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Mammal Species of Special Concern

Mammal species of special concern

List and Species Accounts

The following information is from the 1986 Department of Fish and Game publication “Mammalian Species of Special Concern in California,” by D.F. Williams. The list of mammalian species of special concern is currently undergoing review and is viewable in draft form. This draft does not yet replace the current list until the draft is approved. The new report with an updated listing and status accounts is expected in the first half of 2002.

Due to the life of this current list, two species have been listed by the State of California as threatened or endangered subsequent to the lists origination. Likewise, two species were dropped from the list and 34 new taxa were added to the list.

List Criteria and Categories

Priorities for the investigations were:

  1. species endemic to California;
  2. subspecies endemic to California;
  3. species and subspecies whose geographic ranges extend beyond California and which appear to be jeopardized throughout their geographic range;
  4. populations of taxa threatened within California but which also occur elsewhere and appear not to be threatened throughout their geographic range (e.g., Myotis velifer velifer, the Cave Myotis).

These priorities had some influence on which taxa received greatest consideration for inclusion in detailed investigations. Priority rankings, however, were based solely on the apparent proximity and nature of threats to populations. Locally depleted populations of wider-ranging taxa within California were not studied in detail, with the exception of the American Badger (Taxidea taxus).

Of the species and subspecies investigated for this report, 36 warrant greatest concerns. These are listed in the table below in three categories: Highest, Second, and Third priorities. The definitions for these categories are based on the perceived proximity of threats of extinction. Species listed in the Highest Priority category appear to face a high probability of extinction or extirpation from their entire geographic range in California if current trends continue. Populations of species in the Second Priority category are definitely jeopardized and declining, but the threats of extinction or extirpation appear less imminent. Populations of species listed in the Third Priority category appear not to face extinction in the near future, but they are declining seriously or are otherwise highly vulnerable to extirpation because of human developments, and require special attention in land_ and resource_ management decisions. Some species listed in the Second and Third Priority categories are relatively rare and virtually no current data on their distributions and population status are available; when investigated in detail, some of these may be found to face greater or lesser threats. Accounts of species included in the three priority categories are presented in the following section.

Major contributing factors in jeopardizing most species on the List of Concern are the diminishment and degradation of natural communities. Loss of native plant communities in four regions of California present the most acute problems threatening unique, taxonomically recognized, populations of mammals in: the Colorado River riparian communities; the southern California coastal basins from the San Fernando Valley southward to the Mexican boundary, including lowland grassland and desert communities and tidal marshes along the south coast; the San Joaquin Valley desert, grassland, and riparian and wetland communities; and the tidal marsh communities of San Francisco and San Pablo bays. Loss of riparian and wetland communities is no less serious elsewhere, but fewer unique taxa of mammals are threatened. In addition to loss of habitat, disturbances by humans, especially in hibernacula and maternity roosts is perceived as a serious threat to most of the species of bats. Habitat degradation and lack of information on hunter take and population dynamics for use in management are viewed as potential threats to the five species of rabbits and hares, currently designated as game species, on the List of Concern. Cutting and fragmentation and isolation of blocks of mature and old-growth conifer forests pose potential threats to two species on the List of Concern.

Mammalian Species of Special Concern List

Within each priority category, species are listed in taxonomic order, not in any order of priority.

CLICK ON THE SCIENTIFIC NAME TO GO TO THE SPECIES ACCOUNT

Highest Priority
Buena Vista Lake Shrew Sorex ornatus relictus
Suisun Shrew Sorex ornatus sinuosus
Santa Catalina Shrew Sorex ornatus willetti
Salt-marsh Wandering Shrew Sorex vagrans halicoetes
Arizona Myotis (= Little Brown Myotis, Occult Little Brown Bat) Myotis lucifugus occultus (=Myotis occultus)
Arizona Cave Myotis (=Cave Myotis) Myotis velifer velifer (=Myotis velifer)
* Riparian Brush Rabbit Sylvilagus bachmani riparius
Point Arena Mountain Beaver Aplodontia rufa nigra
Los Angeles Pocket Mouse Perognathus longimembris brevinasus
Pacific Pocket Mouse Perognathus longimembris pacificus
* Tipton Kangaroo Rat Dipodomys nitratoides nitratoides
Colorado River Cotton Rat Sigmodon arizonae plenus
Yuma Mountain Lion Felis concolor browni

Second Priority
So. California Salt-marsh Shrew Sorex ornatus salicornicus
California Leaf-nosed Bat Macrotus californicus
Townsend’s Western Big-eared Bat (=Townsend's Big-eared Bat) Corynorhinus townsendii (=Plecotus townsendii)
Pocketed Free-tailed Bat Nyctinomops femorosacca (=Tadarida femorosaccus)
Western (=California) Mastiff Bat Eumops perotis californicus
Salinas Pocket Mouse Perognathus inornatus psammophilus
White-eared Pocket Mouse Perognathus alticola alticola
Riparian (=San Joaquin Valley) Woodrat Neotoma fuscipes riparia
White-footed Vole Arborimus albipes
Point Reyes Jumping Mouse Zapus trinotatus orarius

Third Priority
Big Free-tailed Bat Nyctinomops (=Tadarida) macrotis
Pygmy Rabbit Brachylagus idahoensis
Oregon Snowshoe Hare Lepus americanus klamathensis
Sierra Nevada Snowshoe Hare Lepus americanus tahoensis
White-tailed Hare (=Western White-tailed Hare) Lepus townsendii (=Lepus townsendii townsendii)
Point Reyes Mountain Beaver Aplodontia rufa phaea
Tehachapi Pocket Mouse Perognathus alticola inexpectatus
Short-nosed Kangaroo Rat Dipodomys nitratoides brevinasus
Red Tree Vole (=California Red Tree Vole) Arborimus pomo (=longicaudus)
Pacific Fisher Martes pennanti pacificus
Channel Islands Spotted Skunk Spilogale gracilis (=putorius) amphiala

Additions to List
Alameda Island Mole Scapanus latimanus parvus
Mount Lyell Shrew Sorex lyelli
Monterey Shrew (=Salinas Ornate Shrew) Sorex ornatus salarius
Mexican Long-tongued Bat Choeronycteris mexicana
Pallid Bat Antrozous pallidus
Pale Big-eared Bat Corynorhinus (=Plecotus) townsendii pallescens
Spotted Bat Euderma maculatum
San Diego Black-tailed Jackrabbit Lepus californicus bennettii
Sierra Nevada Mountain Beaver Aplodontia rufa californica
San Bernardino Flying Squirrel Glaucomys sabrinus californicus
Palm Springs Round-tailed Ground Squirrel Spermophilus tereticaudus chlorus
Dulzura (=California) Pocket Mouse Chaetodipus (=Perognathus) californicus femoralis
Northwestern San Diego Pocket Mouse Chaetodipus (=Perognathus) fallax fallax
Pallid San Diego Pocket Mouse Chaetodipus (=Perognathus) fallax pallidus
Marysville California Kangaroo Rat Dipodomys californicus eximus
Big-eared Kangaroo Rat Dipodomys elephantinus
San Bernardino Merriam’s Kangaroo Rat Dipodomys merriami parvus
Palm Springs Pocket Mouse Perognathus longimembris bangsi
Jacumba Pocket Mouse Perognathus longimembris internationalis
Mojave River Vole Microtus californicus mohavensis
San Pablo Vole Microtus californicus sanpabloensis
Stephens’ California Vole Microtus californicus stephensi
Owens Valley Vole Microtus californicus vallicola
San Francisco Dusky-footed Woodrat Neotoma fuscipes annectens
Monterey Dusky-footed Woodrat (=Monterey Woodrat) Neotoma fuscipes luciana
San Diego Desert Woodrat Neotoma lepida intermedia
Southern Grasshopper Mouse Onychomys torridus ramona
Tulare Grasshopper Mouse Onychomys torridus tularensis
Anacapa Island Deer Mouse Peromyscus maniculatus anacapae
San Clemente Deer Mouse Peromyscus maniculatus clementis
Yuma Hispid Cotton Rat Sigmodon hispidus eremicus
Southwestern River Otter Lutra canadensis sonorae
Humboldt Marten Martes americana humboldtensis

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