| CSU, Chico home page | Biological Sciences | Paul's home page |

Big Chico Creek at Highway 32

Index.

Introduction | Index |

Each Fall in the last several years, limnology classes have investigated several physical and biological aspects of Big Chico Creek at the Highway 32 bridge (elevation 1100 meters) near the Butte/Tehama County line, California.

Habitat | Index |

A segment of the stream was surveyed for habitat type, habitat length, habitat width, habitat max. depth, type and percentage of total cover. The stream consists of about equal parts rapids, low gradient riffles, and pools. A breakdown of fish cover types is shown to the left:

Substrate | Index |

To analyze substrate, a 10 meter tape was stretched along the stream bed and for each 0.5 meter mark on the tape a record was made of bedrock, sand, silt or mean rock diameter. Out of 102 substrate records, 3% were over bedrock, and 9% overlaid particles less than one centimeter in average diameter. A size distribution of the remaining rocks is shown to the left:

Discharge | Index |

Discharge was estimated from cross sectional area and velocity measurements from either a timed float distance or a velocity meter. While the procedure is not very precise, the measured flow corresponds well with rainfall records.

Riparian | Index |

Canopy cover was measured by an overhead intercept method, and riparian trees were identified in the field. The riparian area is densely wooded with 80 to 95% overhead canopy. Plants along the creek include:

Overstory Trees Understory Trees
Pseudotsuga menziesii Douglas Fir Taxus brevifolia California Yew
Libocedrus decurrens Incense Cedar Alnus rhombifolia White Alder
Pinus ponderosa Ponderosa Pine Cornus sessilis Dogwood
Pinus lambertiana Sugar Pine Acer macropyllum Big-leaf Maple
Abies concolor White Fir .
Quercus kelloggii Black Oak
.
Shrubs Herbaceous Plants
Ribes nevadense Sierra Currant Leersia oxyroides Rice Cutgrass
Dryopteris arguta Common Wood Fern Rubus vitifolius Blackberry
Rubus parviflorus Thimble berry Darmera peltata Indian Rhubarb
Ceanothus integerrimus Deer brush Aster bracteolatus Eaton's Aster

Benthic Invertebrates | Index |

Benthic invertebrates were collected with Surber Samplers and kick nets, preserved with 10% formalin, and identified later in lab. Benthic invertebrates seen year to year are listed in the following chart:

ODONATA
Ophiogomphus bison
Octogomphus specularis
EPHEMEROPTERA
Baetis sp.
Epeorus longimanus
Rhithrogena dodsi
Drunella coloradensis
Serratella micheneri
Paraleptophlebia sp.
PLECOPTERA
Pteronarcys californicus
Yoraperla brevis
Amphinemura sp.
Doroneuria theodora
Calineuria californica
Perlinodes sp.
MEGALOPTERA
Orohermes crepusculus
TRICOPTERA
Hydropsyche sp.
Arctopsyche sp.
Dolophiloides sp.
Ryacophila spp.
Lepidostoma sp.
Glossosma sp.
Gumaga sp.
LEPIDOPTERA
Petrophila confusialis
COLEOPTERA
Eubrianx edwardsi
Lara sp.
Optioservus quadrimaculatus
DIPTERA
Simulium sp.
Tanytarsus sp.
Atherix variegata

Fish | Index |

Fish were collected with two pass electroshocking in a stream section isolated with block nets. All fish captured were ientified, measured and weighed in the field, then released within the stream reach from which they were captured.

Only Rainbow and Brown trout have been collected at the site. Size distributions are shown above and breakdown by numbers and biomass below: The exotic brown trout clearly dominates the native rainbow. Only in 1996 and 1997 were more rainbows than browns collected and even then the larger average size of the browns resulted in their having greater total biomass. However, the native rainbows display a new year class every year while young-of-year browns are missing in 1989, 1993, and 1997. Browns may be less well adapted to extreme variations in the habitat even though they outcompete the rainbows in most years. (For fish data from other parts of Big Chico Creek, see Long Term Effect of Rotenone Treatment on the Fish Community of Big Chico Creek, California.)