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Restoration of Native Shrubland in a Military
Training Area Using Hand-Broadcasting
of Seed
Dana L. Quinney
Marj McHenry
Jay Weaver
The authors decided to try hand-broadcast seeding as a
low-impact method of creating "source islands" of big sagebrush in large wildfire burns dominated by Poa secunda, Poa
secunda and exotic annuals, or exotic annuals only. The
seeding sites were areas where few or no native shrubs had
been present for fifteen years or more (Quinney and others,
unpublished report, maps, and data, Boise District BLM;
personal observation), indicating that natural restoration
was very slow or absent. Hand-broadcasting made it possible to seed into the most promising microsites present
(drainage draws, snowdrifts, and the like), taking advantage of pockets of soil moisture, with little soil disturbance.
Ahstract-The Idaho Army National Guard trains on the Orchard
Training Area, 55,848 hectares ofBLM shrub-steppe in southwestern Idaho. Historically, grazing, wildfire, and military training
have converted thousands of hectares of big sagebrush into stands
of exotic annuals. Other areas remain in good condition. Handbroadcasting of sagebrush seed can introduce "source islands" of
shrubs into areas where sagebrush has been removed by fire.
In the Orchard Training Area, fires caused by lightning,
railroad traffic, military training, and arson, have burned
thousands ofhectares of native shrub-steppe during the past
fifteen years; most significant burns occurred in the early
1980s (Boise District, U.S.D.l. Bureau of Land Management
unpublished fire data). To determine which species to plant
at which sites, various sources are used, including A Grazing
History of Southwestern Idaho (Yensen 1980) and a set of
vegetation maps with an accompanying report and plant
transect summaries, produced by Boise District Bureau of
Land Management biologists in 1981. In this effort, vegetation polygons in the Snake River Birds of Prey Area greater
than 16 hectares were mapped, ground-truthed, and sampled
(Quinney and others, Boise District BLM, unpublished report, maps, and data). When possible, ecotypic seed is
collected in the training area; otherwise, commercial seed is
used. Since 1988, several thousand hectares have been
planted to native shrub, grass, and wildflower species.
Vegetation restoration in the southwestern Idaho desert
poses a challenge. Because of the fine, friable soils; low,
irregular precipitation; multiple land uses; and exotic weeds;
traditional seeding methods may fail.
Every land manager who has seeded into desert environments has encountered the problem of "good year for seed,
bad year for planting." With sagebrush and some other
Great Basin natives, seed must be planted before viability is
lost, regardless of the precipitation. Also, in the authors'
experience, mechanical disturbance of the soil surface by
some seeding equipment may result in invasion of exotic
annuals, and/or destruction ofthe cryptogamic soil crust and
consequent wind erosion.
Methods _ _ _ _ _ _ _ _ __
Twelve sites in Ada County, Idaho, were hand-broadcast
with commercially obtained Wyoming big sagebrush seed
during the winter of 1992-1993. These sites were small (six
or fewer hectares). The sites were not exclosed from military
training and are grazed in spring and fall by sheep and/or
cattle. All sites supported Wyoming big sagebrush communities in 1979, according to the BLM maps and transect
summaries identified above (Quinney and others, Boise
District BLM unpublished report, maps, and data). Seeding
of each site was accomplished in from one to three hours by
one or two people. Seeding rates at each site are shown in
figure 1. Rates are approximations derived from driving or
walking the perimeter of the seeded sites with a global
positioning system to determine the area, and dividing the
number of pounds of seed (PLS) used at the site by the
number of hectares; seed distribution within a site was not
uniform.
I
I
I
SITE
CURLEW I VALLEY
LITHO
I
OBSIDIAN
I
PIT
!
LBS/HECTARE
In: Barrow, Jerry R.; McArthur, E. Durant; Sosebee, Ronald E.; Tausch,
Robin J., comps. 1996. Proceedings: shrubland ecosystem dynamics in a
changing environment; 1995 May 23-25; Las Cruces, NM. Gen. Tech. Rep.
INT-GTR-338. Ogden, UT: U.S. Department of Agriculture, Forest Service,
Intermountain Research Station.
Dana L. Quinney, Marj McHenry, and Jay Weaver are Biologists for the
State of Idaho Military Division Office of Environmental Management,
4715 S. Byrd Street, Boise, ID 83705.
1.98
2.69
3.29
Figure 1-Seeding rates and densities of Artemisia
tridentatafor five sites in the Orchard Training Area,
Idaho.
156
2.96
1.65
52
Hand broadcasting of seed creates irregular, ribbonlike
bands of seedlings. These irregular bands are difficult to
sample with straight-line transects. A modified Daubenmire
(1979) method of canopy coverage sampling was used. An
arc-azimuth method was used to layout sampling transects
on bands of seedlings, allowing for random placement of the
measuring frame within a degree arc the width of the band
at the distance where the next measurement was to be made.
After the point of origin of each transect, a measuring frame
was dropped and read at five-meter intervals. The location
of the next measuring frame was five meters from the
previous one, centered about a point perceived by using a
sighting compass at the previous frame-center point and
determining the arc of seedlings. Then, from a randomnumber table, the first number that fell within this degreearc was chosen as the center point for the next frame. Frame
center points were marked with 45-cm steel rods. At each
site, four 20-frame transects were established, two in seedling bands and two control transects in unseeded interspaces.
Five of the twelve sites, Curlew, Valley, Lithophragma,
Obsidian, and Pit, were monitored in 1995.
Within each frame, the following percents canopy cover
were estimated: cover for each vascular plant species, cryptogamic cover, grass litter, forb litter, shrub litter, cow/sheep
litter. Stem ground cover was also estimated. Within each
frame, big sagebrush individuals were counted and their
heights recorded to the nearest half-centimeter. Two photographs were taken from a fixed height and location at the
first frame of each transect, a frame vertical and a panorama. Annual monitoring of the sites is planned.
Four sites had an understory ofPoa secunda. One site, Pit
Road, had little grass, but an abundance of annual weeds,
includingRanunculus testiculatus and Lepidium perfoliatum.
Hand-broadcasting of sagebrush seed was successful on all
sites, regardless of the presence, absence, or dominance of
the site by native perennial Poa (fig. 2).
Results
48
44
40
36
32
28
24
CURLEW
II
VALLEY
SAGE SEEDLINGS
LITHO
OBSIDIAN
•
PIT
PERENNIAL. GRASSES
Figure 2-Artemisia tridentata seedling density and
canopy cover of native perennial grasses for five sites
in the Orchard Training Area, Idaho.
Since sagebrush transects were placed only within bands
of seedlings, of course, only areas where seedlings appeared
were sampled. Control transects characterize the sites' vegetation where no seedlings occurred. Preliminary results
indicate only that big sagebrush seedlings did appear in the
areas seeded. Subsequent annual monitoring will evaluate
the success ofthis method of shrub restoration through time.
References
-------------------------------
Daubenmire, R. A canopy-coverage method of vegetational analysis. Northwest Science 33(1): 43-64.
Quinney, D. L., Smith, G. W., Nydegger, N. Vegetation Patterns of
the Snake River Birds of Prey Area, unpublished report, maps,
and data, U.S. Department of the Interior, Boise District Bureau
of Land Management.
Yensen, D. L. 1980. A grazing history of southwestern Idaho, with
emphasis on the Snake River Birds of Prey Area. U.S. Department of the Interior, Boise District Bureau of Land
Management. 82 p.
U.S. Department of the Interior, Boise District Bureau of Land
Management. Unpublished fire maps and data.
-----------------------------------
Preliminary results indicate that hand-broadcasting of
big sagebrush can be a viable restoration procedure in the
southwestern Idaho desert. Sagebrush broadcast see dings
can produce seedlings in areas dominated by weeds, and also
in areas dominated by Sandberg's bluegrass (fig. 2). Handbroadcasting of sagebrush into small sites is economical,
does not disturb the soil, and can succeed in dry years
because the most favorable micro sites can be seeded.
157