Establishment\ competition and the distribution of native grasses among Michigan old!_elds

نویسنده

  • BRYAN L FOSTER
چکیده

0 In this study the potential role of competition in in~uencing the distribution of three displaced native perennial grasses across complex gradients of plant productivity and species composition was investigated in Michigan old!_elds[ To do this plant removal and propagule addition experiments were conducted at nine old!_eld sites to examine the e}ects of living plant neighbours and litter on seedling establishment and growth of target species in relation to community biomass[ 1 For two target species\ Andropo`on `erardi and Schizachyrium scoparium\ living plant neighbours suppressed establishment from seed at most sites\ and suppressed the growth of transplants at all sites[ 2 Plant litter strongly inhibited the seedling establishment of both Andropo`on and Schizachyrium at sites of high community biomass and litter accumulation\ but had little impact on the growth rate of transplants at any of the sites[ 3 The total suppressive e}ect of the plant community on seedling establishment and transplant growth of both Andropo`on and Schizachyrium increased in magnitude in a non!linear fashion with community biomass[ These e}ects increased in magnitude more rapidly across sites of low to medium biomass than sites of medium to high biomass[ 4 The results suggest that these native grasses may be restricted to low productivity habitats within this landscape because of strong competitive interference with estab! lishment by the existing vegetation in the most productive sites[

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تاریخ انتشار 1999