Forrest 'Management' Plan Threatens Special Status Species at Tomales Bay State Park

 

California State Parks’ (CSP) proposed “Forest Health & Wildfire Resilience Public Works Plan” at Tomales Bay State Park will allow for “management” and “thinning” of vegetation with chippers, masticators, herbicides, prescribed burning, and prescribed herbivory in a lush forest home to a diverse array of treasured plant and animal species, from owls and hawks to frogs and fish and tiny invertebrates including many special status species threatened by extinction. 

The stated goals of the project are  to “preserve and steward the park’s Bishop pine and mixed hardwood forests, improve resilience of the forested and other habitat areas of the park for ecological benefit and to reduce wildfire risk, and to reestablish tribal priorities for vegetation management in the park.” The effects of this plan, and what it means for those that live, nest, and rest in Tomales Bay State Park have not been adequately assessed. 

Bats

Myotis evotis Photo: Michael Durham/Minden Pictures, Bat Conservation Internation.

Bats are a diverse group of mammals consisting of approximately 1,400 named species (Frick, W. et. al., 2019). As pollinators, seed dispersers, and primary consumers of flying insects, bats provide vital ecosystem services (Tanalgo, K. et. al., 2020). Despite their known importance in a healthy ecosystem and ever increasing concerns over their well-being, major gaps in data related to the population status and trends, behaviors, and life histories of bat species in North America, and California in particular, have been identified (Edson, E. et. al., 2016). As such, coordinated efforts to assess, understand, and monitor  bats have gained considerable momentum (Western Ecological Research Center, 2017, National park Service, 2022). 

Significant declines in global bat populations have been observed and are expected to continue if conservation measures are not undertaken (Bat Conservation International, Hammerson, G.A., et al. 2017). Habitat loss, wind energy production, climate change, and infectious diseases are primary factors perpetuating decline (Ib. id.). Pesticides are believed to be compounding these threats (Dennis and Gartell, 2015) and mass mortality events associated with environmental contaminants are well documented (O’shea et. al., 2016). Low reproductive rates in most bat species challenge their recovery. Additionally, many populations require roosting sites for a large number of individuals, further constraining viability (Williams, 2009). 

Thirteen bat species are known to occur in Marin County (National Park Service, 2019). Most are believed to be at risk and have special conservation status at the state and/or federal level (Species of Special Concern, 2023). Roosting habitats suitable for the Pallid Bat (Antrozous pallidus) (CDFW SSC), Fringed Myotis (Myotis thysanodes), Long-eared Myotis  (Myotis evotis), and Yuma Myotis (Myotis yumanensis) are present within Tomales Bay State Park (USGS Tomales Bay State Park Map, 2013). Moreover, migratory species including the Hoary Bat (Lasiurus cinereus) and Western Red Bat (Lasiurus blossevillii) have been observed at the nearby Farallon Islands nearly every year since records have been kept (F.E.I.S. 3.4.3.2 p. 107; Cryan & Brown, 2007). Many of these species utilize the bark, cavities, or canopy of trees and depend on forests for survival (Kurta, A. et. al., 2007). 

Consider: How will proposed treatment activities including tree thinning and removal affect bat species that depend on forested habitats for roosting, foraging, and raising young?  How will the use of herbicides and reduced habitat for insects and small mammals that serve as important food sources affect bat species known to occur in the area?  

California Red-legged Frog

The California Red-legged Frog (Rana aurora draytonii) is a rare amphibian that can be found in and around streams, ponds, and other freshwater riparian habitats primarily occurring in coastal watersheds from Marin County, California, to Northern Baja California, Mexico (IUCN, 2022). 

The species was once common across central California from the Pacific coast to the Sierra Nevada foothills but has been extirpated from 70 percent of its range (USFWS ECOS, California Red-legged Frog). Habitat loss, fragmentation, and degradation through urbanization, agricultural activities, water diversion, timber harvest, and pesticide use have perpetuated a significant decline in the species’ population (suspected to be between 10–30% over the last 10 years) (IUCN, 2022). Climate change, disease, and the introduction of non-native predators and competitors are further factors compounding these ongoing threats. Recognizing an imminent risk of extinction, the species was federally listed as threatened in 1996 and is a California Species of Special Concern (USFWS, 1996; CNDDB, 2023)  

In addition to quiet aquatic and riparian habitats necessary for breeding and resting, the California Red-legged Frog utilizes upland areas in damp thickets and forests where they are known to disperse and estivate in spaces under leaf litter, debris, downed trees or logs, and small mammal burrows (Recovery Plan, pg. 14). These behaviors render this species sensitive to not only sedimentation and changes in water quality and quantity, but also direct harm or injury to individuals that may be dispersing or sheltering (ibid. at 22).

The well-being of this species is of particular concern considering the essential role amphibians play in the ecosystem, their susceptibility to chemicals and disease, vegetation removal, and the depleted status of the species (Bralower, T. and Brice, D., n.d.). Amphibians play a central role in the food chain serving as both predators that balance insect populations, and as prey for many animals including snakes, birds, mammals, and other amphibians. Consequently, amphibian populations influence other species within their ecosystem and its processes (U.S. Fish & Wildlife Services, 2015). Amphibians also provide a host of important ecological services including nutrient cycling, bioturbation, pollination, seed dispersal, and energy flow through ecosystems (Cortés-Gomez, et al., 2015).

The California Red-legged Frog has been reported in Heart's Desire, and is likely present in wetlands, streams, and/or upland habitats in other areas of the Tomales Bay State Park (General Plan at 68; see also Fellers & Guscio at 14). Additionally, Critical Habitat was designated for this species in Marin County, which encompasses Tomales Bay State Park. 

Consider: How will logging old growth forests impact this rare species? We are concerned increased erosion from vegetation removal and soil destabilization could cause significant impacts to streams, wetland, and upland habitats required for important lifecycle stages. How will proposed activities affect habitat for insects and small mammals that serve as an important food source for this species? 

California Freshwater Shrimp

The California Freshwater Shrimp (Syncaris pacifica) is a rare crustacean found in perennial pools and low-gradient streams among exposed live tree roots in undercut banks, and beneath overhanging vegetation (Serpa, L. 2009). Freshwater shrimp play a key role in aquatic ecosystems by consuming leaf-litter, algae, and detrital materials (ibid.).  Endemic to California, the species is only known to occur in watersheds within Sonoma, Marin, and Napa counties including several tributaries outside Tomales Bay State Park (General Plan at 67). Potential habitat may also exist within Park boundaries (ibid.). 

The International Union for the Conservation of Nature (IUCN) has categorized the California Freshwater Shrimp as Endangered on the basis of its restricted area of distribution characterized by severe fragmentation and occurrence at very few locations (De Grave, S. & Rogers, C. 2013). A significant decline in the species’ area of occupancy, extent of occurrence, and quality of  habitat have been observed and are expected to continue (ibid.). Removal of vegetation and chemical pollution are primary factors driving the species’ decline (ibid.). Recognizing the importance of the species and its significant risk of extinction, the California Freshwater Shrimp was listed as endangered at both state and federal levels (USFWS, 1988;  CNDDB, 2023).

Consider: How will the vegetation treatment remove live trees and potentially cause death of roots, erosion, sedimentation of pools and wetlands downslope from logging, and other impacts to habitat for this endangered species? Water quality impacts of logging mature forests should be analyzed, with winter storms potentially causing erosion from newly-treated vegetation cover.

We will continue to demand answers, defend the interests of these species, and keep decision makers accountable for their actions.

Thank you for supporting our important work.

References:

  1. Bralower, Timothy and David Bice. Human Impacts on Amphibians. College of Earth and Mineral Science, The Pennsylvania State University. https://www.e-education.psu.edu/earth103/node/960

  2. California Natural Diversity Database (CNDDB). January 2023. State and Federally Listed Endangered and Threatened Animals of California. California Department of Fish and Wildlife. Sacramento, CA. https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=109405

  3. California State Parks. 2004. Final General Plan for Tomales Bay State Park. Volume 1: The General Plan. Approved by the State Park and Recreation Commission May 14, 2004.

  4. Cortés-Gomez, A.M., Ruiz-Agudelo, C.A., Valencia-Aguilar, A. and Ladle, R.J., 2015. Ecological functions of neotropical amphibians and reptiles: a review. Universitas Scientiarum, 20(2), pp.229-245. (http://www.scielo.org.co/pdf/unsc/v20n2/v20n2a07.pd)

  5. Cryan, P. M. , & Brown, A. C. (2007). Migration of bats past a remote island offers clues toward the problem of bat fatalities at wind turbines. Biological Conservation, 139, 1–11. 10.1016/j.biocon.2007.05.019. (https://www.sciencedirect.com/science/article/abs/pii/S0006320707002364)

  6. De Grave, S. & Rogers, C. 2013. Syncaris pacifica. The IUCN Red List of Threatened Species 2013: e.T21249A2774672. (https://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T21249A2774672.en)

  7. Edson, E., Farrell, S., Fish, A., Gardali, T., Klein, J., Kuhn, W., Merkle, W., O’Herron, M., and Williams, A., eds. (2016). Measuring the Health of a Mountain: A Report on Mount Tamalpais’ Natural Resources. https://www.onetam.org/peak-health

  8. Fellers, G. and M. Osbourn. 2009. Fire effects on the Point Reyes mountain beaver (Aplodontia rufa phaea) at Point Reyes National Seashore, 10 years after the Vision Fire. Northwest Naturalist 90: 189-193.

  9. G.A. Hammerson et al. Biological Conservation 212 (2017) 144–152 145. http://dx.doi.org/10.1016/j.biocon.2017.05.025

  10. IUCN SSC Amphibian Specialist Group. 2022. Rana draytonii. The IUCN Red List of Threatened Species 2022: e.T136113A53990036. https://dx.doi.org/10.2305/IUCN.UK.2022-2.RLTS.T136113A53990036.en

  11. Kurta, A., Hayes, J.P., & Lacki, M.J. (2007). Bats in Forests: Conservation and Management. Baltimore: Johns Hopkins University Press., doi:10.1353/book.3290.

  12. National Park Service (2019). Team Embarks on Third Year of Bat Monitoring in Marin County. https://www.nps.gov/articles/team-embarks-on-third-year-of-bat-monitoring-in-marin-county.htm?utm_source=article&utm_medium=website&utm_campaign=experience_more&utm_content=small

  13. National Park Service (2022). Marin Bat Monitoring Team Starts Using Motus Tracking System to Study Migratory Species. https://www.nps.gov/articles/000/sfanblog_marin-bat-monitoring-team-starts-using-motus.htm?utm_source=article&utm_medium=website&utm_campaign=experience_more&utm_content=small

  14. Sawyer, Keeler-Wolf, and Evens. 2009. A Manual of California Vegetation, second edition. California Native Plant Society and California Department of Fish and Wildlife. https://wildlife.ca.gov/Data/VegCAMP/Publications-and-Protocols/Vegetation-Manual

  15. Serpa, Larry. 2009. California Freshwater Shrimp: A Ghost-like Crustacean We Can't Afford to Lose. https://web.archive.org/web/20100306194601/http://www.fws.gov/desfbay/Archives/shrimp/shrimp.htm

  16. US Fish & Wildlife Service (March 2019). South Farallon Islands Invasive House Mouse Eradication Project; Farallon Islands National Wildlife Refuge, California - Final Environmental Impact Statement: 3.4.3.2 p. 107. https://drive.google.com/file/d/1Zbl4SmcdV2Y-vj0jNVdlMz684KScv7zG/view

  17. US Geological Survey, 2013. Tomales Bay State Park Map No. 6B. https://www.parks.ca.gov/pages/21299/files/tb-map6b-wildlifehabitats-south.jpg

  18. U.S. Fish & Wildlife Services, 2015. Conserving Amphibians: What the Amphibians are Telling Us and Why We Should Listen. https://www.fws.gov/story/2021-09/backyard-amphibians-reptiles

 
 
Lindsey Zehel