We analysed how changes in community attributes promoted by domestic grazing are reflected on functional traits in canopies of shrubs and perennial grasses in rangelands of the Patagonian Monte. We selected four sites across a gradient of grazing pressure and assessed (i) changes in plant cover, and species richness and diversity and (ii) changes in functional traits (community weighted mean: CWM, functional diversity and redundancy) related to plant growth (leaf N concentration, height of the plant, and specific leaf area-SLA) in shrub and perennial grass canopies. Shrub cover decreased and species and functional diversity increased with increasing grazing pressure. Nonsignificant changes were found in shrub species richness and functional redundancy across the grazing gradient. Positive relationships were found between shrub species diversity and CWM of SLA, and leaf N, while CWM-height was not related to grazing pressure. Perennial grass cover decreased steadily with grazing pressure, while species richness decreased significantly at high grazing pressure. Perennial grass diversity, functional diversity and redundancy of functional plant traits, and CWM-height increased at intermediate grazing pressure, while the inverse pattern was observed for CWM of SLA and leaf N. These results highlighted that species diversity was the community attribute that best reflected functional changes induced by grazing pressure in shrub and perennial grass canopies in these rangelands. We concluded that shrubs persist under high grazing pressure increasing species and functional diversity of relevant plant traits, while perennial grass canopies were only able to persist under intermediate grazing pressure.

我们分析了家庭放牧促进的社区属性变化如何反映在巴塔哥尼亚蒙特牧场的灌木和多年生草冠层的功能性状上。我们在放牧压力梯度上选择了四个地点，并评估了（i）与植物生长相关的植物覆盖率，物种丰富度和多样性的变化以及（ii）功能性状的变化（社区加权平均值：CWM，功能多样性和冗余度）（灌木和多年生草冠层中的叶片氮浓度，植物高度和特定叶面积（SLA）。随着放牧压力的增加，灌木的覆盖减少，物种和功能多样性增加。在整个放牧梯度上，灌木物种的丰富度和功能冗余均无显着变化。灌木物种多样性与SLA和叶片N的CWM之间呈正相关，而CWM的高度与放牧压力无关。随着放牧压力的变化，多年生草地覆盖率稳步下降，而在高放牧压力下，物种丰富度显着下降。在中度放牧压力下，多年生禾草多样性，功能多样性和功能性状植物的冗余性以及CWM高度增加，而SLA和N叶的CWM则呈现相反的模式。这些结果表明，物种多样性是最能反映出群落特征的在这些牧场中，灌木和多年生草冠层的放牧压力引起的功能变化。我们得出结论，灌木在高放牧压力下持续存在，从而增加了相关植物性状的物种和功能多样性，