Terrestrial Community Departures

The lack of available information about the

broad-scale habitat relationships and the population responses to habitat change for most plant

and animal species occurring in the Interior Columbia River Basin creates difficulties for scientists

and managers in predicting the effects of future

habitat outcomes on the persistence of resident

taxa (Hann and others, in press; Jones and Hann

1996). However, estimating broad-scale habitat

departures from historical ranges of conditions

provides an index of broad-scale vegetation

changes in the context of natural systems. Further,

determining how habitat changes with the

dynamics of natural systems provides a means of

conducting coarse-filter inferences of risks to

species persistence (Hunter 1991).

A primary assumption of this coarse-filter approach

to habitat assessment is that conservation of the areal

extent of a community or habitat within its historical conditions should also allow species adapted to

those ranges to persist into the future. In addition,

we recognize that the fitness of many, if not most,

species is also strongly correlated with the future

condition of fine-scale habitat attributes. However, it is not feasible to compute a fine-scale habitat assessment of a future landscape having the

extent and complexity of the Basin.

In our evaluation, we compared the current and

projected future (alternative year 100) broad-scale

habitat availabilities within a subbasin (see map

2.23) to a range of estimated historical conditions.

We assumed that a species' persistence within a subbasin was not at risk if the projected area of their

primary habitat, as described in the SpeciesEnvironment Relations database (Marcot and others,

in press), fell within the 75th percent mid-range of

the historical data. We assumed that risk to persistence increased substantially when habitat availability fell below the 75th percent mid-range of the historical data. Furthermore, the likelihood of extirpation within a subbasin increased when habitat availability fell below the 100th percent range of the historical data. Conversely, persistence likelihood within

a subbasin increased as habitat availability exceeded

the 75th percent mid-range of the historical data.

Methods of Evaluating Terrestrial

Community Departures

Terrestrial community type departures were developed to estimate the magnitude of broad-scale

habitat changes in forests and rangelands within

subbasins. We used 1-km2 (one square kilometer)

resolution continuous broad-scale data, summarized by subbasin, to assess habitat departures of

forest and rangeland ecosystems.

We aggregated 42 cover types and 25 structural

stages into 24 terrestrial community types by further collapsing the communities having late-serai

single-layer and late-serai multi-layer structures

into a "late" class. Next, we estimated the departure from historical condition ranges by subbasin

for 12 terrestrial communities, including nine forest terrestrial community types and three upland

rangeland types (table 2.24). We estimated current departures for terrestrial community types

that comprised at least one percent of the subbasin area for any output period of the historical

simulated run, current period, or 100-year projection of an alternative.

Because their historical occurrences were typically

underestimated and their current occurrences typically overestimated (Hann and others, in press;

Jones and Hann 1996), the following communities were not included in the determination of

departure values:

• Anthropogenic community types such as cropland, exotic herbland, and urban areas.

• Community types that remained relatively stable

between historical and current periods such as

alpine, rock/barren, and water types.

• Riparian community types.

Landscape Ecology
Terrestrial community departures were determined by comparing the current and projected

future areal extent of each type to modeled 75th

and 100th percentile historical ranges of each

type. Historical ranges were developed for individual subbasins using a single 400-year run of

CRBSUM, and cover type and structural stage

outputs for historical years 0, 50, 100, 200, 300,

and 400. Initial conditions for the historical

CRBSUM run and the methods for simulation

are described in Long and others (1996).

Minimum and maximum values from the simulation were used to define the historical range. We

then calculated the 75th percentile historical midrange by adding or subtracting 12.5 percent of the

historical range to the historical minimum and

historical maximum, respectively. Five departure

classes were defined based on the relationships

between the current and projected future areas of

each community type, relative to the simulated

75th and 100th percentile historical ranges (table

2.37, figure 2.48).

Current and projected alternative future departures

of the 12 terrestrial community types for each subbasin were mapped using a computerized geographical inventory system (GIS) (Hann and others, in press). The 84 maps were then assessed for

gross patterns of community departures across the

Basin. The spatial distribution of community

departures was summarized using the ERUs of the

Basin developed by Jensen and others (in press).

We feel the errors in mapping the management

prescriptions in Alternatives 2 and 7 discussed earlier in this chapter do not result in significant

inaccuracies in this departure analysis. The community groups selected and the analytical techniques should substantially dampen the effects of

those errors.

Results of Evaluating Terrestrial

Community Departures

Percentages relative to the historical mid-range of

a community in the following discussions relate to

the increase or decrease from the current percent

of communities in departure class 3, which is the

historical mid-range, to the projected percent for

the subject alternative. For example, for the earlyserai lower montane forest discussed directly

below for Alternative 1, the 1,000 percent increase

relates to the increase from 4 to 47 percent of the

subbasins having that community within their

historical mid-range.

Alternative 1 Departures

Alternative 1 would decrease the average frequency of subbasin membership in class 1 and class 5

departures to 27 and 25 percent, respectively

(table 2.38). Similarly, the average frequency of

communities within class 3 departures would

increase to 36 percent. The 100-year projection

for Alternative 1 indicated that the mid-serai

lower montane forest, mid-serai montane forest,

and upland woodland communities would differ

the most in a positive direction from their historical conditions; at least 50 percent of the subbasins

would contain these communities at levels well

above their historical mid-ranges. The early-serai

montane and two upland communities, herbland

and shrubland, would deviate the most in a negative direction; at least 59 percent of the subbasins

would contain these communities at levels well

below their historical mid-ranges (tables 2.39

and 2.40).

Montane Community Departures in

Alternative 1 —

Early-serai Lower Montane Forest. The 100-

year projection for Alternative 1 indicated that

the availability of the early-serai lower montane

forest community would increase substantially

from the current conditions. The number of

subbasins having this community within its historical mid-range would increase by over 1,000

percent (table 2.39). This increase would primarily occur throughout the Northern Glaciated

Mountains, Lower Clark Fork, Central Idaho

Mountains, Blue Mountains, Northern Great

172 Landscape Ecology
Basin, Columbia Plateau, and Southern Cascades

ERUs (map 2.24).'

Mid-serai Lower Montane Forest. The 100-year

projection of Alternative 1 indicated that virtually

all subbasins in the Basin would contain the midserai lower montane forest community at a level

well above its historical mid-range (table 2.39).

This community's areal extent would dramatically

increase across much of the forested areas of the

Upper Columbia River Basin EIS area (UCRB),

and also within the Upper Klamath ERU and

adjacent areas of the Eastside EIS area (EEIS).

Late-serai Lower Montane Forest. Alternative 1

would increase the areal extent of this community

substantially in respect to the current period. The

number of subbasins having the late-serai lower

montane forest community within its historical

mid-range would increase by over 400 percent

(table 2.39). This increase would occur predominantly within the Columbia Plateau, Blue

Mountains, Northern Glaciated Mountains,

Upper Clark Fork, and Central Idaho Mountains

ERUs. However, the areal extent of this community would decrease well below its historical midrange throughout a substantial portion of the

Southern Cascades ERU.

Early-serai Montane Forest. Alternative 1 would

increase the number of subbasins having this community within its historical mid-range by 61 percent (table 2.39). However, the increasing trend

would not be consistent across the Basin.

Alternative 1 would result in a substantial areal

increase of early-serai montane forests within

many subbasins of the Northern Glaciated

Mountains, Lower Clark Fork, Upper Clark Fork,

Upper Snake, and Snake Headwaters ERUs,

whereas a substantial areal decline would occur

within the Northern Cascades, Blue Mountains,

and Central Idaho Mountains ERUs.

Mid-serai Montane Forest. The 100-year projection for Alternative 1 indicated that the number

of subbasins having the mid-serai montane forest

community within its historical mid-range would

increase by 61 percent (table 2.39). This would

predominantly be attributed to an areal increase

in mid-serai montane forests throughout the

Central Idaho Mountains and Upper Klamath

ERUs. Conversely, we projected areal declines of

this community throughout many subbasins within the Northern Glaciated Mountains and Upper

Clark Fork ERUs.

Late-serai Montane Forest. Alternative 1 would

increase the number of subbasins having the lateserai montane forest community within its historical mid-range by almost 390 percent (table 2.39).

This increase would predominantly be due to

areal increases in late-serai forests throughout the

North Cascades, Upper Clark Fork, Central Idaho

Mountains, and Snake Headwaters ERUs. Areal

declines of the late-serai montane community

within the Southern Cascades and Upper Klamath

ERUs would also increase the frequency of subbasins having this community within its historical

mid-range. The Blue Mountains and Columbia

Plateau ERUs would contain some subbasins with

increases and others with decreases, which would

increase the frequency of subbasins having the

late-serai montane forest community within its

historical mid-range.

Subalpine Community Departures in

Alternative 1 —

Early-serai Subalpine Forest. The 100-year projection for Alternative 1 suggested that the number

of subbasins having the early-serai subalpine forest

community within its historical mid-range would

increase by 180 percent (table 2.39). This increase

would largely be due to areal declines in early-serai

subalpine forests throughout the Central Idaho

Mountains, Blue Mountains, and Snake Head-

'A total of 13 ERUs were delineated for the Basin based on terrestrial and aquatic biophysical environment, as well as social/economic criteria. These delineations were used extensively by the different Science Integration Team (SIT) staff areas in the reporting of assessment results at the regional level.

Landscape Ecology 173
waters ERUs. An areal increase of the early-serai

subalpine forest community within the Northern

Glaciated Mountains ERU would also increase the

frequency of subbasins having this community

within its historical mid-range.

Mid-serai Subalpine Forest. The frequency of

subbasins having the mid-serai subalpine forest

community within its historical mid-range would

increase by 170 percent for the 100-year projection

of Alternative 1 (table 2.39). This increase would

primarily be due to areal increases of mid-serai subalpine forests throughout the Upper Klamath and

Central Idaho ERUs. Areal declines of this community in several subbasins of the Upper Clark

Fork ERU, and to a lesser extent the Northern

Glaciated Mountains ERU, would also increase the

frequency of subbasins having this community

within its historical mid-range.

Late-serai Subalpine Forest. Alternative 1 would

increase the frequency of subbasins having the

late-serai subalpine forest community within its

historical mid-range by 367 percent (table 2.39).

This increase would predominantly be due to an

areal increase of late-serai subalpine forests

throughout the Northern Cascades, Northern

Glaciated Mountains, Lower Clark Fork, Upper

Clark Fork, Central Idaho Mountains, and Upper

Snake ERUs. Areal declines of this community in

several subbasins of the Upper Klamath would

also increase the frequency of subbasins having

this community within its historical mid-range.

Upland Community Departures in

Alternative 1 —

Upland Herbland. The 100-year projection for

Alternative 1 suggested that the frequency of subbasins having areas of the upland herbland community within its historical mid-range would

increase by 117 percent (table 2.40). This increase

would largely be due to an areal increase of upland

herbland within the Columbia Plateau, Northern

Great Basin, and Owyhee Uplands ERUs.

Upland Shrubland. The 100-year projection for

Alternative 1 indicated that the frequency of subbasins having an areal extent of the upland herbland community within its historical mid-range

would remain about the same as the current period (table 2.40). However, the spatial distribution

of these subbasins would change substantially. The

most obvious changes would be an increase in

class 3 subbasins within the Central Idaho

Mountains ERU, and a decrease in class 3 subbasins within the western portion of the Northern

Great Basin ERU.

Upland Woodland. Alternative 1 would increase

the frequency of subbasins containing areas of the

upland woodland community within its historical

mid-range by 62 percent (table 2.40). However,

those subbasins having a substantial component of

this community would be dominated by class 5

departures. The increased number of subbasins

falling within the historical mid-range would

largely be due to areal increases of the upland

Table 2.37—Terrestrial community departure classes.

Departure Class Relationship of Current Area to Historical Ranges

1 Current area is smaller than minimum historical range.

2 Current area is equal to or greater than historical minimum, and equal to or less than

75 percent historical mid-range.

3 Current area is within 75 percent of historical mid-range.

4 Current area is greater than 75 percent historical mid-range, and equal to or less than

historical maximum.

5 Current area is greater than historical maximum.

174 Landscape Ecology
woodland community within subbasins of the

Central Idaho Mountains ERU. In addition, areal

declines of upland woodland in the Columbia

Plateau and Owyhee Uplands ERUs would also

contribute to an increased frequency of class 3

subbasins.

Alternative 2 Departures

Alternative 2 would decrease the average frequency of subbasin membership in class 1 and class 5

departures to 27 and 25 percent, respectively

(table 2.38). Similarly, the average frequency of

communities within class 3 departures would

increase to 36 percent. The 100-year projection

for Alternative 2 suggested that the mid-serai

lower montane forest and upland woodland communities would deviate the most, in a positive

direction, from historical conditions; at least 72

percent of the subbasins would contain these

communities at levels well above their historical

mid-ranges. The upland herbland and upland

shrubland communities would deviate the most in

a negative direction; at least 63 percent of the subbasins would contain these communities at levels

well below their historical mid-ranges (tables 2.39

and 2.40).

Departure Classes

[ Class 1 ) (Class 2 Class 4 Class 5

1

75% Historical Mid Range

Historical

Minimum

Historical

Maximum

Historical Range

Figure 2.48 — Relationship between current areal extent of broad-scale terrestrial communities and their respective historical

ranges.

Landscape Ecology 175
Table 2.38 — Average subbasin frequency distribution across 12 terrestrial community group departure

classes.

Alternative

Percent of Subbasin by Departure Class'

Current

1

2

3

4

5

6

7

47.6

27.0

26.9

27.3

27.6

26.8

26.6

25.2

8.3

8.8

8.7

8.8

8.6

8.7

9.3

8.0

13.8

35.8

35.8

32.4

31.9

33.7

33.7

40.6

2.3

3.7

3.6

4.2

4.4

3.9

4.2

3.3

28.0

24.8

25.1

27.3

27.5

26.9

26.4

22.8

'Departure class: See table 2.37 and figure 2.48.

Due to rounding, total percents of departures classes may sum to more or less than 100 percent.

Montane Community Departures in

Alternative 2 —

Early-serai Lower Montane Forest. The 100-

year projection for Alternative 2 indicated that the

availability of the early-serai lower montane forest

community would increase substantially from the

current conditions; the number of subbasins having this community within its historical midrange would increase by 950 percent (table 2.39).

This would largely occur throughout the

Northern Glaciated Mountains, Lower Clark

Fork, Central Idaho Mountains, Blue Mountains,

Northern Great Basin, and Columbia Plateau

ERUs.

Mid-serai Lower Montane Forest. The 100-year

projection of Alternative 2 indicated that virtually

all subbasins within the Basin would contain the

mid-serai lower montane forest community at a

level well above its historical mid-range (table

2.39). The area! extent of this community would

increase dramatically across much of the forested

areas of the Upper Columbia River Basin, and

also within the Upper Klamath ERU and adjacent

areas of the Eastside EIS area.

Late-serai Lower Montane Forest. Alternative 2

would substantially increase the availability of the

late-serai lower montane forest community above

the current conditions. The number of subbasins

having the areal extent of this community type

within its historical mid-range would increase by

over 400 percent (table 2.39). Its areal increase

would occur predominantly within the Columbia ~

Plateau, Blue Mountains, Northern Glaciated

Mountains, Upper Clark Fork, and Central Idaho

Mountains ERUs. However, the area of the lateserai lower montane forest community would

decrease to a point well below its historical midrange throughout a substantial portion of the

Southern Cascades ERU.

Early-serai Montane Forest. Alternative 2 would

increase the number of subbasins having the earlyserai montane forest community within its historical mid-range by 83 percent. However, this

increasing trend would not be consistent across all

subbasins within the Basin (table 2.39). Alternative

2 would result in a substantial areal increase of

early-serai montane forests within many subbasins

of the Northern Glaciated Mountains, Lower

Clark Fork, Upper Clark Fork, Upper Klamath,

Upper Snake, and Snake Headwaters ERUs.

However, substantial areal declines of these forests

would occur within the Blue Mountains and

Central Idaho Mountains ERUs. In addition, the

early-serai montane forest community would

decrease substantially throughout the northern half

of the Northern Cascades ERU, but increase substantially within its southern half.

178 Landscape Ecology
Map 2.23 - Subbasins (4th field hydrologic unit codes) of the Basin. There are 164 subbasins and portions of subbasins in the Basin, and they

range from approximately 500,000 to 1,000,000 hectares in size. This stratification was the basic data element for addressing ecological integrity

and landscape patterns.

Landscape Ecology 177
Table 2.39 — Summary of subbasin frequency distribution by current and projected future (alternative

year 100) forest terrestrial community group departures.

Terrestrial Community

Group

Lower Montane

Early-serai Forest

Lower Montane

Mid-serai Forest

Lower Montane

Late-serai Forest

Montane

Early-serai Forest

Montane

Mid-serai Forest

Alternative

Current

1

2

3

4

5

6

7

Current

1

2

3

4

5

6

7

Current

1

2

3

4

5

6

7

Current

1

2

3

4

5

6

7

Current

1

2

3

4

5

6

7

Number of

Subbasins1

117

119

118

118

118

118

118

119

125

124

124

124

124

124

124

124

125

125

125

125

125

125

125

125

136

136

135

135

135

135

135

135

133

130

130

130

130

130

130

130

Percent Subbasin by

Departure Class2

1

79

20

31

17

17

19

19

30

23

0

0

0

0

0

0

0

78

45

48

37

37

39

39

41

44

51

32

41

42

40

42

32

19

2

5

3

3

1

1

11

2

15

19

20

20

21

20

22

17

5

0

0

0

0

0

0

0

8

8

4

8

10

7

8

6

7

8

8

11

13

12

12

8

3

2

5

5

4

5

6

5

3

4

47

42

45

45

42

42

45

10

2

6

10

12

10

12

13

7

38

37

35

34

36

33

37

18

29

33

30

26

31

30

34

19

34

38

42

44

42

42

46

4

1

3

1

3

2

3

2

0

3

2

2

9

6

7

6

4

0

3

3

5

5

4

6

4

4

1

4

2

1

1

1

4

2

12

12

11

12

12

10

6

5

2

11

7

15

15

15

15

8

58

95

92

81

81

83

82

83

6

6

8

15

15

14

14

12

28

11

23

16

17

16

16

22

57

51

40

39

38

41

41

32

178 Landscape Ecology
Table 2.39 (continued)

Terrestrial Community

Group

Montane

Late-serai Forest

Subalpine

Early-serai Forest

Subalpine

Mid-serai Forest

Subalpine

Late-serai Forest

Alternative

Current

1

2

3

4

5

6

7

Current

1

2

3

4

5

6

7

Current

1

2

3

4

5

6

7

Current

1

2

3

4

5

6

7

Number of

Subbasins1

127

126

128

127

127

127

127

128

75

70

70

72

73

73

71

70

90

92

91

90

90

90

90

90

91

91

91

91

91

91

91

91

Percent Subbasin by

Departure Class2

1

59

34

27

30

30

28

28

23

21

9

9

4

3

4

4

11

38

13

16

28

29

28

29

13

63

23

20

37

35

35

30

12

2

4

10

9

7

6

11

8

4

3

13

14

10

10

8

13

14

9

9

16

9

7

7

6

10

9

10

11

8

9

7

11

10

3

9

44

43

46

45

44

46

48

20

56

54

29

26

38

38

66

20

54

48

42

42

46

44

60

12

56

57

45

46

47

48

51

4

1

2

5

4

6

4

5

6

0

6

6

4

5

4

7

1

3

3

5

4

4

3

3

4

0

3

0

1

1

3

1

4

5

27

9

15

13

13

13

14

19

56

17

17

53

56

45

38

7

30

21

13

17

18

17

18

12

16

8

12

9

9

8

10

23

'Subbasins (4th field HUCs) having at least 1 percent of the terrestrial community group.

'Departure class: See table 2.37 and figure 2.48.

Due to rounding, total percents of departure classes may sum to more or less than 100 percent.

Mid-seral Montane Forest. The number of subbasins having the mid-serai montane forest community within its historical mid-range would nearly double as a result of implementing Alternative 2

(table 2.39). The increased number of subbasins

falling within the historical mid-range would primarily be due to areal increases in mid-serai montane forests throughout the Central Idaho

Mountains, Upper Klamath, and Northern Great

Basin ERUs. In addition, our projected declines of

this community throughout many subbasins within the Northern Glaciated Mountains, Lower

Clark Fork, and Upper Clark Fork ERUs would

also increase the frequency of class 3 departures.

Landscape Ecology 179
Map 2.24 -The Ecological Reporting Units (ERUs) of the Basin. ERUs are aggregates of subwatersheds (6th field hydrologic unit codes) that generally represent similar terrestrial and aquatic characteristics.

Landscape Ecology
Table 2.40 — Summary of subbasin frequency distribution (percent) by current and future (alternative

year 100) range community group departure classes.

Terrestrial Community

Group

Upland Herbland

Upland Shrubland

Upland Woodland

Alternative

Current

1

2

3

4

5

6

7

Current

1

2

3

4

5

6

7

Current

1

2

3

4

5

6

7

Number of

Subbasins1

145

145

145

145

145

145

145

145

129

128

128

128

128

128

128

129

104

94

95

94

94

94

94

98

Percent Subbasin by

Departure Class2

1

66

59

63

61

61

61

59

56

47

63

70

62

65

62

63

65

34

5

2

7

9

4

5

8

2

15

9

6

7

6

6

9

5

14

13

10

15

12

16

13

12

7

4

1

5

5

5

4

5

3

12

26

31

29

26

30

26

37

22

22

18

20

20

20

22

22

13

21

22

16

17

18

21

28

4

0

3

0

2

4

1

3

0

8

2

2

2

2

2

2

0

6

4

3

3

5

3

4

7

5

7

3

1

1

3

1

3

3

9

1

1

1

1

1

1

1

40

65

72

68

64

69

65

52

'Subbasins (4th field HUCs) having at least 1 percent of the terrestrial community group.

'Departure class: See table 2.37 and figure 2.48.

Due to rounding, the percent totals for departure classes may sum to more or less than 100 percent.

Late-serai Montane Forest. The 100-year projection for Alternative 2 indicated that the number

of subbasins having the late-serai montane forest

community within its historical mid-range would

increase by 378 percent (table 2.39). This increase

would largely be due to areal increases in late-serai

forests throughout the North Cascades, Lower

Clark Fork, Upper Clark Fork, Central Idaho

Mountains, and Snake Headwaters ERUs. Areal

decreases in the late-serai montane community

within the Southern Cascades and Upper Klamath

ERUs would also increase the frequency of subbasins having this community within its historical

mid-range. The Blue Mountains and Columbia

Plateau ERUs would have some subbasins with

areal increases and others with areal declines,

which would increase the frequency of subbasins

having this community within its historical

mid-range.

Subalpine Community Departures in

Alternative 2 —

Early-serai Subalpine Forest. Alternative 2

would increase the number of subbasins having

the early-serai subalpine forest community within

its historical mid-range by 170 percent (table

2.39). This increase would primarily be a result of

areal decreases in early-serai subalpine forests

throughout the Central Idaho Mountains, Blue

Landscape Ecology 181
Mountains, and Snake Headwaters ERUs. Areal

increases of the early-serai subalpine forest community within the Northern Glaciated Mountains

ERU would also increase the frequency of subbasins having this community within its historical

mid-range.

Mid-serai Subalpine Forest. The frequency of

subbasins having the mid-serai subalpine forest

community within its historical mid-range would

increase by 140 percent as a result of implementing Alternative 2 (table 2.39). This increase would

largely be due to an increase of mid-serai subalpine forests throughout the Southern Cascades

and Central Idaho Mountains ERUs. Areal

declines of this community in several subbasins of

the Lower Clark Fork, Upper Clark Fork, and the

Northern Glaciated Mountains ERUs would also

increase the frequency of subbasins having the

mid-serai subalpine forest community within its

historical range mid-range.

Late-serai Subalpine Forest. Alternative 2 would

increase the frequency of subbasins having the

late-serai subalpine forest community within its

historical mid-range by 375 percent (table 2.39).

This increase would predominantly be due to

areal increases of late-serai subalpine forests

throughout the Northern Cascades, Northern

Glaciated Mountains, Lower Clark Fork, Upper

Clark Fork, Central Idaho Mountains, and Upper

Snake ERUs. Conversely, the areal declines of this

community in several subbasins of the Upper

Klamath and Central Idaho Mountains ERUs

would also increase the frequency of subbasins

having this community within its historical midrange.

Upland Community Departures in

Alternative 2 —

Upland Herbland. The 100-year projection for

Alternative 2 indicated that the frequency of subbasins having areas of upland herbland community at levels within its historical mid-range would

increase by 158 percent relative to the current

period (table 2.40). This increase would mostly be

attributed to the areal increase of upland herbland

within the Columbia Plateau, Northern Great

Basin, and Owyhee Uplands ERUs.

Upland Shrubland. Relative to the current period, Alternative 2 would not substantially change

the frequency of subbasins having the upland

shrubland community within its historical midrange (table 2.40). However, the spatial distribution of these subbasins would change substantially. The most obvious changes expected would be

an increase of class 3 subbasins in the Central

Idaho Mountains ERU, and a decrease of class 3

subbasins in the western portion of the Northern

Great Basin ERU.

Upland Woodland. Alternative 2 would increase the frequency of subbasins having areas of

the upland woodland community within its historical mid-range by 69 percent (table 2.40).

However, as with the current period, the Basin

would still be dominated by class 5 departures.

The increased number of those subbasins falling

within the historical mid-range would predominantly be due to areal increases of the upland

woodland community within subbasins of the

Central Idaho Mountains ERU. In addition, the

areal declines of upland woodland in the Columbia Plateau and Owyhee Uplands ERUs would

also contribute to an increased frequency of class

3 subbasins.

Alternative 3 Departures

Alternative 3 would decrease the average frequency of subbasin memberships in class 1 and class 5

departures to 27 percent (table 2.38). Similarly,

the average frequency of communities within class

3 departures would increase to 32 percent. The

100-year projection for Alternative 3 indicated

that the mid-serai lower montane forest, earlyserai subalpine forest, and upland woodland communities would deviate the most, in a positive

direction, from historical conditions; at least 53

percent of the subbasins would contain these

communities at levels well above their historical

mid-ranges. Two upland communities, herbland

and shrubland, would deviate the most in a negative direction; at least 61 percent of the subbasins

Landscape Ecology
would contain these communities at levels well

below their historical mid-ranges (tables 2.39

and 2.40).

Montane Community Departures in

Alternative 3 —

Early-serai Lower Montane Forest. The 100-

year projection for Alternative 3 indicated that the

availability of the early-serai lower montane forest

community would increase substantially from the

current conditions; the number of subbasins having this community within its historical midrange would increase by over 1,000 percent (table

2.39). This increase would largely occur primarily

throughout the Northern Glaciated Mountains,

Lower Clark Fork, Central Idaho Mountains, Blue

Mountains, Northern Great Basin, and Columbia

Plateau ERUs.

Mid-serai Lower Montane Forest. The 100-year

projection for Alternative 3 indicated that virtually all subbasins within the Basin would contain

the mid-serai lower montane forest community at

a level well above its historical mid-range (table

2.39). This community would increase substantially across much of the forested areas of the

Upper Columbia River Basin area, within the

Upper Klamath ERU, and in adjacent areas of the

Eastside EIS area.

Late-serai Lower Montane Forest. Alternative 3

would increase the availability of the late-serai

lower montane forest community substantially

from its current condition; the number of subbasins having this community within its historical

mid-range would increase by over 400 percent

(table 2.39). The increased number of subbasins

having areas of this community type within its

historical mid-range would occur predominantly

within the Columbia Plateau, Blue Mountains,

Northern Glaciated Mountains, Upper Clark

Fork, and Central Idaho Mountains ERUs.

Early-serai Montane Forest. The 100-year projection for Alternative 3 indicated that the number of subbasins having the early-serai montane

forest within its historical mid-range would

increase by 67 percent (table 2.39). However, the

trends of this community would vary spatially

across the Basin. Alternative 3 would result in a

substantial increase of early-serai montane forests

within many subbasins of the Northern Glaciated

Mountains (especially in the north Idaho and

northwestern Montana portions), Lower Clark

Fork, Upper Clark Fork, Upper Klamath, Upper

Snake, and Snake Headwaters ERUs. However,

there would be a substantial decrease of the earlyserai montane forests within the Blue Mountains

and Central Idaho Mountains ERUs. In addition,

the areal extent of the early-serai montane forest

community would decrease substantially throughout the northern half of the Northern Cascades

ERU, but increase substantially within its southern half.

Mid-serai Montane Forest. Although Alternative

3 would increase the number of subbasins having

the mid-serai montane forest community within

its historical mid-range by 121 percent, half of the

subbasins would still contain areas of this community above its historical mid-range (table 2.39).

The increased number of subbasins falling within

the historical mid-range would be due predominantly to areal increases in mid-serai forests

throughout the Central Idaho Mountains and

Upper Klamath ERUs. In addition, we projected

areal declines of this community throughout

many subbasins within the Northern Glaciated

Mountains, Lower Clark Fork, and Upper Clark

Fork ERUs, which would also increase the frequency of subbasins having this community within its historical mid-range.

Late-serai Montane Forest. The 100-year projection for Alternative 3 suggested that the number

of subbasins having the late-serai montane forest

community within its historical mid-range would

increase by 411 percent (table 2.39). This increase

would occur largely because of areal increases in

late-serai montane forests throughout the Lower

Clark Fork, Upper Clark Fork, Central Idaho

Mountains, and Snake Headwaters ERUs. Areal

declines in the late-serai montane forest community within the Southern Cascades and Upper

Klamath ERUs would also increase the frequency

Landscape Ecology 3,83
of subbasins having this community within its

historical mid-range.

The Blue Mountain and Columbia Plateau ERUs

would contain some subbasins with upward

trends and others with downward trends, which

would also increase the frequency of subbasins

having the late-serai montane forest within its historical mid-range.

Subalpine Community Departures in

Alternative 3 —

Early-serai Subalpine Forest. Alternative 3

would increase the frequency of subbasins having

the early-serai Subalpine forest community within

its historical mid-range by 45 percent, yet the

Basin would still be dominated by subbasins

where this community would occur well above its

historical mid-range (table 2.39). The increased

number of subbasins falling within the historical

mid-range would predominantly be due to areal

declines of early-serai forests throughout the

northern portion of the Central Idaho Mountains

ERU.

Mid-serai Subalpine Forest. The frequency of

subbasins having the mid-serai subalpine forest

community within its historical mid-range would

increase by 110 percent for the 100-year projection of Alternative 3 (table 2.39). This increase

would predominantly be due to increases of midserai subalpine forests throughout the Central

Idaho Mountains ERU. Areal declines of this

community that would occur in several subbasins

of the Lower and Upper Clark Fork ERUs would

also increase the frequency of subbasins having

this community within its historical mid-range.

Late-serai Subalpine Forest. Alternative 3 would

increase the proportion of subbasins having the

late-serai subalpine forest community within its

historical mid-range by 275 percent (table 2.39).

This increase would predominantly be due to

areal increases of late-serai subalpine forests

throughout the Northern Glaciated Mountains,

Lower Clark Fork, and Upper Clark Fork ERUs.

Areal declines that would occur in several subbasins of the Upper Klamath and Central Idaho

Mountains ERUs would also increase the frequency of subbasins having this community within its

historical mid-range.

Upland Community Departures in

Alternative 3 —

Upland Herbland. The 100-year projection for

Alternative 3 indicated that the frequency of subbasins having areas of the upland herbland community within its historical mid-range would

increase by 142 percent (table 2.40). This increase

would predominantly occur within the Columbia

Plateau, Northern Great Basin, and Owyhee

Uplands ERUs.

Upland Shrubland. Alternative 3 would decrease

the frequency of subbasins having the upland

shrubland community within its historical midrange by approximately 9 percent (table 2.40).

This decrease would be attributed primarily to the'

loss of upland shrubland across subbasins within

the Northern Great Basin. However, an increase

of class 3 subbasins was projected within the

Central Idaho Mountains and Snake Headwater

ERUs.

Upland Woodland. The 100-year projection for

Alternative 3 indicated that the frequency of subbasins having areas of the upland woodland community within its historical mid-range would

increase by 23 percent (table 2.40). However, the

Basin would still be dominated by subbasins having this community well above its historical midrange. The increased number of subbasins falling

within the historical mid-range would predominantly be due to areal increases in upland woodland within subbasins of the Central Idaho

Mountains ERU.

Alternative 4 Departures

Alternative 4 would decrease the average frequency of subbasin membership in class 1 and class 5

departures to 28 percent (table 2.38). Similarly,

the average frequency of communities within class

3 departures would increase to 33 percent. The

184 Landscape Ecology
100-year projection for Alternative 4 indicated

that the mid-serai lower montane forest, earlyserai subalpine forest, and upland woodland communities would deviate the most, in a positive

direction, from historical conditions; at least 56

percent of the subbasins would contain these

communities at levels well above their historical

mid-ranges. The upland herbland and upland

shrubland communities would deviate the most in

a negative direction; at least 61 percent of the subbasins would contain these communities at levels

well below their historical mid-ranges (tables 2.39

and 2.40).

Montane Community Departures in

Alternative 4 —

Early-serai Lower Montane Forest. The 100-

year projection for Alternative 4 indicated that the

availability of the early-serai lower montane forest

community would increase substantially from the

current conditions; the number of subbasins having areas of this community within its historical

mid-range would increase by over 1,000 percent

(table 2.39). This increase would primarily occur

throughout the Northern Glaciated Mountains,

Lower Clark Fork, Central Idaho Mountains, Blue

Mountains, Northern Great Basin, and Columbia

Plateau ERUs.

Mid-serai Lower Montane Forest. This community would occur well above its historical midrange in virtually all subbasins of the Basin after

100 years of implementing Alternative 4 (table

2.39). The mid-serai lower montane forest would

increase substantially across much of the forested

areas of the Upper Columbia River Basin area,

within the Upper Klamath ERU, and in adjacent

areas of the Eastside EIS area.

Late-serai Lower Montane Forest. The 100-year

projection for Alternative 4 indicated that the

availability of the late-serai lower montane forest

community would increase substantially from the

current conditions. The number of subbasins having this community within its historical midrange would increase by approximately 385 percent (table 2.39). This increase would occur predominantly within the Columbia Plateau, Blue

Mountains, Northern Glaciated Mountains,

Upper Clark Fork, and Central Idaho Mountains

ERUs.

Early-serai Montane Forest. Alternative 4 would

increase the number of subbasins containing the

early-serai montane forest community within its

historical mid-range by 44 percent. However, spatial variations across the Basin were apparent

(table 2.39). Alternative 4 would result in a substantial increase of early-serai montane forests

within many subbasins of the Northern Glaciated

Mountains (especially in the north Idaho and

northwestern Montana portions), Lower Clark

Fork, Upper Clark Fork, Upper Klamath, Upper

Snake, and Snake Headwaters ERUs. However,

there would be a substantial areal decline of the

early-serai montane forest community within the

Blue Mountains and Central Idaho Mountains

ERUs. The early-serai montane forest community

would decrease substantially throughout the

northern half of the Northern Cascades ERU, but

increase substantially within the southern half.

Mid-serai Montane Forest. Alternative 4 would

increase the number of subbasins having the midserai montane forest community within its historical mid-range by 132 percent (table 2.39). This

increase would predominantly be due to increases

in mid-serai forest throughout the Central Idaho

Mountains and Upper Klamath ERUs. Areal

declines of this community were projected

throughout many subbasins within the Northern

Glaciated Mountains, Lower Clark Fork, and

Upper Clark Fork ERUs, which also would

increase the frequency of subbasins having this

community within its historical mid-range.

Late-serai Montane Forest. The 100-year projection for Alternative 4 suggested that the number

of subbasins having the late-serai montane forest

community within its historical mid-range would

increase by 400 percent (table 2.39). This increase

would largely be due to increases in the late-serai

montane forest community throughout the Lower

Clark Fork, Upper Clark Fork, Central Idaho

Mountains, and Snake Headwaters ERUs. Areal

Landscape Ecology 185
declines of the late-serai montane forest community within the Southern Cascades and Upper

Klamath ERUs would also increase the frequency

of subbasins having this community at a level

within its historical mid-range. The Blue

Mountains and Columbia Plateau ERUs would

have some subbasins with increases and others

with decreases, which would also increase the frequency of subbasins having the late-serai montane

forest community within its historical mid-range.

Subalpine Community Departures in

Alternative 4 —

Early-serai Subalpine Forest. Alternative 4

would increase the number of subbasins having

the early-serai subalpine forest community within

its historical mid-range by 30 percent. However,

the Basin would still be dominated by subbasins

having this community well above its historical

mid-range (table 2.39). The increase of those subbasins that had this community within its historical mid-range would predominantly be due to

areal declines in the early-serai forest community

throughout the northern portion of the Central

Idaho Mountains ERU.

Mid-serai Subalpine Forest. The frequency of

subbasins having the mid-serai subalpine forest

community within its historical mid-range

increased by 110 percent for the 100-year projection of Alternative 4 (table 2.39). This increase

was largely due to areal increases in mid-serai

subalpine forests throughout the Central Idaho

ERU. Areal declines in this community that

would occur in several subbasins of the Lower

Clark Fork and Upper Clark Fork ERUs would

also increase the frequency of subbasins having

this community at a level within its historical

mid-range.

Late-serai Subalpine Forest. The number of subbasins having the mid-serai subalpine forest community within its historical mid-range increased

by 283 percent for the 100-year projection of

Alternative 4 (table 2.39). This increase was predominantly due to increases in late-serai subalpine

forests throughout the Northern Glaciated

Mountains, Lower Clark Fork, Upper Clark Fork,

and Snake Headwaters ERUs. Areal declines of

this community that would occur in several subbasins of the Upper Klamath and Central Idaho

Mountains ERUs would also increase the frequency of subbasins having this community within its

historical mid-range.

Upland Community Departures in

Alternative 4 —

Upland Herbland. Alternative 4 would increase

the frequency of subbasins having the upland

herbland community within its historical midrange by 117 percent (table 2.40). This increase

would largely be due to increases in upland herbland within the Columbia Plateau, Northern

Great Basin, and Owyhee Uplands ERUs.

Upland Shrubland. The 100-year projection for

Alternative 4 indicated that the frequency of subbasins having areas of the upland herbland community at levels within the historical mid-range

would decrease by approximately nine percent

(table 2.40). This decrease would be attributed

primarily to the loss of upland shrubland across

subbasins within the Northern Great Basin ERU.

However, the simulations indicated an increase of

class 3 subbasins within the Snake Headwater

ERU.

Upland Woodland. Alternative 4 would increase

the number of subbasins having the upland woodland community within its historical mid-range

by 31 percent (table 2.40). However, those subbasins having a substantial component of the

upland woodland community would be dominated by class 5 departures. The increase of those

subbasins falling within the historical mid-range

would predominantly be due to increases in the

upland woodland community in subbasins within

the Central Idaho Mountains and Upper Klamath

ERUs. In addition, areal declines of the upland

woodland community in the Blue Mountains and

Owyhee Uplands ERUs would also contribute to

an increased frequency of class 3 subbasins.

Landscape Ecology
Alternative 5 Departures

Alternative 5 would decrease the average frequency of subbasin memberships in class 1 and 5

departures to 27 percent (table 2.38). Similarly,

the average frequency of communities within class

3 departures would increase to 34 percent. The

100-year projection for Alternative 5 indicated

that the mid-serai lower montane forest and

upland woodland communities would deviate the

most, in a positive direction, from historical conditions; at least 69 percent of the subbasins would

contain these communities at levels well above

their historical mid-ranges. The upland herbland

and upland shrubland communities would deviate

the most in a negative direction; at least 61 percent of the subbasins would contain these communities at levels well below their historical midranges (tables 2.39 and 2.40).

Montane Community Departures in

Alternative 5 —

Early-serai Lower Montane Forest. Alternative 5

would substantially increase the availability of the

early-serai lower montane forest community relative to current conditions. The number of subbasins containing levels of this community within

its historical mid-range would increase by 950

percent (table 2.39). This increase would occur

primarily in the Northern Glaciated Mountains,

Lower Clark Fork, Central Idaho Mountains, Blue

Mountains, Northern Great Basin, and Columbia

Plateau ERUs.

Mid-serai Lower Montane Forest. The 100-year

projection for Alternative 5 indicated that virtually

all subbasins within the Basin would contain the

mid-serai lower montane forest community at levels well above its historical mid-range (table 2.39).

The areal extent of this community would increase

across much of the forested areas of the Upper

Columbia River Basin EIS area, within the Upper

Klamath ERU, and in areas within the Eastside

EIS area adjacent to the Upper Klamath ERU.

Late-serai Lower Montane Forest. Under

Alternative 5, the availability of the late-serai lower

montane forest community would increase substantially from the current conditions. The number of subbasins that contained levels of this community within its historical mid-range would

increase by over 400 percent (table 2.39). The

increase of this community type would occur predominantly within the Columbia Plateau, Blue

Mountains, Northern Glaciated Mountains, Upper

Clark Fork, and Central Idaho Mountains ERUs.

Early-serai Montane Forest. The 100-year projection for Alternative 5 suggested that the number of subbasins having the early-serai montane

community within its historical mid-range would

increase by 72 percent. However, trends of the

early-serai montane forest community were not

consistent throughout the Basin (table 2.39).

Alternative 5 would result in substantial increases

of early-serai montane forests within many subbasins of the Northern Glaciated Mountains

(especially in the north Idaho and northwestern

Montana portions), Lower Clark Fork, Upper

Clark Fork, Upper Klamath, Upper Snake, and

Snake Headwaters ERUs. However, there would

be substantial areal declines of the community

type in the Blue Mountains and Central Idaho

Mountains ERUs. Similarly, the early-serai montane forest community would decrease substantially throughout the northern half of the Northern

Cascades ERU, but increase substantially within

the southern half.

Mid-serai Montane Forest. Alternative 5 would

increase the number of subbasins having the midserai montane forest community within its historical mid-range by 121 percent (table 2.39). This

increase would predominantly be due to increases

in mid-serai forests throughout the Central Idaho

Mountains and Upper Klamath ERUs.

Conversely, we projected decreases in this community throughout many subbasins within the

Northern Glaciated Mountains, Lower Clark

Fork, Upper Clark Fork, and Snake Headwaters

ERUs.

Late-serai Montane Forest. The 100-year projection for Alternative 5 indicated that the number

of subbasins having the late-serai montane forest

Landscape Ecology 187
community within its historical mid-range would

increase by 389 percent (table 2.39). Increases

where amounts were below HRV would largely

occur throughout the Lower Clark Fork, Upper

Clark Fork, Central Idaho Mountains, and Snake

Headwaters ERUs. Decreases in the late-serai

montane forest community within the Southern

Cascades and Upper Klamath ERUs where

amounts were above HRV would also increase the

frequency of subbasins having this community

within its historical mid-range. The Blue Mountains and Columbia Plateau ERUs would contain

some subbasins with increases and others with

decreases, which would improve the frequency of

subbasins having the late-serai montane forest

community within its historical mid-range.

Subalpine Community Departures in

Alternative 5 —

Early-serai Subalpine Forest. Alternative 5

would nearly double the number of subbasins

having the early-serai subalpine forest community

within its historical mid-range (table 2.39). This

increase would largely be due to decreases in the

early-serai subalpine forest throughout the Central

Idaho Mountains ERU. Increases in the early-serai

subalpine forest community within the Northern

Glaciated Mountains ERU would also increase the

frequency of subbasins having this community at

a level within its historical mid-range.

Mid-serai Subalpine Forest. The frequency of

subbasins having the mid-serai subalpine forest

community within its historical mid-range would

increase by 130 percent for the 100-year projection of Alternative 5 (table 2.39). This increase

would predominantly be due to increases in midserai subalpine forests throughout the Central

Idaho ERU. Decreases in this community that

would occur in several subbasins of the Lower

Clark Fork and Upper Clark Fork ERUs would

also increase the frequency of subbasins having

this community type at a level within its historical

mid-range.

Late-serai Subalpine Forest. Alternative 5 would

increase the frequency of subbasins having the

mid-serai subalpine forest community within its

historical mid-range by 292 percent (table 2.39).

This increase would mostly be attributed to

increases in late-serai subalpine forests throughout

the Northern Glaciated Mountains, Lower Clark

Fork, Upper Clark Fork, and Snake Headwaters

ERUs. Decreases in this community, which would

occur in several subbasins of the Upper Klamath

and Central Idaho Mountains, would also increase

the frequency of subbasins having this community

at historical mid-range levels.

Upland Community Departures in

Alternative 5 —

Upland Herbland. The 100-year projection for

Alternative 5 indicated that the number of subbasins having the upland herbland community

within its historical mid-range would increase by

150 percent relative to the current period (table

2.40). This increase would primarily be due to

areal increases in upland herbland within the

Columbia Plateau, Northern Great Basin, and

Owyhee Uplands ERUs.

Upland Shrubland. Alternative 5 would not

increase the frequency of subbasins having the

upland herbland community within its historical

mid-range; in fact, the frequency of subbasins

would decrease by approximately 9 percent (table

2.40). This decrease would be attributed primarily

to the loss of the upland shrubland community

within subbasins of the Northern Great Basin

ERU.

Upland Woodland. The 100-year projection for

Alternative 5 indicated that the frequency of subbasins having areas of the upland woodland community within its historical mid-range would

increase by 38 percent (table 2.40). However, subbasins having a substantial component of the

upland woodland community would still be dominated by class 5 departures. The increased number of subbasins within the historical mid-range

would primarily be attributed to areal increases in

the upland woodland community within subbasins of the Central Idaho Mountains and Upper

Klamath ERUs. In addition, areal declines of

188 Landscape Ecology
upland woodland in the Owyhee Uplands ERU

would contribute to an increased frequency of

class 3 subbasins.

Alternative 6 Departures

Alternative 6 would decrease the average frequency of subbasin membership in classes 1 and 5

departures to 26 percent (table 2.38). Similarly,

the average frequency of communities within class

3 departures would increase to 34 percent. The

100-year projection for Alternative 6 indicated

that the mid-serai lower montane forest and

upland woodland communities would differ the

most, in a positive direction, from historical conditions; at least 65 percent of the subbasins would

contain these communities at levels well above

their historical ranges. The upland herbland and

upland shrubland communities would diverge the

most in a negative direction; at least 59 percent of

the subbasins would contain these communities at

levels well below their historical ranges (tables

2.39 and 2.40).

Montane Community Departures in

Alternative 6 —

Early-serai Lower Montane Forest. The 100-

year projection for Alternative 6 indicated that the

availability of the early-serai lower montane forest

community would increase substantially from the

current conditions; the amount of subbasins having levels of this community within its historical

mid-range would increase by 950 percent (table

2.39). This increase would largely occur throughout the Northern Glaciated Mountains, Lower

Clark Fork, Central Idaho Mountains, Blue

Mountains, Northern Great Basin, and Columbia

Plateau ERUs.

Mid-serai Lower Montane Forest. The 100-year

projection for Alternative 6 indicated that virtually

all subbasins within the Basin would contain the

mid-serai lower montane forest community at levels well above its historical mid-range (table 2.39).

The areal extent of the mid-serai lower montane

forest community would increase substantially

across much of the forested areas of the Upper

Columbia River Basin area, within the Upper

Klamath ERU, and in areas within the Eastside

EIS area adjacent to the Upper Klamath ERU.

Late-serai Lower Montane Forest. Alternative 6

would substantially increase the availability of the

late-serai lower montane forest community relative to the current conditions. The number of

subbasins having this community within its historical mid-range would increase by approximately 370 percent (table 2.39). This increase would

occur predominantly within the Columbia

Plateau, Blue Mountains, Northern Glaciated

Mountains, Upper Clark Fork, and Central Idaho

Mountains ERUs.

Early-serai Montane Forest. Under Alternative

6, the number of subbasins having the early-serai

montane community within its historical midrange would increase by 67 percent. However, this

increasing trend would not be consistent across

the Basin. Alternative 6 would result in a substantial increase of this community within many subbasins of the Northern Glaciated Mountains

(especially in the north Idaho and northwestern

Montana portions), Lower Clark Fork, Upper

Clark Fork, Upper Klamath, Upper Snake, and

Snake Headwaters ERUs. However, there would

be a substantial areal decline within the Blue

Mountains and Central Idaho Mountains ERUs.

In addition, the early-serai montane forest community would decline substantially throughout

the northern half of the Northern Cascades ERU,

but increase substantially within the southern half.

Mid-serai Montane Forest. Alternative 6 would

increase the number of subbasins having the midserai montane forest community within its historical mid-range by 121 percent (table 2.39). This

increase would largely be attributed to increases in

mid-serai montane forests throughout the northern portion of the Central Idaho Mountains and

southern portion of the Upper Klamath ERUs.

Conversely, we projected decreases in this community throughout many subbasins within the

Northern Glaciated Mountains, Lower Clark

Fork, Upper Clark Fork, Blue Mountains, and

Snake Headwaters ERUs.

Landscape Ecology
Late-serai Montane Forest. The 100-year projection for Alternative 6 indicated that the frequency

of subbasins having the late-serai montane forest

community within its 75 percent historical midrange would increase by 411 percent (table 2.39).

This increase would predominantly be due to

increases of late-serai montane forests throughout

the Northern Glaciated Mountains, Lower Clark

Fork, Upper Clark Fork, Central Idaho

Mountains, and Snake Headwaters ERUs. Areal

declines of the late-serai montane forest community within the Southern Cascades ERU would

also increase the frequency of subbasins having

this community within its historical mid-range.

The Blue Mountains and Columbia Plateau ERUs

would contain some subbasins with increases and

others with decreases, which would also improve

the frequency of subbasins having the late-serai

montane forest community within its historical

mid-range.

Subalpine Community Departures in

Alternative 6 —

Early-serai Subalpine Forest. Alternative 6

would nearly double the number of subbasins

having the early-serai subalpine forest community

within its historical mid-range (table 2.39). This

increase would largely be due to decreases in

early-serai forests throughout the Central Idaho

Mountains ERU. Areal increases of the early-serai

subalpine forest community within the Northern

Glaciated Mountains ERU would also increase the

frequency of subbasins having this community

within its historical mid-range.

Mid-serai Subalpine Forest. The proportion of

subbasins having the mid-serai subalpine forest

community within its historical mid-range would

increase by 120 percent for the 100-year projection of Alternative 6 (table 2.39). This increase

would predominantly be due to increases in midserai subalpine forests throughout the Central

Idaho Mountains and Snake Headwaters ERUs.

Expected decreases in this community in several

subbasins of the Lower Clark Fork and Upper

Clark Fork ERUs would also increase the frequency of subbasins having this community within its historical mid-range.

Late-serai Subalpine Forest. The number of subbasins having the late-serai subalpine forest community within its historical mid-range would

increase by 300 percent for the 100-year projection of Alternative 6 (table 2.39). This increase

would predominantly be due to increases in lateserai subalpine forests throughout the Northern

Glaciated Mountains, Lower Clark Fork, Upper

Clark Fork, and Snake Headwaters ERUs.

Expected areal decline of this community in several subbasins of the Central Idaho Mountains ERU

would also increase the frequency of subbasins

having this community at a level within its historical mid-range.

Upland Community Departures in

Alternative 6 —

Upland Herbland. The 100-year projection for

Alternative 6 indicated that the frequency of subbasins having areas of die upland herbland community within its historical mid-range would

increase by 117 percent (table 2.40). This increase

would largely be due to areal increases of upland

herbland within the Columbia Plateau, Northern

Great Basin, and Owyhee Uplands ERUs.

Upland Shrubland. Alternative 6 would not substantially change the frequency of subbasins containing areas of the upland herbland community

within its historical mid-range (table 2.40)

However, the spatial distribution of class 3 subbasins of the 100-year projection differed substantially from the current period. We observed a loss

of class 3 subbasins in the western portion of the

Northern Great Basin ERU and across some of

the Owyhee Uplands ERU, but an increase of

class 3 subbasins within the Central Idaho

Mountains ERU.

Upland Woodland. The 100-year projection for

Alternative 6 indicated that the frequency of subbasins having areas of the upland woodland community at levels within its historical mid-range

would increase 62 percent (table 2.40). However,

Landscape Ecology
those subbasins having a substantial component of

the upland woodland community would still be

dominated by class 5 departures. The increase in

number of subbasins falling within the historical

range would predominantly be due to areal

increases of the upland woodland community

within subbasins of the Central Idaho Mountains

and Upper Klamath ERUs. In addition, areal

declines of upland woodland in the Owyhee

Uplands and Blue Mountains ERUs would contribute to an increased frequency of class 3 subbasins.

Alternative 7 Departures

Alternative 7 would decrease the average frequency of subbasin memberships in classes 1 and 5

departures to 25 and 23 percent, respectively.

Similarly, the average frequency of communities

within class 3 departures would increase to 41

percent (table 2.38).

The 100-year projection for Alternative 7 indicated that the mid-serai lower montane forest and

upland woodland communities would differ the

most, in a positive direction, from historical conditions; at least 52 percent of the subbasins

would contain these communities at levels well

above their historical mid-ranges. Also, the

upland herbland and upland shrubland communities would differ the most in a negative direction; at least 56 percent of the subbasins would

contain areas of these communities at levels well

below their historical mid-ranges (tables 2.39

and 2.40).

Montane Community Departures in

Alternative 7 —

Early-serai Lower Montane Forest. The 100-

year projection for Alternative 7 indicated that the

availability of the early-serai lower montane forest

community would increase substantially from the

current conditions. The number of subbasins containing areas of this community within its historical mid-range would increase by over 1,000 percent (table 2.39). This increase would largely

occur throughout the Northern Glaciated

Mountains, Lower Clark Fork, Central Idaho

Mountains, Blue Mountains, Southern Cascades,

and Columbia Plateau ERUs.

Mid-serai Lower Montane Forest. The 100-year

projection for Alternative 7 indicated that virtually all subbasins within the Basin would contain

areas of the mid-serai lower montane forest community at levels well above its historical mid-range

(table 2.39). The areal extent of the mid-serai

lower montane forest community would dramatically increase across much of the forested areas of

the Upper Columbia River Basin, as well as within the Upper Klamath ERU and areas of the

Eastside EIS area adjacent to the Upper Klamath

ERU.

Late-serai Lower Montane Forest. Alternative 7

would substantially increase the areal extent of the

late-serai lower montane forest community above

the current conditions. The number of subbasins

having levels of this community within its historical mid-range would increase by over 400 percent

(table 2.39). This increase would occur predominantly within the Northern Cascades, Columbia

Plateau, Blue Mountains, Northern Glaciated

Mountains, Upper Clark Fork, and Central Idaho

Mountains ERUs.

Early-serai Montane Forest. Alternative 7 would

increase the number of subbasins having areas of

the early-serai montane forest community within

its historical mid-range by 89 percent (table 2.39).

However, the increasing trend would be spatially

variable across the Basin. Alternative 7 would

result in a substantial increase of early-serai montane forests within many subbasins of the

Northern Glaciated Mountains, Lower Clark

Fork, Upper Clark Fork, Upper Klamath, Upper

Snake, and Snake Headwaters ERUs, whereas

there would be a substantial decrease within the

Blue Mountains and Central Idaho Mountains

ERUs (table 2.39). Additionally, the early-serai

montane forest community would decrease substantially throughout the northern half of the

Northern Cascades ERU, but increase substantially within its southern half.

Landscape Ecology 191
Mid-serai Montane Forest. The 100-year projection for Alternative 7 indicated that the number

of subbasins having the mid-serai montane forest

community within its historical mid-range would

increase by 142 percent (table 2.39). This increase

would predominantly be due to increases in midserai forests throughout the Central Idaho Mountains and Upper Klamath ERUs. Conversely, we

projected areal declines of this community

throughout many subbasins within the Northern

Glaciated Mountains and Lower Clark Fork

ERUs.

Late-serai Montane Forest. Alternative 7 would

increase the number of subbasins having the lateserai montane forest community within its historical mid-range by 433 percent, relative to the current period (table 2.39). This increase would

largely be attributed to increases in late-serai

montane forests throughout the Northern

Glaciated Mountains, Lower Clark Fork, Upper

Clark Fork, Central Idaho Mountains, and Snake

Headwaters ERUs. Areal declines of the late-serai

montane forest community within the Southern

Cascades ERU would also increase the frequency

of subbasins having this community within its

historical mid-range. The Northern Cascades,

Blue Mountains, and Columbia Plateau ERUs

would contain some subbasins with areal increases and others with areal declines, which would

increase the frequency of subbasins having the

late-serai montane forest community within its

historical mid-range.

Subalpine Community Departures in

Alternative 7 —

Early-serai Subalpine Forest. The 100-year projection for Alternative 7 indicated that the number of subbasins having the early-serai subalpine

forest community within its historical mid-range

would increase by 230 percent (table 2.39). This

increase would predominantly be due to decreases

in early-serai forests throughout the Northern

Cascades, Lower Clark Fork, Snake Headwaters,

and Central Idaho Mountains ERUs. Expected

increases in the early-serai subalpine community

within the Northern Glaciated Mountains ERU

would also increase the frequency of subbasins

having this community within its historical midrange.

Mid-serai Subalpine Forest. The frequency of

subbasins having the mid-serai subalpine forest

community within its historical mid-range

increased by 200 percent for the 100-year projection of Alternative 7 (table 2.39). This increase

would predominantly be due to increases in midserai subalpine forests throughout the Southern

Cascades, Blue Mountains, and Central Idaho

Mountains ERUs, and to a lesser extent, the

Snake Headwaters ERU. Expected areal declines

of this community in several subbasins of the

Lower Clark Fork, Upper Clark Fork, and Snake

Headwaters ERUs would also increase the proportion of subbasins having an areal extent of this

community within its historical mid-range.

Late-serai Subalpine Forest. The frequency of

subbasins having the mid-serai subalpine forest

community within its historical mid-range

increased 292 percent for the 100-year projection

of Alternative 7 (table 2.39). This increase would

predominantly be due to areal increases of the

late-serai subalpine forest community throughout

the Northern Cascades, Northern Glaciated

Mountains, Lower Clark Fork, Upper Clark Fork,

Central Idaho Mountains, and Snake Headwaters

ERUs.

Upland Community Departures in

Alternative 7 —

Upland Herbland. The 100-year projection for

Alternative 7 indicated that the frequency of subbasins having the upland herbland community

within its historical mid-range would increase by

208 percent (table 2.40). This increase would

largely be due to areal increases of upland herbland within the Northern Great Basin, Owyhee

Uplands, Central Idaho Mountains ERUs, and

the most northern extension of the Blue Mountains ERU. These changes are substantially different from those observed in other alternatives.

192 Landscape Ecology
Upland Shrubland. The 100-year projection for

Alternative 7 did not substantially change the proportion of subbasins that would have the upland

herbland community at levels within its historical

mid-range (table 2.40). However, the spatial distribution of class 3 subbasins would change substantially. We observed a decline of class 3 subbasins in the western portion of the Northern

Great Basin ERU and across some of the Owyhee

Uplands ERU, but an increase of class 3 subbasins

within the Central Idaho Mountains ERU.

Upland Wsodland. Alternative 7 would increase

the frequency of subbasins containing areas of the

upland woodland community within its historical

mid-range by 115 percent (table 2.40). However,

those subbasins having a substantial component of

the upland woodland community would still be

dominated by class 5 departures. The increased

number of subbasins falling within the historical

mid-range would predominantly be due to areal

increases of the upland woodland community in

subbasins within the Central Idaho Mountains

ERU. In addition, areal declines of upland woodland in the Columbia Plateau and Owyhee

Uplands ERUs would also contribute to an

increased frequency of class 3 subbasins.

Discussion on Departures of the

Alternatives

For most alternatives, a major shift was projected

in the frequency distribution of departure classes

between the current and 100-year periods, from a

class 1 to a class 5 departure or vice versa. This

wide fluctuation occurred with the community

groups that commonly composed very low proportions of the subbasins. Therefore, when the historical range of a community was relatively small, only

minor changes of areal extent were required to

cause rather large fluctuations of departure classes.

Even with the major shift in departure classes

between the current and 100-year periods, overall

there were relatively minor differences between

the seven alternative projections in subbasin

departure frequency reported at the Basin scale

(tables 2.39 and 2.40). However, there are substantial differences between alternatives in the spatial distribution of terrestrial community groups

and their associated departures. Spatial arrangement of communities and associated disturbances

are discussed in greater detail in the "Vegetation

Response and Disturbance Patterns" and "Summary and Synthesis" sections later in this chapter.

With few exceptions, most alternatives are expected to increase the frequency of subbasins having

most community groups within their historical

mid-range, which is class 3 departure (tables 2.39

and 2.40). Two communities, the lower montane

mid-serai forest and the upland shrubland, were

exceptions. The frequency of subbasins having

the lower montane mid-serai forest community

within its historical mid-range remained about

the same, or decreased in Alternatives 1, 2, 3, and

5 as did the number of subbasins having the

upland shrubland community for all alternative

projections.

However, rarely did any alternative projection

indicate more than a 50 percent increase in the

proportion of subbasins in which any community

occurred within its historical mid-range (tables

2.39 and 2.40). Overall, Alternative 7 would have

the greatest average frequency of subbasins containing the 12 terrestrial community groups within their historical mid-ranges (table 2.38).

Departure Discussion by

Community

Montane Departures

Early-Serai Lower Montane Forest — All

alternatives would decrease the number of subbasins having areas of the early-serai lower montane community group at levels well below its historical mid-range, constituting a class 1 departure.

Conversely, all alternatives would substantially

increase the frequency of subbasins having this

community within its historical mid-range.

Although this increase would be ten-fold, none of

the alternatives were projected to have more than

50 percent of the subbasins in this community

within its historical mid-range.

Landscape Ecology 193
Mid-Serai Lower Montane Forest — All alternatives would decrease the frequency of subbasins

having the mid-serai lower montane community

at levels well below its historical mid-range, constituting a class 1 departure. However, all alternatives would increase the frequency of subbasins

having areas of this community well above its historical mid-range. None of the alternatives would

substantially change the frequency of subbasins

having this community within its historical midrange; rather, the alternatives would merely

change the sign of the departures, from being

below to being above the historical mid-range of

conditions.

Late-Serai Lower Montane Forest — All alternatives would decrease the number of subbasins

having the late-serai lower montane community at

levels well below its historical mid-range, constituting a class 1 departure. Conversely, all alternatives would substantially increase the frequency of

subbasins having this community within its historical mid-range. Although all alternatives would

increase the frequency of subbasins having this

community within its historical mid-range by

nearly five-fold, no alternative would result in

more than 40 percent of the subbasins having the

late-serai lower montane community within its

historical mid-range.

Early-Serai Montane Forest — The frequency

of subbasins having the early-serai montane forest

community at a level within its historical midrange would increase under all alternatives.

However, no alternative was expected to have

more than 34 percent of their subbasins with this

community within its historical mid-range.

Mid-Serai Montane Forest — All alternatives

would increase the frequency of subbasins having

the areal extent of the mid-serai montane forest

community within its historical mid-range.

However, the frequency of subbasins having this

community within its historical range would not

exceed 46 percent under any alternative. All alternatives would substantially decrease the frequency

of subbasins having this community well below its

historical mid-range. To a lesser degree, all alternatives would also decrease the frequency of subbasins having this community well above its historical mid-range.

Late-serai Montane Forest — All alternatives

would result in at least a four-fold increase in the

frequency of subbasins having the late-serai montane forest community at a level within its historical mid-range. However, less than 50 percent of

the subbasins would contain areal extents of this

community within its historical mid-range as a

result of implementing any alternative. All alternatives would substantially decrease the frequency of

subbasins having this community well below its

historical mid-range; to a lesser degree, all alternatives would also decrease such frequency well

above its historical mid-range.

Subalpine Departures

Early-serai Subalpine Forest — All alternatives,

except Alternatives 3 and 4, would result in nearly

a two-fold increase in the frequency of subbasins

having an areal extent of the early-serai subalpine

forest community within its historical mid-range.

However, only Alternatives 1, 2, and 7 would

result in more than 50 percent of the subbasins

having the area of this community within its historical mid-range. All alternatives would substantially decrease the frequency of subbasins having

this community well below its historical midrange. Similarly, Alternatives 1, 2, and 7, and to

a lesser degree Alternatives 5 and 6, would substantially decrease the frequency of subbasins

having this community well above its historical

mid-range.

Mid-serai Subalpine Forest — All alternatives

would result in at least a two-fold increase in the

frequency of subbasins having an areal extent of

the mid-serai subalpine forest community within

its historical mid-range. However, only in

Alternatives 1 and 7 would more than 50 percent

of the subbasins have this community within its

historical mid-range. All alternatives would substantially decrease the frequency of subbasins having this community well above its historical midrange. Similarly, Alternatives 1, 2, and 7, and to

194 Landscape Ecology
a lesser degree Alternatives 3 through 6, would

substantially decrease the frequency of subbasins

having this community well below its historical

mid-range.

Late-serai Subalpine Forest — All alternatives

would result in nearly a four-fold increase in the

frequency of subbasins having an areal extent of

the late-serai subalpine forest community within

its historical mid-range. However, only Alternatives 1,2, and 7 would result in more than 50

percent of the subbasins having this community

within its historical mid-range. All alternatives

would substantially decrease the frequency of subbasins having this community well below its historical mid-range.

Similarly, Alternatives 1 and 3 through 6, and to a

lesser degree Alternative 2, would substantially

decrease the frequency of subbasins having this

community well above its historical mid-range.

Conversely, Alternative 7 would increase the frequency of subbasins having the late-serai subalpine forest well above its historical mid-range.

Upland Departures

Upland Herbland — All alternatives would

result in nearly a two- to three-fold increase in the

frequency of subbasins having extents of the

upland herbland community within its historical

mid-range. However, no alternative would result

in more than 37 percent of the subbasins having

the area of this community within its historical

mid-range. Although all alternatives would

decrease the frequency of subbasins having this

community well below its historical mid-range,

and constituting a class 1 departure, these subbasins would still dominate the Basin.

Upland Shrubland — None of the alternatives

would substantially change the frequency of subbasins having the areal extent of the upland

shrubland community within its historical midrange. In fact, Alternatives 2 through 5 would

actually decrease the proportion of subbasins having this community within its historical midrange. All alternatives would substantially increase

the proportion of subbasins having the upland

shrubland community well below its historical

mid-range. For all alternatives, the upland shrubland community departure class 5 would dominate the Basin.

Upland Woodland — Alternatives 1, 2, 6, and 7

would substantially increase the proportion of subbasins having the areal extent of the upland woodland community within its historical mid-range.

However, no alternative would result in more than

28 percent of the subbasins having the area of this

community within its historical mid-range. All

alternatives would substantially increase the proportion of subbasins having the upland woodland

community well above its historical range. For all

alternatives, the upland woodland community

departure class 5 would dominate the Basin.

Currently, nearly one-third of the subbasins having a substantial area of the upland woodland

community type contain this community at a

level well below its historical mid-range. Since all

of these subbasins are most closely associated with

forest environments, the apparent decline of the

upland woodland community is most likely

attributed to woodlands converting into forests.

For example, mixed-conifer woodlands develop an

adequate stocking level of trees to be classified as

forest types.

Nine of the subbasins having at least a one percent upland woodland component had previously

been classified as the "juniper woodland theme"

(Quigley and others 1996). These nine subbasins

are dominated by a western juniper component

well above the historical mid-range. Alternatives

1, 2, and 7 would substantially increase the proportion of subbasins having juniper woodlands

within its historical mid-range, to four out of

nine. To a lesser degree, Alternatives 3 through 6

would also increase the proportion of subbasins

having juniper woodlands within its historical

mid-range, to two out of nine. However,

Alternatives 3 through 6 would also increase the

proportion of these subbasins having the juniper

component below its historical mid-range, to

three out of nine.

Landscape Ecology 195
Summary of Terrestrial

Community Departures

We observed a major shift in the frequency distribution of departure classes between the current

period and the 100-year projections of most terrestrial community types for most alternatives.

With few exceptions, most alternatives would

increase the frequency of subbasins having the

areal extents of most terrestrial community types

within their historical mid-ranges.

While we detected relatively minor differences

overall among the subbasin frequency distributions of habitat departures, we did detect substantial spatial differences of subbasin habitat departures among the seven alternatives.

With one exception (100-year projection of the

early-serai montane forest community under

Alternative 2), regardless of alternative, the Basin

would be dominated by subbasins having the areal

extents of the early-serai montane forest, upland

herbland, and upland shrubland communities below

their historical mid-ranges. Consequently, none of

the alternatives would reduce the risks to persistence for those plant and animal taxa whose fitness is strongly dependent upon the areal extents

of these coarse-scale community types.

Relative to the historical period, none of the alternatives would be effective in reducing the apparent

over-abundance of the mid-serai lower montane forest, mid-serai montane forest, and upland woodland

community types. Therefore, Basin-wide, we would

expect a low risk to persistence for taxa whose fitness is closely associated with the areal extents of

these coarse-scale communities.

We feel the errors in mapping the management

prescriptions in Alternatives 2 and 7 discussed earlier in this section do not result in significant

inaccuracies in this departure analysis. The community groups selected and the analytical techniques should substantially dampen the effects of

these errors.

We would recommend that any future analysis of

broad-scale communities as terrestrial habitats use

the physiognomic type groups stratified by potential vegetation group (PVG) or, for a coarser

grouping, by forest and rangeland. The changing

nature of lower montane, montane, subalpine and

non-forest terrestrial communities in relation to

existing vegetation cover types with no tie to the

biophysical environment is a substantial hindrance

to this analysis. Without the tie to the biophysical

environment little inference can be made relative

to temperature, moisture, soils, terrain, or consistency of the terrestrial communities with the

biophysical system and inherent succession and

disturbance processes.

19S Landscape Ecology