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CHAPTER 2
Landscape Ecology
Evaluation of the
Preliminary Draft EIS
Alternatives
WendelJ. t-Iann
Michael G. "Sherm" Karl
Jeffrey L. Jones
Rebecca A. Gravenmier
Donald G. Long
James P. Menakis
Robert E. Keane
Wendel J. Haim, Landscape Ecologist, USDA Forest Service and USDI Bureau of Land Management,
Interior Columbia Basin Ecosystem Management Project, Walla Walla, WA/Boise, ID
Michael G. "Sherm" Karl, Rangeland Management Specialist-Ecologist, USDA Forest Service, Pacific
Northwest Research Station, Interior Columbia Basin Ecosystem Management Project, Walla Walla, WA
Jeffrey L. Jones, Ecologist and Wildlife Biologist, USDA Forest Service, Northern Region, Missoula, MT
Donald G. Long, Forester, USDA Forest Service, Intermountain Fire Sciences Laboratory, Missoula, MT
Rebecca A. Gravenmier, Natural Resource Specialist/GIS, USDI Bureau of Land Management, Oregon
State Office, Portland, OR
James P. Menakis, Forester, USDA Forest Service, Intermountain Fire Sciences Laboratory, Missoula, MT
Robert E. Keane, Research Ecologist, USDA Forest Service, Intermountain Fire Sciences Laboratory,
Missoula, MT
30
Landscape Ecology
TABLE OF
CONTENTS
Introduction
Landscape Evaluation Process
Assumptions About Landscape Integrity and Management Approaches
Landscape Integrity Assumption 1
Landscape Integrity Assumption 2
Landscape Integrity Assumption 3
Landscape Integrity Assumption 4
Landscape Integrity Assumption 5
Landscape Integrity Assumption 6
Landscape Integrity Assumption 7
Landscape Integrity Assumption 8
Landscape Integrity Assumption 9
Simulation Strategies Used for Evaluation of Alternatives
Prescription Models
Alternative Emphasis and Prescription Assignments
Preliminary Draft EIS Alternative Disturbances and Simulated Disturbances
Implementation and Allocation of Activity Levels from Preliminary Draft EIS
Alternative 1 and 2
Alternatives 3 through 7
S u m m a r y of Cont~dence in Predictions and Qualifiers
Evaluation of Landscape Disturbances
Relation of Disturbance Levels and Standards in Preliminary Draft EISs to
Evaluation of Alternatives
Forest Disturbances
Prescribed Fire
Thinning and Harvest
Wildt~re
Forest Crown Wildfire
Forest Mortality Susceptibility
Forest Disturbance Summary
Landscape Ecology
37
37
38
38
41
42
43
44
45
45
45
46
47
47
51
52
79
79
79
79
91
91
92
92
92
92
98
98
101
Rangeland Disturbances
Prescribed Fire
Range Improvements and Plan Revision/Implementation
Grazing
Exotics
Rangeland Wildfire
Rangeland Disturbance Summary
Landscape Scale Disturbances
Total Direct Disturbance
Wildfire
Soil Disturbances
Ability to Mimic Native Composition and Structure
Spatial Distribution of Disturbances
Alternative Management Activity Levels
Simulations Compared to Alternative Management Activities
Terrestrial Communities
Methods for Evaluating Terrestrial Communities
Assumptions and Notes About Simulation Methods and Results
Riparian Communities
Exotic Herbland
Terrestrial Communities in Alternative 7
Results of Evaluating Terrestrial Communities by Alternative
Alternative 1
Alternative 2
Alternative 3
Alternative 4
Alternative 5
Alternative 6
Alternative 7
Discussion
Eastside EIS Area
Montane Forests
Subalpine Forests
Upland Communities
Riparian Communities
Exotic Herbland Communities
Upper Columbia River Basin
Montane Forests
Subalpine Forests
Upland Communities
32
Landscape Ecology
101
101
102
102
102
102
106
106
106
107
109
109
110
112
114
119
120
120
120
122
122
122
122
129
137
139
140
142
143
145
146
146
154
154
162
162
162
162
163
169
Riparian Communities
Exotic Herbland Communities
Summary
169
169
170
Terrestrial Community Departures
171
Methods of Evaluating Terrestrial Community Departures
Results of Evaluating Terrestrial Community Departures
171
172
Alternative 1 Departures
Montane Community Departures in Alternative 1
Subalpine Community Departures in Alternative 1
Upland Community Departures in Alternative 1
Alternative 2 Departures
Montane Community Departures in Alternative 2
Subalpine Community Departures in Alternative 2
Upland Community Departures in Alternative 2
Alternative 3 Departures
Montane Community Departures in Alternative 3
Subalpine Community Departures in Alternative 3
Upland Community Departures in Alternative 3
Alternative 4 Departures
Montane Community Departures in Alternative 4
Subalpine Community Departures in Alternative 4
Upland Community Departures in Alternative 4
Alternative 5 Departures
Montane Community Departures in Alternative 5
Subalpine Community Departures in Alternative 5
Upland Community Departures in Alternative 5
Alternative 6 Departures
Montane Community Departures in Alternative 6
Subalpine Community Departures in Alternative 6
Upland Community Departures in Alternative 6
Alternative 7 Departures
172
172
173
174
175
176
181
182
182
183
184
184
184
185
186
186
187
187
188
188
189
189
190
190
191
Montane Community Departures in Alternative 7
Subalpine Community Departures in Alternative 7
Upland Community Departures in Alternative 7
Discussion on Departures of the Alternatives
191
192
192
193
Departure Discussion by Community
193
Montane Departures
Subalpine Departures
Upland Departures
Summary of Terrestrial Community Departures
193
194
195
196
Landscape Ecology
33
Vegetation Response and Disturbance Patterns
Forest Potential Vegetation Groups
Lower Montane Forest Response
Early-Serai Lower Montane Forest
Mid-Serai Lower montane Forest
Late-serai Multi-layer Lower montane Forest
Late-serai Single-layer Lower Montane Forest
Montane Forest Response
Early-serai Montane Forest
Mid-serai Montane Forest
Late-serai Multi-layer Montane Forest
Late-serai Single-layer Montane Forest
Subalpine Forest Response
Early-Serai Subalpine Forest
Mid-serai Subalpine Forest
Late-serai Multi-layer Subalpine Forest
Late-serai Single-layer Subalpine Forest
Rangeland Potential Vegetation Groups
Upland Herbland
Exotic Herbland
Upland Shrubland
Upland Woodland
Rangeland Riparian
Alpine
34
198
198
200
203
206
209
209
212
216
220
223
223
225
228
230
232
234
236
238
240
241
241
Summary
Effects of Alternatives on Selected Noxious Weeds and
Cheatgrass on Rangeland
Methods Used in Evaluating the Effects of Alternatives on Noxious Weeds
and Cheatgrass
Assumptions for Rangelands
Rangeland Assumption
Rangeland Assumption
Rangeland Assumption
Rangeland Assumption
Rangeland Assumption
Rangeland Assumption
Rangeland Assumption
Rangeland Assumption
Rangeland Assumption
197
197
1
2
3
4
5
6
7
8
9
Landscape Ecology
241
243
243
244
244
245
246
246
246
246
246
246
247
Discussions on Effectiveness of Alternatives in Integrated Weed Management
247
Dry Grass Potential Vegetation Group, EEIS
Dry Grass Potential Vegetation Group, UCRB
Dry Shrub Potential Vegetation Group, EEIS
Dry Shrub Potential Vegetation Group, UCRB
Cool Shrub Potential Vegetation Group, EEIS
Cool Shrub Potential Vegetation Group, UCRB
247
252
258
264
268
275
Summary and Synthesis of Landscape Findings
281
Results and Discussion
281
Forests
Rangeland
281
282
Summary of Response
283
Succession/Disturbance Regime
Vegetation Change
Consistency of Standards
Landscape Integrity Summary Ratings
Simulations Compared to Alternative Management Activities
283
288
289
289
290
Terrestrial Communities
292
Acknowledgments
References
Appendix 2-A
Appendix 2-B
Appendix 2-C
Appendix 2-D
Appendix 2-E
Appendix 2-F
Appendix 2-G
Appendix 2-H
Appendix 2-1
Appendix 2-J
Appendix 2-K
Appendix 2-L
Appendix 2-M
Appendix 2-N
294
295
299
305
321
327
329
331
341
347
349
351
365
405
419
429
Landscape Ecology
35
36
Landscape Ecology
Introduction
The landscape evaluation of alternatives for the
Eastside and Upper Columbia Preliminary Draft
Environmental Impact Statements (PDEISs) presents a comparison of outcomes for key landscape
variables across the seven alternatives for the
Basin.1 The evaluation process involved simulation
and analyses of predicted effects, and also qualitative evaluation, of the alternatives as described in
direction to the Science Integration Team (SIT) in
a letter dated February 26, 1996.2 The relationship of the Evaluation of Alternatives to both the
assessment and the EIS alternatives is shown in
figure 2.1. The relation between the assessment
data and EIS scale is shown in figure 2.2.
This chapter has seven sections:
1) Overview of the landscape ecology evaluation
of alternatives, including a statement of
assumptions.
2) Overview of the simulation methods used for
predicting spatial and temporal responses to
different levels of management treatments and
disturbances.
3) Responses of vegetation to management and
other disturbances.
4) Responses of terrestrial vegetation and habitats,
and their interrelationships.
5) Evaluation of vegetation response and disturbance patterns.
6) Effects of selected noxious weeds and cheatgrass on rangeland in the Basin.
7) Summary, including conclusions.
The methods used for the evaluation of alternatives involved mapping land management and disturbance prescription response and assumptions
based on alternatives developed by the EIS teams.
Background information on the development,
characteristics, and response of various landscapes
to the different types of prescriptions is documented in Landscape Dynamics of the Basin (Hann
and others, in press), Chapter 3 of the Assessment
of Ecosystem Components in the Interior Columbia
Basin and Portions of the Klamath and Great Basins
(Quigley and others, in press). Vegetation and disturbance responses are modeled using the Columbia River Basin SUccession Model (CRBSUM)
(Keane and others 1996), in association with the
Columbia River Basin Landscape Analysis Data
Base (CRBLAD) (Gravenmier and others, in
press), and a variety of associated simulation
methods (Hann and others 1997).
The purpose of landscape dynamics evaluation is
to predict the effects of the alternatives on landscape components (table 2.1). These components
vary depending on the management emphasis of
the alternatives (table 2.2; appendix 2-C). The
seven different alternative themes in the preliminary draft EIS have a broad range of outcomes
considering the variation in landscape components and the differences in spacial location and
effects through time.
Landscape Evaluation Process
Direct linkages between each alternative's desired
future conditions (DFCs),3 objectives and standards (appendix I), and the emphasis areas by
'The Basin is defined as those portions of the Columbia River basin inside the United States east of the crest of the Cascades and
those portions of the Klamath River basin and the Great Basin in Oregon.
The version of the EIS alternatives under evaluation here was presented to the SIT on February 26, 1996 in a package titled
"Alternatives Package for SIT Evaluation for Eastside and UCRB EISs." On file with: U.S. Department of Agriculture, Forest
Service; U.S. Department of Interior, Bureau of Land Management; Interior Columbia Basin Ecosystem Management Project,
112 E. Poplar, Walla Walla, Washington, 99362.
3
Desired Future Condition (DFC) is a portrayal of the land, resource, or social and economic conditions that are expected to
result in 50 to 100 years if objectives are achieved; in this document, portrayed as a range of conditions. A vision of the long-term
condition of the land. See appendix I for a description of the DFCs for each of the alternatives.
Landscape Ecology
37
forest and range clusters in the EISs were not
always clear. For example, many of the objectives
and standards were written for fine-scale features
that were not necessarily linked, in either a spatial
or temporal context, with the broad-mid-fine
scale hierarchy depicted in figure 2.2. Many of the
standards apply single size/state conditions to ecological functions that are inherently variable. As
such, standards applicable to the finer scales may
be unrelated to the mid and broad scale. As an
alternative is implemented, potential for conflict
between the overall theme, objective, forest and
range cluster emphasis, activity levels, mid-scale
patterns, and the finer-scale standards exists. To
reduce this potential for conflict and proceed with
outcome projections, it was necessary to make
assumptions relative to management prescriptions,
management activities, and ecological "fit" of the
single size/state standards. The purpose of the
assumptions was to provide clarity about implementation of an alternative.
Treatment prescriptions were assumed to be either
traditional or ecological, or to have minimal treatment (as in the reserves) (table 2.3). Treatment
emphasis differs among alternatives. Management
prescriptions emphasized in Alternatives 1 and 2
are traditional, Alternatives 3 through 6 are ecological, and Alternative 7 is a mix of reserve and ecological. It was also assumed that Alternatives 1 and
2 would be implemented in a traditional programmatic allocation with no emphasis on multi-scale
relationships, while Alternatives 3 through 7 would
be implemented with varying emphasis on interconnected spatial and temporal scales (figure 2.2).
Assumptions About Landscape
Integrity4 and Management
Approaches
Two important measures of landscape integrity at
all scales are: (1) ecosystem integrity (both ecological and socioeconomic), and (2) diversity of
native habitats and associated processes. Generally,
in wildland environments, native communities are
more productive and more resilient to disturbances such as fire, drought, and insects/disease,
than are communities that have been simplified
by traditional agricultural, forest, or range management, or by conversion to exotic5 communities. As native habitats are simplified or converted
to exotics, there is a decline in the native fauna
and flora that depend on these habitats. Management that conserves native habitats avoids further
declines in native species, productivity and
resiliency.
Listed below are the assumptions about the types
of management that would be used to implement
the alternatives. The assumptions are expectations
of how management would sustain landscape
integrity on BLM- and FS-administered lands.
Landscape Integrity Assumption 1:
Landscape Approach to Management —
Through time, the management of BLM- and FSadministered lands shifts increasingly toward a
landscape approach. Under this assumption, the
BLM- and FS-administered lands are managed as
a whole within watersheds and as connected lands
between watersheds. Forests and rangelands intermingled within or between watersheds are managed on an integrated basis for both resources and
habitats. Hydrologic and riparian regimes within
watersheds are managed as integral networks.
Managers recognize that ownership pattern strongly affects implementation of a landscape approach.
Watersheds dominated by continuous BLM and
FS oversight would have the best chance for
achieving long-term desired patterns, while watersheds with mosaic or mixed ownership would have
less chance. In contrast, managers recognize that
disjunct BLM or FS parcels in environments with
little BLM or FS ownership may be highly valuable for remnant native habitats.
'Landscape integrity is synonymous to landscape health based on proper functioning systems at a landscape scale. See Chapter 3
of the landscape assessment (Hann and others, in press) for definitions and discussion.
^Exotics are non-native plants; biota from a different area or environment that migrated to the area with the assistance of humans.
38
Landscape Ecology
Science
Assessment
ElSand
Decision
Evaluation of
Alternatives
Figure 2.1 — Relationship of Evaluation of Alternatives to the Science Assessment and EISs.
Landscape Ecology
Scale
EIS
Assessment
Broad
Theme, DFCs,
Strategic emphases,
Objectives, Activity
standards and
guidelines
>
Forest/Range clusters
Management
prescription models
predicted response
I (from CRBSUM)
Mid
Standards,
Guidelines,
Subbasins and
watershed type
priorities
Patterns of fragmentaiton,
Patch size/shape,
Potential disturbance
(from watershed sample
data), Assumptions in
management prescription
models
Fine
Standards and
guidelines,
Species habitats,
Snags, Riparian,
Soil productivity <
Figure 2.2 — Relationship between Assessment data and EIS scales.
Landscape Ecology
Composition and
structure, Species, Snags
(from Stand, Patch, Plot
Data), Assumptions in
management prescription
3
models
Landscape Integrity Assumption 2:
Successful Ability to Mimic/Represent
Processes — Managers develop the ability to
assess and implement landscape management to
more closely resemble native landscape mosaics,
biotic community structure and composition, and
processes over space and time. This does not infer
that these conditions are representative of the historical range of variability (HRV), which is the
variability of regional or landscape composition,
structure, and disturbances during a period of
time for several cycles of the common disturbance
intervals and for similar environmental gradients.6
In essence, managers promote a balance of land
use and ecosystem integrity that sustains native
habitats while producing human resource values
within the limitations of biophysical systems and
inherent disturbance processes.
also provides a useful tool for understanding cause
and effect, and thus, risk of undesired outcomes.
Managing for HRV in a regime that has a substantially unbalanced biophysical composition
could cause changes detrimental to native conditions and processes. Unbalanced regimes include
areas having: exotic species, historically common
species that are now rare, disrupted hydrologic
systems, high fuel loading, simplified native diversity, composition and structure that are incompatible with the biophysical succession/disturbance8
regime, or have degraded soils. Management for
HRV is not appropriate for many types of land
use that balance restoration and mitigation to sustain ecological integrity and native habitats with
socioeconomic resiliency.
Emphasis should be placed on understanding and
managing within the limitations and options of
the biophysical template (BPT)7 to conserve
processes associated with native composition and
structure. The biophysical template refers to an
area's mosaic of inherent patterns of composition
and structure, including environmental gradients
and dynamics of disturbance that developed
through evolutionary time. This concept, developed from work by Jenny (1958) and Major
(1951), is described in detail by Hann and others
(in press).
Representation of native conditions and processes
is generally most successful in natural and natural/
human-influenced management areas. In these
areas, managers utilize planned and unplanned
prescribed fire and flexible wildfire suppression
strategies to represent native landscape patterns
and represent native fire regime severity and intervals. Livestock grazing is managed in these areas to
generally preclude departure from the native
succession/disturbance regimes. However, the transition to native patterns occurs carefully to avoid
loss of key elements (such as large trees or stronghold rare aquatic populations), site capability, or
invasion of exotic species.
The historical range of variability provides an
assessment tool to monitor biodiversity for either
departure, or similarity of conditions or processes,
to native pre-Euro-American settlement. HRV
On human-influenced management areas, managers use various treatments to produce the types
of communities and landscape structures somewhat characteristic of the native regime. These
''Historical range of variability (HRV) refers to the "pre-Euro-American settlement" or "native" regime. It is not synonymous with
the historic or historical time period which we define as beginning circa 1850.
'The biophysical template can be visualized as the biological, physical, and disturbance characteristics of an environment over a
period of relatively stable climate. It is the current expression of the collective adaptations of species to competition, disturbances,
and the physical environment. It is also the current expression of the soils, landform, and hydrologic system development in
response to biotic and geomorphologic processes. Biophysical templates have characteristic succession and disturbance regimes
that are governed by the interaction oetween biotic and abiotic components. They may be altered by any disturbance (or repeated
disturbances) that change the relationships between the biotic and abiotic systems.
"We provide a classification that integrates aquatic and terrestrial systems, and succession/disturbance. We classified succession/
disturbance regimes according to 1) the severity of the disturbance relative to the subsequent change of community composition
and structure, 2) the time interval between disturbances, 3) the resiliency or rate of community development in response to the
disturbance, and 4) the mosaic created by disturbance through time.
Landscape Ecology
43.
Table 2.1 — Landscape components evaluated for alternatives.
Landscape Component
• Management prescription assumptions.
• Succession/disturbance trends and regimes.
• General trends of fine-scale variables such as snags, upland down wood, riparian down wood, forest riparian,
range riparian, and vegetation mosaic patterns.
• Similarity of current vegetation and alternative vegetation to historical range of variability.
• Physiognomic types by potential vegetation group changes.
• Physiognomic type transitions from historical to current and current to 100 years.
• Terrestrial community changes.
• Terrestrial community departure of current from historical range and alternatives from historical range.
• Forest harvest.
• Forest thinning.
• Forest prescribed fire.
• Forest insect/disease susceptibility.
• Forest wildfire.
• Forest wildfire crown susceptibility.
• Range improvements such as seeding, spraying, and woodland cutting.
• Range allotment plan revision assumptions.
• Range prescribed fire.
• Range wildfire.
• Range grazing effects.
• Exotic plants, noxious and undesirable weeds.
• Total wildfire.
• Total prescribed fire.
• Wildfire cost.
• Prescribed fire cost.
• Total fire management cost.
• Wildfire intensity.
• Prescribed fire smoke.
• Wildfire smoke.
• Total smoke and effect on visual condition.
• Ecosystem productivity processes.
treatments may include timber harvest, livestock
grazing, prescribed fire, wildfire suppression
strategies, range cultural treatments, and forest
cultural treatments. Monitoring and evaluation
are conducted to compare the outcomes and make
improvements in the landscape and communitylevel treatments.
Landscape Ecology
Landscape Integrity Assumption 3:
Hierarchical Assessment, Implementation,
Monitoring, and Evaluation — Inventory
programs and methods are redesigned based on
landscape processes and gradients to integrate ecological conditions and resource values. Vegetation
mapping emphasizes techniques such as remote
sensing using multi-scale satellite imagery to
provide information that is consistent, continuous, and current. Classification methods for mapping vegetation use hierarchies based on the vegetation's composition and structure. Landscape
planning is accomplished in a hierarchical manner
reflecting integrated broad- to fine-scale findings
in project design. Activities and changes are monitored by sampling mid- and fine-scale data, and
then statistically extrapolated to support broadscale monitoring. The evaluation process inte-
grates broad- to fine-scale landscape conditions to
evaluate change, as well as the effects of cumulative activities.
Landscape Integrity Assumption 4:
Prioritization and Integration of
Activities — Through time, activities that produce commodities and restore landscape conditions are prioritized and then implemented
with emphasis on achieving an integrated landscape and maintaining aquatic, terrestrial, and
Table 2.2 — Alternatives by management emphasis and ecological interpretation.
Alternative
Alternative
Group1
Management
Emphasis2
Management Interpretation
Alt. 1
Existing BLM/FS
Traditional prescriptions: Produce and sustain commodity
Plans. Commodity
values. Traditional commodity and wilderness managewith minimal reserves. ment and wildfire suppression.
Alt. 2
Interim BLM/FS
Plans. Commodity
with reserves.
Traditional prescriptions: Provide protection in aquatic
riparian ecosystems; same as Alternative 1 in other areas.
Reduce traditional commodity and continue traditional
wilderness management and wildfire suppression.
Alt. 3
B
Restore/produce with
local priority.
Ecological prescriptions: Restore, produce, and conserve.
Restore and/or conserve areas that have local high
priority and produce commodities.
Alt. 4
C
Restore with Basin
priority.
Ecological prescriptions: Restore, produce, and conserve.
Restore and/or conserve areas according to Basin priorities and produce commodities.
Alt. 5
B
Restore/produce with
economic
efficiency priority.
Ecological prescriptions: Conserve, produce, and restore.
Produce and/or restore where economically efficient in the
Basin and conserve with Basin priorities.
Alt. 6
C
Restore with
adaptive management
and with Basin
priority.
Ecological prescriptions: Restore, produce, and conserve
with adaptive management. Restore and/or conserve
areas based on Basin priorities, and produce commodities
with reduced rates in higher risk areas.
Alt. 7
B
Reserve the
undeveloped areas;
restore/ produce in
other areas.
Ecological/reserve prescriptions: Minor management in
reserves with minimal investment in fire suppression and
restoration; same as Alternative 3 in other areas.
'Alternative Group:
A = Alternatives with traditional prescriptions that have high departure from native succession/disturbance regimes.
B = Alternatives with ecological prescriptions that have moderate departure from native succession/disturbance regimes due to spatial and temporal
fragmentation in response to emphasis on local priorities (alternative 3); economic priorities (alternative 5), or reserve management (alternative 7).
C = Alternatives with ecological prescriptions that have low departure from native succession/disturbance regimes.
Management emphasis - see appendix 2-C for description of catagories; see table 2.4 footnote 1 for definitions.
Landscape Ecology
43
hydrologic integrity and social and economic
resiliency. These priorities are set regionally using
assessment results at the subbasin [4th-field
Hydrologic Unit (HUC)9] level and associated
interpretations (see Quigley and others 1996).
These priorities are placed in context with national and international integrated priorities scaled at
the Basin level. Priorities are set at the watershed
and subwatershed scale using a similar analytical
process for 5th- and 6th-field HUCs within subbasins. The process of ecosystem risk and opportunity analysis follows the concepts of assessment
for proper functioning landscape patterns as
described in the Landscape Dynamics assessment
by Hann and others (in press).
Landscape Integrity Assumption 5:
Concentration of Activities Temporally
and Spatially — Through time, the implementation of activities such as access for timber harvest, use of prescribed fire, and road access management tends to be concentrated in time and
space to better reflect patterns of the inherent disturbance regimes and biophysical template. In
general, disturbances at the watershed level are
consistent with the template and concentrated
within periods of a few years, across a relatively
large part of the watershed, and with relatively
long time intervals of little or no disturbance.
Management for individual activities occurs over
larger areas to represent natural disturbances and
'As part of the need to integrate terrestrial and aquatic ecosystem information to address many of the issues related to the biophysical and social ecosystem components within the Basin, it was necessary to develop consistent and continuous delineations of
watersheds across the assessment area. A total of approximately 7,500 base unit subwatersheds (6th-field HUCS) were identified
within the Basin. Watersheds by their very nature are a nested hierarchy; a small watershed is contained within a larger watershed,
which, in turn, is contained within a still larger one. The numeric coding system was based on the one prepared by the USGS in
cooperation with the Water Resources Council. This system consists of fields of paired digits referred to as Hydrologic Unit Code
(HUC). The first four fields (8 digits) are assigned and published by the USGS and are commonly referred to as 4th-field HUCs.
The ICBEMP watershed delineation further subdivides 4th-field hydrologic code units into smaller, nested 5th-field and 6th-field
hydrologic units. It is the 6th-field hydrologic unit (referred to as 6th-field HUC or subwatershed) that was used as the basic
characterization unit for the ICBEMP assessment effort.
Table 2.3 — General descriptions of traditional, ecological, and reserve management prescriptions.
Management
Prescription
Description
Traditional
Emphasis on managing primary natural resource variables related to providing for human needs
(such as wood production, livestock, recreation, visual condition, water, and big game). Manage
as an aggregation of effects from a fine scale (such as stands, allotments, campgrounds, and
point source) with no broader scale context. Measure sustainability directly from the variables.
Manage to control landscape dynamics to maximize production of primary natural resource
variables.
Ecological
Emphasis on managing relationships of humans and other species with their environments (recognizing primary natural resource variables and their relationship with ecological composition,
structure, and function). Manage using broad spatial and temporal scales to provide context for
management of finer scale patterns. Measure sustainability from both primary natural resource
variables and ecological processes. Manage landscape succession/disturbance regimes to shift
current spatial patterns and temporal trajectories to fit the basic biophysical template and represent native succession/disturbance regimes.
Reserve
Emphasis on minimal production of natural resource commodity variables and minimal direct
management treatments. Manage landscape dynamics to allow the current spatial patterns to
achieve their own balance with the environment through time.
44
Landscape Ecology
to maintain structures that "fit" the biophysical
template. This management shift, prioritized
through time, would result in improved landscape
integrity and more efficient production of
resource values.
Landscape Integrity Assumption 6:
Road Management — New road construction
is prioritized for low sensitivity landtypes and 6thfield HUC subwatersheds within the context of
objectives specifying no net increase in road densities in any cluster or in applicable subwatersheds.
Road management prioritizes reductions in road
density in moderate-to-high sensitivity watersheds
and landtypes. Permanent roads are surfaced with
asphalt or stable aggregate to reduce the need for
grading and cut/fill slopes, and ditches are stabilized with herbaceous cover. Drainage systems and
culverts are reconstructed, as needed, and maintained to eliminate delivery of sediment into
streams. Bridges and culverts are reconstructed, as
needed, in locations that reduce impacts on the
river and stream channel dynamics.
Landscape Integrity Assumption 7:
Fire Management — The fire suppression and
fuels programs are managed to attain landscape
conditions consistent with inherent disturbance
processes and within the capabilities of the biophysical system. Fire suppression resources are
maintained to manage wildfires when needed.
During periods when wildfire activity is low, these
resources are used for prescribed fire and fuel
management. Large wildfires are managed in the
context of the total landscape and risk to lives,
property, and resource investments, with a full
range of strategies capable of achieving landscape
vegetation and fuel management objectives, as
well as wildfire suppression.
Wildfire management strategies fully recognize the
dangers of various fuel and weather conditions
and place emphasis on the safety of firefighters, as
well as the need to meet fire suppression objectives. Fuels in wilderness and semi-primitive areas
are managed with an active prescribed fire program that includes unplanned ignitions where
appropriate, and planned ignitions where needed,
to trend toward the appropriate landscape pattern
of succession/disturbance regimes and to meet
resource objectives.
Landscape Integrity Assumption 8:
Forest and Range Integrated Landscape
Management — Management activities are
designed and implemented to integrate planning,
implementation, and monitoring for ecological
integrity, while considering social and economic
resiliency. Management emphasis shifts towards
managing landscape processes to provide the most
effective "fit" with the biophysical template and
associated pattern of succession/disturbance
regimes.
Management would improve the integrity of many
processes by managing activities such as harvest,
prescribed fire, wildfire, and grazing to mimic or
represent effects of native succession and disturbance processes at .the physiognomic level. Key
processes include photosynthesis, decay, fire,
insect/disease, and herbivory. Landscape patterns
of succession/disturbance regimes provide a basis
for integrated improvement of integrity by "best
fit" of treatments to their appropriate landscape
position and scale. Through time, management
activities that affect these processes would provide
for a supply of dead and live standing and down
wood that structurally represent the essential range
of associated habitats and conditions for nutrient
cycling.
By considering net primary productivity and
water/nutrient balance at levels consistent with
the native system, management would provide for
productivity and stress levels consistent with biophysical limitations. Managing for soil cover and
structure as appropriate for the biophysical template would provide for long-term soil productivity, and also limit erosion and sediment delivery.
Designing roads that reduce sediment delivery
and bare soil would improve hydrologic integrity.
Monitoring of multi-scale landscape patterns
and adjusting for landscape processes would
change the trends in community and landscape
patterns to be more consistent with inherent disturbance processes. The broad-scale composition
Landscape Ecology
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of physiognomic types would become more similar to the biophysical template, in both structure
and composition of communities, and landscape
patterns of succession/disturbance regimes, at the
watershed scale.
Landscape Integrity Assumption 9:
Management of Different Potential
Vegetation Groups (PVGs)10 — Management
of potential vegetation groups is done in a landscape context with their adjacent PVGs. There is
emphasis to avoid both the introduction and
spread of exotic plants and noxious weeds. Any
seeding that is deemed necessary would use native
species whenever possible; any non-native species
used should, when possible, be ones that do not
produce viable seed. Desired non-native species
are used for restoration only if there are no native
species that can compete with undesirable exotics
or that will stabilize the site.
Over time, the integrity of potential vegetation
groups would improve by addressing conditions
related to current integrity problems. By improving inventory, remote sensing, and ecological
modeling, management would develop a better
understanding of potential vegetation groups and
their relationships to landscape patterns and succession/disturbance regimes at finer scales.
Through time and with die use of prescribed fire,
flexible strategies on wildfire management, noncommercial tree cutting, commercial harvest, livestock grazing, and other treatments, the mix of
physiognomic types would show a trend toward a
mix consistent with properly functioning landscape systems (also equivalent to landscape health).
Additional information about assumed management of potential vegetation groups is included in
appendix 2-A.
10
A PVG is a group of potential vegetation types (PVTs) that have similar environmental conditions and are dominated by similar
types of plants. A potential vegetation type is a physical and biological environment that produces a kind of vegetation, such as
the dry Douglas-fir type.
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Landscape Ecology
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