“Eragrostis lehmanniana”的意思、由来-开放百科全书

This grass produces loose, open clumps of stems up to {{convert|61|to|80|cm|ft}} long,^[1]^[2] with some stems growing erect and some lying across the ground and rooting where nodes come in contact with the substrate. The leaves are up to {{convert|15|cm|in}} long.^[1] The inflorescence is a panicle up to {{convert|18|cm|in}} long by {{convert|8|cm|in}} wide, with branches appressed to the stems or held out at an angle. The spikelets are up to {{convert|1.4|cm|in|abbr=on}} long and contain up to 14 flowers each.^[2] The grass may spread via stolons.^[1]

In its native African range this grass is common in several habitat types such as Acacia woodland and Kalahari grasslands and savanna.^[3] It has been introduced to North and South America.^[4] In 1930 the grass was introduced to Arizona in the United States to replace the native grasses that had been severely overgrazed by livestock. In the 1940s the grass was spreading and could be found growing in areas where it had not been planted.^[5] By 1980 the grass had been sown on over 100,000 acres but it failed to take hold in many regions, such as parts of Texas and New Mexico. In the desert grasslands and shrublands of southeastern Arizona, however, it did well, growing best in areas with sandy soils, rare freezes, and summer rainfall totals of about {{convert|15|to|22|cm|in|abbr=on}}. Much beyond these parameters it does not spread or fails to survive. In 1988 it was a major species on 347,000 acres of Arizona desert.^[1] In parts of the region, the native ecosystem has been replaced by velvet mesquite woodland with an understory dominated by Lehmann lovegrass.^[6] This species sometimes hybridizes with Eragrostis curvula ("weeping lovegrass").^[7]

The grass produces large monotypic stands that crowd out native grasses and reduce plant and animal diversity.^[8] It forms a soil seed bank that can withstand long dry periods, giving it an advantage over some native grasses.^[9] It has been shown to have a negative impact on other types of plants, such as Agave palmeri, a key component in the local ecosystem.^[10]

References

1. ^¹²³⁴Uchytil, Ronald J. (1992). Eragrostis lehmanniana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Retrieved 12-22-2011.
2. ^¹Eragrostis lehmanniana. Grass Manual Treatment. Retrieved 12-22-2011.
3. ^Skarpe, C. (1986). Plant community structure in relation to grazing and environmental changes along a north-south transect in the western Kalahari. Plant Ecology 68(1) 3-18. Retrieved 12-22-2011.
4. ^{{GRIN | accessdate = 19 January 2018}}
5. ^Cox, J. R. (1992). [https://www.jstor.org/pss/4002564 Lehmann lovegrass live component biomass and chemical composition.] Journal of Range Management 45(6) 523-27. Retrieved 12-22-2011.
6. ^Biedenbender, S. H. and B. A. Roundy. (1996). Establishment of native semidesert grasses into existing stands of Eragrostis lehmanniana in southeastern Arizona. Restoration Ecology 4(2) 155-62. Retrieved 12-22-2011.
7. ^Halvorson, W. L. and P. Guertin. (2003). USGS Weeds in the West project: Status of Introduced Plants in Southern Arizona Parks. page 8. USGS. Retrieved 12-22-2011.
8. ^Moran, M. S., et al. Soil evaporative response to Lehmann Lovegrass Eragrostis lehmanniana invasion in a semiarid watershed. The Third Interagency Conference on Research in the Watersheds, 8–11 September 2008, Estes Park, CO. Retrieved 12-22-2011.
9. ^Abbott, L. B. and B. A. Roundy. (2003). [https://www.jstor.org/pss/4003882 Available water influences field germination and recruitment of seeded grasses.] Journal of Range Management 56(1) 56-64. Retrieved 12-22-2011.
10. ^Lindsay, D. L. Effects of invasives on the distribution of keystone desert plants on military lands. US Department of Defense Legacy Program. Retrieved 12-22-2011.

References

Further reading