Appendix I:
Ecoregion Schemes for the Old Crow Basin
In this appendix the history and nature of the various ecoregion classification schemes for the Old Crow Basin area, found in the published literature, are reviewed. From these classifications and the results of the present synthesis a classification system is developed for use in this Vuntut National Park Resource Description and Analysis.
The first ecoregion classification system for the area was that developed during the 1971-72 terrain mapping study for the Northern Pipeline study (Zoltai and Pettapiece 1973, Tarnocai 1973, and GSC Open File 167). These and later studies produced a surficial geology map and a terrain sensitivity map. The surficial geology map (Hughes 1972, GSC map 1319A) can be seen in the Supplement to this RD&A (mapsurgeo1&2 and Hmapsmall and Hmapleg1,2) and the terrain sensitivity map can be seen in
Soils Figure 6.7b and in the Supplement (TerainSenmap and TerainSenmapleg). Most of Vuntut National Park and the Old Crow Flats Special Management Area fall in Zone 1 (Figure A1.1). The British Mountains in the northern park area are shown as Zone 0 and the Old Crow Range area is shown as Zone 0 on the early versions of this map.
Wiken et al. (1981) published an extensive ecological land survey report and map which establishes ecoregions and ecodistricts for the Northern Yukon. Their four ecoregions are shown in Figure A1.2a. These were further subdivided into ecodistricts as seen in Plate VI. For their study of Ivvavik National Park they also defined ecosections and digitized the attributes (the various features of the ecosection e.g., physiography, vegetation, soils) of these ecosections on Spans (GIS). These data were not available to the present study. The relationship of the Wiken ecoregions and ecodistricts to Vuntut National Park and the Old Crow Flats Special Management Area is shown in Figure A1.2a and Plate VI. The Wiken et al. (1981) classification and ecodistricts will be referred to as "Wiken" ecodistricts in the present report. In the Wiken classification system, the Old Crow Basin Ecoregion includes the Old Crow Flats as well as the Old Crow Pediments and Thomas Creek, the northwestern portion of the transition from the Northern Mountains to the Old Crow Flats. The Wiken Northern Mountains ecoregion includes the northern third of Vuntut National Park and the very easternmost part of the Old Crow Flats Special Management Area (Figure A1.2a).
A more recent system of classification based on the national ecological framework for Canada (Figure A1.2b and Figure A1.2c, Environment Canada 1997) was adopted by the Yukon Ecoregion Working Group (YEWG 1999). As shown in Figure A1.2d., the relationship of these ecoregions to the topography shows particularly well on the three-dimensional map of the Old Crow Basin (Plate III). The attributes for this classification will be published in 2000 and will include a digital database. This ecoregion system has both names and numbers (Figure A1.2c).
The main difference in the YEWG system in comparison to the Wiken system is that the Old Crow Flats has been made an ecoregion rather than an ecodistrict. The YEWG Old Crow Basin Ecoregion refers only to the pediments and transition zone surrounding the Flats but not to the Flats themselves. The Bluefish Basin (in which the town of Old Crow is situated) and the portion of the Old Crow River valley joining it to the Old Crow Flats has been classified as part of the Old Crow Flats Ecoregion in the YEWG scheme (Figure A1.2d and Plate VII).
The mountainous region is called the British-Richardson Mountains Ecoregion in the YEWG system and does not cover as much of the park and special management area as Wiken’s Northern Mountains Ecoregion did. In the north, this is largely because the Timber Creek Ecodistrict and the western portion of the Whitefold Hills Ecodistrict are included in the YEWG Old Crow Basin Ecoregion rather than the mountains ecoregion. The reason for this can be seen on the 3D projection of the basin (Plate III) which shows that most of this area is of relatively low relief except for a line of hills running across the southern edge of the basin bordering the Old Crow Flats. In the east, the boundary of the YEWG mountain region is generally further to the east, closer to the Richardson Mountains, than the Wiken boundary. In the south, the Old Crow Range is in the YEWG Old Crow Basin Ecoregion, while in the Wiken classification it was in the North Ogilvie Mountains Ecoregion.
In the YEWG classification (Plate VII) there is at present considerably less detail at the ecodistrict level than in the Wiken classification (Plate VI). The Old Crow Flats and the Old Crow Basin Ecoregions are not subdivided at all and only a few ecodistricts are delineated in the YEWG British-Richardson Ecoregion. In order to allow for the incorporation of the YEWG digital database in future studies of the Park, but not lose the added detail available from the Wiken ecodistricts, a combination classification system has been developed for the Vuntut National Park RDA. This uses the YWEG ecoregions and subdivides these ecoregions into "Vuntut Ecodistricts" based mainly on the on the Wiken ecodistricts. This Vuntut eco-unit system is illustrated in Figure A1.3 (Plate V). The YEWG names are used for the ecoregions and new "Vuntut" ecodistricts are referred to as "Vuntut Thomas Creek Ecodistrict" etc. The outer boundaries of the Vuntut ecodistricts coincide with the outer boundary of Vuntut National Park and the Old Crow Flats Special Management Area, except in the south, where the study area is extended to include the village of Old Crow and the southern extension of the Old Crow Flats Ecoregion (which is actually the Bluefish Basin). This ecoregion thus also includes the part of the Old Crow Range which lies between the southern boundary of the Special Management Area and the southern extension of the Old Crow Flats Ecoregion. The Ecoregions and Ecodistricts used in the present report are as follows (refer to Figure A1.3 and Plate V):
i) Old Crow Flats Ecoregion OCF -YEWG 167 is the largest unit in the study area and is characterized in Figure A1.3 (and Plate V) by the pattern of (blue) lakes and rivers. The northern third of this ecoregion is in Vuntut National Park and the rest, with the exception of the southern extension into the Bluefish Basin, is in the Old Crow Flats Special Management Area. The town of Old Crow is located in this southern portion of the YEWG Old Crow Flats Ecoregion 167.
ii) Old Crow Basin Ecoregion OCB - YEWG 166 (green on Plate V)
a) Vuntut Old Crow Pediments Ecodistrict is the next largest unit in the study area. Most of this edodistrict falls in the Old Crow Flats Special Management Area but it extends into eastern Vuntut National Park.
b) Vunut Thomas Creek Ecodistrict is a transition area from the Old Crow Flats to the British-Richardson Mountains. This area extends into the National Wildlife Refuge of Alaska.
c) Vuntut Timber Creek Basin Ecodistrict is the area of mainly low relief shown on the 3D map (Figure 5). It includes the northernmost point in Vuntut National Park.
d) Vuntut Timber Creek Hills and Pediments Ecodistrict is comprised of the hills which form the southern rim of the Timber Creek Basin (which Wiken included in the Whitefold Hills Ecodistrict) and the pediments which slope south from these hills into the Old Crow Flats.
e) Vuntut Old Crow Range Ecodistrict includes the northern half of the Old Crow Range which fall in the Old Crow Flats Special Management Area, as well as the southern half of the range which falls outside the Old Crow Flats Special Management Area.
iii) British-Richardson Mountains Ecoregion BRM - YEWG 165 (brown on colour Plate V)
a) Vuntut Riggs Mountain Ecodistrict is a very small but distinctive ecodistrict in northwestern Vuntut National Park. It is the southern tip of Wiken’s Riggs Mountain Ecodistrict which is in southwestern Ivvavik National Park.
b) Vuntut Whitefold Hills Ecodistrict is the largest mountain ecodistrict in Vuntut National Park.
c) Vuntut Blackfold Hills Ecodistrict separates the Whitefold Hills from the west Barn Range in northeastern Vuntut National Park.
d) Vuntut West Barn Range Ecodistrict covers the northeastern corner of Vuntut National Park.
e) Vuntut Blow Pass Ecodistrict falls in the eastern Old Crow Flats Special Management Area. Blow Pass is the main opening into the Old Crow Basin from the north.
f) Vuntut Bonnet Lake Ecodistrict is the easternmost extension of the Old Crow Flats Special Management Area.
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