Mt. Tam hosts over 750 native plant species that make up rich array of native plant communities. These communities, and their arrangement on the landscape, are the foundation of ecosystem health.
Not every plant community type or rare plant species on Mt. Tam was included in this health assessment process. Additional information about this health assessment process, including how indicators were chosen, is available in the What We Did article on this site.
Good indicators are easily measured, have low “noise,” and often reveal some other aspect of ecosystem health. Rare plants—important aspects of biodiversity in their own right—also play a role in indicating the health of particular ecosystems. Both vegetation communities and individual rare plant populations may also show the effects of stressors such as alteration of natural disturbance regimes (e.g., grazing, fire), climate change, and invasion by non-native species. Lichen and fungi are also important components of the mountain's health about which much less is known. You can learn more about this and some of the other vegetation data gaps revealed through this health assessment process here.