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?


Mt. Tam is home to many native animal species, including at least 35 mammals, 184 birds, 11 fish, and 25 amphibians and reptiles. Wildlife are found in every habitat type on the mountain, where they may be grazers, predators, prey—or play some combination of these key ecosystem roles. Changes in their abundance or distribution across the landscape can indicate the effects ecological stressors like climate change, invasive species, and human disturbance.

There are many ways that wildlife can be used to help measure the health of Mt. Tam. In some cases, entire guilds or groups of wildlife (e.g., mammals or oak woodland birds) can reveal things about the condition of the habitats upon which they depend. In other instances, individual species may prove to be good indicators of certain aspects of ecosystem health.


How Were Wildlife Indicators Chosen?

The wildlife indicators included here were chosen, in part, based on the amount of information available on them. The amount of data available on Mt. Tam’s wildlife vary widely depending on whether they have ever been inventoried or if they are regularly monitored. Some species, like the threatened Northern Spotted Owl (Strix occidentalis caurina), have been monitored for years, whereas mammal monitoring is just now underway. Other groups, like invertebrates, have never been systematically inventoried or monitored on the mountain. You can learn more about some of these important data gaps here.

Indicators were also chosen if their condition and/or trend might reveal something about other aspects of ecosystem health, even if existing information was limited. For example, American badgers (Taxidea taxus) are good indicators of grassland ecosystem extent and quality, and North American river otters (Lontra canadensis) can reveal a number of things about both riparian and terrestrial habitats.

The links in the photos above will take you through the different wildlife indicators used in this health assessment from their broadest categories down to the individual species level.

Additional information about this health assessment process, including how indicators were chosen, is available in the What We Did section of this site.

Learn More

The links below provide additional information about Mt. Tam's wildlife.