This case study assessed changes in vegetation composition of a 0.8 ha rangeland site over the past four decades, in relation to changes in temperature and to an increase in grazing pressure. The frequency and standing crop (biomass) of species and functional groups were sampled in the spring of 1979 and 2016. Mean annual temperature increased, whereas changes in frequency varied between species and functional groups. Species that decreased included perennial plants, whereas species that increased were comprised mostly of annuals and unpalatable herbaceous plants. An NMDS ordination showed significant differences in species composition between 1979 and 2016. Total biomass, as well as the biomass of annual and perennial grasses and forbs did not differ between 1979 and 2016. Shrub biomass, however, decreased by 60% between years. Biomass of the ‘graminoids’ (e.g. Carex divisa), on the other hand, increased fourfold between 1979 and 2016. Species richness and the Shannon–Weaver diversity index H′ declined in 2016. This, together with a decline in the frequency of palatable species and a shift in species composition, could signal a decline in resilience over the long term. Changes in vegetation were most likely driven by a combination of higher temperatures and increased grazing pressure.

该案例研究评估了过去40年中0.8公顷牧场的植被组成与温度变化和放牧压力升高相关的变化。在1979年和2016年春季采样了物种和功能组的频率和常年作物（生物量）。年平均温度升高，而频率的变化在物种和功能组之间变化。减少的物种包括多年生植物，而增加的物种则主要由一年生和难吃的草本植物组成。NMDS排序显示，1979年至2016年间物种组成存在显着差异。1979年至2016年之间，总生物量以及一年生和多年生草和Forbs的生物量无差异。然而，灌木生物量在年间下降了60％。另一方面，Carex divisa）在1979年至2016年之间增长了四倍。物种丰富度和Shannon-Weaver多样性指数H ′在2016年下降。这与可口物种的频率下降和物种组成的变化一起，从长期来看，这可能预示着弹性下降。更高的温度和更高的放牧压力共同驱动了植被的变化。