Historical land use by domestic grazing revealed by the soil seed bank: a case study from a natural semi-arid grassland of NW Patagonia
FRANZESE J.; GHERMANDI L.; GONZALEZ S.
GRASS AND FORAGE SCIENCE (PRINT)
WILEY-BLACKWELL PUBLISHING, INC
Lugar: Londres; Año: 2015 vol. 71 p. 315 - 327
Livestock can affect the soil seed bank through variousmechanisms associated with changes in vegetation.We sampled vegetation and seed banks ofPatagonian grasslands, in areas with different historicaluse by grazing (exclosure, moderate use andhigh use) to evaluate to what extent changes invegetation are reflected in the seed bank. We alsoevaluated the effect of historical grazing on horizontalspatial seed distribution by sampling undershrubs and in between plant gaps. We focused thestudy on functional groups, and on the palatablePoa ligularis, an indicator of grassland status. In general,the proportional changes in composition andabundance of functional groups produced in grazedsectors (relative to each exclosure) were bigger forthe seed bank than for the aboveground vegetation.Impacts on seed bank were led by a decrease (moderateuse), or total disappearance (high use) ofperennial grasses, results clearly reflected by P. ligularis.Although shrubs were represented in vegetation,they were undetected in the seed bankthrough germination, probably due to the lack ofthe conditions required for breaking seed dormancy.Intensive grazing produced homogenization in seedspatial distribution. Our work revealed a poor contributionof the seed bank to vegetation regenerationat increasing historical use by grazing. We recommendsampling the seed bank when monitoring theconservation status of grasslands to obtain consistentmanagement guidelines.