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Table 3 (cont’d). Hierarchical associations among ecosystem components for ecotypes found within Fort Greely.

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M. Torre Jorgenson, Joanna E. Roth, Michael D. Smitl Sharon Schlentner, Will Lentz, Erik R. Pullman, and Charles H. Racine Approved for public release; distribution is unlimited.

Alaska; Ecosystem mapping; Fort Greely, Alaska; Vegetation; Geomorpholog}

An ecological land survey (ELS) of Fort Greely land was conducted to map ecosystems at three spatial scales to aid in the management of natural resources. In an ELS, an attempt is made to view landscapes not just as aggregations of separate biological and earth resources, but as ecological systems with functionally related parts that can provide a consistent conceptual framework for ecological applications. Field surveys at 74 sites along 7 toposequences, and at an additiona 178 ground physiography, geomorphology, hydrology, permafrost, and vegetation. The of fire and geomorphic processes, such as groundwater discharge, floodplain development, permafrost degradation, and paludification. Ecosoystems were mapped at three spatial scales. Ecotypes ( :50,000 sca -reference locations, were used to identify relationships among association among ecosystem components also revealed effects e) delineated areas with homogenous topography, terrain, soil, surface-form, hydrology, and vegetation. Ecosections (1:100,000 scale) are homogeneous with respect to geomorphic features and water regime and, thus, have recurring patterns of soils and vegetation. Ecodistricts (1:500,000) are broader areas with similar geology, geomor- phology, and physiography. Development of the spatial database within a geographic information system will facilitate numerous manage- ment objectives such as wetland protection, integrated-training-area management, permafrost protection, wildlife management, and recre- ational area management.

b. Factors affecting ecosystem distribution occur over a range of scales within a nested hierarchy.

a. Ecotypes are local-scale ecosystems composed of various elements that exist within large regional ecosystems, or ecoregions. An ecological land classification a so requires that ecosystem components be organized at various scales (Wilken 1981, O’Neil et al. 1986, K ijn and Udo de Haes 1994, Bailey 1996) on the basis of recognizing that the state factors operate within a hierarchy of dif- fering spatial and temporal scales (Allen and Starr 1982, Delcourt and Delcourt 1988, Forman 995). This hier- archical linkage reveals that smaller scale features, such as vegetation, are nested within larger scale components, such as climate or physiography (Fig. 1b). The climate factor, particularly temperature and precipitation, ac- counts for the largest amount of variation in ecosystem structure and function globally (Walter 1979, Vitousek 994, Bailey 1998). Physiography, or broad-scale land- forms, with a characteristic geologic substrate, surface shape, and relief are the boundary conditions that con- rol the spatial arrangement and rate of geomorphic processes and thus affect the material (characteristic ithologies or soil texture) and energy flows, which in turn affect ecosystem development (Wahrhaftig 1965,

Figure 2. Location of study area and survey transects for the ecological land survey for Fort Greely.

Within interior Alaska, the interrelationships among geomorphology, slope, aspect, hydrology, permafrost, and fire result in a complex pattern of vegetation types

for their own individual purposes. Ground data can be reclassified and analyzed by regrouping characteristics in Appendix A and applying the new organization to the plot database (Appendix B). tion of Landsat Imagery, geomorphology derived from the ecosections map, and physiography from the digi- tal elevation model and ecodistricts map, we could in- tegrate several landscape components in a way that was similar to the integrated-terrain-unit (ITU) method used for mapping Fort Wainwright (Jorgenson et al. 1999).

The Landsat TM image was georectified to UTM 6, NAD 27 using 66 control points, which we obtained from prominent features on 1:63,000 USGS quad- In spring 1998, initial image classification was done using a cluster analysis algorithm (ISOCLASS) in ERMapper to generate 81 spectral classes. The process- ing incorporated bands 5 and 7 and two new bands de- rived from these bands. A “vegetation index” was cre- ated using the ratio of bands 4/3. The second band was based on the PCA of bands 1, 2, and 3 because these

Within the Molybdenum Ridge Mountains (Transect 5), geomorphology is dominated by weathered bedrock and talus on steep slopes, and colluvium and retransported deposits on toe slopes (Fig. 7a). We as- sumed that permafrost generally was present, although rocky soils prevented positive determination. The soils on upper slopes were rocky, excessively drained, and lacked organic matter accumulations, whereas the soils Within the Little Delta River Glaciated Highlands (Transect 2), the geomorphology was dominated by glacial moraines, with glaciofluvial deposits near the moraine terminus (Fig. 7c). The soils on the moraines were highly variable, ranging from massive gravel on ridges to fines with trace gravel where eolian silt has accumulated, to stratified silt and sandy material in

c. Transect 2 in the Little Delta River Glaciated Highlands.

exposed ridges supported bearberry dwarf scrub tun- dra and open low mesic shrub birch—ericaceous scrub, both of which had abundant lichens. Poorly drained soils on slopes had permafrost and supported black spruce forests. Basins had thick organic matter accumulations and supported subarctic lowland sedge wet meadows. kettle depressions. Organic matter accumulation also was highly variable. Well-drained upland sites withou permafrost had open paper birch forest and closed tal willow scrub. Poorly drained sites with permafrost had open low mixed shrub-sedge tussock bogs and open black spruce. Subarctic lowland sedge moist meadows an uncommon vegetation type, occurred in somewha well-drained, fine-grained lacustrine material in drained kettle basins. >

*Vegetation structure based on Alaska Vegetation Classification (Viereck et al. 1992): Level 2 for trees and shrubs and Level 3 for herbaceous. tIndicator species are the dominant and differentiating species.

Figure 8. Ground views of alpine, upland, gravelly lowland, and lacustrine ecotypes on Fort Greely.

Figure 9. Ground views of lowland and riverine ecotypes on Fort Greely.

Eriophorum vaginatum, V. uliginosum, Ledum decumbens, Carex bigelowii, Empetrum nigrum, and Sphagnum spp. In areas with water near the surface, Eriophorum angustifolium, Carex aquatilis, Carex canescens, Salix planifolia, Potentilla palustris, and Sphagnum spp. were important. Vegetation.The following discussion highlights some of the similarities and differences in species com- position among ecotypes. Ecotypes were grouped suc- cessively by physiography, soil texture and moisture, and vegetation structure to help us compare species composition (Table 6).

a. Mean (+SD) elevations, frequency of occurrence of permafrost, and mean thaw depths.

Figure 13. Active layer depths and permafrost occurrence at ground-reference plots on Fort Greely.

Table 8. Areal extents of geomorphic units used for differentiating ecosections found within Fort Greely.

Figure 15. Depth to gravel at ground-reference plots on Fort Greely.

Figure 16. Depth of organics at ground-reference plots on Fort Greely.

Figure 18. Aerial views of ecosubdistricts within Fort Greely.

Figure 21. Generalized profile of ecological characteristics of glaciated terrain within the Delta Lowlands ecodistrict on Fort Greely.

Figure 22. Generalized profile of ecological characteristics of floodplains and flats within the Delta Lowlands ecodistrict on Fort Greely.

Table A1 (cont’d). System used for aggregating geomorphic and vegetation classes into ecotypes classes, Fort Greely, central Alaska, 1999.

Table A1 (cont’d). System used for aggregating geomorphic and vegetation classes into ecotypes classes, Fort Greely, central Alaska, 1999.

Table B1 (cont'd). Data file listing environmental characteristics of ground-reference plots, Fort Greely Alaska, 1999.

Table C1. Omission and commission errors used to approximate the accuracy associated with mapping of ecotypes (37 classes) on Fort Greely, Alaska, 1999.

Table D3. Omission and commission errors used to approximate the accuracy associated with mapping of aggregated ecotypes (20 classes) on Fort Greely.