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Wildlife, Animals, and Plants
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BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Hesperostipa comata
| Needle-And-Thread Grass
Needle-and-thread grass is a cool-season, native, perennial bunchgrass [66]. The bunches are small, from 1 to 3 inches (2.5-7.6 cm) in diameter, and widely spaced [128].
Needle-and-thread grass is shallow-rooted [10] to medium-rooted and produces numerous fibrous roots of 0.04 inches (1 mm) or less in diameter [126]. Roots grow both vertically and laterally, more than 14 inches (36 cm) from the base of the plant in the first 0.5 foot (0.15 m) of soil. These profusely branched roots reach 3 to more than 5 feet (0.9-1.5 m) deep [34,57,116,127,126,128], but more than 50% of the total root biomass is within the first 0.6 foot (0.2 m) of soil [95]. In a Saskatchewan prairie, number of roots per shoot of needle-and-thread grass averaged 3.8 to 5.4, and the mean number of lateral roots per decimeter of main root was 39 to 75 [34].
Needle-and-thread grass is moderately to highly drought resistant [10,101,116,128] and recovers well from drought [53,116].
Needle-and-thread grass is colonized by vesicular-arbuscular mycorrhizae (VAM). In a study in northern Nevada, 83% of plants within a grazing exclosure were colonized with VAM, while only 33% of grazed plants were colonized, a significant (p<0.05) difference [13].
Hemicryptophyte
Propagation is by seed [94] and by tillers [1,46,128]. Seeds are long-lived. Sixty-three percent of seeds stored in an open warehouse in Utah germinated after 9 years [120]. Seeds may germinate in spring or fall, but more commonly in the fall [52].
Because of a long awn on the seed, needle-and-thread grass seeds can imbed themselves in the soil by a twisting action of the awn in response to daily humidity changes [52,92].
Needle-and-thread grass seeds are not a prominent component of soil seedbanks. Hassan and West [77] studied soil seedbank properties under burned and unburned Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis)-Utah juniper-bunchgrass sites in Utah. Despite relatively high presence of needle-and-thread grass as ground cover, there were very few viable needle-and-thread grass seeds in the upper 2 inches (5 cm) of soil on both the burned and unburned treatments.
In a Nebraska sandhills prairie site, needle-and-thread grass contributed the fewest seeds to the 0 to 2 inch (0-5 cm) depth seedbank of several perennial grasses [107]. Only 2% of needle-and-thread grass seeds germinated in greenhouse germination trials.
Needle-and-thread grass is common on dry hills and plains, and on stony and sandy soils throughout its range [36,130]. Soils are usually slightly high pH, low water-holding capacity, low clay percentage and high bulk density [108]. On the Upper Snake River Plains in Idaho, needle-and-thread grass is common on sandy soils and dry areas [11]. In southwestern Saskatchewan, needle-and-thread grass often dominates on loam soils but is usually absent from heavy clays [83].
Needle-and-thread grass occurs on well-drained soils from 660 to 11,550 feet (200-3500 m) in California [79]. In Arizona, needle-and-thread grass occurs from 3,500 to 8,500 feet (1061-2576 m) on dry hills, open woods, and sandy soils, often with juniper [89]. In Montana, needle-and-thread is found from 2,000 to 8,000 feet (606-2424) [116]. In Utah, needle-and-thread occurs from 3,498 to 10,065 feet (106-3050 m) [130].
Needle-and-thread grass generally requires at least 10 inches (254 mm) of annual precipitation [44] but grows in areas with less [130]. In Montana, needle-and-thread grass grows best with 10-18 inches (254-457 mm) of precipitation [116].
The aspect on which needle-and-thread grass appears most frequently varies by geographic location. In the sandhills of Nebraska, needle-and-thread grass is commonly found on north-facing slopes [23].
In Saskatchewan, needle-and-thread grass reaches highest densities on warm, dry, upper, south-facing slopes [19]. In Alberta, needle-and-thread grass is largely restricted to south-facing slopes and is most dense on the upper slopes [35]. In eastern Colorado, needle-and-thread grass is most common on north and east-facing slopes [39].In Montana, needle-and-thread grass performs worst on southwest slopes [94].
At the Idaho National Engineering Laboratory Site, density and frequency of needle-and-thread grass was significantly (p<0.01) correlated with April precipitation, but not with May or June precipitation [60].
Needle-and-thread grass is generally a mid-seral species. Needle-and-thread is considered an early seral species in Montana [94] and Wyoming [113], following the 1st annual forbs and grasses and biennial forbs. Needle-and-thread grass is a mid-successional species in semi-arid big sagebrush communities in Colorado [58].
Freeman and Emlen [59] evaluated interspecific competition in a cold desert shrub community in western Utah. They found needle-and-thread grass was negatively affected by competition with Indian ricegrass, galleta, blue grama (Bouteloua gracilis), shadscale, saltbush, winterfat, and cheatgrass (Bromus tectorum), and positively associated with the forbs sand dropseed and red threeawn (Aristida purpurea).
Germination of needle-and-thread grass seeds is strongly inhibited by aqueous extracts of absinth wormwood (Artemisia absinthium) but positively affected by extracts of fringed sagewort (A. frigida) and tarragon (A. dracunculus) [82].
In wetter than average moisture conditions, needle-and-thread grass may be replaced by wheatgrass (Triticeae) and Canadian needlegrass [32].
Needle-and-thread grass becomes dormant during hot weather, but it will green up again in the fall given sufficient precipitation [92,128]. According to Wright [132], needle-and-thread grass never becomes truly dormant in the summer in Idaho.
Seasonal development of needle-and-thread grass in the Great Plains is as follows [128]:
| Stage |
Approx. date |
| Growth resumes |
Late March, early April |
| Flowering |
Early June |
| Ripe seeds shed |
July |
On the Upper Snake River Plain, Idaho, seasonal development is as follows [11]:
| Stage |
Date |
| Growth starts |
4/4 |
| Flowerstalks appear |
5/21 |
| Heads fully out |
6/18 |
| Flowers in bloom |
6/22 |
| Seed ripe |
7/1 |
| Dissemination starts |
7/4 |
| Dissemination over |
7/20 |
| Plant drying |
7/3 |
| Plant dried |
8/1 |
Related categories for
SPECIES: Hesperostipa comata
| Needle-And-Thread Grass
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