Wildlife-Habitat Types

This section offers detailed descriptions of each wildlife-habitat type to support a common understanding for their delineation, inventory, and management across the region.  These wildlife-habitat types update and expand the prior regional works of Thomas (1979), Maser (1984), and Brown (1985) and for the first time give a complete two-state perspective.  For a description of how these wildlife-habitat types were determined, please see Chapter 1 in Wildlife-Habitat Relationships in Oregon and Washington (Johnson and O'Neil, 2001).

Each wildlife habitat below is described as to its geographic distribution, physical setting, landscape setting, structure, and composition. Additionally, we include other information that might help managers, researchers, and others gain further insight into each habitat, like listing other classifications systems and key references, natural disturbance regimes, succession and stand dynamics, effects of management and anthropogenic impacts, and its status and trends. Importantly, we have included photographs of each wildlife-habitat type to give the reader an idea of what each habitat type looks like, multiple photographs are offered for most habitats, to depict some of the variability (vegetationally or structurally) that exist within each type. Each of the habitats below (Table 1) is numbered. The descriptions in this section reflect the same numbering sequence and can be viewed by clicking on each wildlife-habitat type name in Table 1 below. The authors of this section reference over 200 literature citations in these descriptions.

Table 1. The 32 wildlife-habitats and their total acreage in Oregon and Washington. The marine waters extend out to the 200-mile Exclusive Economic Zone.

The following are definitions of each category used to characterize the wildlife-habitat types:

Geographic Distribution. Describes the broad geographic range within which the habitat is located, both within Oregon and Washington and elsewhere.

Physical Setting. Describes physical features of the environment on sites where the habitat is found in Oregon and Washington. These typically include climate, elevation, soils, hydrology, geology, and topography.

Landscape Setting. Describes the landscape pattern and distribution of the habitat in relation to other habitats. Primary land use is also noted.

Structure. Describes the physical structure of the habitat, both its typical aspect and the range of variation in structure present within the habitat. Aspects of physical structure include some description of cover or density (horizontal dimension) of vegetation or sessile invertebrate communities; layering (vertical dimension) of vegetation or sessile invertebrate communities; dominant growth forms, leaf phenologies (evergreen or deciduous), leaf characters (conifer or broadleaf), and vegetation persistence (annual or perennial) represented in different structural layers; and significant structural components of dead and decaying vegetation. Growth forms include trees, shrubs (>1.6 ft [0.5 m] tall), dwarf-shrubs (<1.6 ft [0.5 m] tall), graminoids (grasses, sedges, rushes), forbs, ferns, mosses, lichens, algae, and marine invertebrates. Vegetation cover categories frequently referred to include forest (>60% cover of trees), woodland (25-60% cover of trees), shrubland (>25% cover of shrubs), dwarf-shrubland (>25% cover of dwarf-shrubs), and grassland (graminoids dominant). Water-dominated habitats (e.g., marine and open water) may be described in terms of the physical aspects of the water column and the bottom substrate of the habitat.

Composition. Describes the species composition of the vegetation or sessile invertebrate communities that create structure. Composition is described as dominant, co-dominant (shares dominance with ³1 species), or important indicator species by structural layer. English names for all vertebrates are used in the text and corresponding standard names are in Appendix I. The geographic distribution or physical setting is noted for those dominant species that occur only in particular physical settings or specific geographic areas of the overall habitat’s range of occurrence.

Other Classifications and Key References. Notes other names that have been applied to this habitat by other classifications or major summary publications and important references that describe the habitat or parts of the habitat in greater detail.

Natural Disturbance Regime. Describes the major natural disturbances that are important in the habitat. The regime includes the disturbance type, severity, frequency, extent, and range of variation in these characteristics.

Succession and Stand Dynamics. Describes the way in which structure and composition change over time in relation to natural disturbances.

Effects of Management and Anthropogenic Impacts. Describes typical changes in structure and composition observed after typical management activities (human disturbances) and widespread changes in the habitat that have occurred since Euro-American settlement. Disturbances addressed include land uses that do not necessarily convert the habitat to urban or agriculture, but have a significant influence on structure or composition, e.g., hydrologic alterations, logging, and grazing. Exotic species that have become abundant in the habitat are noted.

Status and Trends. Describes the general extent of the type in Oregon and Washington, its current ecological condition, and historical and current trends in extent and condition. Ecological condition refers primarily to how similar the current structure, composition, and disturbance regime is to natural or pre-settlement conditions. The total number of plant associations recognized in the habitat and the number of those that are considered globally imperiled provide some idea of the degree of loss, degradation, and threat that is associated with the habitat.

Authors