Fort Greely ecological land survey
Swanson et al. 1988, Bailey 1996). Soil moisture and
hydrologic movement are critical factors in the water
In this report, we evaluate and present three levels
balance of plants and the availability of nutrients (Fit-
of ecosystem organization, ecotypes (1:50,000 scale),
ter and Hay 1987, Oberbauer et al. 1989). Vegetation
ecosections (1:100,000), and ecodistricts (1:500,000).
typically is the most important factor controlling the
Ecotypes (also called local ecosystems, ecotopes,
trophic structure of ecosystems, because it controls pri-
landtype phases, or vegetation types) delineate areas
mary productivity, affects material and energy ex-
with homogenous topography, terrain, soil, surface-
changes, provides structure and energy for other trophic
form, hydrology, and vegetation. Ecosections (also land-
levels, and affects soil erosion and geomorphic pro-
scapes, landtype associations, or geomorphic sections)
cesses (Walter 1979, Bailey 1996). For biotic classifi-
are homogeneous with respect to geomorphic features
cations, vegetation has an advantage over faunal com-
and have recurring patterns of water regimes, soils, and
ponents because plants are relatively immobile and
vegetation. Although several vegetation classes can be
therefore easier to characterize and map (Brown et al.
included in an ecosection, the vegetation classes usu-
1998). Natural and human disturbances have long been
ally are related because they occur as different stages
recognized as important factors affecting the timing and
in a successional sequence. Ecodistricts (or subregions,
development of ecosystems (Watt 1947, Pickett et al.
physiographic districts) are broader areas with similar
1989, Forman 1995).
geology, geomorphology, and hydrology. Ecoregions
Beyond this conceptual framework of state factor
(or climatic zones), which differentiate areas based on
control, however, there is no single natural scale at
their climatic regimes and gross physiography, have
which ecological phenomena should be studied. This
been mapped recently for Alaska by Gallant et al.
leads observers to impose their own perceptual bias in
(1995), although their criteria differed slightly from
the study of the patterns and processes of ecological
those mentioned above.
phenomena (Levin 1992, Shugart 1998). In addition,
The spatial databases produced by this project are
there is no nationally accepted approach to classify-
being incorporated into numerous studies. Associations
ing ecosystems, although recent efforts have been
between ecotypes and wetland status will be used to
made to develop a consensus among Federal agencies
delineate jurisdictional wetlands (Lichvar and Sprecher,
(ECOMAP 1993) and among nations (Klijn and Udo
in prep.). The mapping has been used to stratify field
de Haes 1994, Uhling and Jordan 1996). In this
sampling and to analyze habitat use (Anderson et al.
report, we generally have followed the scales and
1999). Other applications include analysis of perma-
differentiating criteria described by Klijn and Udo de
frost occurrence and degradation, and stratification of
Haes (1994), which combine elements of both
monitoring locations for the Land Condition and Trends
the Canadian (Wiken and Ironside 1977) and U.S.
Analysis program.*
systems (ECOMAP 1993). Our system uses numerous
Study area
spatial scales for mapping ecosystems and identifies
various ecosystem components as the prime criteria
Fort Greely is located near Delta Junction in central
for differentiating successive levels of hierarchical
Alaska and covers approximately 267,636 ha (661,341
organization.
acres) of land (Fig. 2). Included within Fort Greely are
In Alaska, a hierarchical approach to vegetation and
the West Training Area (231,479 ha between the
land cover mapping has been developed for northern
Richardson Highway and Little Delta River), the East
Alaska by Walker and his colleagues (Walker 1983,
Training Area (20,879 ha between the Richardson High-
Walker et al. 1989, Walker and Walker 1991). They also
way and Granite Creek), and the Main Post. Three out-
applied an integrated, geobotanical approach to map-
lying training areas, the Gerstle River Test Site, Black
ping ecosystem components in the Prudhoe Bay region,
Rapids Training Area, and the Whistler Creek Rock
but they did not create a hierarchy of integrated units
Climbing Area, were not included in this ELS; thus,
(Walker et al. 1980). Recently, an integrated-terrain unit
our study area for mapping covered 260234 ha.
approach has been used for large-scale mapping of eco-
Fort Greely originated as Station 17, Alaska Wing
systems on the Arctic Coastal Plain (Jorgenson et al.
of the Air Transport Command, in 1942 to serve as a
1997) and in interior Alaska (Jorgenson et al. 1999),
refueling stop and was reduced to inactive status in 1945
and for mapping vegetation complexes across the en-
(CEMML 1998). In 1948, the installation was reacti-
tire North Slope (Walker 1997). Land cover mapping
also has been done for Tanana Valley and adjacent
*Personal communication with Cal Bagley, Center for Eco-
Alaska Range by the Bureau of Land Management
logical Management of Military Lands, Fort Collins, Colo-
(USBLM 1997).
rado, 1999.
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