As the basis of livestock feeding and related performances, pastures evolution and dynamics need to be carefully monitored and assessed, particularly in the Alps where the effects of land abandonment are further amplified by climate change. As such, increases in temperature associated with changes in precipitation patterns and quantity are leading to modifications of grassland extent and composition with consequences on the pastoral systems. This study applied a machine learning approach (Random Forest) and GIS techniques to map the suitability of seven pasture macro types most representative of the Italian Alps and simulated the impact of climate change on their dynamics according to two future scenarios (RCP4.5, 8.5), two time-slices (2011–2040, 2041–2070), and three RCMs (Aladin, CMCC, ICTP). Results indicated that (i) the methodology was robust to map the current suitability of pasture macro types (mean accuracy classification = 98.7%), so as to predict the expected alterations due to climate change; (ii) future climate will likely reduce current extend of suitable pasture (−30% on average) and composition, especially for most niche ecosystems (i.e., pastures dominated by Carex firma and Festuca gr. Rubra); (iii) areas suited to hardier but less palatable pastures (i.e., dominated by Nardus stricta and xeric species) will expand over the Alps in the near future. These impacts will likely determine risks for biodiversity loss and decreases of pastoral values for livestock feeding, both pivotal aspects for maintaining the viability and profitability of the Alpine pastoral system as a whole.

中文翻译：

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未来气候条件下高山草场范围和组成的预期变化

作为牲畜饲养和相关性能的基础，需要仔细监测和评估牧场的演变和动态，特别是在阿尔卑斯山地区，因为气候变化进一步加剧了土地遗弃的影响。因此，与降水模式和降水量变化相关的温度升高导致草原范围和组成的变化，对牧草系统产生影响。这项研究运用机器学习方法（Random Forest）和GIS技术绘制了七个最能代表意大利阿尔卑斯山的牧场宏类型的适用性，并根据两种未来情况（RCP4.5、8.5）模拟了气候变化对其动态的影响），两个时间片（2011-2040、2041-2070）和三个RCM（阿拉丁，CMCC，ICTP）。结果表明：（i）该方法可用于绘制当前牧场宏类型的适用性（平均准确度分类= 98.7％），从而预测气候变化引起的预期变化；（ii）未来的气候可能会减少适当牧场的当前扩张（平均-30％）和组成，特别是对于大多数利基生态系统（即以牧场为主的牧场）苔草和Festuca gr。Rubra）; （iii）在不久的将来，适合于较硬但不那么可口的牧场的地区（即以纳尔达斯和干燥物种为主）将在阿尔卑斯山扩展。这些影响将可能确定生物多样性丧失的风险以及牲畜饲养的牧草价值下降，这对于维持整个高山牧草系统的生存能力和获利能力都是至关重要的方面。