Monitoring: (1) Aerial photo monitoring and interpretation of vegetation communities repeated every five years to examine SOD distribution and impact (MMWD); (2) Invasive plant species early detection mapping and monitoring (MMWD, NPS, and MCP)
  • Outreach: Partnership with UC Cooperative Extension on public outreach to build awareness about SOD spread, impacts, and risk reduction measures

Shrubland Habitat

  • Management: (1) Coyote brush reduction efforts where coastal scrub is expanding into grasslands (State Parks); (2) Ongoing brush reduction in designated fuel load reduction zones, often in conjunction with grassland and open canopy oak woodland preservation goals (MMWD and MCP)
  • Monitoring: (1) Aerial photo monitoring and interpretation of vegetation communities is repeated every five years (MMWD); (2) Weed distribution maps are also updated once every five years

Maritime Chaparral

  • Management: Forest understory manipulation to reduce SOD thickets, which may reduce spore load and infection of Marin manzanitas (MMWD)
  • Monitoring: Rare plant surveys within Golden Gate National Recreation Area lands on Bolinas Ridge every one to three years (as resources allow) focused on confirming and mapping presence of previously recorded individual rare plants and searching for new occurrences in suitable habitat (NPS)
  • Conservation: Mason’s ceanothus and Marin manzanita seedbanked as part of the California Native Plant Society’s “Rare Plant Rescue” program in 2015 (MMWD)

Grasslands

  • Restoration: (1) Volunteer workdays to pull weeds and cut Douglas-fir in some areas; (2) Succession management: additional conifer and weed removal, plus some coyote bush cutting and mowing by staff and contractors (MMWD and State Parks); (3) Grassland protection (removal of erosion gullies, re-alignment of trail, planting of grassland species) as a part of the Dias Ridge trail corridor re-alignment process; (4) Wide Area Fuelbreak project at Pine Point (MMWD) to maintain open grassland and oak woodlands included succession management (removal of Douglas-fir and coyote brush)
  • Mapping/Monitoring: Completed an analysis of species richness, spatial extent and stressors for approximately 185 grassland patches within Mount Tamalpais State Park to prioritize restoration actions (State Parks and UC Berkeley)

Serpentine Barrens

  • Management: Barbed goatgrass removal at Azalea Hill/Pine Mountain (MMWD)

Wildlife

Anadromous Fish

  • Restoration: (1) Extensive habitat restoration in Lagunitas Creek including installing large wood structures and reducing fine sediment inputs (MMWD); (2) Redwood Creek habitat restoration including removal of fish passage barriers, installation of habitat structures, native plant restoration, and restoration of natural processes and hydrology at the creek’s mouth (NPS); (3) Realignment and reconnection of Green Gulch Creek it to Redwood Creek for the first time in many decades, providing valuable off-channel habitat for coho salmon (NPS and SF Zen Center); (4) Removal of culvert barriers for adult and juvenile steelhead in Jewel Creek (NPS land, implemented by MMWD); (5) Banducci restoration including large woody debris installation and creek realignment (2003), removal of levees and fill from floodplain (2007), and groundwater recharge improvements (2015) (NPS); Identification of high priority sites for barrier removal on Redwood Creek through the 2003 Marin County Fish Passage Assessment, leading to the installation of a new culvert connecting Kent Canyon and the mainstem of Redwood Creek and replacement of an undersized culvert under Muir Woods Road (NPS)
  • Management: (1) Multi-agency Coho Jumpstart program to rear and release coho salmon back into Redwood Creek starting in 2015; (2) Water releases into Lagunitas Creek to maintain streamflow for salmonids (MMWD); (3) Reduction of sedimentation as a result of the Dias Ridge restoration project (NPS), multiple projects along the Bootjack Trail (NPS and State Parks), Alice Eastwood Road culvert removal (State Parks), fire road and trail sediment reduction projects in San Geronimo/Lagunitas Watershed (MCP), and several significant projects stemming from the implementation of the MMWD 2005 Mt. Tamalpais Watershed Road and Trail Management Plan
  • Monitoring: Long-term life-cycle (juvenile, smolt, adult spawner/redds) monitoring of salmonids in Lagunitas and Redwood creeks (MMWD and NPS) and annual adult and smolt monitoring in the San Geronimo Valley (SPAWN)
  • Outreach: (1) AmeriCorps-led volunteer salmon enhancement projects and watershed education programs in schools (MMWD); (2) Spawner Day Program at Samuel P. Taylor State Park; (3) Annual “Welcome Back Salmon” event at Muir Beach, held in partnership with the Federated Indians of Graton Rancheria (NPS); (4) Thousands of volunteer hours spent on habitat restoration, stewardship, and salmonid monitoring

California Red-legged Frogs

  • Restoration: Creation of breeding pond and backwater habitats at Muir Beach beginning in 2009 and at Banducci in 2007; (2) Relocation of egg masses and/or adult frogs to help bolster the population at the Banducci farm and Muir Beach restoration sites (NPS)
  • Monitoring: Annual breeding frog surveys (NPS)
  • Research: (1) Habitat use and movement study at Olema, Bolinas, and Redwood Creek watersheds; (2) Genetic studies to determine diversity of the Redwood Creek Watershed population (NPS and USGS)

Foothill Yellow-legged Frogs

  • Management: (1) A trail reroute and informational signs at Carson Falls in 2007 to reduce recreational impacts to breeding pools while increasing visitor safety and opportunities to observe frogs from a designated viewing area; (2) Annual removal of signal cray fish and bullfrogs in Little and Big Carson Creeks during breeding session surveys; (3) Thinning the tree canopy at the Big Carson Creek road crossing in 2013 to promote breeding outside road crossings and minimize trampling potential (MMWD)
  • Outreach: A seasonal public education program at Carson Falls begun in 2005 to increase visitor awareness of the frogs and the need to stay out of breeding pools between February and June

Western Pond Turtle

  • Restoration: Stream and wetland restoration and enhancement activities in the Muir Beach vicinity from 2006 to present
  • Management: (1) Red-eared slider removal in 2004, 2005, 2014, 2015, and 2016; (2) Nest site protection measures and exclusion fencing in the Phoenix Lake area in 2009 and 2010; (3) Basking habitat enhancements (log installations) in Phoenix Lake and Lake Lagunitas (multiple years between 2004 and present) (MMWD)
  • Monitoring and Surveys: (1) Habitat and population survey in 2003 (MMWD); (2) Irregular mark and release efforts between 2004 and 2016 (MMWD); (3) Periodic turtle trapping to remove non-native turtles and to provide some data on Western Pond Turtle population sizes, age estimates, and sex ratios in each reservoir (MMWD); (4) Volunteer “Turtle Observer” program to collect age, date, time interval, weather and a series of qualitative observations about each turtle’s appearance and behavior (MMWD); (5) Turtle inventories in 1996 and 2014-present (NPS)

Birds

  • Restoration: Invasive plant removal and revegetation in the Redwood Creek Watershed for over 15 years
  • Monitoring: Ongoing monitoring to periodically assess population trends (NPS [Redwood Creek Watershed], MMWD/Point Blue)

Northern Spotted Owls

  • Management: Breeding season habitat protections for Northern Spotted Owls
  • Monitoring: (1) Data collection on occupancy rates of territories, fecundity, and nest site characteristics; (2) Recording information on Barred Owls during Northern Spotted Owl surveys.
  • Inventories: Northern Spotted Owl surveys in the late 1980s and early 1990s (NPS), with more complete inventories in 1997, 1998, and 2006 (NPS and State Parks)

Osprey

  • Monitoring: Two nesting status surveys throughout Kent Lake each year (MMWD and Avocet) since 1981

Mammals

  • Monitoring: Long-term data collection through the Marin Wildlife Picture Index project to assess condition and trends beginning in 2014
  • Inventories: Mammal inventories in 1990–97 and 2014 (NPS and MMWD)

American Badger

  • Monitoring: Collection of Marin Wildlife Picture Index Project data to confirm the presence of this species in the One Tam area of focus
  • Outreach: Communication of the environmental dangers of rodenticides with the public

North American River Otter

  • Restoration: Improvement of aquatic habitats and salmonid populations at Muir Beach
  • Management: Installation of otter crossing signs near Muir Woods National Monument to help reduce road kills (NPS, State Parks)

Ongoing weed management is an integral part of maintaining Mt. Tam's health.