United States

Department of

Agriculture

Forest Service

Pacific Northwest

Research Station

United States

Department of the

Interior

Bureau of Land

Management

Research Paper

PNW-RP-545

March 2003

Disturbance Departure and

Fragmentation of Natural Systems

in the Interior Columbia Basin

Wendel J. Hann, Michael J. Wisdom, and Mary M. Rowland
Authors

Wendel J. Hann is a landscape fire ecologist, U.S. Department of Agriculture, Forest Service, Fire

Management, 50 Highway 93 South, Salmon, ID 83467; Michael J. Wisdom is a research wildlife

biologist, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, 1401

Gekeler Lane, La Grande, OR 97850; Mary M. Rowland is a wildlife biologist, U.S. Department of

the Interior, Bureau of Land Management, 1401 Gekeler Lane, La Grande, OR 97850.
Disturbance Departure and Fragmentation of

Natural Systems in the Interior Columbia Basin

Wendel J. Hann, Michael J. Wisdom, and Mary M. Rowland

Interior Columbia Basin Ecosystem Management

Project: Scientific Assessment

Thomas M. Quigley, Editor

U.S. Department of Agriculture

Forest Service

Pacific Northwest Research Station

Portland, Oregon

Research Paper PNW-RP-545

March 2003
Abstract

Hann, Wendel J.; Wisdom, Michael J.; Rowland, Mary M. 2003. Disturbance departure and

fragmentation of natural systems in the interior Columbia basin. Res. Pap. PNW-RP-545. Portland,

OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 19 p.

We integrated landscape data from science assessments of the interior Columbia basin (basin) into

one variable that functions as a robust index of departure from native conditions. This variable,

referred to as the disturbance departure and fragmentation index, is a spatially explicit measure of

landscape quality and resiliency. Primary causes of departure and fragmentation include fire exclusion, timber harvest, mining, oil and gas development, livestock grazing, invasive species, road networks, and the interface of these activities with agricultural and urban development. We derived four

classes of the disturbance departure and fragmentation index: very high, high, moderate, and low.

Very high departure and fragmentation was associated with low-elevation subwatersheds dominated

by agricultural and urban lands. High departure and fragmentation was found in subwatersheds

containing a mix of agricultural lands with low-elevation forests, woodlands, or rangelands. Subwatersheds with moderate departure and fragmentation were associated with low- to mid-elevation forests,

woodlands, or rangelands in public ownership. Subwatersheds with low departure and fragmentation

typically occurred at higher elevations, on public lands within or near wilderness areas, roadless areas,

or national parks. Because the disturbance departure and fragmentation index represents the composite effects of management activities that do not mimic native or natural processes, the index appears

useful as a planning tool for integrated restoration of wildland landscapes.

Keywords: Disturbance departure, fragmentation, historical range of variability, interior Columbia

basin, land use planning, landscape ecology, resiliency, similarity index, wildland landscapes.

Summary

We developed a disturbance departure and fragmentation index as a composite estimate of departure

of current landscapes from their natural or native conditions. The index is an integration of landscape

variables that measure departure of succession and disturbance regimes, composition and structure of

vegetation, and associated mosaic patterns at coarse, mid, and fine scales. Departure from natural or

native conditions was associated with both active (e.g., timber harvest and road-building, livestock

grazing) and passive (e.g., fire exclusion) management, as such activities typically have not mimicked

natural processes or resulted in landscapes that resemble native conditions. Departure from the

natural frequencies and severities of disturbance (disturbance regimes), departure from natural

recovery rates or pathways from disturbance (succession regimes), and fragmentation of mosaics

and disturbance regimes have widespread, substantial effects on resiliency and quality of wildland

landscapes. We define wildland landscapes as the environmental conditions present under historical

disturbance and succession regimes. Departure has resulted in conditions unlikely to provide habitats

needed to support historical diversity and richness of native species, or to maintain basic soil and

hydrologic components. Fragmentation has occurred as a result of both active and passive management that does not represent natural disturbance processes. Decreasing patch size has resulted in

fragmentation of habitats and their connectivity. At the same time, increasing patch size has resulted

in fragmentation of disturbance and succession regimes. The disturbance departure and fragmentation index provides an efficient means of characterizing these patterns and processes on large landscapes for integrated restoration planning and management.
Preface

The Interior Columbia Basin Ecosystem Management Project was initiated by the Forest Service

and the Bureau of Land Management to respond to several critical issues including, but not limited

to, forest and rangeland health, anadromous fish concerns, terrestrial species viability concerns, and

the recent decline in traditional commodity flows. The charter given to the project was to develop a

scientifically sound, ecosystem-based strategy for managing the lands of the interior Columbia River

basin administered by the Forest Service and the Bureau of Land Management. The Science Integration Team was organized to develop a framework for ecosystem management, an assessment of the

socioeconomic and biophysical systems in the basin, and an evaluation of alternative management

strategies. This paper is one in a series of papers developed as background material for the framework, assessment, or evaluation of alternatives. It provides more detail than was possible to disclose

directly in the primary documents.

The Science Integration Team, although organized functionally, worked hard at integrating the approaches, analyses, and conclusions. It is the collective effort of team members that provides depth

and understanding to the work of the project. The Science Integration Team leadership included

deputy team leaders Russell Graham and Sylvia Arbelbide; landscape ecology—Wendel Hann, Paul

Hessburg, and Mark Jensen; aquatic—Jim Sedell, Kris Lee, Danny Lee, Jack Williams, Lynn Decker;

economic--Richard Haynes, Amy Horne, and Nick Reyna; social science—Jim Burchfield, Steve

McCool, Jon Bumstead, and Stewart Allen; terrestrial—Bruce Marcot, Kurt Nelson, John Lehmkuhl,

Richard Holthausen, Randy Hickenbottom, Marty Raphael, and Michael Wisdom; spatial analysis—

Becky Gravenmier, John Steffenson, and Andy Wilson.

Thomas M. Quigley

Editor

United States

Department of

Agriculture

Forest Service

United States

Department of

the Interior

Bureau of Land

Management

Interior

Columbia

Basin

Ecosystem

Management

Project
blank
1

Introduction

Wildland landscapes are declining in quality and

resiliency across most areas of the world (Lavorel

1999, Sala et al. 2000, Walker et al. 1999). The

quality of wildland landscapes, defined as the

degree to which native conditions and processes

occur over large areas, has been substantially

reduced during the past century (e.g., see Hann

and Bunnell 2001; Hann et al. 1997, 1998; Hardy

et al. 2001; Hemstrom et al. 2001). The result has

been a rapid increase in extinction rates of native

species (Flather et al. 1994, 1998).

Resiliency, or rate and degree to which such

wildland landscapes and their native biota renew

the natural cycle of functions, processes, and

conditions following disturbance (Allen and

Hoekstra 1992, Hann et al. 1997), also has

declined in concert with quality (Noss 2001). Fire

exclusion, timber harvest, mining, oil and gas

development, livestock grazing, invasive exotic

flora and fauna, road networks, and the interface

of these activities with agricultural and urban

development all have contributed to declining

wildland quality and resiliency, as such activities

typically do not mimic processes in native

systems (Hann et al. 1997, 1998; Landres et al.

1999; Morgan et al. 1994).

Pre-European conditions and processes in the

Western United States, as estimated by the

historical range of variability (HRV), provide a

useful baseline for assessing current and future

quality and resiliency of wildland landscapes

(Hann et al. 1997, 1998; Hardy et al. 2001;

Hemstrom et al. 2001; Huston 1994; Landres et

al. 1999; Morgan et al. 1994). We define native

conditions as the plants and animals that are

indigenous to a specified area, the relations of

these native species to each other and their

environment, and the associated background

processes that occurred in such areas before

European settlement of the interior Columbia

basin (referred to as basin, fig. 1). Native conditions are synonymous with those fitting within the

HRV, as measured just before European settlement of the basin (Hann et al. 1997).

Because native landscapes respond to the cumulative effects of all disturbance regimes, the

degree to which landscapes have departed from

HRV can be integrated and mapped to provide an

accurate index of conditions (Caprio and Graber

2000; Hann et al. 1997, 1998; Hardy et al. 2001;

Hemstrom et al. 2001; Quigley et al. 1998;

Rieman et al. 2000). However, development of an

integrated index can be difficult: multiple input

variables can have opposing trends that confound

results, or the algorithms used to synthesize

multiple variables may not provide an equitable

representation of all such variables. Yet, successful prioritization and planning to maintain or

restore quality and resiliency of landscapes

depends in large part on the ability to assess and

map the composite departure from natural systems, based on the combined effects of major

landscape patterns and processes (Allen and

Hoekstra 1992, Sayre et al. 2000). A composite

measure provides an important component for the

design of landscape plans to restore a diverse

array of wildland resources (Caprio and Graber

2000, Hann and Bunnell 2001, Hann et al. 2001,

Hardy et al. 2001, Hemstrom et al. 2001, Quigley

et al. 1998, Rieman et al. 2000).

In designing a composite, integrated index of

departure from native conditions, two problems

are apparent from past approaches. The first is

that most efforts have focused on departure from

a specific disturbance regime (such as fire regime), from composition and structure of a

particular ecosystem (such as forests), or from a

particular set of native species (such as fish)

(Caprio and Graber 2000, Quigley et al. 1998,

Rieman et al. 2000). These indices are useful for

developing management priorities for the associated disturbance regimes, ecosystems, or sets of

species, but do not provide a composite estimate

for prioritization and planning of holistic restoration of large landscapes and all associated

resources. The second problem is that most

efforts focus on data from one scale, such as the

broad or coarse scale for a large area (Hardy

et al. 2001), or the fine scale for a smaller area

(Caprio and Graber 2000). Such approaches fail

to integrate the departure of characteristics
2

expressed at different scales, and therefore fail to

account for important processes that may change

across scales.

For integrated restoration planning across large

areas, a desirable index is one that accounts for

the integrated departure of landscape disturbance

regime, composition and structure of vegetation,

and associated mosaic pattern, and that also can

index departure of fine-scale characteristics such

as snag density or populations of selected species.

Landscape disturbance processes can be measured

at both coarse and mid scales, whereas mosaic

patterns are generally a mid-scale measure (Hann

et al. 1997, Hessburg et al. 1999). We define

broad or coarse scale as regional landscape

extents (such as the basin, an ecological province,

or a subbasin) that are mapped with a large pixel

or polygon size (such as 1 km2

), with estimates

from each pixel representing the dominant class

of an underlying composite of patches or stands.

We define mid scale as the conditions and patterns common to subregional landscape extents

(such as multiple watersheds or subwatersheds)

that are mapped with a moderate pixel or polygon

size (such as 4 ha), with the pixel size generally

equivalent to or smaller than a patch or stand. By

contrast, fine scale is defined as patch or stand

characteristics mapped and summarized at a

resolution typically smaller than 1 ha.

Figure 1—Boundaries of the Interior Columbia Basin Ecosystem Management Project (ICBEMP) science

assessment area and mapped classes of the disturbance departure and fragmentation index in the basin. The

ICBEMP science assessment area includes eastern Washington, eastern Oregon, most of Idaho, northwestern

Montana, and small portions of Wyoming, Nevada, and Utah.
3

Because past measures of landscape departure

have not addressed a large set of resources

holistically, or have not considered multiscale

patterns and processes, we sought to overcome

these deficiencies by characterizing and mapping

a multiscale “disturbance departure and fragmentation index” (ICBEMP theme number 933,

similarity/fragmentation index for succession/

disturbance and vegetation composition, assessment data; www.icbemp.gov/spatial) for the

interior Columbia basin (fig. 1). We specifically

selected a comprehensive and relevant set of

coarse-scale variables for analysis that also were

proxies for mid- and fine-scale conditions,

provided rationale for their selection, and developed from them a composite index of disturbance

departure and fragmentation. Our purpose in

developing this composite index was to characterize subwatersheds according to their overall

departure from native systems at a landscape

scale. Subwatersheds (6th hydrologic unit codes,

as defined by Gravenmier et al. [1997] and

Quigley et al. [1996]) average 7700 ha, and are

used commonly for landscape assessment and

planning in the basin (e.g., Hemstrom et al. 2001,

Raphael et al. 2001). Characterization at this

scale, therefore, is useful for developing integrated restoration strategies for wildland resources

that have declined in quality and resiliency across

large landscapes such as the basin.

Our work was conducted as part of the Interior

Columbia Basin Ecosystem Management Project

(ICBEMP). The ICBEMP was established in

January 1994 through a charter signed by the

Chief of the USDA Forest Service (FS) and the

Director of the USDI Bureau of Land Management (BLM). The charter directed that work be

undertaken to develop and adopt an ecosystembased strategy for management of lands

administered by the FS and BLM (FS-BLM)

within the basin. The project developed a

framework for ecosystem management and a

scientific assessment of the ecological,

biophysical, social, and economic conditions

existing in the basin. Scientists prepared many

publications to aid technology transfer of key

science findings; they also projected environmental consequences from implementation of

broad-scale management scenarios and alternatives (e.g., Hemstrom et al. 2001, Raphael

et al. 2001). These projections, along with more

than 100 supporting research publications

(www.icbemp.gov), provide information that

can be used effectively in land use planning for

FS- and BLM-administered lands in the basin.

Study Area

The science assessment area of ICBEMP extends

over 58 million ha in Washington, Oregon, Idaho,

Montana, and small portions of Wyoming,

Nevada, and Utah (fig. 1). Fifty-three percent of

the basin is public land administered by FS-BLM,

which was the focus of the ICBEMP environmental impact statement (USDA Forest Service and

USDI Bureau of Land Management 2000). For

the ICBEMP, the basin was subdivided into four

nested spatial scales (Gravenmier et al. 1997,

Jensen et al. 1997): (1) ecological reporting unit

(ERU), (2) subbasin, (3) watershed, and (4)

subwatershed. Ecological reporting units, of

which there are 13, range in size from about

740 000 to 6 800 000 ha (mean size of about

2 375 000 ha). The 164 subbasins average about

345 000 ha, whereas the 2,562 watersheds

average about 22 500 ha each. There are 7,654

subwatersheds, with a mean size of 7700 ha.

Quigley et al. (1996) described these spatial

scales and the diverse ecological components of

the basin in detail. Hann et al. (1997) further

described landscape systems occurring in the

basin.

Methods

Description and Purpose of Index

Our goal in developing the disturbance departure

and fragmentation index was to integrate several

landscape variables to derive one composite

variable that represented the overall pattern and

effects from a myriad of underlying landscape

processes. We derived our index by combining

and extrapolating landscape data from multiple

scales relative to HRV departure. The resulting

index was designed to estimate the level of

deviation from historical succession and disturbance regimes, structure and composition of
4

vegetation, and the associated mosaic patterns. As

part of this process, a diverse set of landscape

variables was integrated to yield four classes of

disturbance departure and fragmentation that

ranged from low to very high. Low departure and

fragmentation was designed to index landscapes

with high wildland resiliency and quality, which

could be used to prioritize areas for maintenance

of such conditions. By contrast, increasingly

higher classes of departure and fragmentation

indexed landscapes with increasing loss of

wildland resiliency and quality, with increasing

opportunities for integrated restoration.

Concepts and data underlying the development of

the disturbance departure and fragmentation index

are from Keane et al. (1996), Hann et al. (1997,

1998), Hemstrom et al. (2001), and Hessburg et

al. (1999). The index is a composite measure of

departure from HRV, as caused by the cumulative

effects of human activities that do not mimic

native patterns and processes. Primary management activities associated with this departure

include past fire exclusion, timber management,

livestock grazing, road development, mining, oil

and gas development, dams and water diversions,

agricultural conversions, and invasions of exotic

plants and animals (app. 1; Hann et al. 1997,

1998; Hemstrom et al. 2001). Such management

practices do not lead uniformly to departure but

may result in departure if not designed or mitigated in ways that sustain natural or native

characteristics at multiple scales (Hann et al.

1998, Landres et al. 1999, Morgan et al. 1994).

Levels of disturbance departure and fragmentation

also were designed to index the relative change in

patch size, composition, and arrangement; frequency and intensity of fire events; timing and

severity of tree mortality associated with insect

defoliation and pathogen events; successional

rates and pathways; timing and intensity of

ungulate grazing; composition of native versus

nonnative vegetation; and human activities and

presence.

Hann et al. (1997) and Hessburg et al. (1999)

found that landscapes dominated by active

management, such as road development and

timber harvest, depart in vegetation mosaic and

fragmentation patterns by becoming more fragmented (more heterogeneous) than historical

systems. By contrast, areas dominated by passive

management, such as fire exclusion (suppression)

and custodial (nonactive) protection of terrestrial

resources, depart by becoming less fragmented

(more homogenous) than were historical systems.

Keane et al. (1996) and Hann et al. (1997) observed that succession and disturbance processes

change in opposite ways than do the vegetation

mosaic and fragmentation patterns documented

by Hessburg et al. (1999). That is, as the vegetation mosaic has become more fragmented (more

heterogeneous) under active management, the

associated succession and disturbance regimes

have become less fragmented (more homogenous)

than those in historical systems. In contrast, vegetation under passive management has become

less fragmented (more homogenous) than historical, while succession and disturbance regimes

have become more fragmented (more heterogeneous).

Although the changes in mosaic and fragmentation of vegetation under management are different

than those of succession and disturbance processes, the departure of all such variables from

historical conditions is consistent in its spatial

pattern and correlation (Hann et al. 1997).

Consequently, these many changes can be measured efficiently as a composite variable. Accordingly, the disturbance departure and fragmentation index is designed to capture these diverse

changes in landscape patterns and processes

relative to de-parture from historical (late 19thcentury) conditions at multiple scales. The

variable indexes fine-scale, within-stand composition and structure of vegetation, as well as

coarse-scale composition and mid-scale spatial

arrangement and pattern of vegetation, and is

strongly associated with changes in landscape

patterns and processes from historical to current

periods, reflecting causal management activities.

For example, density of large snags and large logs

affects survival of a large number of vertebrates

of conservation concern in the basin (Wisdom

het al. 2000). Snag and log densities decline with

increasing road density, timber harvest, and

wildfire suppression (Hann et al. 1997), all of
5

which are correlated with increasing levels of the

disturbance departure and fragmentation index.

Consequently, the variable appears to function as

a reasonable index of landscape quality for

terrestrial resources.

The disturbance departure and fragmentation

index also corresponds to resiliency because the

recovery rate of native vegetation and natural

ecosystem processes after disturbance is associated closely with variables that compose the

departure index. For example, resiliency of native

vegetation in rangelands is increasingly disrupted

by invasion of exotic plants and by increased

road density, increased frequency and intensity of

wildfire events, and excessive livestock grazing,

all of which are correlated with increasing levels

of disturbance departure and fragmentation of

either the vegetation mosaic or ecosystem processes (app. 1).

Reference Period for Measuring

Disturbance Departure and Fragmentation

For our analysis, we defined the historical period

for native conditions as the late 19th century (circa

1850-1890), based on the methods and assessment of Hann et al. (1997). Landscapes during

this time functioned largely without the pervasive,

subsequent influences of European settlement and

provide a useful reference for comparing current

and future changes in the basin’s patterns and

processes at landscape scales (e.g., see Hann et al.

1997, 1998; Hemstrom et al. 2001; Raphael et al.

2001). This reference period, however, reflects

climate and associated succession and disturbance

dynamics that may be different than current and

potential future climates (Tausch et al. 1993).

Consequently, to better address the dynamics of

native conditions in current and future climates,

we modeled HRV for 400 years (Hann et al.

1997, Hemstrom et al. 2001). From this data, we

developed variables reflecting native conditions

and ranges of such conditions that represent

general patterns of succession and disturbance

dynamics across time.

Nevertheless, we acknowledge that climate

change, such as that from global warming, may

affect future ranges of native conditions in ways

that are different from past dynamics (Tausch et

al. 1993). Such change in climate, therefore, will

increase the probability that future landscapes

will increase in departure from HRV. The spatially explicit effects of such climate change,

however, have not been estimated for local scales

such as those of the watershed or subwatershed,

given the high uncertainty about future effects at

such scales. Improved predictions of future

climate change are needed to provide reliable

estimates of such change across landscapes and to

modify our disturbance departure and fragmentation index for future uses. We assume that future

improvements in predictions of climate change in

the basin can be used as the basis for like improvements in our index.

Deriving the Variable

The disturbance departure and fragmentation

index was derived as four classes (low, moderate,

high, and very high), with very high representing

the greatest level of deviation from historical

conditions. These classes were developed directly

from values of a similarity index of current landscapes to natural or native landscapes (table 1).

The similarity index was in turn derived from

unique combinations of three broad-scale variables: (1) landscape management pattern, (2)

landscape vegetation pattern, and (3) potential

vegetation group pattern (table 2). In combination, these variables reflect multiscale changes in

coarse-scale vegetation composition and disturbance regimes, mid-scale landscape mosaic pattern,

and fine-scale attributes reported in Hann et al.

(1997), Hessburg et al. (1999), and Keane et al.

(1996). These multiscale patterns and processes,

as represented in the three variables, are highly

correlated with a much larger and diverse set of

landscape variables related to human disturbances

and their effects in the basin (as described

earlier). Consequently, these three variables

appeared most useful in accurately representing

the major patterns and effects of human activities

and management on the quality and resiliency of

wildland landscapes in the basin.
6

Table 1—Area and percentage of the interior Columbia basin by class

of similarity index, and by class of disturbance departure and fragmentation index, as estimated for 7,467 subwatersheds in the basin

Disturbance departure

Similarity index and fragmentation index Area Basin

 Hectares Percent

0 Very high 4 002 600 6.8

 Total Very high 4 002 600 6.8

1 High 183 700 0.3

2 High 2 669 600 4.6

3 High 8 646 600 14.8

 Total High 11 499 900 19.7

4 Moderate 21 305 200 36.4

5 Moderate 11 205 400 19.2

6 Moderate 1 187 200 2.0

 Total Moderate 33 697 800 57.6

7 Low 3 511 100 6.0

8 Low 2 802 500 4.8

9 Low 2 174 600 3.7

10 Low 776 900 1.3

 Total Low 9 265 000 15.8

Total All classes 58 465 400 100

Data used to derive the three variables were

obtained from several sources: (1) coarse-scale

vegetation composition and structure mapping

(Hann et al. 1997); (2) historical to current change

in vegetation data derived from photo interpretation (Hessburg et al. 1999) and oblique photographs (Losensky 1995); (3) change in fine-scale

vegetation features from historical to current

estimated from plot data (Hann et al. 1997); and

(4) changes in composition, succession, and

disturbance processes estimated from empirically

based modeling (Keane et al. 1996) (summarized

in app. 1). The landscape management pattern

variable was specifically developed from coarsescale data on current and historical landscape

management patterns, land ownership, and road

density. By contrast, the variable of landscape

vegetation pattern was developed from coarsescale data on current and historical system

dynamics, potential vegetation group, and fire

regime patterns. The variable of potential vegetation group pattern was derived from a coarsescale site stratification that grouped potential

vegetation types based on terrain and climate

features, and was subsequently used to classify

each vegetation pattern as uniform, mosaic, or

mixed for each subwatershed (table 2; Hann et al.

1997; see ICBEMP Web site metadata,

www.icbemp.gov, for all three variables).
7

Table 2—Classes of the disturbance departure and fragmentation index and its input variables:

landscape management pattern (LMP), landscape vegetation patterns (LVP), and potential

vegetation group pattern (PVGPT)a

Disturbance

departure and Landscape Landscape Potential Potential

fragmentation management vegetation vegetation vegetation

index pattern pattern group group pattern

Very high Traditional Agricultural (AGL) Other: Mixed (<60%

commodity (TC) Agricultural, Agricultural composition of one

High Traditional reserve rangeland, forest Rock PVG)

(TR) (ARF) Urban Mosaic (360% and <80%

Moderate Moderate similarity Forest and Water composition of one

to native (MN) rangeland (FRL) Rangeland: PVG)

Low High similarity to Forest (FTL) Alpine Uniform (380%

native (HN) Rangeland (RGL) Cool shrub composition of one

Dry shrub PGV)

Woodland

Riparian:

Riparian herb

Riparian shrub

Riparian woodland

Forest:

Dry forest

Moist forest

Cold forest

aNote that rows do not indicate relations between variables.

The variable PVGPT was entered as a combination of 1 of 3 patterns and the associated PVGs as follows: if the pattern was

“uniform,” it was entered with only 1 PVG; e.g., uniform—moist forest; if the pattern was “mixed” or “mosaic,” it was entered

with both the primary and secondary PVGs; e.g., mosaic—dry forest—agricultural. Not all combinations of LMP/LVP/PVGPT

occur in the basin; e.g., the LVP “agricultural” occurs in only 3 of the 299 unique combinations of the 3 input variables.

The assignment of the similarity index to each

subwatershed was based on results of a multivariate cluster and ordination analysis, which

identified subwatersheds that grouped together

according to their similarity in relation to the

three broad-scale variables. The cluster and

ordination analysis was conducted by using a data

matrix of the approximately 300 combinations of

the three variables (app. 2). Results from the

cluster and ordination analyses were then used to

develop the similarity index, ranging from 0 to

10, and to assign this index to each subwatershed.

A detailed list of data sources used in these

analyses is provided in appendix 1. Assignment

of the similarity index to each subwatershed

resulted in a ranking of subwatersheds from 0

(lowest) to 10 (highest), based on the similarity

of the succession/disturbance regime, vegetation

composition and structure, and landscape pattern

compared to that estimated from HRV (Hann et

al. 1997, Hessburg et al. 1999, Keane et al. 1996).

The inverse of the similarity index yields the

degree of disturbance departure and fragmentation. Consequently, we established four classes of

disturbance departure and fragmentation, based

on clear breaks in the frequency distribution of

the similarity index values (table 1). Each

subwatershed was assigned to one of the four

classes of disturbance departure and fragmentation, as follows, in relation to values of the

similarity index: very high—0 similarity; high—

1, 2, or 3 similarity; moderate—4, 5, or 6 similarity; and low—7, 8, 9, or 10 similarity (table 1).
8

These four classes, and the resulting spatial

pattern of the index across the basin, appeared to

identify consistent and substantial differences in

landscape conditions across the basin (fig. 1).

Importantly, this assignment of classes reflected

similar patterns in associated landscape variables,

as described earlier.

Results and Discussion

Spatial Patterns and Amounts

Very high departure and fragmentation occurred

primarily in low-elevation subwatersheds of

eastern Washington and southern Idaho; these

areas are dominated by private lands and used

mostly as agricultural and urban areas (fig. 1).

By contrast, high departure and fragmentation

was found in subwatersheds that contain a mix of

agricultural lands with low-elevation forests,

woodlands, or rangelands; these areas were

typically adjacent to subwatersheds of very high

departure and fragmentation (fig. 1). Subwatersheds in the high class reflected diverse land uses

that span a wide mix of land ownerships and

management philosophies.

Subwatersheds in the very high class represent

those lands where substantial investments in

agriculture have helped maintain soil and water

capability (Hann et al. 1997). Because of this

investment, resiliency may not be at high risk, but

habitat quality is low. Subwatersheds in the high

class represent those lands where substantial

management activities have occurred in recent

times; such activities may have altered disturbance regimes such that they cannot recover

without aggressive restoration. These environments typically have been invaded by exotic

species or are highly vulnerable to such invasion.

The close proximity and intermingling of these

lands with agricultural lands increase their

exposure to invasive species. These environments

are typically warmer, and changes in natural

succession and disturbance intervals or severities

can be substantial. In addition, the close proximity and intermingled nature of these wildlands

with urban and urban interface areas place them

at risk from urban-associated disturbances

(Collins et al. 2000). Conversely, this interface of

wildlands with urban areas may place urban areas

at risk, such as when intense wildfires start in

wildlands and spread to adjacent urban areas

(Collins et al. 2000).

By contrast, the moderate class occurred largely

in subwatersheds with high public ownership

composed of low- to mid-elevation forests,

woodlands, or rangelands; these areas were

widespread and particularly common in eastern

Oregon, northern Washington, northern Idaho,

and northwestern Montana (fig. 1). Subwatersheds with low departure and fragmentation

typically occurred at higher elevations with

rugged terrain, and were composed of public

lands associated with or adjacent to wilderness

areas, roadless areas, and national parks (fig. 1).

These subwatersheds have undergone the least

change from historical conditions and represent

areas of highest quality and resiliency.

Most of the basin was characterized as having

moderate departure and fragmentation (table 1);

this finding reflects the dominance of low- to

mid-elevation forests, woodlands, and rangelands

that have experienced less severe human-induced

changes in succession/disturbance regime and

landscape mosaics. These areas contrast strongly

with subwatersheds dominated by agricultural and

urban lands that were classified as having very

high or high departure and fragmentation. The

moderate departure subwatersheds generally have

fairly high resiliency because of their more moist

environments and because basic soil and hydrologic processes are largely intact (Hann et al.

1997). Habitat quality, however, may be low

because of past management activities that have

substantially changed vegetation composition,

structure, and patch mosaics.

Subwatersheds of very high departure and fragmentation composed 7 percent of basin lands,

reflecting a relatively low amount of the most

intensive land uses (table 1). However, the high

class composed 20 percent of basin lands, indicating that low resiliency and quality occurred over a

substantial area that was composed of wildlands

intermingled with agricultural and urban lands.
9

Subwatersheds in low departure and fragmentation composed 16 percent of basin lands, reflecting

a substantial portion of wildlands with high

resiliency and sustainability. Areas in the low

class, however, were concentrated in two large

blocks in central Idaho and western Montana

(fig. 1). Few other areas of low departure and

fragmentation occurred across most of the basin,

except for scattered areas in southeastern Oregon

and southwestern Idaho. The moderate departure

class dominated the basin (table 1), representing a

substantial portion of the land base with moderate

resiliency but potentially low habitat quality.

The spatial distribution of the different classes

resulted in a high degree of contagion for each

class. Subwatersheds with very high departure

and fragmentation, associated with large agricultural and urban areas, had the most highly concentrated or clumped distribution. By contrast, subwatersheds with either high or low departure had

more uniform distributions, with small areas of

each scattered throughout the basin.

Subwatersheds in the high class typically formed

a ring around those in the very high class,

whereas subwatersheds in the moderate class

generally surrounded those of the low class.

Large, contiguous areas of the high class were

typically found in areas dominated by dry rangelands, which have been substantially affected by

invasive, exotic plants and excessive livestock

grazing (Hann et al. 1997). The large, contiguous

areas of the low class were typically found in

large blocks of wilderness and roadless areas,

where lack of access, naural fuel loadings, and

high lightning ignitions have maintained historical fire regimes and provided high wildland

resiliency and quality (Hann et al. 1997).

Management Applications

The disturbance departure and fragmentation

index reflects the composite effects of changes

from the natural or native system at multiple

scales. As such, this composite variable may be

useful for efficient and effective land use planning

within and across land ownerships. For example,

classes of this variable can be used to identify

how much area is in departure from the historical

or natural regime, with summaries possible at

many spatial scales. Large groups of subbasins,

watersheds, or subwatersheds could be ranked

and mapped according to their class of departure

and fragmentation, and results used to identify

key management issues associated with each

class. Such rankings could be used as an effective

foundation for “coarse-filter” land use strategies,

which by definition assume that conservation and

restoration of a representative set and amount of

native habitats in time and space will meet the

needs of all associated native flora and fauna

(Marcot et al. 1994, Noss and Cooperrider 1994).

Such coarse-filter strategies help ensure that

suitable environments for all native flora and

fauna are managed in an efficient and holistic

manner, as opposed to “fine-filter” strategies

designed to meet the needs of few or single

species in specific environments (Hunter 1991).

In one recent application, Wisdom et al. (2002)

used the classes of disturbance departure and

fragmentation index to rank landscape quality and

resiliency for terrestrial resources as part of a

coarse-filter approach. Specifically, Wisdom et al.

(2002) used the index, in combination with estimates of habitat abundance, to map the composite

abundance, quality, and resiliency of habitats for

44 terrestrial species of conservation concern.

Areas were characterized as one of three conditions: (1) habitats where little change in abundance, quality, or resiliency has occurred since the

historical period; (2) habitats where abundance

was high but quality and resiliency were moderate; and (3) habitats where abundance, resiliency,

and quality were low.

Results from Wisdom et al. (2002) appear useful

as a basis for broad-scale landscape planning for

this large set of species of conservation concern.

Wisdom et al. (2002) suggested that the approach

could be used to guide managers in maintaining

habitats in a relatively unchanged state from

historical conditions (condition 1), to improve

habitats where quality and resiliency have declined (conditions 2 and 3), to restore habitats in

areas of extirpation or low abundance (condition

3), and to improve connectivity where spatial

gaps have developed (condition 3). Such planning
10

is a coarse-filter approach, developed for a large

set of vertebrates of conservation concern, for

efficient use in broad-scale conservation and

restoration of critical habitats.

Hann et al. (1998) found that when land use,

ecosystem health, and species diversity are out of

balance with inherent disturbance processes and

biophysical capabilities, the landscape system

tends toward disequilibria and eventually

recalibrates to a new equilibrium with reduced

biophysical capability and lower species diversity. Subwatersheds with a disturbance departure

and fragmentation index of high and very high

are likely at great risk of this recalibration or may

have already permanently lost biophysical

capability. Rieman et al. (2000) concluded,

“terrestrial and aquatic ecosystems that shared a

common management history often also shared

common patterns and trends.” In our analysis of

multiple variables as inputs to the disturbance

departure and fragmentation index, we found that

these shared patterns and trends are common to

landscapes because each landscape integrates

these effects through time. Hemstrom et al.

(2001) used similarity to HRV and other ecological indices, as well as human land uses, as key

measures for assessing landscape health.

Hemstrom et al. (2001) concluded that “past types

and levels of human use have caused extensive

changes that run counter to the historical ecological conditions.” In our analysis of disturbance

departure and fragmentation, we also found that

management activities and land uses dating from

the time of European settlement to the current

period have “run counter” to the natural or native

landscape conditions and dynamics. A reversal of

this trend will require substantial changes in

design and implementation of management

activities and land use.

Throughout the conservation biology literature,

issues of fragmentation of natural patches and of

patch connectivity are a concern (Forman and

Godron 1986, Noss and Cooperrider 1994, Shafer

1990). Our use of data on patch fragmentation

and homogenization from Hessburg et al. (1999)

as part of the disturbance departure and fragmentation index accounts for issues of patch size and

connectivity. Moreover, results from our index

for current landscapes suggest that fragmentation

and homogenization of patches may be of substantial concern in the basin. We emphasize,

however, that fragmentation or homogenization

of succession and disturbance regimes, as well as

the associated, multiscale effects on composition

and structure of vegetation, are of equal concern.

Dis-ruption of key processes, such as change in

fire regimes or widespread invasion of exotic

species, may present more risk to native species

and bio-physical capabilities in the long term than

do de-parture of patch sizes and connectivity

(Huston 1994). Our disturbance departure and

fragmentation index is designed to account for

these processes and effects in a holistic manner.

Hann et al. (2001) identified many changes that

are required to implement cost-effective, integrated, multiscale management. One of these, the

“development and update of a consistent set of

broad-scale data,” is addressed substantially by

the disturbance departure and fragmentation

index. This index could be consistently mapped

and updated across areas much larger than the

basin to evaluate and monitor departure from

natural or native conditions. Hemstrom et al.

(2001) conclude that focused and prioritized

restoration within the basin would produce substantial improvements in landscape health compared to current management. In analysis of

multiscale planning issues at a national scale,

Hann and Bunnell (2001) identify ”three fundamental issues that appear to stymie achievement

of multiple land and fire management objectives.” Their third issue is the lack of “a system to

monitor or summarize changes across large areas”

to provide cumulative context for local managers,

and to display the regional and national consequences and benefits of programs and policies to

regional and national managers. The disturbance

departure and fragmentation index could provide

the basis for this type of integrated monitoring

system. In addition, Hann and Bunnell (2001)

emphasize the need for identification and prioritization of areas requiring maintenance or

restoration at multiple landscape scales to achieve

national objectives in the most cost-effective
11

manner. The disturbance departure and fragmentation index could be a key component to this

type of prioritization, allowing spatial identification of low-departure areas for maintenance

and moderate- or high-departure areas for restoration. A key benefit to the methods used for the

disturbance departure and fragmentation index is

the multiscale nature of integrating finer scale

data into an index across an area of large extent.

The input variables can then be individually

addressed at finer scales of planning and

prioritization in order to address more specific

issues of departure or fragmentation.

Applications of the disturbance departure and

fragmentation index across large spatial extents

may have high utility, but fine-scale applications

within small areas should be avoided, owing to

the relatively coarse nature of our estimates for

areas the size of a subwatershed or larger. The

classification of low, moderate, high, and very

high is relative and has a potential error of

approximately 20 percent for small groups of

subwatersheds or watersheds within a subbasin,

ERU, or the basin; this accuracy is similar to that

for other watershed or subwatershed variables, as

described by Hann et al. (1997) and Wisdom et

al. (2000). Consequently, our index should not be

used to identify departure and fragmentation for a

small number of subwatersheds or watersheds.

Moreover, because the classes are relative, they

should be used in this context, rather than as an

absolute estimate of conditions.

Consideration of these caveats will enable users

to apply the disturbance departure and fragmentation index in an effective and efficient manner as

a key component of landscape planning. We urge

managers to consider the use of this variable in

the development of landscape plans for restoration of wildland resources in the basin. Moreover,

we suggest that researchers further test the

efficacy of our index as a composite indicator of

a large group of individual landscape variables.

Such comprehensive approaches to test and apply

landscape variables for multiple, integrated

management applications will likely be of keen

interest in the future, considering the many

diverse wildland resource issues, and the paucity

of methods available for holistic and efficient

management of these resources.

Acknowledgments

Steve Bunting, Penny Morgan, Miles Hemstrom,

and Becky Gravenmier provided helpful reviews

of our paper. Becky Gravenmier and Arthur

Miller conducted data and GIS analyses for our

work, and Dani Huck assisted in preparing the

manuscript for publication. The Pacific Northwest Research Station and other ICBEMP funding sources from the USDA Forest Service and

USDI Bureau of Land Management supported the

work. Data, maps, and associated documentation

and source materials are available from the

ICBEMP Web site: www.icbemp.gov. Source

materials from earlier publications also are

available on the ICBEMP Web site.

English Equivalents

1 hectare (ha) = 2.47 acres

1 kilometer (km) = 0.621 mile

1 square kilometer (km2

) = 0.386 square mile
12

References

Allen, T.F.H.; Hoekstra, T.W. 1992. Toward a unified ecology. New York: Columbia University

Press. 384 p.

Caprio, A.C.; Graber, D.M. 2000. Returning fire to the mountains: Can we successfully restore the

ecological role of pre-Euroamerican fire regimes to the Sierra Nevada? In: Cole, D.N.; McCool, S.F.;

Borie, W.T.; O’Loughlin, J., comps. Proceedings, wilderness science in a time of change. Proc.

RMRS-P-15, Vol. 5: Wilderness ecosystems, threats, and management. Ogden, UT: U.S. Department

of Agriculture, Forest Service, Rocky Mountain Research Station: 233–241.

Collins, J.P.; Kinzig, A.P.; Grimm, N.B. [et al.]. 2000. A new urban ecology. American Scientist. 

88: 416–425.

Flather, C.H.; Joyce, L.A.; Bloomgarden, C.A. 1994. Species endangerment patterns in the United

States. Gen. Tech. Rep. RM-GTR-241. Fort Collins, CO: U.S. Department of Agriculture, Forest

Service, Rocky Mountain Research Station. 42 p.

Flather, C.H.; Knowles, M.S.; Kendall, I.A. 1998. Threatened and endangered species geography:

characteristics of species hotspots in the conterminous United States. BioScience. 48(5): 365–376.

Forman, R.T.T.; Godron, M. 1986. Landscape ecology. New York: Wiley. 640 p.

Gravenmier, R.A.; Wilson, A.; Steffenson, J. 1997. Information system development and

documentation. In: Quigley, T.M.; Arbelbide, S.J., tech. eds. An assessment of ecosystem

components in the interior Columbia basin and portions of the Klamath and Great Basins.

Gen.Tech. Rep. PNW-GTR-405. Portland, OR: U.S. Department of Agriculture, Forest Service,

Pacific Northwest Research Station; U.S. Department of the Interior, Bureau of Land Management:

2012–2066. Chap. 8. Vol. 4. (Quigley, T.M., tech. ed.; The Interior Columbia Basin Ecosystem

Management Project: scientific assessment).

Hann, W.J.; Bunnell, D.L. 2001. Fire and land management planning and implementation across

multiple scales. International Journal of Wildland Fire. 10(3/4): 389–403.

Hann, W.J.; Hemstrom, M.A.; Haynes, R.W. [et al.]. 2001. Costs and effectiveness of multi-scale

integrated management. Forest Ecology and Management. 153: 127-145.

Hann, W.J.; Jones, J.L.; Karl, M.G. [et al.]. 1997. Landscape dynamics of the basin. In: Quigley,

T.M.; Arbelbide, S.J., tech. eds. An assessment of ecosystem components in the interior Columbia

basin and portions of the Klamath and Great Basins. Gen. Tech. Rep. PNW-GTR-405. Portland, OR:

U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station; U.S.

Department of the Interior, Bureau of Land Management: 337–1055. Chap. 3. Vol. 2. (Quigley,

T.M., tech. ed.; The Interior Columbia Basin Ecosystem Management Project: scientific assessment).

Hann, W.J.; Jones, J.L.; Keane, R.E. [et al.]. 1998. Landscape dynamics. Journal of Forestry. 96(10):

10–15.

Hardy, C.C.; Schmidt, K.M.; Menakis, J.P.; Samson, R.N. 2001. Spatial data for national fire

planning and fuel management. International Journal of Wildland Fire. 10(3/4): 353–372.

Hemstrom, M.A.; Korol, J.J.; Hann, W.J. 2001. Trends in terrestrial plant communities and

landscape health indicate the effects of alternative management strategies in the interior Columbia

River basin. Forest Ecology and Management. 153: 105-125.
13

Hessburg, P.F.; Smith, B.G.; Kreiter, S.D. [et al.]. 1999. Historical and current forest and range

landscapes in the interior Columbia River basin and portions of the Klamath and Great Basins.

Part 1: Linking vegetation patterns and landscape vulnerability to potential insect and pathogen

disturbances. Gen.Tech. Rep. PNW-GTR-458. Portland, OR: U.S. Department of Agriculture,

Forest Service, Pacific Northwest Research Station. 357 p. (Quigley, T.M., tech. ed.; The Interior

Columbia Basin Ecosystem Management Project: scientific assessment).

Hunter, M.L., Jr. 1991. Coping with ignorance: the coarse-filter strategy for maintaining biodiversity.

In: Kohm, K.A., ed. Balancing on the brink of extinction. Covelo, CA: Island Press: 266–281.

Huston, M.A. 1994. Biological diversity: the existence of species on changing landscapes. Cambridge,

England: Cambridge University Press. 701 p.

Jensen, M.; Goodman, I.; Brewer, K. 1997. Biophysical environments of the basin. In: Quigley,

T.M.; Arbelbide, S.J., tech. eds. An assessment of the ecosystem components of the interior

Columbia basin and portions of the Klamath and Great Basins. Gen. Tech. Rep. PNW-GTR-405.

Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station;

U.S. Department of the Interior, Bureau of Land Management: 99-335. Chap. 2. Vol. 1. (Quigley,

T.M., tech. ed.; The Interior Columbia Basin Ecosystem Management Project: scientific assessment).

Keane, R.E.; Long, D.G.; Menakis, J.P. [et al.]. 1996. Simulating course-scale vegetation dynamics

using the Columbia River basin succession model—CRBSUM. Gen. Tech. Rep. INT-GTR-340.

Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 50 p.

Keane, R.E.; Rollins, M.; McNicoll, C.; Parsons, R. 2002. Integrating ecosystem sampling,

gradient modeling, remote sensing, and ecosystem simulation to create spatially explicit landscape

inventories: the landscape ecosystem inventory system. Gen. Tech. Rep. RMRS-GTR-92. Fort

Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station.

61 p.

Landres, P.B.; Morgan, P.; Swanson, F.J. 1999. Overview of the use of natural variability concepts

in managing ecological systems. Ecological Applications. 9(4): 1179-1188.

Lavorel, S. 1999. Global change effects on landscape and regional patterns of plant diversity. 

Diversity and Distributions. 5(6): 239–240.

Losensky, B.J. 1995. A description and photographic record of the historical vegetation of the

Columbia River basin; completion report; contract INT-94951-RJVA. [Irregular pagination]. On file

with: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Forestry

Science Laboratory, 800 Block E. Beckwith, P.O. Box 8089, Missoula, MT 59807.

Marcot, B.G.; Wisdom, M.J.; Li, H.W.; Castillo, G.C. 1994. Managing for featured, threatened,

endangered, and sensitive species and unique habitats for ecosystem sustainability. Gen. Tech. Rep.

PNW-GTR-329. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest

Research Station. 39 p.

Morgan, P.; Aplet, G.H.; Haufler, J.B. [et al.]. 1994. Historical range of variability: a useful tool for

evaluating ecosystem change. In: Sampson, N.; Adams, D.L., eds. Assessing forest ecosystem health

in the inland West. New York: Haworth Press, Inc.: 87–111.

Morgan, P.; Bunting, S.C.; Black, A.E. [et al.]. 1996. Fire regimes in the interior Columbia River

basin: past and present. Contract report. On file with: Interior Columbia Basin Ecosystem

Management Project, c/o U.S. Department of the Interior, Bureau of Land Management, Idaho

State Office, 1387 S. Vinell Way, Boise, ID 83709-1657.
14

Noss, R.F. 2001. Beyond Kyoto: forest management in a time of rapid climate change. Conservation

Biology. 15: 578–590.

Noss, R.F.; Cooperrider, A.Y. 1994. Saving nature’s legacy: protecting and restoring biodiversity.

Washington, DC: Island Press. 416 p.

Quigley, T.M.; Haynes, R.W.; Graham, R.T., eds. 1996. Integrated scientific assessment for

ecosystem management in the interior Columbia basin and portions of the Klamath and Great Basins.

Gen. Tech. Rep. PNW-GTR-382. Portland, OR: U.S. Department of Agriculture, Forest Service,

Pacific Northwest Research Station. 303 p.

Quigley, T.M.; Haynes, R.W.; Hann, W.J. [et al.]. 1998. Using an ecoregion assessment for

integrated policy analysis. Journal of Forestry. 96(10): 33–38.

Raphael, M.G.; Wisdom, M.J.; Rowland, M.M. [et al.]. 2001. Status and trends of habitats of

terrestrial vertebrates in relation to land management in the interior Columbia River basin. Forest

Ecology and Management. 153: 63–88.

Rieman, B.E.; Lee, D.C.; Thurow, R.F. [et al.]. 2000. Toward an integrated classification of

ecosystems: defining opportunities for managing fish and forest health. Environmental Management.

25(4): 425–444.

Sala, O.E.; Chapin, F.S.; Armesto, J.J. [et al.]. 2000. Biodiversity-global biodiversity scenarios for

the year 2001. Science. 287: 1770–1774.

Sayre, R.; Roca, E.; Sedaghatkish, G. [et al.]. 2000. Nature in focus: rapid ecological assessment.

Washington, DC: Island Press. 202 p.

Shafer, C.L. 1990. Nature reserves: island theory and conservation practice. Washington, DC:

Smithsonian Institution Press. 189 p.

Tausch, R.J.; Wigand, P.E.; Burkhardt, J.W. 1993. Viewpoint: plant community thresholds,

multiple steady states, and multiple successional pathways: legacy of the Quaternary? Journal of

Range Management. 46(5): 439–447.

U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior, Bureau of Land

Management. 2000. Interior Columbia basin final environmental impact statement. BLM/OR/WA/

PT-01/010+1792. Portland, OR: Bureau of Land Management. [Irregular pagination].

Walker, B.; Steffen, W.; Canadell, J.; Ingram, J., eds. 1999. The terrestrial biosphere and global

change: implications for natural and managed ecosystems. Cambridge, England: Cambridge

University Press. 452 p.

Wisdom, M.J.; Holthausen, R.S.; Wales, B.C. [et al.]. 2000. Source habitats for terrestrial vertebrates

of focus in the interior Columbia basin: broad-scale trends and management implications. Gen. Tech.

Rep. PNW-GTR-485. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific

Northwest Research Station. 3 vol. (Quigley, T.M., tech. ed.; The Interior Columbia Basin

Ecosystem Management Project: scientific assessment).

Wisdom, M.J.; Wales, B.C.; Holthausen, R.S. [et al.]. 2002. A habitat network for terrestrial wildlife

in the interior Columbia basin. Northwest Science. 76(1): 1–14.
15

Appendix 1Table 3—Variables related to the disturbance departure and fragmentation index developed for the Interior ColumEcosystem Management Project (ICBEMP)

ICBEMP Relation to disturbance

Time theme ID departure and 

Variable period/scale export name ICBEMP theme name fragmentation index relatDisturbance Current/HUC6a 933 BDBSIM Similarity/fragmentation Same variable This 

 departure and index for succession/ www fragmentation disturbance and index vegetation

 composition/structure (ASMNT)

Landscape Current/HUC6 974 BDBLMP Landscape management Input variable www

 management pattern patternLandscape Current/HUC6 939 BDBLVP Landscape vegetation Input variable www

 vegetation pattern patternPotential Current/HUC6 950 BDBPVGPT Potential vegetation group Input variable www vegetation pattern group patternSuccession/ Current/ SDR Associated variable Hann  disturbance historical/HUC6 ICBE regimes (SDR) dataForest health Current/HUC6 988 BDBFHV Current forest health Associated variable www vulnerability vegetation vulnerabilityRangeland Current/HUC6 990 BDBRHV Current rangeland health Associated variable www health vegetation vulnerability vulnerability
16

Similarity of Current/1 km Similarities of current and Findings proxied via Table current to historical compositions of BDBLVP 3.20 historical succession/disturbance 199

 regimes, fire regimes, and physiognomic types within potential vegeta- tion groups (PVGs)

Regional and Current/subbasin Regional and subbasin Findings proxied via Table

 subbasin landscape similarity to BDBLMP, BDBPVGPT 3.18 landscape native (HRV), other, 3.18 pattern traditional reserve, and 199 similarity to traditional commodity HRVb landscape patterns

Ownership Current/HUC6 OWNPAT Ownership pattern Input to BDBLMP www

 patternHistorical Historical/HUC6 Fire regime Findings proxied to SDR ICBE regime pattern patternCurrent fire Current/1 km 954 BGBCFRSD Disturbance-current fire Findings proxied to SDR Hann  regimes regimes (SDEIS) Morg

www

Historical fire Historical/1 km 955 BGBHFRSD Disturbance-historical fire Input to fire regime Hann  regimes regimes (SDEIS) pattern Morg

www

Exotic plant Current/HUC6 935 BDBEPIV Exotic plant invasion Findings proxied via www invasion vulnerability BDBPVGP, BDBLMP vulnerability

Table 3—Variables related to the disturbance departure and fragmentation index developed for the Interior ColumEcosystem Management Project (ICBEMP) (continued)

ICBEMP Relation to disturbance

Time theme ID departure and 

Variable period/scale export name ICBEMP theme name fragmentation index relat
17

Hydrologic Current/HUC6 936 BDBHII Hydrologic impacts index Findings proxied via www

 impacts index BDBLMPRoad density Current/HUC6 722 BDBRDDN6 Road density (predicted) Findings proxied via www

 by HUC6 BDBLMP

Current and Current and 807 BGBVEG CRBSUM current and Base vegetation Hann  historical historical/1 km historical vegetation data input Kean vegetation (DEIS) wwwModeled Historical/1 km 931 BGBLTVEG CRBSUM long-term Findings proxied to SDR, Hann  historical historical vegetation BDBLVP, BDBLMP, Kean range of variation BDBPVGPT www

Ecosystem plot Current/fine scale 817 BDBECOD Ecodata plot inventory Findings proxied to SDR, Hann  data database (1940s-1994) BDBLVP, BDBLMP, Kean

 BDBPVGPT www

Vegetation Mid and fine 883 CMBVDDTS Management scenario Findings proxied to SDR, Hann  dynamics scale data files for VDDT BDBLVP, BDBLMP, Hem models BDBPVGPT Kean

www

Current/ Mid scale 677, 896, 897, Vegetation-current mid- Findings proxied to SDR, Hess historical/ 900, 901, 790, scale subsample (Pt 1-5), BDBLMP, BDBLVP, www aerial photo 902-905 vegetation-historical BDBPVGPT fragmentation mid-scale subsample index findings (Pt 1-5)Current to Mid scale HUC6 Findings proxied to SDR, Hann  historical BDBPVGPT find similarity on selected HUC6

Table 3—Variables related to the disturbance departure and fragmentation index developed for the Interior ColumEcosystem Management Project (ICBEMP) (continued)

ICBEMP Relation to disturbance

Time theme ID departure and 

Variable period/scale export name ICBEMP theme name fragmentation index relat
18Table 3—Variables related to the disturbance departure and fragmentation index developed for the Interior Colum

Ecosystem Management Project (ICBEMP) (continued)

ICBEMP Relation to disturbance

Time theme ID departure and 

Variable period/scale export name ICBEMP theme name fragmentation index relatCurrent/ Fine scale Findings proxied to input Hann  historical/ variable Hann 

 oblique photo find data LoseHistorical range Current/HUC6 932 BDBHRVD, Current year historical Main variable used to Hem of variability SDEIS variable range of variability characterize the index www

 composite 16 (VB16) composite departure departure (SDEIS)aHydrologic unit code; a sixth-code HUC is a subwatershed.b Historical range of variability.
19

Appendix 2

Coarse-, mid-, and fine-scale data used in cluster and ordination analysis to develop rationale to assign a

similarity index to the 299 unique combinations of the three input variables (landscape management

pattern, landscape vegetation pattern, and potential vegetation group pattern; see table 2) are listed. A

detailed list of data and findings used in the analysis is provided in appendix 1.

Coarse scale: Land ownership, forest health vulnerability, rangeland health vulnerability, exotic plant

invasion vulnerability, hydrologic impacts index, similarity of succession/disturbance, similarity of fire

regime, and similarity of composition/structure.

Mid scale: Patch (stand) fragmentation of mosaic pattern, patch (stand) homogenization of mosaic

pattern, similarity of succession/disturbance, similarity of composition/structure, and similarity of

landscape patterns.

Fine scale: Plot data on surface fuels, plot data on composition and structure of vegetation, plot data on

density of large trees, plot data on density of large snags, historical fire interval, historical fire severity,

and basal native vegetation cover/ground cover.
blank
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