3.0 BEU MAPPING METHODOLOGY

During the early development of the Biophysical Habitat Mapping Methodology, two main goals were identified: (1) to provide a framework to assess the suitability and capability of the land surface for supporting wild animals (Demarchi et. al., 1983; Fuhr and Demarchi, 1990), and (2) to provide a framework for improving animal habitat (Demarchi et. al., 1990). Therefore, mapping was completed based on existing mapping and data sources including: ecoregion, biogeoclimatic zonation mapping, terrain, soil and vegetation mapping where available, landsat imagery, forest cover mapping, as well as unpublished data available from regional and headquarters offices. This mapping was completed without any fieldwork required. The smallest scale maps are used for provincial planning.

3.1 Basemap Development

Ecoregion Classification and Biogeoclimatic Ecosystem Classification each have their place in the broad ecosystem mapping framework. The ecosection is the ecoregion classification unit displayed on ecosystem maps; it is always mapped as a simple map unit. Within each ecosection polygon, there may be a number of BEC subzone, variant, and/or phase polygons, as well as numerous broad ecosystem unit polygons. Each BEC subzone/variant unit is always mapped as a simple map unit. British Columbia is mapped to the ecosection at 1:250,000 and to the BEC subzone/variant level at scales ranging between 1:100,000 and 1:500,000 for each of the forest regions (MoF, Research Branch unpubl.).

Delineation of Broad Ecosystem Units is completed by independent contractors who utilize standardized basemap information which is provided to them by government inventory agencies. The first step in the mapping process is to define the project area (i.e., spatial and non-spatial attributes) at a 1:250,000 scale. A basemap is created by delineating the project boundary, then mapping the ecosection lines, BEC lines, and waterbody features taken from 1:250,000 topographical maps. These polygons are delineated by major slope classes and then by major landform types. This basemap is provided to the contractor(s).

3.2 Map Unit Delineation and Labelling

Broad ecosystem map unit delineation begins with the collection of all relevant materials. The next step is involves registering a mylar copy of the basemap over 1:250,000 satellite images. Ecoregion and biogeoclimatic polygons are labeled with the appropriate symbols for the ecosection, biogeoclimatic zone, subzone, and/or variant. The ecosystem map units are then typed out and labelled accordingly. One or two broad ecosystem units may occur per broad ecosystem map polygon. When the polygon represents a complex of two BEUs the label will display the approximate percentage of the polygon that is represented by each ecosystem types.

If necessary, the appropriate symbols for the ecosystem unit modifiers and structural stages are also included in the label. Broad ecosystem unit modifiers define a set of particular site characteristics that vary from the typical characteristics described for each broad ecosystem unit (see table 1). Structural stages are used as a way of classifying the gradual transition of an ecosystem from a non-vegetated pioneer state to a potential over-mature climax state. The structural stages used in the broad ecosystem classification are listed in table 2.

Table 1. Modifiers used for the 1:250,000 scale broad ecosystem mapping (definitions adapted from Resources Inventory Committee, 1995).

Symbol	Modifier	Defining Criteria
c	coarse-textured soils	ecosystems occur over coarse-textured soils, including sandy loam, loamy sand and sand textures; fine matrix with over 70% coarse fragments and medium matrix with over 35% coarse fragments.
f	fine-textured soils	ecosystems occur over fine-textured soils, including heavy clay, silty clay, clay and sandy clay textures.
g	gently sloping	limited to alpine ecosystems that have slope gradients which are greater than 3% and less than 15%.
l	shallow (lithic) soils	ecosystems occur where the soils are considered shallow to bedrock (0 - 100 cm depth).
m	moist soils	ecosystems occur where the soils are considered wetter than average.
n	cool (northerly) aspect	ecosystems occur on moderately steep to steep slopes (slope gradient greater than 25%) which have a cool, northerly or easterly aspect (285 to 135 degrees).
s	steep, warm (southerly) aspect	ecosystems occur on steep slopes (slope gradient greater than 35%) which have a warm, southerly or westerly aspect (135 to 285 degrees).
t	moderate, warm (southerly) aspect	ecosystems occur on moderately steep slopes (slope gradient between 25% and 35%) which have a warm, southerly or westerly aspect (135 to 285 degrees).
u	upper elevation, gentle slope	limited to upper elevation forested ecosystems, that have slope gradients which are greater than 3% and less than 15%.

A maximum of three seral stages can be listed for each ecosystem map unit. When multiple seral stages are mapped for a single ecosystem unit, the approximate percentage of the map unit that is covered by each of the seral stages must also be displayed in the map label. Some examples of broad ecosystem map labels are shown in figures 1 and 2.

Table 2. Seral stages used for 1:250,000 scale BEU mapping (RIC, 1995).

#	Seral Stages	Defining Seral Stage Characteristics	Age Criteria
0	non-forested units	Climax or disclimax communities dominated by herbaceous or shrubby vegetation less than 10m tall (ie; alpine, snow fields, avalanche tracks, grasslands, wetlands).Some communities dominated by bryophytes and lichens, especially where there is little or no soil development (ie; rock outcrops, talus).	Up to 100+ yrs.
1	recent disturbance	Communities representative of early successional stages following recent disturbance (ie; fire, logging). Includes initial stages in primary or secondary succession with less than 10% cover of vascular plants; as well as more advanced stages of succession where the communities may be shrub or herb dominated, with greater than 20% shrub or herb cover (or greater than 33% of total cover) and total tree cover less than 10% (seedling and advance regeneration may be abundant).	less than 20 yrs. for normal forest succession
2	young forests, coniferous	Forests dominated by coniferous trees (cone-bearing with needle-shaped, scalelike leaves), that are greater than 10 m tall and have overtopped the shrub and herb layers. Younger stands (usually 10 -30 yrs) are typically dense and remain this way until self-thinning and canopy differentiation into distinct layers (dominant, co-dominant and suppressed) becomes evident. This may be begin as early as age 30, depending on the tree species and ecological conditions.	less than 60 yrs.
3	young forests, broad-leaved or mixed	Forests dominated by broad-leaved trees (broad, flat surface leaves) or dominated by a mixture of coniferous and broad-leaved species, that are greater than 10 m tall and have overtopped the shrub and herb layers. Younger stands (usually 10 -30 yrs) are typically dense and remain this way until self-thinning and canopy differentiation into distinct layers (dominant, co-dominant and suppressed) becomes evident. This may be begin as early as age 30, depending on the tree species and ecological conditions.	less than 60 yrs.
4	mature forests, coniferous	Coniferous trees that were established after the last disturbance have matured and a second cycle of shade tolerant trees may have become established; understories become well developed as the canopy opens up.	60 to 140 yrs.
5	mature forests, broad-leaved or mixed	Broad-leaved and coniferous (if present) trees that were established after the last disturbance have matured and a second cycle of shade tolerant trees may have become established; understories become well developed as the canopy opens up.	60 to 140 yrs.
6	old-growth	Old, structurally complex stands comprised mainly of climax tree species, although older seral remnants may still be present in the upper canopy; standing snags and rotting logs on the ground are common and understories are typically patchy.	greater than 140 yrs.

Figure 1. A Sample Broad Ecosystem Unit Map Label

* The example above depicts how a broad ecosystem map unit can represent more than one seral stage.
** Note: not all of the required information is included in this sample label.

* The example above shows all information which is required to appear in a complex broad ecosystem.

Figure 2. A Sample Broad Ecosystem Polygon Map Label.

A draft 1:250,000 mapsheet is edited and once completed a final version of the BEU map is created. The maps are digitized and all relevant information is stored in an accompanying database(s). Standardized BEU polygon ratings are completed for different values (i.e., wildlife capability and suitability) from which interpretive maps may be drafted.