[Table of Contents]
[Errata]

EXECUTIVE SUMMARY

Wayne R. Ferren Jr.[1], Peggy L. Fiedler[2], Robert A. Leidy[3]

Wetlands of the central and southern California coast and coastal watersheds belong to one of the five wetland and deepwater habitat systems (i.e., Marine, Estuarine, Riverine, Lacustrine, and Palustrine) proposed in the classification technique by Cowardin et al. (1979). This classification, however, does not include enough alternatives to capture the great variety of wetland types that can be attributed to the special environmental characteristics of the region, including the many hydrogeomorphic units that result in part from the special attributes of the Mediterranean climate and varied landscape.

We present a modified Cowardin et al. methodology that incorporates keys, water regimes, water chemistry, hydrogeomorphic units (categories, series, and units), substrate/dominance/ characteristic types, data pages, and illustrations to identify wetland types and place them in the context of a numerical, hierarchical system. This technique provides the detail that is necessary to differentiate wetland types and that can be useful in identifying their corresponding ecosystem functions and socio-economic values.

Marine wetlands cover approximately 400 mi of linear coast. We provide examples of 32 types of marine wetlands from four classes (Rocky-Shore, Unconsolidated-Shore, Reef, and Aquatic-Bed), three water regimes, and 25 series of hydrogeomorphic units.

Estuarine wetlands occur in seven different types of estuaries. We provide examples of 33 types of estuarine wetlands from eight classes (Unconsolidated- Bottom, Streambed, Rocky-Shore, Unconsolidated-Shore, Aquatic-Bed, Reef, Emergent, and Scrub-Shrub), four water regimes, and 21 series of hydrogeomorphic units.

Riverine wetlands occur in six subsystems of intermittent and perennial stream and river types. We provide examples of 29 types of riverine wetlands in seven classes (Rock-Bottom, Unconsolidated-Bottom, Streambed, Rocky-Shore, Unconsolidated-Shore, Aquatic-Bed, and Emergent), six water regimes, and 13 series of hydrogeomorphic units.

Lacustrine wetlands occur within four types of natural lakes and three types of reservoirs. We provide examples of 17 types of lacustrine wetlands from six classes (Rock-Bottom, Unconsolidated-Bottom, Rocky-Shore, Unconsolidated-Shore, Aquatic-Bed, and Emergent), and 15 hydrogeomorphic units.

Palustrine wetlands occur in the context of many ecosystems including those from riverine and lacustrine environments. We provide examples of 52 types of palustrine wetlands from nine classes (Rock-Bottom, Unconsolidated-Bottom, Unconsolidated-Shore, Aquatic-Bed, Moss-Lichen, Emergent, Scrub-Shrub, and Forested), eight water regimes, and 36 series of hydrogeomorphic units.

To provide a functional assessment of the wetlands in one of the watersheds of the study region, the Ventura River Watershed was selected because of its size, location, richness of wetland types, and existing database. Of the 562 different wetlands evaluated, there are 400 types divided amond 70 hydrogeomorphic units and 147 dominants or cover types. The five systems of wetlands are represented by 13 marine, 26 estuarine, 11 lacustrine, 85 riverine, and 265 palustrine types. The diversity of types in the watershed is not surprising given the wide array of physical conditions in the basin. The assessment os ecosystem functions and socio-economic values shows that the basin is only moderately impacted.

We did not attempt to identify all types of wetlands represented in the study, nor did we attempt to conduct an inventory of all examples of the types. Rather, we provide a frame work with which to identify the types and include many examples of types from each of the five systems. We offer this approach to assist with the conservation of the rich wetland heritage that remains in California in spite of considerable losses.