Classification Scheme

     The photo interpretation of riparian vegetation is accomplished as outlined in the Methodology Section using the classification scheme outlined in Table 1 below.  This classification scheme is a modification of the one used in cooperation with the U.S. Forest Service to map the Pike-San Isabel National Forest and Cimarron/Comanche National Grasslands ( Table 2 ).  In addition a classification scheme employed by the Routt National Forest is used on several quads (Table 3).  Potential riparian habitats are not delineated.  Mixed communities are delineated when obvious spectral differences in vegetation can be discerned within a common area.  This classification system works very well in relation to the scale, resolution, and emulsion of the NAPP photography.

     For each of the classes listed below, a single label indicates that the class is dominant and comprises at least 75% or more of the vegetation.  Other vegetation may be present but less than the Minimum Mapping Unit (MMU) of 1/2 acre.  Mixed communities consist of classes that are less than 75% cover with a lesser amount of one or more other groups.  The dominant type is annotated first with the lesser type following.  For example, if a polygon is attributed as RT1/RS1, the vegetation in the area is less than 75% dominant of any particular class but is a mixed community of Aspen and Willow with Aspen being the dominant type between the two classes.  A forward slash ( / ) is used to separate the dominant/subdominant classes both on the hard copy and within the digital data.

   The design of the riparian classification scheme is such that, with use of a Geographic Information System (GIS), the subclass elements can be "rolled up", or aggregated into more broadly inclusive classes.  The primary reason for this is to maintain classification accuracy.  If a particular subclass is difficult to discern and creates confusion and classification inaccuracy then it can be aggregated into a broader category.  Additionally, the data can be aggregated into broader classes for applications purposes.  For example, during the Preble's Meadow Jumping Mouse Riparian Mapping effort it was determined, through logistic regression techniques, that the mice were primarily keying in on the riparian shrub component where it was a dominant type.  Through use of the GIS, we were able to aggregate all categories and permutations of the classification where riparian shrub was dominant into a single category.  This made it much easier to use the data specific to the needs of this particular species.  Finally, maintaining the three major riparian classes (i.e. riparian tree, riparian shrub, riparian herbaceous) more readily facilitates the Division of Wildlife's efforts to merge our data with data from other independent mapping efforts and, as best we can, provide seamless data products.  This worked especially well when merging the CDOW data with the USFS data.
 
 

TABLE 2 USFS (Pike-San Isabel NF)/CDOW COOPERATIVE RIPARIAN HABITAT MAPPING PROJECT CLASSIFICATION SCHEME
CATEGORY	MAP CODE
RIPARIAN TREES
Aspen (ASA=10-40% Crown Density,  ASB=40-70%, ASC=70-100%)	AS, ASA, ASAPOLY, ASB, ASBPOLY, ASC, ASCPOLY
Cottonwood (COA=10-40% Crown Density, COB=40-70%, C0C=70-100%)	CO, COA, COAPOLY, COB, COBPOLY, COC, COCPOLY
Evergreen	E, EPOLY
RIPARIAN SHRUBS
Riparian Shrub - General	S, SPOLY
Riparian Shrub - Willow	W
Riparian Shrub - Alpine Willow	AW
RIPARIAN HERBACEOUS
Mesic Meadow	M, MPOLY
WATER BODIES
Open Water - Standing	L, LPOLY, PPOLY
Open Water - Riverine	ST, STPOLY
OTHER RIPARIAN
General Riparian	R, RPOLY
Unvegetated	NV, NVPOLY
Sandbar	SB, SBPOLY
NON-RIPARIAN
Upland Grass	GR, GRPOLY
Non-Riparian	X, XPOLY, NONFSPOLY, USFSPOLY
Both polygon features and line features are mapped using this classification scheme, color infrared (CIR) aerial photographs, 7.5 minute topographic base maps and a minimum mapping unit (MMU) of 0.5 acres.  Riparian line features were delineated where the width of the riparian area was less then 80 feet.  This classification scheme utilizes a dominant/subdominant methodology of describing riparian habitat.  Unless a polygon is at least 75% homogeneous, the dominant category is listed first followed by a slash (/) and the subdominant category. Example:  AS/S = Aspen/Riparian Shrub with Aspen being the dominant category within the mapped polygon.

 

    The Division of Wildlife has included data from the Routt NF riparian classification scheme on quads in Routt County.  This was possible as the Routt classification lent itself to the riparian tree, riparian shrub, and riparian herbaceous scheme developed by CDOW.  However with this data there is no subdominant class.
 
 

TABLE 3 USFS (ROUTT NF) RIPARIAN HABITAT MAPPING PROJECT CLASSIFICATION SCHEME
CATEGORY	MAP CODE
RIPARIAN TREES
Wet Spring, Aspen	WS/TAA
Wet Stream, Aspen	WST/TAA
Wet Stream, Cottonwood	WST/TCW
Wet Spring, Lodgepole Pine	WS/TLP
Wet Stream, Lodgepole Pine	WST/TLP
Wet Spring, Spruce/Fir	WS/TSF
Wet Stream, Spruce/Fir	WST/TSF
RIPARIAN SHRUBS
Wet Spring, Willow	WS/SWI
Wet Stream, Willow	WST/SWI
RIPARIAN HERBACEOUS
Wet Spring, Grass	WS/GRA
Wet Stream, Grass	WST/GRA
WATER BODIES
Pond	P
Lake	WLK
NON-RIPARIAN
Non-Riparian	X
Both polygon features and line features are mapped using this classification scheme, color infrared (CIR) aerial photographs, 7.5 minute topographic base maps and a minimum mapping unit (MMU) of 2 acres.  Riparian line features were delineated where the width of the riparian area was less then 160 feet.  This classification scheme utilizes a dominant methodology of describing riparian habitat.

       The Division of Wildlife continues to modify the Riparian Vegetation Classification Scheme on an ongoing basis adding additional subclasses as we encounter new habitat types in different geographic regions of the State.  What must be kept in mind, however, is balancing classification complexity, classification accuracy, and cost.  The more complex the classification scheme the greater potential for reducing the overall classification accuracy.  Additionally, the more complex the classification scheme the greater the cost to delineate and process the maps.  A balance must be maintained and these trade-offs weighed when making any changes to the classification scheme.
 

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