首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Reducing Competitive Suppression of a Rare Annual Forb by Restoring Native California Perennial Grasslands
Authors:Tina M Carlsen  John W Menke  Bruce M Pavlik
Institution:Environmental Restoration Division, Lawrence Livermore National Laboratory, Livermore, CA 94551, U.S.A.; Department of Agronomy and Range Science, University of California, Davis, CA 95616, U.S.A.; Department of Biology, Mills College, Oakland, CA 94613, U.S.A.
Abstract:Populations of the rare annual forb Amsinckia grandiflora may be declining because of competitive suppression by exotic annual grasses, and may perform better in a matrix of native perennial bunchgrasses. We conducted a field competition experiment in which Amsinckia seedlings were transplanted into forty 0.64‐m2 experimental plots of exotic annual grassland or restored perennial grassland. The perennial grassland plots were restored using mature 3 cm‐diameter plants of the native perennial bunchgrass Poa secunda planted in three densities. The exotic annual grassland plots were established in four densities through manual removal of existing plants. Both grass types reduced soil water potential with increasing biomass, but this reduction was not significantly different between grass types. Both grass types significantly reduced the production of Amsinckia inflorescences. At low and intermediate densities (dry biomass per unit area of 20–80 g/m2), the exotic annual grasses reduced Amsinckia inflorescence number to a greater extent than did Poa, although at high densities (>90 g/m2) both grass types reduced the number of Amsinckia inflorescences to the same extent. The response of Amsinckia inflorescence number to Poa biomass was linear, whereas the same response to the annual grass biomass is logarithmic, and appeared to be related to graminoid cover. This may be because of the different growth forms exhibited by the two grass types. Results of this research suggest that restored native perennial grasslands at intermediate densities have a high habitat value for the potential establishment of the native annual A. grandiflora.
Keywords:Amsinckia grandiflora  Poa secunda  rare plants  native plants  exotic plants  interspecific plant competition  light competition  water competition  grassland restoration
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号