Historical land use by domestic grazing revealed by the soil seed bank: a case study from a natural semiarid grassland of NW Patagonia

FRANZESE JORGELINA; GHERMANDI LUCIANA; GONZALEZ SOFIA

GRASS AND FORAGE SCIENCE (PRINT)

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 71 p. 315 - 327

0142-5242

Livestock can affect the soil seed bank throughvarious mechanisms associated with changes in vegetation. We sampled vegetationand seed banks of Patagonian grasslands, in areas with different historical useby grazing (exclosure, moderate use, and high use) to evaluate to what extentchanges in vegetation are reflected in the seed bank. We also evaluated theeffect of historical grazing on horizontal spatial seed distribution bysampling under shrubs and in between plant gaps. We focused the study onfunctional groups, and on the palatable Poaligularis, an indicator of grassland status. In general, the proportionalchanges in composition and abundance of functional groups produced in grazedsectors (relative to each exclosure) were bigger for the seed bank than for theabove ground vegetation. Impacts on seed bank were led by a decrease (moderateuse), or total disappearance (high use) of perennial grasses, results clearlyreflected by P. ligularis. Althoughshrubs were represented in vegetation, they were undetected in the seed bankthrough germination, probably due to the lack of the conditions required forbreaking seed dormancy. Intensive grazing produced homogenization in seed spatialdistribution. Our work revealed a poor contribution of the seed bank to vegetationregeneration at increasing historical use by grazing. We recommend sampling theseed bank when monitoring the conservation status of grasslands in order toobtain consistent management guidelines.