Alaska Arctic Toposequence Examples
- Bioclimate Subzones
- Floristic Provinces
- Lake Cover
- NDVI and Phytomass
- Substrate Chemistry
Figure 3. Toposequence of vegetation and soils along an actual west-facing hill slope on middle-Pleistocene age (about 125,000 years B.P) moraine at Imnavait Creek, Alaska (Walker and Walker 1996).
Figure 4. Six ecosystem types along a toposequence beginning in tussock tundra and ending on the floodplain of the Sagavanirktok River. The total vertical drop is about 20 m, and the horizontal distance is about 200 m (Shaver et al. 1991).
Figure 5. Sampling approach used for the analysis of soils and vegetation on 41 pingos in northern Alaska. The concentric lines are topographic isoline of a 12-m high pingo. Each pingo was sampled at the seven microsites (black dots): (1) ENE wind-exposed, (2) summit (usually site of animal dens and bird perches), (3) dry leeward side above the snowbank, (4) middle of snowbank on leeward side (well drained), (5) bottom of snowbank at leeward base of pingo (poorly drained), (6) south slope, (7) north slope. Sites 1, 2, 3, 4 and 5 formed a toposequence (Walker MD 1990).
Examples from the literature for northern Alaska:
Toposequences have been used to conceptualize the natural vegetation variation of four key vegetation and soil studies in northern Alaska:
- at Prudhoe Bay (Fig. 2)
- Imnavait Creek (Fig. 3)
- a river terrace of the Sagavanirktok River (Fig. 4)
- pingos of the central Arctic Coastal Plain (Fig. 5)
Generalized toposequences for Arctic Alaska
Mesotopic Gradient Position legend colors:
- Dry exposed site
- Moist site
- Wet site
- Snowbed, early-melting
- Snowbed, late-melting
- Riparian site, active
- Riparian site, stable
During the making of the CAVM, a generalized toposequence was used to help organize the plant-community information from each bioclimate subzone and floristic province (Fig. 6). The table for the Alaska portion of the CAVM is presented on the back of the Alaska Arctic Vegetation Map (Raynolds et al. 2006). This table has been reformatted with short names for each plant community (Table 1) with an explanation of the naming convention for the plant communities and the organization of the table.
This information has been used to make toposequence diagrams for the Zonal toposequences in the Northern Alaska Province of the AATVM, which is currently the main focus of the Arctic Geobotanical Atlas.
More information about toposequences.