TY - JOUR
T1 - Effects of grazing on soil seed bank dynamics
T2 - An approach with functional groups
AU - Sternberg, Marcelo
AU - Gutman, Mario
AU - Perevolotsky, Avi
AU - Kigel, Jaime
PY - 2003/6
Y1 - 2003/6
N2 - The relationship between intensity and timing of cattle grazing on changes in the size and composition of the soil seed bank were investigated in a 3-yr study in a Mediterranean grassland in northeastern Israel. Treatments included manipulations of stocking rates and of grazing regimes, in a factorial design. The retrieved soil seed bank community was rich in species, with 133 species accounting for 80% of the 166 species recorded at the site. Within the seed bank, 89% of the species were annuals. Seed bank dynamics was analysed in terms of plant functional groups and germination strategies. In terms of total seed bank density and including all functional groups, 42% of the seeds present in the soil did not germinate under watering conditions. The dormancy level differed greatly among functional groups. The seed bank of annual legumes, crucifers, annual thistles and annual forbs had a large fraction of non-germinated seeds and characterized areas grazed early in the growing season under high and very high grazing intensity. These functional groups were considered to have a higher potential for persistent seed banks production. In contrast, short and tall annual grasses and tall perennial grasses, that were dominant in ungrazed or moderately grazed paddocks, generally had seed banks with a very small fraction of non-germinated seeds. Seed bank densities varied widely between grazing treatments and years. Under continuous grazing, heavy grazing pressure reduced seed bank densities of grasses and crucifers in comparison to moderate grazing. The greatest reduction on the seed bank densities resulted from heavy grazing concentrated during the seed-set stages.
AB - The relationship between intensity and timing of cattle grazing on changes in the size and composition of the soil seed bank were investigated in a 3-yr study in a Mediterranean grassland in northeastern Israel. Treatments included manipulations of stocking rates and of grazing regimes, in a factorial design. The retrieved soil seed bank community was rich in species, with 133 species accounting for 80% of the 166 species recorded at the site. Within the seed bank, 89% of the species were annuals. Seed bank dynamics was analysed in terms of plant functional groups and germination strategies. In terms of total seed bank density and including all functional groups, 42% of the seeds present in the soil did not germinate under watering conditions. The dormancy level differed greatly among functional groups. The seed bank of annual legumes, crucifers, annual thistles and annual forbs had a large fraction of non-germinated seeds and characterized areas grazed early in the growing season under high and very high grazing intensity. These functional groups were considered to have a higher potential for persistent seed banks production. In contrast, short and tall annual grasses and tall perennial grasses, that were dominant in ungrazed or moderately grazed paddocks, generally had seed banks with a very small fraction of non-germinated seeds. Seed bank densities varied widely between grazing treatments and years. Under continuous grazing, heavy grazing pressure reduced seed bank densities of grasses and crucifers in comparison to moderate grazing. The greatest reduction on the seed bank densities resulted from heavy grazing concentrated during the seed-set stages.
KW - Cattle
KW - Dormancy
KW - Germination
KW - Management
KW - Mediterranean
KW - Persistence
KW - Rangeland
KW - Regeneration strategy
UR - http://www.scopus.com/inward/record.url?scp=0042140325&partnerID=8YFLogxK
U2 - 10.1111/j.1654-1103.2003.tb02163.x
DO - 10.1111/j.1654-1103.2003.tb02163.x
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AN - SCOPUS:0042140325
SN - 1100-9233
VL - 14
SP - 375
EP - 386
JO - Journal of Vegetation Science
JF - Journal of Vegetation Science
IS - 3
ER -