Herbivory resistance traits in populations of Poa ligularis subjected to historically different sheep grazing pressure in Patagonia

摘要: Seeding selected populations with high grazing resistance may foster recovery of plant threatened by overgrazing. Resistance to depends on avoidance (escape from grazers) and tolerance (ability growth after defoliation). Many studies defoliate plants at a fixed height instead removing the same proportion biomass therefore confound avoidance. For this reason, information evolution defoliation intraspecific level is remarkably scarce despite abundance papers published that evaluate responses defoliation. The estimation cost also troublesome because current methods usually include spurious correlations due correlation between variables share common terms. objectives paper were assess variation in traits associated different sheep histories. We estimated percentage removed when treatment was imposed order separate Finally, we using new method proposed for correlations. Results greenhouse experiment indicated no difference among three compared populations. However, overgrazed fields had more prostrate form, higher specific leaf area, tillering rate (when defoliated) than exclosures. confirmed would have shoot taller shorter individual plants, confounding Regarding tolerance, found differences null model cost, indicating (or future breeding) tolerant genotypes not be constrained cost.