This file was created by scanning the printed publication.
Errors identified by the software have been corrected; however, some errors may remain.
1
John C. Garcia 2
Abstract.-SCIES provides a method for fish and wildlife managers to measure the habitat value of stream corridors,. quantifying in explicit terms many complex values and factors. It was developed to have broad applications, to be flexible, to be capable of incorporating existing methods and knowledge, and to be comprehensive, easy to use, and verifiable.
INTRODUCTION
The fact that this symposium has been convened shows the need for specialized management of streams and stream corridors for fish and wildlife. Proper management must begin with a systematic inventory to identify riparian and stream resource values. To be successful, the inventory should make use of all available information on fish and wildlife requirements and habitat values, and the assessment usually must be rapid. The method should apply over a wide range of ecological conditions and for a variety of kinds of information. The result of such inventories should allow managers to identify areas with potential for restoration and high-value areas needing special protection.
In response to these needs, the U.S. Fish and
Wildlife Service contracted with BioSystems Analysis,
Inc., to develop procedures to identify actual and potential value of stream corridors to fish and wildlife.
That procedure is called SCIES, Stream Corridor
Inventory and Evaluation System. A complete exposition of SCIES is found in Garcia et al. (1984).
KEY FEATURES OF SCIES
Special features of SCIES are the following.
First, SCIES provides both a comprehensive list of factors thought to be important to fish and wildlife in stream corridors and a set of scoring curves which translate measurements of biological and physcal factors into scores.
Second, SCIES is flexible in allowing the user to choose the factors to be scored and to determine which stream corridor characteristics to emphasize in the evaluation.
1 Paper presented at the North American Riparian
Conference. (University of Arizona, Tucson, April
16-18 1985).
2John C. Garcia is a principal of BioSystems
Analysis, Inc., Sausalito, Calif.
335
Third, SCIES max1m1zes the use of existing biological and physical data and evaluation systems. It accepts both direct population measures and indirect habitat parameters as evidence of stream corridor values, and readily incorporates the methods and results of other classification and evaluations systems, such as
IFI M and HEP.
Fourth, all value scores, relative weights assigned to each parameter, and methods of calculation must be specified and recorded when completing an evaluation.
SCIES recording procedures make all value judgements explicit.
HOW SCIES WORKS
In essence, SCIES identifies areas of high value by scoring important stream corridor characteristics (e.g., instream flow or density of snags in the corridor) on a scale of zero to 100. For some adverse land and water uses, a scale of zero to -100 is used. High value stream corridors are those scoring near 100.
Figure 1 illustrates the conceptual approach to
SCIES valuation. Stream corridor characteristics which contribute to the final fish and wildlife scores are arranged in a hierarchy with three levels. Lowest-level measures of physical and biological attributes are converted to scores. The scores from several attributes are combined, following simple arithmetic rules, to produce second-level scores. A series of second-level scores is then combined to produce third-level scores, one for each major component of stream corridor value.
The procedure provides scores for four separate third-level components: fish, wildlife, species of concern, and human use of land and water resources in the corridor. These four components are called factors.
The second-level characteristics which comprise a factor are called criteria. For example, the wildlife factor includes criteria such as species abundance, species diversity, terrestrial habitat characters, aquatic habitat characters, adjacent communities, and adjunct evaluations. There can be two or more levels of

STEP 1
IDENTIFY AND MEASURE
PARAMETERS
STEP 2
DERIVE VALUE SCORES w j
..... c(
>
Score
100
90
10
10
~
0 25% 50 o/o 75,. 100%
PERCENT COVfR
STEP 3
SYNTHESIZE VALUE SCORES
FACTOR
•~-C Rl TE RIA ----t~
Figure I.--Conceptual approach to SCIES valuation.
336

criteria, with higher levels incorporating information from lower levels. E.g., terrestrial habitat can be subdivided into herbaceous species, shrub species, shrub stratification, tree species, . tree stratification, snags, talus, and vertical cliff subcriteria. The user can add or substitute others.
Value scores for criteria are derived from measurement of biological and physical attributes.
Each such measurable atribute is termed a parameter.
The value score for a criterion is determined by combining the scores of its component parameters. As an example, Figure 2 shows how the fish factor is segregated into some of its constituent criteria and parameters.
DETAILS OF. THE PROCEDURE
Each application of SCIES begins with selection of a group of parameters thought to be important to fish and wildlife in the stream corridor under investigation.
These parameters are the measurements familiar to field workers. They include indices of population abundance and characteristics of stream corridors that affect abundance. E.g., hydraulic and water quality conditions, a criterion of the fish factor, include temperature, depth, velocity, substrate, dissolved oxygen, pH, and turbidity.
Because different parameters may be important in different places or under different conditions, SCIES allows flexibility in choosing parameters to be used in a given evaluation. A preliminary list of parameters, criteria, and factors is provided in Garcia et al. (1984-).
This list is not exhaustive, but is comprehensive and includes what we consider to be the more important parameters.
Often the choice of parameters is restricted by the availability of field measurements. SCIES allows full use of existing data, so long as the same kinds of measurements have been taken in each stream corridor of interest.
Once the parameters are measured, either through field work, aerial reconnaissance, or taken from previous studies, they are translated to dimensionless value scores. The translation is accomplished through use of evaluation curves, histograms, equations, and matrices to equate scores from zero to 100 with the possible range of measurements of each parameter. For example, for salmonid fishes a stream water temperature of 20 C may have a value of 50, and at some higher temperature, say, 25 C, stream value would drop to zero.
Garcia et al. (1984-) provide preliminary scoring curves for the parameters contained in SCIES. The curves were developed for Pacific Northwest conditions, and users should construct, or at least review, the curves for each new area in which SCIES is applied.
The scores of various parameters may not reflect the full picture for management. For various reasons certain parameters-such as the existence of migratory barriers for anadromous salmonids or the preservation of habitat elements needed by an endangered
338 species-may receive more management· attention or may be more important in a particular biogeographic region. SCIES allows important stream corridor characteristics to be emphasized during evaluation.
This is accomplished by using variable weighting factors, which are coefficients that multiply base value scores. ·The sum of all weighting factors at any level of analysis must equal 1.0. This rule insures that the total score will always be a number between zero and 100 (or
-100) at every level.
Just as parameter scores are weighted and then summed to produce criterion scores, criterion scores are weighted and combined to obtain factor scores.
Although factor scores may be combined to express the overall value of a stream corridor, it is probably more useful to keep them separate.
As with value scores, weighting factors associated with each parameter, criterion, and factor must be specified and recorded during the evaluation.
APPLICATIONS
The two chief uses of SCIES are ( 1) to compare the value to fish and wildlife of different stream corridors and (2) to focus the evaluation on specific issues and species, where it is desirable to do so.
Scoring may be calibrated to compare various reaches against the best reach in the stream, the watershed, or the region. The user can model stream corridor impacts by plugging in parameter values expected after an impact occurs. Several runs of SCIES may be made, changing parameter scores or weighting factors to reflect options in management, and resultant values compared. The user can focus the evaluation by appropriate choice of parameters, criteria and weighting factors.
By applying weighting factors to the scores,
SCIES makes room for value judgement and makes such judgement explicit at each level of analysis.
Researchers seeking to compare the results of independent studies thereby have a firm basis for understanding how human values have influenced the results, and for standardizing results according to their own scale of weighting factors. Professional and public reviewers similarly have a solid basis for understanding and responding to SCIES results.
LITERATURE CITED
Garcia, J., J. Pratt, G. Ahlborn, S. Orloff, K. Richter,
J. Dragavon, J. Eby. 1984-. A method for assessing the value of stream corridors to fish and wildlife resources. Vol. I, methods and applications. Vol II, parameter selection and scoring. BioSystems Analysis, Inc., Sausalito,
Calif •.