---

Chapter 4: Key Species and Communities

---

Contents

Fish and Wildlife Species

Plant Communities

---

The initial task of the focus teams was to develop a list of key species. Key species are those species that collectively represent the overall complexity of the baylands ecosystem, and they are the species for which Project participants would develop habitat goals. Key species are sometimes referred to in other Project documents as evaluation or target species.

Fish and Wildlife Species

The four focus teams dealing with fish and wildlife (i.e., Fish, MARI, Shorebirds and Waterfowl, and Other Birds focus teams) developed lists of key species based on their own criteria. Although the selection criteria varied among the teams, there were many similarities. For example, each team focused on species that use major habitat types and that strongly influence community structure. They also each emphasized native and threatened or endangered species. These similarities led to the development of a set of "standardized" selection criteria which were later used to help evaluate the adequacy of the lists of selected species. Table 4.1 presents the criteria that each focus team used to select their key species, and Table 4.2 presents the standardized selection criteria.

Using the species selection criteria, the focus teams screened nearly 400 species, ultimately selecting 121 key species to represent the baylands communities of fish and wildlife. These species are listed in Table 4.3. The table also shows the standardized selection criteria for each species. A review of the table shows that most of the species were selected because they are habitat indicators, dominant species, or community indicators. Each group of species includes sensitive species, and the fish, waterfowl, and mammals groups include important commercial or recreational species.

Plant Communities

The Plant Focus Team chose to focus on plant communities rather than species. This is partly because more is understood about the ecology of the communities in which species occur than about the species themselves, particularly for species which are now regionally extinct or reduced to minimal remnants of their original populations. Also, many rare plant species are united by similar and related habitat requirements. The Plant Focus Team selected seven general communities including intertidal and subtidal bayland, tidal salt marsh, tidal brackish marsh, salt pond, diked bayland, seasonal wetland/vernal pool, and ecotonal habitats. Chapter 5 presents additional information on the key plant communities.

Table 4.1 Criteria Developed by Focus Teams For Selecting Key Species

---

 

Fish and Macroinvertebrates

• Currently has some protected status due to concern over low population numbers, loss or degradation of habitat, etc. (e.g., Federal or State-listed Threatened or Endangered Species).

• Is a principal element (e.g., prey item) in the food web or webs of the estuarine ecosystem.

• Inhabits ecotones or moves across habitat-type edges in such a way as to establish an ecological link between them.

• Possesses recognized commercial or recreational values.

• Is considered an "indicator" species for a particular habitat type.

• Is a fish or invertebrate species known to be native to the San Francisco Bay estuary.

• Is, or has been, relatively abundant in one or more of the sub-regions of the estuary and baylands (e.g., Suisun Bay).

• There is believed to be sufficient information available about this species or group to aid the Focus Team in establishing regional habitat goals.

• Represents or is an "indicator" species for a particular taxon, guild, life history characteristic, or some other feature of the ecosystem deemed to have significant value.

---

Terrestrial Invertebrates

• Major/dominant prey item for a key species selected by other Focus Teams usually occurs in large numbers within the project area.

• Breeds within the habitat type.

• Unique to the project area (could be a listed/protected taxon but does not have to be).

• Listed or candidate taxon (FE/SE, FT/ST, PE/PT, Extirpated).

• Known major pest taxon (historical and current significance, emphasizing native orientation).

---

Shorebirds and Waterfowl

• Currently or historically very abundant in the San Francisco Bay.

• Strongly associated with marine or estuarine habitats.

• San Francisco Bay is a critical area within the Pacific Flyway for the species.

• Fresh and brackish wetlands are a critical habitat component for the species.

• Salt ponds are a critical habitat component for the species.

• Federally listed or candidate species.

• Nests in the San Francisco Bay region.

• Rocky intertidal areas are a critical habitat component for the species.

• Symbolic species.

• Economic, recreation, or harvested species of importance.

• SF Bay provides major wintering area.

---

Other Baylands Birds

• Requires large, well developed tidal marsh habitat.

• Uses salt pond or shallow saline pond habitat.

• Uses high tidal marsh and upland transition area.

• Representative of a particular habitat type, for example: riparian, seasonal ponds, freshwater marshes, adjacent uplands, open bay, and rocky shores or islands.

• Dependent upon baylands habitats for critical support function, i.e., breeding, foraging, or migration.

• Represents a broader group or guild of species which use the baylands.

• Endemic to or breeds only in the baylands.

• Locally or regionally of limited number and distribution.

---

Mammals, Amphibians, and Reptiles

• Threatened/endangered species (including threatened/endangered genetic diversity of a species).

• Essential to threatened or endangered species.

• Keystone for larger communities.

• Keystone in food webs.

• Important for productivity, diversity, or other ecological standard.

• Dependent on wetland habitat.

• Indicator of wetland health.

• Significant pest species (to be controlled or removed).

---

 

Table 4.2 Standardized Selection Criteria

1. Community Indicator: Species is indicative of a community, guild, or assemblage of species. A community indicator can represent other species because of similar habitat requirements or behavior.

2. Habitat Indicator: Species is indicative of a key habitat. The presence of the species defines the habitat.

3. Sensitive Species: Species is at the geographic limits of its range, and slight changes in habitat conditions might cause large changes in population status, or the species has been recommended (differentiated from "candidate" status below) for legal protection because it is rare, threatened, or endangered.

4. Protected Species: Species is listed or is a candidate to be listed for protection under state and/or federal law.

5. Economic Indicator: Species is an important commercial or recreational species.

6. Dominant Species: Species strongly influences community structure as a major prey item, keystone species, pollinator, or ecological engineer. In the strictest sense, a keystone species is a predator that exerts a strong measurable influence on the species composition and relative abundance of other species in the community. In the Project, the term applies to any species, predator or not, that exerts such influence. An ecological engineer is a plant or animal that changes the physical environment in a way that affects other species.

7. Pest Species: Species is an invasive species or a pest to people.

8. Practical Species: Species is a convenient indicator of community, guild, assemblage or habitat because it is well-studied or easily studied. This criterion helps to select among the many possible community or habitat indicator species.

---

 

Table 4.3 Key Species and Standardized Selection Criteria

Common Name	Scientific Name	Standardized Selection Criteria
Fish
Chinook salmon	Oncorhynchus tshawytscha	2,4,5,6,8
Steelhead trout	Oncorhynchus mykiss	2,5,6,8
White sturgeon*	Acipenser transmontanus	1,2,4,6,8
Striped bass	Morone saxatilis	2,5,6,8
Sacramento splittail	Pogonichthys macrolepidotus	2,4,5,6,8
Pacific herring	Clupea pallasi	2,4,6,8
Northern anchovy	Engraulis mordax	2,4,6,8
Arrow goby	Clevelandia ios	1,2,6,8
Bay goby	Lepidogobius lepidus	2,4,6,8
Delta smelt	Hypomesus transpacificus	2,4,6,8
Jacksmelt	Atherinopsis californiensis	5,6,8
Topsmelt	Atherinops affinis	2,5,6,8
Longfin smelt	Spirinchus thaleichthys	6,8
Pacific staghorn sculpin	Leptocottus armatus armatus	5,6,8
Prickly sculpin	Cottus asper	6,8
Rainwater killfish*	Lucania parva	2,8
Plainfin midshipman*	Porichthus notatus	2,5,6,8
Shiner perch	Cymatogaster aggregata	2,5,6,8
Tule perch	Hysterocarpus traski	2,6,8
Threespine Stickleback	Gasterosteus aculeatus	6,8
White croaker	Genyonemus lineatus	2,5,6,8
Leopard shark	Triakis semifasciata	1,4,6,8
Bat ray	Myliobatus californica	2,6,8
Brown rockfish	Sebastes auriculatus	2,5,6,8
California halibut	Paralichthys californicus	2,5,6,8
Starry flounder	Platichthys stellatus	2,5,6,8
Longjaw mudsucker	Gillichthys mirabilis	2,5,6,8
Macroinvertebrates
Dungeness crab	Cancer magister	2,4,6,7,8
Rock crab	Cancer antennarius	2,4,6,7,8
Rock crab	Cancer productus	2,4,6,7,8
Mud crab*	Hemegrapsus oregonensis	1,4,6,7,8
California bay shrimp*	Crangon franciscorum	2,4,6,8
Blacktail shrimp*	Crangon nigricauda	6,8
Opossum shrimp	Neomysis mercedis (relicta)	2,6
Softshell clam*	Mya arenaria	2,6,8
Japanese littleneck clam*	Tapes japonica	2,4,6,7,8
Ribbed horsemussel*	Arcuatula demmisum	2,4,6,7,8
California horn snail*	Cerithidea californica	2,6,7,8
Amphipods*	Amphipoda spp.	1,2,6,7,8
Terrestrial Invertebrates
Franciscan Brine Shrimp*	Artemia franciscana (salina)	2,5,6,8
Packard's Tadpole Shrimp*	Lepidurus packardi	2,3,4,6
Reticulate Water Boatman	Trichocorixa reticulata	2,3,6,8
Delphacid Planthopper	Prokelisia marginata	1,2,6,8
Cixiid Planthopper	Cixius praecox	1,2,6
Tiger Beetle	Cicindela haemorrhagica	2,3
Tiger Beetle	Cicindela oregona	2,3
Tiger Beetle	Cicindela senilis senilis	2
Diffuse Water Scavenger Beetle*	Enochrus diffusus	2,6
Minute Moss Beetle*	Ochthebius rectus	2
Western Tanarthrus Beetle	Tanarthrus occidentalis	2,3,6
Leaf Beetle*	Erynephala morosa	2,6
Inchworm Moth	Perizoma custodiata	2,6,8
Pygmy Blue Butterfly	Brephidium exilis	2,6,8
Summer Salt Marsh Mosquito	Aedes dorsalis	2,7,8
Winter Salt Marsh Mosquito	Aedes squamiger	2,7,8
Washino's Mosquito	Aedes washinoi	2,7,8
Western Encephalitis Mosquito	Culex tarsalis	2,7,8
Winter Marsh Mosquito	Culiseta inornata	2,7,8
Grodhaus's Midge*	Tanypus grodhausi	2,6
Flower Fly*	Eristalinus aeneus	6
Cinereus Brine Fly	Ephydra cinerea	1,2,6,8
Millbrae Brine Fly	Ephydra millbrae	1,2,6,8
Riparian Shore Fly (Brine Fly)*	Ephydra riparia	2
Brine Fly	Lipochaeta slossonae	2,6,8
Jamieson's Compsocryptus Wasp	Compsocryptus jamiesoni	2,3
Amphibians
California Tiger Salamander	Ambystoma californiense	1,3,4,6
California Red-legged Frog	Rana aurora draytonii	1,2,3,4,6
California Toad	Bufo boreas halophilus	2,6
Pacific Treefrog	Hyla regilla	2,6
Reptiles
San Francisco Garter Snake	Thamnophis sirtalis tetrataenia	3,4
Western Pond Turtle	Clemmys marmorata	3,4
California Alligator Lizard	Elgaria multicarinata multicarinata
Coast Garter Snake	Thamnophis elegans terrestris	2
Central Coast Garter Snake	Thamnophis atratus atratus	2
Waterfowl
Canvasback	Aythya valisineria	1,2,5
Mallard	Anas platrhynchos	1,2,5
Northern Pintail	Anas acuta	1,2,5
Ruddy Duck	Oxyura jamaicensis	1,2
Surf Scoter	Melanitta perspicilata	1,2
Tule Greater White-fronted Goose	Anser albifrons gambelli	1,2,3,4
Shorebirds
Black Turnstone	Arenaria melanocephala	1,2
Red Knot	Calidris canutus	1,2,3
Wilson's Phalarope	Phalaropus tricolor	1,2,3
Long-billed Dowitcher	Limnodromus scolopaceus	1,2
Marbled Godwit	Limosa fedoa	1,2
Western Snowy Plover	Charadrius alexandrinus	2,3,4
Western Sandpiper	Calidris mauri	2
Other Baylands Birds
Eared Grebe	Podeceps nigricollis	2
Western/Clark's Grebe	Aechmophorus occidentalis	2
American White Pelican	Pelecanus erythrorhynchus	2,3
Brown Pelican	Pelecanus occidentalis	2,3
Double-crested Cormorant	Phalacrocorax auritus	1
Snowy Egret	Egretta thula	2
Black-crowned Night Heron	Nycticorax nycticorax	2
Northern Harrier*	Circus cyaneus	2
Peregrine Falcon*	Falco peregrinus	1,2,3,4
California Clapper Rail	Rallus longirostris obsoletus	2,3,4
California Black Rail	Laterallus jamaicensis corturniculus	2,3,4
Common Moorhen	Gallinula chloropus	2
California Gull	Larus californicus	6
Western Gull*	Larus occidentalis	6
California Least Tern*	Sterna antillarum browni	1,2,4
Forster's Tern	Sterna forsteri	1,2
Caspian Tern	Sterna caspia	1,2
Burrowing Owl	Speotyto cunicularia hypugaea	2,3
Belted Kingfisher*	Ceryle alcyon	2
Horned Lark*	Eremophila alpestris	2
Yellow Warbler*	Dendroica petechia	2
Salt Marsh Common Yellowthroat	Geothlypis Trichas sinuosa	2
Savannah Sparrow	Passerculus sandwichensis	2
Song Sparrow (3 subspecies)	Melospiza melodia samuelis
	Melospiza melodia pusillul
	Melospiza melodia maxillaris	2
Red-winged Blackbird*	Agelaius phoeniceus	1,2
Western Meadowlark*	Sturnella neglecta	2
Barn Swallow*	Hirundo rustica	2
Mammals
Salt Marsh Harvest Mouse	Reithrodontomys raviventris	1,2,3,4,6
California Vole	Microtus californicus	6,8
Salt Marsh Wandering Shrew	Sorex vagrans haliocoetes	1,2,3,4,6
Suisun Shrew	Sorex ornatus sinuosis	1,2,3,4,6
Ornate Shrew	Sorex ornatus californicus	2,6
North American River Otter	Lutra canadensis	2,3
Southern Sea Otter	Enhydra lutris nereis	2,3,4
Harbor Seal	Phoca vitulina richardi	2,3
California Sea Lion	Zalophus californianus	2,3
Norway Rat	Rattus norvegicus	7
Roof Rat	Rattus rattus	7
Red Fox	Vulpes vulpes regalis	7

---

* Species account not prepared	3. Sensitive Species	6. Dominant Species
1. Community Indicator	4. Protected Species	7. Pest Species
2. Habitat Indicator	5. Economic Indicator	8. Practical Species