3.5 key issue: special sitesa123.g.akamai.net/7/123/11558/abc123/forestservic... · 2015. 6....

Grand River Ranger District – Allotments 1- 5 Vegetative Management Environmental Assessment

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3.5 Key Issue: Special Sites

Scoping respondents raised concern over the management of special sites. In the project area, these

include the White Butte Special Interest Area, the Allotment 1A, 5A, and Humphrey Draw wildlife

areas, and the Aspen Stand Special Interest Area.

3.5.1 Existing Condition (Special Sites)

White Butte (Figure 71) encompasses approximately 131 acres in Allotment 5A (Figure 3). It is

designated as Management Area 2.1

(―Special Interest Area‖). The White

Butte Special Interest Area is not

managed separately from the

surrounding allotment, nor is there a

separate management plan that pertains

only to the White Butte Special Interest

Area itself.

The Grasslands Plan (p. 3-11) states of

White Butte:

―It is of archaeological interest and

is of potential significance to the

Lakota tribes. Several Forest

Service sensitive plants are

suspected to occur on the butte

escarpment. Geologic interest is

high in the area given its landform

and the petrified rock found in the area. White Butte is the highest point in the area and

provides excellent vista views of the surrounding plains. Management emphasis is on

geologic interpretation and education and scenic viewing.‖

The Grasslands Plan also directs (p. 3-10, as modified by Kimbell 2006 p. 12):

―Livestock grazing is not permitted.‖ Guideline.

White Butte has no developed livestock facilities, nor are mineral supplements placed there. There

are no water sources or subirrigated areas present. The relatively low amount of forage available is

provided mostly by treadleaf sedge (Figure 71.a). Overall, the site has little attraction to livestock.

Past field reviews, including one as recent as August 2009 (Figure 71.c), have found only incidental

use there (Dan Svingen, periodic pers. obs. since 1999). Forest Service personnel have not identified

current grazing levels as detrimental to the purpose for which the White Butte Special Interest Area

was designated, nor has current livestock grazing been determined to be incompatible with the site’s

geologic, educational, archeological (Merv Floodman, archeologist pers. comm. with Dan Svingen,

December 2008), or scenic qualities.

Figure 71. White Butte Special Interest Area (under white arrow).

Allotment 5A. Grand River National Grassland, Perkins Co., SD.

September 2007. Photo by Dan Svingen.


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Figure 71.a. White Butte Special Interest Area. Grand River National Grassland, Perkins Co., SD. 21 August 2009. a)

looking south from top of White Butte: note sparse vegetation on butte, b) west slope of White Butte; note creeping

juniper, Juniperus horizontalis, a species which receives little browsing from livestock, c) east end of White Butte; note

Dakota Prairie Grasslands’ personnel examining White Butte crest for evidence of livestock use. Photos by Mark

Gonzalez and Dan Svingen.

a)

b)

c)


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The project area contains three ―wildlife

areas.‖ The 1A Wildlife Area, (Figure

72) encompasses 75 acres, whereas the

5A Wildlife Area (Figure 73) covers 167

acres. Both sites are subdivisions of

larger grazing allotment, and as such are

typically grazed annually, albeit for a

comparatively short period, typically late

in the grazing season. Neither site is

known to harbor unique plant

communities, although both contain large

riparian areas, and so are relatively

diverse biologically. The primary

riparian area in the 1A Wildlife Area is

provided by the North Fork Grand River

(Figure 72). The primary riparian area in

the 5A Wildlife Area is provided by Giles

Creek, including an instream dugout

stock pond (Figure 73). Neither site has a unique management plan; both are managed in

compliance with the AMP for their entire allotment. The 1A Wildlife Area is designated as

Management Area 6.1 (―Rangeland with Broad Resource Emphasis‖). The 5A Wildlife Area is

designated as Management Area 3.64 (―Special Plant and Wildlife Habitat‖). Periodic site-visits

over the last 10 years have shown that these two sites are usually in better ecological condition than

is typical for the surrounding allotment (Dan Svingen, pers. obs.). High structure vegetation is

usually more available in these wildlife areas than it is elsewhere within the 1A and 5A allotments

(Dan Svingen, periodic pers. obs. since

1999), though the amount present varies

greatly, year-to-year (ibid)

The Humphrey Draw Wildlife Area

(Figures 10, 74, 79) encompasses 894 acres,

including some intermingled private land.

Several unique vegetative species occur

there (Hansen 2008), as do some unique

wildlife species, including barn owl (Dan

Svingen, pers. obs.). The Humphrey Draw

Wildlife Area is managed as a separate

entity from the neighboring 3B Allotment.

The ―Humphrey Draw Wildlife Area

Management Plan‖ was developed in 1982.

That plan has the stated goal to: ―…enhance

wildlife habitat in coordination with range

management.‖

The Humphrey Draw Wildlife Area is

designated as Management Area 3.64

Figure 72. North Fork Grand River. 1A Wildlife Area, Allotment

1A, Grand River National Grassland, Perkins Co., SD. May 2008.

Photo by Mark Gonzalez.

Figure 73. Aerial photograph of 5A Wildlife Area, Allotment 5A,

Grand River National Grassland, Perkins Co., SD. Black line (black

arrows) shows approximate location of perimeter fence. Note dugout

(white arrow). 2008 NAIP image.


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(―Plant and Wildlife Area‖). That designation includes a desired condition statement that

emphasizes maintaining or enhancing habitat quality (Table 4). The Grasslands Plan also directs (p.

3-30, as modified by Kimbell 2006 p. 12):

Protect wetlands habitat to maintain their hydrologic regimes. Standard.

Maintain disturbance processes (fire, grazing) if required for habitat enhancement, restoration, or species viability. Standard.

Conflicts that cannot be mitigated are resolved in favor of specific plant and wildlife species and communities. Standard.

In most years, the Humphrey Draw Wildlife Area has been grazed for a short period in the autumn.

In the last few years, however, it has been grazed early, rather than late. The early season entry is

conducive to livestock management. Early season entry also appears conducive to maintaining

habitat quality (recent field visits by Mark Gonzalez, Dan Svingen, prof. opin.).

Figure 74. Aerial photograph of Humphrey Draw Wildlife Area, Grand River National Grassland, Perkins Co., SD.

Black line is approximate location of perimeter fenceline. Note Humphrey Draw (white arrow), Aspen Stand Special

Interest Area (yellow arrow) and North Fork Grand River (black arrow). 2008 NAIP image.


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The Aspen Stand Special Interest Area (SIA)

(Figures 75, 76 and 77) encompasses 9 acres

within the Humphrey Draw Wildlife Area.

This SIA encompasses one of the Grand

River Ranger District’s few quaking aspen

(Populus tremuloides) stands. The

management emphasis for this area is on

protecting that unique botanical community

(LRMP p. 3-11).

The Aspen Stand SIA was visited on 4 June

2009 by Dakota Prairie Grasslands’

personnel, as well as personnel from South

Dakota Game, Fish, and Parks (Figure 77)

who have expertise in aspen management.

The team concluded that the current

management was appropriate, and should be

continued. As noted above, that

management consisted of short-term early-

season grazing by domestic livestock.

Figure 76. Aspen Stand Special Interest Area,

September 2009. Photo by Dan Svingen.

Figure 75. Aspen Stand Special Interest Area, Humphrey

Draw Wildlife Area, Grand River National Grassland, Perkins

Co., SD. September 2009. Photo by Dan Svingen.

Figure 77. Aspen Stand Special Interest Area being

inspected by David Kimble, South Dakota Game, Fish,

and Parks. June 2009. Photo by Dan Svingen.


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3.5.2 Direct and Indirect Effects (Special Sites)

The White Butte Special Interest Area

(Figure 78) would continue to be grazed

by livestock under Alternatives A, B,

and C. This does not implement the

LRMP guideline described above (see p.

97). However, the continued absence of

water, mineral supplements, or other

attractants atop White Butte would be

expected to continue to limit livestock

use, as would the butte’s steep side slopes.

A continuation of the current level of

incidental livestock use would have

negligible impacts to vegetative structure

or composition under all alternatives (Paul

Drayton, Mark Gonzalez, Dan Svingen

prof. opinions). The creation of crested

wheatgrass pastures to the north of the

White Butte Special Interest Area under

Alternatives B and C has the potential to

increase livestock use of White Butte

itself by creating a ―drift fence‖; that risk would be reduced by careful on-the-ground consideration

of fence location during its construction (see ―Features Common to Alternatives‖, p. 35). The total

lack of grazing that would occur under Alternative D would likely have little impact on the White

Butte Special Interest Area. The most likely adverse impact, the excessive build up of litter and

subsequent invasion of exotic grasses, is less likely to occur at this site within the project period than

it is elsewhere in the project area, due to White Butte’s thin, relatively unproductive soils; and

comparatively low incidence of exotic grasses currently (Figure 71).

Alternative A would allow continued annual grazing within the 1A and 5A Wildlife Areas. These

sites would continue to meet Grasslands Plan’s objectives for riparian areas. Resource objectives for

high vegetative structure would only be partially met, however, particularly in the 1A Wildlife Area.

Under Alternative A, the Humphrey Draw Wildlife Area (and the Aspen Stand Special Interest

Area) would continue to be managed with early or late grazing most years, and would be expected to

meet or exceed Grasslands Plan’s objectives.

Alternatives B and C would modify management of the 1A Wildlife Area to allow only periodic (i.e.

1 year in 3) livestock grazing. Periodic burning would also be performed. This approach would be

expected to result in the site meeting or exceeding Grasslands Plan’s objectives most years. The

Allotment 5A Wildlife Area would be grazed most years under both Alternatives B and C, albeit

with lighter stocking rates than what would occur under Alternative A. Grasslands Plan’s objectives

would likely be met or exceeded. Under Alternative B, Humphrey Draw Wildlife Area (and the

Aspen Stand Special Interest Area) would be managed as it has been in recent years, with early-

season use emphasized. Under Alternative C, however, grazing would only occur 1 in 3 years.

Under either Alternative B or C, Grasslands Plan’s objectives for the Humphrey Draw Wildlife Area

(and the Aspen Stand Special Interest Area) would be expected to be met or exceeded.

Figure 78. Allotment 5A, Grand River National Grassland, Perkins

Co., SD. Note White Butte Special Interest Area in the background,

crested wheatgrass in the foreground. July 2008. Photo by Amanda

Gearhardt.


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Alternative D would result in complete rest for the 1A, 5A, and Humphrey Draw Wildlife Areas, as

well as for the Aspen Stand SIA. Excessive litter buildup could be mitigated on the uplands and

midslopes with prescribed fire but would be problematic in the wooded draw areas, where fire might

injure or kill trees (which subsequently may, or may not, resprout). An increase in exotic grasses,

particularly smooth brome and Kentucky bluegrass, would be expected. The above discussion is

repeated in Table 20, to facilitate comparison of alternatives and sites.

Table 20. Expected effects of proposed alternatives to Special Sites in the project area.

ALTERNATIVES

SPECIAL SITE A B C D

White Butte Special

Interest Area

Incidental and light

grazing by livestock

would occur.

Negligible impact

expected.



would occur.

Negligible impact

expected.



would occur.

Negligible impact

expected.

No grazing by

livestock would

occur. Negligible

impact expected.

1A Wildlife Area Annual livestock

grazing would occur.

Riparian objectives

would be met.

Vegetative structure

objectives would be

partially met.

Periodic (i.e. 1 year

in 3) grazing by

livestock would

occur. Periodic

burning would be

used. Riparian and

vegetative structure

objectives would be

met or exceeded

most years.


in 3) grazing by

livestock would

occur. Periodic

burning would be

used. Riparian and


objectives would be

met or exceeded

most years.

No grazing would

occur. Prescribed

fire would be used to

control excessive

litter build-up in

uplands, but would

be problematic in

riparian areas due to

impacts to shrubs

and trees. Increase

in exotic grasses

expected.

5A Wildlife Area Annual livestock


Riparian objectives

would be met.

Vegetative structure

objectives would be

partially met.

Annual livestock

grazing would occur,

but with lighter

stocking rates than

those used under

Alternative A.

Riparian and

vegetative objectives

would be met or

exceeded.

Annual livestock


but with lighter

stocking rates than

those used under

Alternative A.

Riparian and


would be met or

exceeded.

No grazing would

occur. Prescribed

fire would be used to

control excessive

litter build-up in

uplands, but would

be problematic in

riparian areas due to

impacts to shrubs

and trees. Increase

in exotic grasses

expected.

Humphrey Draw

Wildlife Area and

Aspen Stand Special

Interest Area

Annual livestock


Riparian and


objectives would be

met. Quaking aspen

stand would continue

to flourish.

Annual livestock


with early-season use

emphasized.

Riparian and


would be met or

exceeded. Quaking

aspen stand would

continue to flourish.


in 3) livestock


with early-season use

emphasized.

Riparian and


would be met or

exceeded. Quaking

aspen stand would

continue to flourish.

No grazing would

occur. Prescribed

fire would be used in

uplands, but would

be problematic in

riparian areas.

Increase in exotic

grasses expected.

Quaking aspen stand

would continue to

flourish.


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3.5.3 Cumulative Effects (Special Sites)

The main cumulative factors affecting the project area’s Special Sites are the same as the ones

described above for riparian areas, native vegetation, and exotic vegetation. Of particular

importance are: livestock grazing, beaver, wildfire, and exotic species, including noxious weeds,

Past livestock grazing, particularly that which has occurred within the previous 10 years has likely

been the single factor having the greatest influence on the project area’s Special Sites. As explained

above, that grazing has generally been managed to provide moderate to high levels of vegetative

diversity, density, and robustness.

The three wildlife areas and Aspen Stand Special Interest Area all contain riparian areas (White

Butte Special Interest Area contains no riparian habitat). Because the wildlife areas’ and Aspen

Stand’s stream segments are currently in Proper functioning condition, they will be better buffered

against various impacts to riparian habitat quality than would otherwise be the case (i.e. being in

Proper functioning condition makes them more resilient). That condition is expected to continue

under all proposed alternatives. The three wildlife areas have also been recently colonized by beaver

(the Aspen Stand SIA’s riparian area is ill-suited to beaver because of topography). Due to the

wildlife areas’ relatively high riparian habitat quality, beaver occupancy is likely to be relatively

persistent, further increasing overall habitat quality under all proposed alternatives.

Wildfire can occur at any of the special sites throughout much of a given year. For example, a

recent wildfire burned a part of the Humphrey Draw Wildlife Area (Figure 79), outside of the Aspen

Stand SIA. Even under current livestock grazing (which would be continued by Alternative A),

however, vegetative recovery appears to be advancing rapidly (Mark Gonzalez, pers. obs.). In fact,

Alternative A would not be expected to pose a threat to vegetative recovery from wildfire at any of

the special sites. Should a wildfire occur, the other proposed alternatives would result in even less

impacts from livestock grazing compared to Alternative A.

Noxious weeds will remain of particular concern, especially in the Humphrey Draw and 1A wildlife

areas, which have chronic infestations of leafy spurge (Chancey Odell, pers. comm.). These

species’ presence will reduce the Special Sites’ ecological resiliency; noxious weed control efforts

may also depress native forb abundance. Noxious weed presence is not expected to vary by

alternative.


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3.6 Key Issue: Wildlife

The project area contains hundreds of wildlife

species. Input received during scoping

specifically referred to: threatened, endangered,

and sensitive species; fish; and management

indicator species.

No wildlife species within the project area is

federally listed as threatened or endangered.

Several, however, have been designated by the

USDA Forest Service’s Regional Forester as

―sensitive‖, due to known or suspected declines

in habitat or populations. Those that are most

likely to be affected by proposed management

are three birds: Baird’s sparrow (Figure 80),

loggerhead shrike, and Sprague’s pipit; and two

butterflies: Ottoe skipper and regal fritillary.

Figure 80. Baird’s sparrow, a sensitive species found

within the project area. Little Missouri National

Grassland, McKenzie Co., ND. Undated photo. Photo

by Gary Foli.

Figure 79. Humphrey Draw Wildlife Area, Grand River National Grassland, Perkins Co. SD. On right side of photo,

note vegetation burned as a result of the July 2007 Harris Fire. August 2007. Photo by Mark Gonzalez.


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Fish populations within the project area are largely limited to the North Fork Grand River and Flat

Creek. Species known to be present there include: black bullhead, black crappie, brassy minnow,

brook stickleback, channel catfish, common carp, creek chub, fathead minnow, golden shiner, green

sunfish, Iowa darter, northern pike, sand shiner, shorthead redhorse, stonecat, walleye, white sucker,

and yellow perch (Brooks 2002). In general, habitat conditions for these populations is a function of

riparian habitat conditions, which is discussed above (see p. 51-62). Both the North Fork Grand

River and Flat Creek are in Proper functioning condition. Additional information on the project

area’s fish community is available in the project file.

The only management indicator species that currently occurs on National Forest System lands within

the project area is the sharp-tailed grouse. The remainder of this discussion will focus on: sensitive

birds, sensitive butterflies, and sharp-tailed grouse.

3.6.1 Existing Condition (Sensitive Birds)

The Baird’s sparrow (Figure 80) and Sprague’s

pipit (Figure 81) are grassland-dependent birds

that have suffered extensive population declines

due to the loss of native prairie across their

ranges. Both species are breeding endemics to

the Northern Great Plains.

The loggerhead shrike (Figure 82) is a predatory

songbird found in grassland and savannah

habitats throughout most of North America

south of boreal Canada. Several loggerhead

shrike populations, especially those in the

Midwest and Northeast parts of the United

States, have declined. Likely causes of these

declines include: habitat loss to agricultural

conversion, habitat loss to reforestation, and

pesticide accumulation.

Volunteer birders have conducted extensive surveys for Baird’s sparrow, Sprague’s pipit, and

loggerhead shrike within the project area for several years (Svingen 2001, Svingen 2002, Svingen

2003, Svingen 2005, Svingen 2007). These surveys have been supplemented with incidental

observations by Dakota Prairie Grasslands’ staff (ibid). In addition, South Dakota Department of

Fish, Wildlife, and Parks contracted systematic surveys for these species within the project area in

2001 (Knowles 2001). Furthermore, from 2005 to 2007, Dakota Audubon and Dakota Prairie

Grasslands cooperated on an ecological study of Baird’s sparrow and Sprague’s pipit in and near the

project area (Winter 2006, Winter 2007, Winter 2008).

The nesting range of the Baird’s sparrow encompasses only a small part of South Dakota (Tallman et

al. 2002). It is a rare but irregular spring and fall migrant and summer resident on the Grand River

Figure 81. Sprague’s pipit, a sensitive species found within

the project area. Photo by Bob Gress.


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Ranger District (Svingen et al. 2005). The sparrow’s local abundance varies markedly year-to-year

in response to vegetative conditions (ibid). Baird’s sparrows are most numerous in years with

extensive residual vegetation, such as occurs in years following above-normal precipitation during

the growing season. In other years, the species may be completely absent (ibid). Within the project

area itself, Baird’s sparrows have been found in several allotments (Figure 84, Griffiths and Griffiths

undated, Knowles 2001, Svingen 2001, Svingen 2002, Svingen 2003, Svingen et al. 2005, Winter

2006, Winter 2007, Winter 2008).

On the Grand River National Grassland, Baird’s sparrows use lightly grazed native prairie, but also

use lightly grazed, robust stands of crested wheatgrass (Dan Svingen pers. obs.). In fact, Knowles

(2001) found Baird’s sparrows primarily in crested wheatgrass stands. Winter (2008) found that

sites supporting Baird’s sparrows on the

Grand River National Grassland had: a

higher probability of occurrence of

crested wheatgrass, a larger distance to

the closest trees, less bare soil, higher

ground cover by litter, deeper litter, and

higher vegetation than did areas where

the species was not detected. Winter

(ibid) stressed that the probability of

encountering Baird’s sparrows decreased

with increasing stocking rates, i.e. it was

more likely to encounter Baird’s

sparrows in areas that had less grazing

use (at least within the range of such use

investigated on the Grand River National

Grassland).

The nesting range of the Sprague’s pipit encompasses the northwestern quarter of South Dakota

(Tallman et al. 2002). It is a fairly common spring and fall migrant and summer resident on the

Grand River National Grassland (Svingen et al. 2005). Within the project area itself, the species has

been found in several allotments (Figure 84, Griffiths and Griffiths undated, Knowles 2001, Svingen

2001, Svingen 2002, Svingen 2003, Svingen et al. 2005, Winter 2006, Winter 2007, Winter 2008).

Locally, Sprague’s pipit are found almost exclusively in native prairie areas that have been

moderately grazed; they seem to avoid extensive monocultures of crested wheatgrass (Svingen et al.

2005). This observation was also noted by Knowles (2001), who found this bird ―…associated with

broad areas of upland prairie with a significant native grass component‖. Winter (2008), however,

did not demonstrate an avoidance of crested wheatgrass by Sprague’s pipit. She did find that sites

supporting Sprague’s pipits on the Grand River National Grassland had less bare soil and more and

deeper litter than did areas where the species was not detected. In comparison to Baird’s sparrows,

Sprague’s pipits used sites with lower amounts of litter as well as sites with higher stocking rates.

Winter (ibid) concluded that both species preferred sites with relatively tall vegetation and deep

litter. Thus, both species would probably benefit from a decreased stocking rate which would allow

for taller vegetation and a deeper buildup of litter (Winter 2008).

Figure 82. Loggerhead shrike, a sensitive species found within

the project area. Photo courtesy of VIREO.


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Loggerhead shrike can be found

throughout South Dakota during the

breeding season (Tallman et al. 2002).

Svingen et al. (2005) classified the

loggerhead shrike as a fairly common

spring and fall migrant and summer

resident on the Grand River National

Grassland. The species has been found at

scattered locations throughout the project

area (Griffiths and Griffiths undated,

Knowles 2001, Svingen 2001, Svingen

2002, Svingen 2003, Svingen 2005,

Svingen et al. 2005, Winter 2006).

Loggerhead shrikes prefer grassland

habitats interspersed with shrubs or low

trees. The shrikes forage for their prey

(mostly insects, but also small mammals,

amphibians, and reptiles) in the grass

areas. The scattered shrubs or trees,

particularly those that are thick or thorny (Figure 83), serve as nesting substrates and hunting perches

(Yosef 1996). In less productive parts of their range, such as Alberta and the project area,

loggerhead shrikes prefer to forage in ungrazed areas, which provide taller (>8 in) grass (Prescott

and Collister 1993, Dechant et al. 2003, Dan Svingen pers. obs.).

Figure 83. Wild plum (Prunus americana), one of the thorny species used by loggerhead shrike. Little Missouri National

Grassland, Billings Co., ND. Undated photo. Photo by Joe

Washington.


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Figure 84. Known locations of sensitive wildlife species and sharp-tailed grouse leks within the Allotments 1-5 project

area. Loggerhead shrike data points not shown (see text).


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3.6.2 Existing Condition (Sensitive Butterflies)

The regal fritillary (Figure 85) and Ottoe skipper are grassland-specialist butterflies whose

populations have declined sharply due to a loss of native prairie habitats.

The regal fritillary historically occurred from New England to North Carolina and westward to the

Rocky Mountains. It is now absent from most of New England and occurs sparingly throughout the

remainder of its range. In South Dakota it is still common in: remnant tallgrass prairie in the

northeastern part of the state, in undisturbed mixed-grass prairie along the Missouri River breaks,

and on the Fort Pierre National Grassland (Marrone 2002).

The Ottoe skipper is very local and uncommon to rare throughout its historical range, which

encompasses parts of the Great Plains and

Midwest parts of the United States. In South

Dakota, Ottoe skipper are present in

scattered, relatively undisturbed, mixed-grass

to tall prairie sites, including the Grand River

National Grassland (Marrone 2002).

The Dakota Prairie Grasslands contracted

butterfly surveys within the project area in

2002 (Marrone 2002). No other systematic

butterfly inventories have been conducted

there. In the project area, regal fritillaries

have been confirmed in the Hermann, 3A,

3B, and 5A allotments (Marrone 2002,

Figure 84). Ottoe skippers have been

confirmed in Allotment 5A (Marrone 2002,

Figure 84).

The regal fritillary is most commonly found in tallgrass or mixed-grass bluestem prairies. Preferred

habitats are grasslands with big and little bluestem, western wheatgrass, and green needlegrass, with

a variety of Asteracea species that serve as adult nectar sources. Preferred nectar sources include

milkweeds (Asclepias species), purple prairie coneflower (Dalea purpurea), coneflower (Echinacea

angustifolia), white prairie clover (Dalea candida), harebell (Campanula rotundifolia), and fleabane

(Erigeron species). Other nectar sources for adults include Asclepias species, Cirsium species,

Monarda species, and Liatris species. Larvae feed only on violets (Viola species). The principle

requirement appears to be the presence of extensive grasslands with high densities of violets and

nectar sources (Royer and Marrone 1992).

The Ottoe skipper prefers relatively undisturbed mixed-grass and tallgrass prairie (Marrone 2002).

Favored nectar plants include blazing star (Liatris punctata), vervain (Verbena bracteata), and

coneflower. Larval host plants include native prairie grasses, such as little bluestem, big bluestem,

and sideoats grama (Bouteloua curtipendula).

Figure 85. Regal fritillary, a sensitive species found within the

project area. Photo by US Fish and Wildlife Service.


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3.6.3 Existing Condition (Sharp-tailed Grouse)

Sharp-tailed grouse are uncommon or

common throughout most of South Dakota

(Tallman et al. 2002). The species is a

common year-round resident on the Grand

River Ranger District (Svingen et al. 2005).

Every spring, sharp-tailed grouse gather at

leks (a.k.a. ―dancing grounds‖). Males

perform courtship displays (Figure 86) there

in hopes of attracting mates. This behavior

provides managers with an important

opportunity to monitor grouse populations.

The number of males present, as well as the

number of leks that are active, provides an

important index to each year’s breeding

population.

Volunteer birders, as well as Dakota Prairie Grasslands’ staff, have conducted extensive surveys for

sharp-tailed grouse within the project area for several years (Svingen 2001, Svingen 2002, Svingen

2003, Svingen 2005, Svingen 2007). Confirmed or suspected leks have been found in or near the

following allotments: 1A, 1B, 2A, 2B, 2C – east, 2C – west, 3A, 3B, 4A, 4B, 5A, 5B – north, 5B –

south, 5C, Dyson, Erlandson, Evridge, Gunn, Krisle, Herm, Hermann, and Smith (Figures 3 and 84).

Little data are as yet available on site-specific population trends. In addition, North Dakota State

University and the Dakota Prairie Grasslands have initiated a cooperative study of sharp-tailed

grouse ecology in and near the project area. Field work began in spring 2009. This research will

supplement data already available on sharp-tailed ecology collected on other parts of the Dakota

Prairie Grasslands, as well as other areas of the Northern Great Plains.

One of the key factors believed to influence local grouse populations is the availability of high

structure vegetation. High structure vegetation is especially important as nesting cover during April

and May. Nesting-cover quality is a function, in part, of the amount of residual graminoid growth

that has persisted from the previous year’s growing season. Because of the vital role that residual

cover plays in providing nesting habitat, the Grasslands Plan (pp. 1-13 to 1-14, 1-19 to 1-20, 2-7 to

2-8, Appendix H), contains extensive direction on where, when, how, and how much residual

vegetation should be retained after each year’s growing season. The Grasslands Plan (Appendix H)

also directs that vegetative structure is to be measured using the visual obstruction reading method

(Figure 87).

Visual obstruction reading (VOR) surveys were conducted in the project area in 1995, 1997, 2007,

and 2008. In 1995, VOR transects varied in length, comprising 10-20 stations. From 1997 onward,

all transects were standardized at 20 stations. The most recent effort was curtailed by relatively

heavy and early snowfall in autumn 2008.

Figure 86. Male sharp-tailed grouse displaying at lek. Photo

by Bob Gress.


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VOR data summarized by transect are

defined as high structure vegetation if the

transect average is 3.5‖ or more (Grasslands

Plan p. H-2). The Scientific Review Team

(2006), recommended displaying these data by

station (vs. transect) averages. Therefore,

VOR data collected since that time are

summarized as both transect and station

averages. VOR data summarized by station

are defined as high structure vegetation if the

station average is 5.5‖ or more (Dakota Prairie

Grasslands 2006, p. 8).

Regardless of whether the VOR data collected

in the project area are summarized by transect

or station averages, it is apparent that the

extent of high structure vegetation (8% in

1995; 0% in 1997, 2007 and 2008; Table 21)

has been well below Grasslands Plan’s

objectives (i.e. 20%-30%).

It should be noted that the Grasslands Plan’s

vegetative-structure objectives apply only to

―biologically capable‖ areas. Biologically

capable areas are those that have adequate soil

productivity to produce enough herbaceous

material to achieve high structure vegetation.

During the Scientific Review Team process, the question arose as to how such sites were defined.

On the Little Missouri National Grassland, where habitat types maps have been created and ground-

truthed, the Dakota Prairie Grasslands has defined biologically capable sites as any one of a series of

productive habitat types, that are generally capable of producing 1100 pounds or more of herbaceous

material per acre each year (Dakota Prairie Grasslands 2006, p. 6). On the Grand River National

Grassland, however, habitat type maps have not been ground-truthed. Therefore, following a

recommendation by the Scientific Review Team (see Dakota Prairie Grasslands 2006, p. 4), the

interdisciplinary team for this project used the USDA Natural Resource Conservation Service’s soil

type maps and forage production estimates as a basis for defining biologically capable.

Even relatively unproductive sites can produce high structure vegetation if residual vegetation is

allowed to accumulate for more than one year. For the purposes of this project, however, the

interdisciplinary team has hereafter defined biologically capable areas as those with soils that are

productive enough to produce 1600 pounds or more of forage/acre/year (Gonzalez 2009). This

criterion is higher than that used elsewhere on the Dakota Prairie Grasslands. Therefore, the amount

of high structure vegetation that must be produced to meet the Grasslands Plan objectives is biased

low. Nevertheless, the majority of the project area still qualifies as biologically capable (Figure 88).

Figure 87. Visual obstruction reading pole. October 2008,

Heinitz Allotment, Sioux County, North Dakota, Cedar

River National Grassland. Photo by Dan Svingen.


113

As noted above (Table 9), additional monitoring will be conducted to refine the definition of

biologically capable under all alternatives.

Table 21. Visual Obstruction Reading (VOR) transect data collected in the project area. # sta. high struc. = number of

transect stations that qualified as high structure.

Sample size (n)/Average (Ave.) of all transect readings/# stations of high structure

UNIT 1995 1997 2007 2008

1A (n=1). Ave. = 2.9‖

(n=1). Ave. = 1.1‖

(n=10). Ave. = 1.5‖

# sta. high struc. = 0

1B (n=2). Ave. = 2.7‖

(n=2). Ave. = 1.5‖.

(n=2). Ave. = 1.3‖


2A (n=1). Ave. 3.0‖

(n=1). Ave. = 1.3‖ (n= 5). Ave. = 1.8‖


2B (n=3). Ave. 1.1‖

(n=4). Ave. = 1.4‖

(n=1). Ave. = 1.2‖


2C - east (n=2). Ave. = 2.1‖.

(n=2). Ave. = 1.4‖ (n=5). Ave. = 1.6‖


2C - west (n=1). Ave. = 2.8‖

(n=4). Ave. = 2.2―


3A (n=4). Ave. = 3.5‖

[2 transects high

structure]

(n=7). Ave. = 1.8‖ (n=13). Ave. = 1.4‖


3B (n=2). Ave. = 2.7‖

(n=7). Ave. = 1.8‖ (n=7). Ave. = 1.6‖


4A (n=5). Ave. = 1.8‖


4B (n=7). Ave. = 2.6‖

(n=3). Ave. = 1.6‖

(n=9). Ave. = 2.1‖


5A (n=6). Ave. = 2.4‖

(n=18). Ave. = 1.9‖


5B - north (n=1). Ave. 2.9‖

(n=2). Ave. 2.5‖

(n=12). Ave. = 1.2‖*


(n= 6). Ave. = 1.5‖


5B - south (n=1). Ave. 2.9‖

(n=3). Ave. 2.5‖

(n=12). Ave. = 1.2 ‖*


(n= 6). Ave. = 1.4‖


5C (n=1). Ave. 1.9‖

(n=2). Ave. 1.7‖


(n=2). Ave. = 1.4‖


DYSON (n=2). Ave. = 1.6‖


HERMANN (n=2). Ave. = 2.2‖


KRISLE (n=1). Ave. = 1.6‖


TOTAL n 25 39 110 14

*Data are for all of Allotment 5B as a whole.


114

Figure 88. Distribution of acres that are biologically capable (light green, dark green, and blue areas) of producing high

structure vegetation, based on soil productivity.


115

3.6.4 Direct and Indirect Effects (Sensitive Birds)

In a study of Baird’s sparrows and

Sprague’s pipits on the Grand River

National Grassland, Winter (2008) found

that the vegetation characteristic that had

one of the strongest effects on these

species’ distribution was litter depth

(Figure 89). Habitat quality for Baird’s

sparrow and Sprague’s pipit increased

with increased litter depth.

Litter depth would be expected to increase

under those alternatives that proposed less

livestock grazing. Litter depth would be

expected to decrease at burned sites,

although that effect would be short-lived

(i.e. 1-2 years post-treatment). Litter

depth at mown sites would also decrease

if cut material was removed. These

predications are based on the fact that if

livestock, fire, or haying removes

herbaceous material, that material is not retained on-site to eventually become vegetative litter.

Under Alternative A, current habitat quality for Baird’s sparrows and Sprague’s pipits would

continue. This means that habitat quality would remain relatively low for Baird’s sparrow, as the

low availability of suitable litter depths currently restricts the species to comparatively few locations.

Habitat quality for Sprague’s pipits, however, would continue to be fair to moderate, as that species

will tolerate lower litter depths than will the Baird’s sparrow.

Alternatives B and C would result in greater litter depths throughout the project area. Both

alternatives propose mowing and burning, but the relatively low acreage proposed for any given year

(Table 7), would still result in a net increase in habitat quality for Baird’s sparrow and Sprague’s

pipit.

Alternative D would be expected to benefit Baird’s sparrow and Sprague’s pipit greatly for the short

term (e.g. up to ~5 years for the Baird’s sparrow, up to ~3 years for the Sprague’s pipit). Over the

remainder of the analysis period, however, these species would likely be excluded from some parts

of the project area as both birds avoided the sites with excessive litter buildup. Some suitable

habitat, however, would be provided in a shifting mosaic, as the birds colonized sites one or two

years post-burning or post-mowing.

Overall, Baird’s sparrow and Sprague’s pipit would be least benefited by Alternative A, and most

benefited by Alternative C. Alternatives B and D would be intermediate, with habitat quality under

Alternative B likely being limited by a lack of sufficient vegetative litter, whereas habitat quality

under Alternative D would more likely be limited by excessive vegetative litter.

Figure 89. Measuring litter. Litter, the broken pieces of grass and

sedges lying on the ground surface, is an important habitat feature for

Baird’s sparrows and Sprague’s pipits. Pasture 9, Grand River

National Grassland, Perkins Co. , SD. September 2007. Photo by

Chancey Odell.


116

Loggerhead shrike habitat quality is a function of the

availability of: high structure grasses (such sites

harbor high densities of favored prey), low structure

grasses (where prey are particularly vulnerable to the

shrike); and scattered thick, thorny trees (such sites

are favored for nest placement). In and near the

project area, low structure grass areas are abundant.

The availability of high structure grasses is addressed

below (see Sharp-tailed Grouse discussion, p. 117-

119). The remainder of this analysis of loggerhead

shrike habitat quality will focus on availability of

potential nest sites.

Alternative A is the only alternative that does not

propose removing non-native trees, such as the

Russian olive, a thick, thorny species often used by

nesting shrikes. Non-native trees would be removed

under Alternatives B, C, and D. These same

alternatives, however, propose planting native shrubs

and trees (Table 7), including wild plum (Figure 83)

and buffaloberry (Figure 90), thick, thorny species

often used by nesting shrikes.

Overall, the number of trees and shrubs on the project

area’s National Forest System lands would increase

under all alternatives. This is because Alternative A

would allow invasive Russian olives to continue to spread, whereas Alternatives B and C would

establish planted native shrubs and trees. Alternative D would see increased woody availability as

native shrubs and trees became established naturally (see p. 81 for more discussion). However, the

trees and shrubs expected to establish under Alternative A (through further invasion of non-native

trees and shrubs) or Alternatives B, C, and D (through planting of native trees or through passive

management) would require several years of growth before becoming suitable nest sites for

loggerhead shrikes. Therefore, there would be a short-term (i.e. 1-10 year) decline in the net

availability of nest sites on the project area’s National Forest System lands under Alternatives B, C,

and D, whereas Alternative A would perpetuate the current number of available nest sites during the

same time period.

Figure 90. Silver buffaloberry, Shepherdia

argentea. This native shrub provides an excellent

nesting site for loggerhead shrikes. The bird

sometimes skewers its’ prey on the shrub’s thorns

for storage. Photo by Robin Nieto.


117

3.6.5 Direct and Indirect Effects (Sensitive Butterflies)

Vegetative structure is important to the

two sensitive butterflies that occur

within the project area, with both species

preferring high structure vegetation. The

availability of high structure grasses is

addressed below (see Sharp-tailed Grouse

discussion, p. 117-119). Even more

important than vegetative structure,

however, is vegetative sere, with both

butterfly species preferring mid- or late

seral vegetative communities, especially

those with an abundance of favored nectar

species (Figure 91).

Under Alternative A, regal fritillary and

Ottoe skipper habitat would remain at

their current extent and quality.

Alternative B, and especially Alternative

C, would benefit sensitive butterfly

species by resulting in greater availability of late seral stage mixed-grass prairie. The greatest extent

of high structure, late seral mixed-grass prairie would occur under Alternative D. Long (>10-15

years) periods of no disturbance, such as would occur under Alternative D, however, are not

necessarily beneficial to these butterflies. For example, the fritillary’s main larval host plant, violets,

are easily overshadowed and are excluded by larger, more robust vegetation over time.

Alternatives B, C, and D propose prescribed burning, whereas Alternative A does not. While

burning can have a net indirect benefit to butterflies, depending on vegetative response, it can also

cause widespread injury and death to the insects themselves, as regal fritillaries and Ottoe skippers

are vulnerable to fire during all of their life stages. No alternative proposes prescribed burning in

sites known to be occupied by regal fritillary or Ottoe skipper. Although clearance surveys would be

conducted in mixed-grass prairie sites before burning would occur, Alternatives B, C, and D would

still pose a risk.

When all anticipated effects of proposed management are considered, Alternative C would result in

the greatest net benefit to regal fritillary and Ottoe skipper, followed by Alternatives D, B, and

finally A, which would at most maintain current habitat quality.

3.6.6 Direct and Indirect Effects (Sharp-tailed Grouse)

For sharp-tailed grouse, the most important effect of any alternative would be the change in the

availability of residual high structure vegetation (Figure 92).

Figure 91. Purple coneflower (Echinacea angustifolia), a nectar

source favored by several butterfly species in the project area. Little

Missouri National Grassland, Billings Co., ND. Photo by Curt

Glasoe.


118

Alternative A would perpetuate current low levels (i.e. 0%-8%) of high structure vegetation.

Compared to Alternative A, Alternatives B, C, and D would all dramatically increase high structure

vegetation, though the extent of that structure would vary greatly.

Under Alternative B, high structure

vegetation levels would be expected

to increase slowly over the next 10-

15 years, as less intensive livestock

grazing was phased-in over time. The

creation of crested wheatgrass pastures

would also facilitate deferment of

grazing on native grass pastures. By

the end of the project period, the

anticipated levels of residual high

structure vegetation on biologically

capable acres during non-drought

years would likely average 10%-20%

(Paul Drayton, Mark Gonzalez, Dan

Svingen prof. opin.), and thus might

achieve the lower-end of the

Grasslands Plan objective for high

structure vegetation (i.e. 20% to 30%). This is far from assured, however. Note, for example, that

the Grasslands Plan (Appendix I) predicts that stocking levels similar to those suggested by

Alternative B would retain moderate (not high) structure residual vegetation.

In comparison to Alternative B, Alternative C would result in both a faster rate of attainment and a

greater overall amount of high structure vegetation. This is due to Alternative C’s greater reductions

in livestock grazing levels, and the quicker phase-in period of those reductions. Within 5 years of

implementation, the anticipated levels of residual high structure vegetation on biologically capable

acres during non-drought years would average 10%-20% (Paul Drayton, Mark Gonzalez, Dan

Svingen prof. opin.). It is anticipated that by the end of the project period, that level of high

structure vegetation would increase to 20%-30% of the biologically capable acres (Paul Drayton,

Mark Gonzalez, Dan Svingen prof. opin; Grasslands Plan Appendix I). This increase would be due

to the natural successional changes in vegetative composition afforded by lighter grazing levels as

well as the expanded acreage of native flora establishment (Table 8).

Alternative D would result in the quickest and largest change in high structure vegetation, as this

alternative would soon cease all livestock grazing. Within 2 years of implementation, the anticipated

level of residual high structure vegetation on biologically capable acres during non-drought years

would average 10%-20% (Paul Drayton, Mark Gonzalez, Dan Svingen prof. opin.). By the end of

the 10-15 year project period, it is anticipated that high structure vegetation would occur on

approximately 50% or more of the biologically capable acres. This increase would be due to the

natural successional changes in vegetative composition afforded by the absence of grazing, as well

as the acreage of native flora establishment (Table 8). It should be noted that sharp-tailed grouse,

like Sprague’s pipits and Baird’s sparrows, do not benefit from large patches of habitat that have

been long protected from disturbance (such as would happen under Alternative D). The grouse’s

Figure 92. Residual high-structure vegetation provides critical hiding

cover for nesting sharp-tailed grouse. Note incubating hen. Photo by

Dr. Ben Geaumont.


119

tolerance of litter build-up, however, is greater than that of the two smaller birds. Degradation in

grouse habitat quality, therefore, would be expected to occur at a later time, such as after 10-20 years

of Alternative D’s implementation. Such degradation would occur even quicker, if Alternative D’s

proposed prescribed burning and mowing did not occur.

3.6.7 Cumulative Effects (Sensitive Birds, Sensitive Butterflies, Sharp-tailed Grouse)

The project area’s sensitive birds, sensitive butterflies, and sharp-tailed grouse are also affected by

other factors on and near the project area. The past, present, and reasonably foreseeable event that

has the greatest influence on these grassland species has been, is, and will be, the loss of grassland

habitat, deriving primarily from the conversion of native prairie to cropland agriculture. That impact

has been, and will be, exacerbated by the loss of tame grasslands as some of the fields currently

enrolled in the Conservation Reserve Program are put back into cropland.

The more grassland that is lost, the less wildlife populations in the project area are able to buffer

themselves from weather, disease, predators, etc. (Knowles 2001). Furthermore, grassland loss has,

and will, result in a decrease of the total habitat available, leading to a reduction in the size of each

species’ total population. These impacts will continue to affect all of the species analyzed above

regardless of the alternative chosen, but would be at least partially ameliorated under those

alternatives that improved habitat quality on the intermingled National Forest System lands.

Alternative D would be the most effective alternative in that regards, followed by Alternatives C, B,

and finally A, which would be the least effective.

The impacts of grassland conversion would be especially critical to the regal fritillary and Ottoe

skipper, because their existing populations in the cumulative-effects area are already very small (as

best as is known). The two sensitive butterflies vulnerability to local habitat loss is further

heightened due to the facts that the butterflies are resident species (unlike the sensitive birds); have

scattered, tiny, home ranges separated by relatively vast stretches of unsuitable or at least

unoccupied habitat (unlike the sharp-tailed grouse); and have very low dispersal capabilities

(particularly for the Ottoe skipper). Extant populations likely persist as part of a ―metapopulation‖;

the loss of any of the links in the chain of that metapopulation could threaten the persistence of the

whole. These cumulative impacts make the retention of quality habitat on the National Forest

System lands all the more critical to the continued persistence of sensitive birds, sensitive butterflies,

and sharp-tailed grouse in the project area. Again, Alternatives D and C would do more to preserve

quality habitat on National Forest System lands than would Alternatives B or A.

As noted above, an important determinant of Baird’s sparrow and Sprague’s pipit habitat quality is

availability of vegetative litter. Recent changes on other National Forest System lands within the

cumulative-effects area will result in stable to modest increases in litter availability and habitat

quality for these sensitive birds in those areas (see USDA Forest Service 2005, USDA Forest Service

2006). These improvements would be additive to those deriving from Alternatives B, C, and D, and

would at least partially mitigate the lack of such improvements that would occur under Alternative

A. Habitat quality for Baird’s sparrow and Sprague’s on the intermingled private rangelands is

expected to remain relatively unchanged under all alternatives, except for sites converted to

cropland.


120

The availability of suitable nesting sites for loggerhead shrikes in the cumulative-effects area will

change over the next 10-15 years. As discussed on p. xx to xx and xx to xx, native tree availability

overall (i.e. on all landownerships) is expected to decline. Therefore, the short-term net loss in nest

site availability described above (p. xx) due to the removal of exotic trees on National Forest System

lands in the project area for Alternatives B, C, and D, would be additive to that more widespread

trend. Local loggerhead shrike population viability would not be threatened, however, as available

nesting sites would still far exceed the number of active territories (Dan Svingen prof. opin.).

The wildlife species analyzed in this document would also be affected by continued private land

grazing. In general, this grazing is not focused on maintaining or improving availability of high

structure or late seral vegetation, or optimum litter depth for sensitive birds. Nevertheless, much of

the private rangeland within the cumulative-effects area provides habitat for Baird’s sparrow,

Sprague’s pipit, loggerhead shrike, and sharp-tailed grouse, and may provide habitat for sensitive

butterflies as well. This habitat is expected to remain under all alternatives, unless it is converted to

other land uses as described above.

Under all alternatives, sharp-tailed grouse would continue to benefit from the woody plantings,

haylands, crop residue, and waste feed provided on intermingled private lands throughout the

cumulative-effects area. Recent changes on other National Forest System lands within the

cumulative-effects area will result in stable to modest increases in residual cover availability and

habitat quality for sharp-tailed grouse (see USDA Forest Service 2005, USDA Forest Service 2006).

Attainment of Grasslands Plan’s objectives regarding high structure vegetation would also be

affected by management of National Forest System across the remainder of the Grand River Ranger

District. This is because Grasslands Plan’s objectives (Table 4) pertain to the entire Grand River

Geographic Area, which includes the Cedar River National Grassland and Grand River National

Grassland in their entirety.

The 6800 acres of National Forest System lands on the Cedar River National Grassland have a site-

specific objective to retain 15% high structure vegetation on biologically capable lands in non-

drought years, and to retain 7% high structure vegetation in drought years (USDA Forest Service

2004). Since the allotment management plans were updated there in 2005, annual monitoring has

recorded the following amounts of high structure vegetation: 2005=17% (Svingen and Hansen

2005), 2006 (a drought year)= 4% (Svingen and Gonzalez 2006), 2007= 30% (Svingen et al. 2007a),

and 2008= 77% (Svingen et al. 2008c).

The 67,000 acres of National Forest System lands in the Allotments 6 to 9 part of the Grand River

National Grassland have a site-specific objective to retain 20%-30% high structure vegetation on

biologically capable lands in non-drought years, and to retain 10% high structure vegetation in

drought years (USDA Forest Service 2005). Since allotment management plans were updated there

in 2007, annual monitoring has recorded the following amounts of high structure vegetation: 2007=

15% (Svingen et al. 2007b), and 2008= 19% (Svingen et al. 2008b).

The 35,000 acres of National Forest System lands in the Corson County part of the Grand River

National Grassland have a site-specific objective to retain 20%-30% high structure vegetation on

biologically capable lands in non-drought years, and to retain 10% high structure vegetation in


121

drought years (USDA Forest Service 2006). Since allotment management plans were updated there

in 2006, annual monitoring has recorded the following amounts of high structure vegetation: 2007=

22% (Svingen et al. 2007c), 2008= 51% (Svingen et al. 2008a).

Finally, a key cumulative-effects factor for this analysis will be weather, particularly the amount of

precipitation received during the April through June period, the critical growing season for cool-

season graminoids. If future precipitation levels are above normal, the anticipated increases in high

structure vegetation and late seral vegetation described above will be obtained quicker than

projected, and would likely encompass a greater area. Conversely, below normal precipitation levels

would delay and reduce anticipated increases in habitat quality. Weather-driven cumulative effects

would be most apparent under Alternative A because that alternative proposes no changes to current

management any weather-driven impacts would result in further departure from desired conditions)

and Alternative B (because that alternative proposes the least amount of change in livestock grazing

densities that might result in attainment of the LRMP objectives). Weather-driven cumulative

effects would be less apparent under Alternatives C and D, as those alternatives would provide more

buffering for weather permutations in the form of greater amounts of high structure and late seral

vegetation.

3.7 Key Issue: Grazing Levels

Grazing levels directly or indirectly affect

the other key issues identified for this

project. For example, the lack of residual

cover is often the result of too much forage

being removed by grazing animals.

Furthermore, riparian areas can lose or

maintain function depending on the levels

and timing of the grazing they receive.

Grazing levels also have a direct tie to

grazing economics. During scoping, several

comments were received about how many

livestock should be grazed in the project

area.

3.7.1 Existing Condition (Grazing Levels)

Authorized grazing levels are based, in part, on a site’s biotic ability to produce forage. Several

factors affect forage production, including soils, vegetative composition, and precipitation. Soil data

(Figure 94) have been previously compiled for Perkins County, including the project area, by the

USDA Natural Resources Conservation Service (Wiesner et al. 1980). Those data are now available

online from the USDA Natural Resources Conservation Service’s Soil Data Mart

(http://soildatamart.nrcs.usda.gov/). The USDA Natural Resources Conservation Service has also

mapped the ecological sites (Figure 95) in Perkins County, including the project area.

Figure 93. Herding cattle. File photo.

http://soildatamart.nrcs.usda.gov/


122

Using vegetative clipping data collected over several decades, the USDA Natural Resources

Conservation Service has developed forage production estimates and maps (Figure 93) for the

ecological site’s found within the project area. These models provide information on:

The site’s vegetation at or near its ―historic climax plant community‖, as well as other plant-community states;

The site’s vegetative production under a variety of weather conditions during the growing season, including ―near average‖, ―above average‖, and ―below average‖ growing conditions;

and,

The site’s likely vegetative responses to management and natural ecological processes.

The USDA Natural Resources Conservation Service (2006), using the above information, has

developed a chart of estimated initial stocking rates for each ecological site. Those data formed the

basis for our calculation of the project area’s ―estimated initial stocking rates‖. Specifically, we used

the USDA Natural Resources Conservation Service’s North Dakota Electronic Field Office

Technical Guide Section 4 (2006) to calculate estimated initial stocking rate for each grazing

allotment, based on the combination of ecological sites present. Note: it was appropriate to use the

North Dakota Technical Guide, even though the project area begins at the North Dakota/South

Dakota border and then extends southward, because the project area is within Major Land and

Resource Area (MLRA) 54, which encompasses portions of both states. Soils, plant communities,

and forage productivity are comparable throughout a given MLRA.

Figure 94. Example of the online soil information available to help quantify a site’s biotic ability to produce forage.

Allotment 2C-east, Grand River National Grassland, Perkins Co., SD. Data courtesy of USDA Natural Resources

Conservation Service.


123

Figure 95. Example of the online ecological site information available to help quantify a site’s biotic ability to produce

forage. Allotment 2C-east, Grand River National Grassland, Perkins Co., SD. Data courtesy of USDA Natural Resource

Conservation Service.


124

Figure 96. Potential forage production (lbs/acre/yr) under normal conditions, assuming vegetation is at ―historical

climax plant community.‖ Allotment 5C, Grand River National Grassland, Perkins Co, SD. Data courtesy of USDA

Natural Resources Conservation Service.


125

One of the Grasslands Plan’s objectives (p. 1-5) is to use a standardized process to determine

stocking rates. We have done that using the method described above and compared those ―estimated

initial stocking rates‖ to the stocking rates that have actually been used in the project area in the last

40-50 years. As shown in Table 22, stocking rates have generally become heavier (i.e. more cows

have been added) through time.

In general, the stocking rates in the 1960s were very close to the estimated initial stocking rate

(Table 22), even though the range managers of the 1960s did not have the advantages of today’s

detailed soil maps or decades of forage-production data. Since the 1960s, the USDA Forest Service

has authorized stocking rate increases due to real or perceived improvements in range health.

Increases were also authorized when range improvements and livestock rotations were implemented.

The stocking rate increases granted, however, were often much higher (i.e. 20%-33%) than the

benefits of rotational grazing would actually warrant (0%-7%, Holechek et al. 1999). Note: grazing

rotations generally do not increase forage production at all (i.e. there is a 0% change) for semi-arid

regions such as the project area (ibid, p. 14). Furthermore, it was previously assumed (Forest

Service 2210 range files, unpubl. information) that implementing those livestock rotations in the

project area would result in appropriate use of crested wheatgrass stands so that the crested

wheatgrass stands would bear the burden of the increased grazing use; that has not proven to be the

case. Even without correcting for animal size, current stocking rates are now up to 186% of the

estimated initial stocking rate (Table 22).

Table 22. Weighted average stocking levels within the Allotments 1-5 project area since the 1960s. ni = no information.

ALLOTMENT Estimated Initial

Stocking Rate

(acres per AUM)

1960s

(acres per HM)

1970s and/or

1980s

(acres per HM)

Current

(acres per HM)

1A 3.0 2.6 2.3 2.1

1B 3.0 2.8 2.7 2.7

2A 3.0 2.1 2.7 2.7

2B 3.0 1.8 1.9 2.3

2C-east 3.0 ni 2.4 2.5

2C-west 3.0 3.4 3.0 2.5

3A 3.2 3.1 2.6 2.1

3B 3.0 3.5 2.6 2.2

4A 3.4 ni 3.0 2.6

4B 3.1 5.3 2.6 2.3

5A 3.1 3.0 2.8 2.4

5B-north 3.2 3.1 2.8 2.8

5B-south 3.0 3.1 2.9 2.9

5C 3.0 2.8 1.7 1.7

DYSON 2.9 3.1 4.1 2.6

ERLANDSON 2.4 ni ni 3.5

EVRIDGE 2.7 ni ni 1.3 GUNN 2.7 ni ni 3.9

HERM 2.6 ni ni 2.0

HERMANN 3.2 3.7 3.2 2.4

KRISLE 2.7 ni ni 3.3

SMITH 4.1 ni 2.7 2.2

Weighted Average 3.1 3.2 2.6 2.4


126

3.7.2 Direct and Indirect Effects (Grazing Levels)

Two factors affect allowable grazing levels. These are: 1) how much forage can be grown (Figure

97), and 2) how much forage can be removed.

Over time, Alternatives B, C and D would be expected to result in more forage being grown, as these

alternatives would favor the development of more mid-sere and late-sere plant communities by

lowering stocking rates. This could result

in dramatic changes in forage availability.

For example, a site currently dominated by

blue grama, producing 700 pound per acre,

might eventually (i.e. in 10-20 years) be

dominated by western wheatgrass and green

needlegrass and produce 2400 pounds of

forage per acre. A review of numerous

grazing studies found that forage

production averaged 23% more under

moderate stocking than heavy stocking

rates, and was 36% higher under light

stocking rates compared to heavy stocking

rates (Holochek et al. 1999). Accurately

predicting the extent of future forage

availability in the project area, however, is

difficult due to the wide variety of current

vegetative community compositions, which

vary by ecological site, pasture, and

allotment; all of which influences the seral trajectory over time and space. Therefore, for the

purpose of this comparative analysis, it was assumed that forage production would remain constant

under all alternatives.

The alternatives differ in how much forage would be removed by domestic livestock. Alternative A

would continue with current grazing levels (Table 23), whereas Alternatives B and C would remove

less forage (Table 23). Alternative D would eventually (in year 3), prohibit all livestock grazing.

Alternative B would phase-in an initial reduction of stocking levels. Once that initial stocking level

was reached, it would be maintained for 5 years. If site-specific monitoring showed that the

allotment was then meeting resource objectives, the initial stocking level would remain in place for

the remainder of the life of that allotment management plan (usually 10-20 years total). If, however,

site-specific monitoring showed that the allotment was still not meeting resource objectives, then

another stocking reduction would be implemented to achieve the ―final stocking level‖, which would

remain in place for the remainder of the life of that allotment management plan. Overall, Alternative

B’s initial stocking level is 18% lighter than current stocking levels (i.e. 2.9 acres/HM vs. 2.4

acres/HM; Table 23). Alternative B’s final stocking level is 25% lighter than current stocking levels

(i.e. 3.1 acres/HM vs. 2.4 acres/HM; Table 23).

Alternative C would phase-in a single reduction of stocking levels which would remain in place for

the remainder of the life of the allotment management plans. Alternative C’s stocking level is that

Figure 97. Growing forage, including needleandthread, western

salisfy, and silver sage. File photo.


127

calculated by following the direction contained within the Grasslands Plan’s Appendices C and I.

Alternative C’s final stocking level is 37% lighter than current stocking levels (i.e. 3.7 acres/AEM

vs. 2.4 acres/HM; Table 23). Most of the change in stocking levels between Alternative B and

Alternative C would be as a result of accounting for current cow size, illustrating the magnitude of

that single fact’s influence.

Alternative D would eliminate all livestock grazing after year 2.

Table 23. Proposed stocking rates for Alternatives A, B, and C, compared to estimated initial stocking rates.

PROPOSED STOCKING RATE

ALLOTMENT

ALTERNATIVE

A

(acres/HM)

ALTERNATIVE

B – INITIAL

(acres/HM)

ALTERNATIVE

B – FINAL

(acres/HM)

ALTERNATIVE

C*

(acres/AEM)

ESTIMATED

INITIAL

STOCKING

RATE

(acres/AUM)

1A 2.1 2.8 3.0 3.6 3.0

1B 2.7 3.0 3.0 3.6 3.0

2A 2.7 3.0 3.2 3.8 3.0

2B 2.3 2.9 3.0 3.6 3.0

2C - east 2.5 3.0 3.2 3.8 3.0

2C - west 2.5 3.2 3.4 4.0 3.0

3A 2.1 2.8 3.2 3.8 3.2

3B 2.2 2.8 3.0 3.6 3.0

4A 2.6 3.0 3.4 4.0 3.4

4B 2.3 2.8 3.1 3.7 3.1

5A 2.4 2.8 3.1 3.7 3.1

5B-North 2.8 3.0 3.2 3.8 3.2

5B-South 2.9 3.1 3.1 3.7 3.0

5C 1.7 2.8 3.1 3.7 3.0

Dyson 2.6 2.8 2.8 3.4 2.9

Erlandson 3.5 3.1 3.1 3.7 2.4

Evridge 1.3 2.7 2.7 3.2 2.7

Gunn 3.9 3.9 3.9 4.6 2.7

Herm 2.0 2.0 2.0 2.4 2.6

Hermann 2.4 2.8 3.2 3.8 3.2

Krisle 3.3 3.3 3.3 4.0 2.7

Smith 2.2 2.8 4.1 4.9 4.1

Weighted Average 2.4 2.9 3.1 3.7

3.1

*Based on a correction factor for a 1200# animal using Method #3 (see p. 49-50 for additional

details). See project file for further discussion.


128

3.7.3 Cumulative Effects (Grazing Levels)

Under Alternative A, grazing levels on adjacent ownerships are likely to remain relatively stable

over the next 10-15 years. Under Alternatives B, C, and D, however, grazing levels on adjacent

ownerships could increase to compensate for reduced forage availability on National Forest System

lands. Under all alternatives, available pasture land within the cumulative-effects area would

increase if expired Conservation Reserve Program acres were converted to pasture. Conversely,

available pasture land within the cumulative-effects area would decrease if existing pasture was

converted to cropland. As noted elsewhere, the likelihood of either event will be mostly determined

by USDA agricultural policies and individual business decisions of private landowners, including

those of the permittees that pasture livestock within the Allotments 1 to 5 project area.

Elsewhere in the cumulative-effects area, grazing levels have been reduced on some, but not all

National Forest System lands. For example, in the Corson County part of the Grand River National

Grassland, resource monitoring documented relatively few problems with current management.

Grazing levels there averaged 2.61 acres/HM vs. the recommended stocking level of 2.64

acres/AUM. As a result, grazing levels were reduced

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