does provide an initial framework for a hierarchical clas- 

 sification of wet habitats. Additional research and devel- 

 opment is needed to develop aquatic habitat types in the 

 context of terrestrial habitat types following the concepts 

 of Daubenmire (1952). 



Landform Descriptors 



Landform, as used here, deals with shape or configu- 

 ration of land surface, materials of the upper few meters, 

 and the genesis or geologic/geomorphic process by which 

 the landform developed. Landforms are major ecosystem 

 elements since they influence the nature and behavior of 

 other ecosystem elements (Bailey 1981). For example, the 

 steepness and aspect of a slope influence the kind of vege- 

 tation of an area and the way water flows through a water- 

 shed. Understanding of an ecosystem is enhanced when 

 landform characteristics are described and their effects 

 upon and interaction with other parts of the ecosystem 

 are evaluated. Landform information alone can be used 

 in some preliminary planning, for example, in planning 

 activities such as road building for timber harvest. 



In the absence of a detailed landform classification 

 hierarchy, a glossary of landform and geologic terms is 

 presented in appendix B. The terms, with definitions, are 

 arranged alphabetically. Following the definitions are 

 several block diagrams of landform features and lists of 

 glossary terms organized according to shape, materials, 

 and genesis of landforms. Appropriate landform descrip- 

 tors are needed when describing the physical and geo- 

 graphical setting of a plant community or soil. 



Combining (Integrating) the Elements 



Developing and using classification systems of eco- 

 system elements alone allows evaluation of some of the 

 many land use or land management options. For example, 

 engineering projects, such as road and earthen dam de- 

 signs, depend mainly on soil information coupled with 

 landform descriptors. Information about vegetation and 

 water is needed when planning for removal of vegetation 

 or special construction features dealing with water drain- 

 age. Special consideration must be given to other ele- 

 ments when engineering projects might threaten specific 

 kinds of plant or animal habitats or populations. If the 

 user is interested only in knowing the general vegetation 

 of an area for preplanning to determine amount, kind, 

 and distribution for livestock grazing, wildlife habitat, or 

 timber harvesting, the vegetation hierarchy is most im- 

 portant. Some planning decisions may be best assisted by 



knowing that a geomorphic feature, such as glacial out- 

 wash or river deposits, is a probable source of gravel. 



Many resource planning and monitoring decisions, 

 however, must be based on the whole ecosystem rather 

 than individual elements. Only in this way can interactive 

 effects of actions on multiple or individual resources be 

 logically determined and predictions be made regarding 

 alternative actions. 



Ecosystems, however classified, represent a combi- 

 nation or integration of all ecosystem elements working 

 together to form an entity. Likewise, the individual ele- 

 ments of the ecosystem are expressions of the interactions 

 of climate, organisms, land relief, parent material (rock 

 type), and time to form recognizable ecosystem elements. 

 Vegetation (Major 1951) and soil (Jenny 1941) are two 

 examples. Hence the plant community (or soil) of an area 

 represents a first-order interaction or integration, and 

 classification of them takes advantage of those events. 

 For example, Mollisol soils are characteristically formed 

 under grasslands in subhumid to semiarid climates. Vege- 

 tation of the temperate and subpolar evergreen needle- 

 leaved forest group are, by definition, developed between 

 the tropics and frigid zones and on soils in those zones. 



A second stage of "integration" or "combination" 

 should more precisely define and describe the whole eco- 

 system. However, a logical statistical process to accom- 

 plish the task has not been developed. Thus, this stage of 

 the integration process is descriptive; characteristics from 

 more than one element describe a unit of land with spe- 

 cific limits of features. This integration procedure can be 

 - applied to any level of generalization to represent ecolog- 

 ical units (ecological response units of Driscoll and others 

 (1983)) in which response is more specific at the lower 

 levels of the hierarchy and more general at the higher 

 levels of the hierarchy. 



Specific ecological units, including procedures for 

 developing them, have been reported by Driscoll (1964a,b) 

 and Mueggler and Stewart (1980). These ecological units 

 represent areas of land that may occur in several places 

 and are specific to kinds of vegetation associations and 

 soil series or phases of soils. However, it must not be 

 inferred that specific vegetation associations and soil 

 series always have 1:1 relationships. One vegetation asso- 

 ciation may occur with more than one soil series or phase 

 of series, and one soil series may be associated with more 

 than one vegetation association. Ecological units are not 

 always contiguous; they may be geographically separated 

 as a result of local landform, climate, and topographic 

 differences. However, by the logic with which they are 

 described, they are expected to respond to management 

 similarly. 



14 



