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.
Birds are recognized as indicators of ecological change (Carignan & Villard, 2002). They also provide a wide variety of important ecosystem services including devouring pests, pollinating flowers, dispersing seeds, scavenging carrion, cycling nutrients, and modifying the environment in ways that benefit other species (Whelan et al., 2015).
As predators, prey, scavengers, and grazers, mammals play important roles in Mt. Tam’s terrestrial and aquatic food webs. The abundance, diversity, and even the behavior of mammals may reflect changes in their habitat, population dynamics of species above or below them in the food chain, or the impacts of human activities.
Spending part of their lives in freshwater streams and part in the ocean, anadromous fish like coho salmon (Oncorhynchus kisutch), steelhead trout (O. mykiss), and threespine stickleback (Gasterosteus aculeatus) are good indicators of riparian habitat quality,
Each ecological community or ecosystem roll-up was created by aggregating all of the vegetation and wildlife metrics from individual indicators that were pertinent to that ecosystem. Each individual metric has its own condition, trend, and confidence level as already determined in the individual indicator assessments.