ISSN:
1573-5052
Schlagwort(e):
Buried seed populations
;
Cutting frequency
;
Pioneer herbs
;
Secondary succession
;
Seed bank annuals
;
Therophytic community
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract The establishment and maintenance mechanisms of pioneer communities were investigated in ruderal habitats under two disturbance regimes, frequent and infrequent cutting sites. In the infrequent cutting sites, large perennials dominated through the year and inhibited the invasion of annuals, and the perennial community succeeded to forest stage if the cutting was stopped. In the frequent cutting sites, therophytic communities of winter and summer annuals alternated by season. Fresh seeds of both winter and summer annuals are dormant, but they have different germination times and thus can share the same sites in different seasons. Wind-dispersed biennials and large perennials have nondormant seeds and easily invade the sites; however, they are unable to mature to reproductive phase due to recurrent cuttings. The therophytic species, which can complete their life-cycle in a period between cuttings, accumulate seeds in the soils and are maintained by these buried seeds (seed bank annuals) during recurrent disturbances. The seed bank is compensation for the dispersal inefficiency of seed bank annuals. After abandonment of the frequent cutting sites, the buried seeds of seed bank annuals germinate and become the first-year pioneers. Thus, seed bank annuals are not invasive colonizers but are the remnants of the ruderal weed communities before abandonment.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00038716
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