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How healthy are Mt. Tam's natural resources?

 

Mammals

Mammals

North American River Otter North American River Otter | Photo by Mark Van Bergh

North American River Otter

The current status is Good.

Native Mammal Diversity (Bobcat shown) Native Mammal Diversity | Marin Wildlife Picture Index Project Photo

Native Mammal Diversity (Bobcat shown)

The current condition is Fair.

American Badger American Badger | Photo by Yathin

American Badger

The current status is Unknown.

Assessing the Health of Mt. Tam's Mammals

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.

From the Report: Camera trapping at the landscape level provides a non-invasive tool to obtain these metrics and reliably measure change over time. Networks of remote cameras have proven very effective for gaining valuable information on the diversity, distribution, and abundance of  the mammalian community (O’Brien et al., 2010; Ahumada et al., 2011). Additionally, photographs can be shared with the public, which provides the community with a chance to see mammals that are all around the One Tam area of focus, but are rarely spotted.

Knowledge about the mountain’s mammalian residents varies, but is generally limited. However, new information coming in from remote cameras installed in 2014 as a part of the Marin Wildlife Picture Index project should help land managers better understand the diversity and distribution of mammals across Mt. Tam’s different habitats.

 

Land managers have some information about specific mammal species that are good indicators of ecosystem health, including the American badger (Taxidea taxus). This species requires large patches of grasslands and coastal scrub, and so their presence tells us something about the condition of these habitats. They are also voracious predators of small rodents, and their burrows provide important habitat for other wildlife including reptiles, amphibians, small mammals, and burrowing owls.

 

The charisma of North American river otters (Lontra canadensis) makes them excellent ambassadors for watershed conservation and wetland restoration. These apex predators play an important role in ecosystem health, and their use of both terrestrial and aquatic habitats makes them good indicators of multiple habitat types.

 

While there are many knowledge gaps related to the health of Mt. Tam, bats are an important group that were considered for this health assessment process, but were not included due to a lack of information. One Tam agencies are planning to develop inventory and monitoring plans for bats in the near future.

 

Extirpated Mammals

In addition to looking at the mammals that make their homes on Mt. Tam, species that are no longer found on the mountain are important to consider when thinking about ecosystem health. Changing land use, development, hunting, wildlife persecution, collecting, and the introduction of non-native species since the time of European settlement have resulted in the loss of many native mammals from Mt. Tam. Species lost likely include grizzly bears (Ursus arctos), American black bears (Ursus americanus), gray wolves (Canis lupus), tule elk (Cervus canadensis nannodes), pronghorn antelope (Antilocapra americana), North American beavers (Castor canadensis), California ground squirrels (Otospermophilus beecheyi), ringtail cats (Bassariscus astutus), mountain beavers (Aplodontia rufa), and the salt marsh harvest mouse (Reithrodontomys raviventris). Having already lost many mammals from the mountain, it is important that we maintain the species that are still there, and make sure that the key ecological roles and functions that they serve are not lost.

 

Mammal Species in the One Tam Area of Focus

Life Form

Scientific Name

Common Name

Bats

Antrozous pallidus

Pallid Bat

Bats

Corynorhinus townsendii

Townsend's Big-eared Bat

Bats

Eptesicus fuscus

Big Brown Bat

Bats

Lasionycteris noctivagans

Silver-haired Bat

Bats

Lasiurus blossevillii

Western Red Bat

Bats

Lasiurus cinereus

Hoary Bat

Bats

Myotis californicus

California Myotis

Bats

Myotis thysanodes

Fringed Myotis

Bats

Myotis volans

Long-legged Myotis

Bats

Myotis yumanensis

Yuma Myotis

Bats

Tadarida brasiliensis

Brazilian (Mexican) Free-tailed Bat

Carnivores

Canis latrans

Coyote

Carnivores

Lontra canadensis

North American River Otter

Carnivores

Lynx rufus

Bobcat

Carnivores

Mephitis mephitis

Striped Skunk

Carnivores

Mustela frenata

Long-tailed Weasel

Carnivores

Procyon lotor

Northern Raccoon

Carnivores

Puma concolor

Puma (Cougar, Mountain Lion)

Carnivores

Spilogale gracilis

Western Spotted Skunk

Carnivores

Taxidea taxus

American Badger

Carnivores

Urocyon cinereoargenteus

Gray Fox

Hoofed Mammals

Bos taurus

Cow

Hoofed Mammals

Odocoileus hemionus

Black-tailed (Mule) Deer

Insectivores

Neurotrichus gibbsii

American Shrew-mole

Insectivores

Scapanus latimanus

Broad-footed Mole

Insectivores

Sorex trowbridgii

Trowbridge's Shrew

Insectivores

Sorex vagrans

Vagrant Shrew

Marsupials

Didelphis virginiana

Virginia Opossum

Rabbits and Rodents

Lepus californicus

Black-tailed Jackrabbit

Rabbits and Rodents

Microtus californicus

California Vole

Rabbits and Rodents

Mus musculus

House Mouse

Rabbits and Rodents

Neotamias sonomae

Sonoma Chipmunk

Rabbits and Rodents

Neotoma fuscipes

Dusky-footed Woodrat

Rabbits and Rodents

Peromyscus maniculatus

Deer Mouse

Rabbits and Rodents

Rattus rattus

Black Rat

Rabbits and Rodents

Reithrodontomys megalotis

Western Harvest Mouse

Rabbits and Rodents

Sciurus griseus

Western Gray Squirrel

Rabbits and Rodents

Sciurus niger

Eastern Fox Squirrel

Rabbits and Rodents

Sylvilagus bachmani

Brush Rabbit

Rabbits and Rodents

Thomomys bottae

Botta's Pocket Gopher

*This species list represents current information compiled by One Tam partner agencies at this time, and will likely be updated in the future through further review of additional technical reports, inventories, and validation of other data sources.

Updated 6/16/16

Health Score
Condition, Trend & Confidence

all mammals

  • Condition: Caution
  • Trend: Unknown
  • Confidence: Moderate

 

american badger

  • Condition: Unknown
  • Trend: Unknown
  • Confidence: Unknown

 

north american river otter

  • Condition: Good
  • Trend: Improving
  • Confidence: Moderate