牦牛夏季补饲对青藏高原高寒草甸植物群落和土壤特性的影响

由于气候变化与人类活动的共同作用,青藏高原草地不断退化,草畜矛盾日趋严重,限制着高原畜牧业的可持续发展。夏季补饲可以加快牦牛生产速率、提高出栏率,减小草地放牧压力,是实现草地可持续发展的重要措施之一,但夏季补饲如何影响草地生态系统功能仍不明晰。以高寒草甸为研究对象,以牦牛为放牧实验家畜,设置夏季补饲放牧(FG)、传统重度放牧(TG)和禁牧(NG)3个放牧处理,每个处理设置3个重复。两年补饲试验后的结果表明:夏季补饲减缓传统放牧降低植物群落 α多样性的趋势;夏季补饲与传统放牧均降低了植物群落生物量;传统放牧表层土壤pH 和硝态氮均显著小于禁牧,但夏季补饲减弱了这些变化;夏季补饲显著降低了20-30 cm土层有机碳;夏季补饲增加了土壤表层磷含量。本研究表明夏季补饲放牧具有降低传统放牧压力的潜力,为保护和管理青藏高原高寒草甸生态系统提供重要的科学依据,并为改善牦牛的夏季饲养管理提供参考。

Effects of summer supplemental feeding of yaks on plant communities and soil properties in alpine meadows on the Qinghai-Tibetan Plateau

Climate change and human activities have resulted in grassland degradation on the Qinghai-Tibetan Plateau, enhancing grass-livestock imbalance and restricting the sustainable development of pastoralism on the plateau. Summer supplementary feeding is regarded as an important way to achieve sustainable development goal due to accelerated production rate, enhanced slaughter rate, and reduced grazing pressure. However, the impact of summer supplementary feeding of yaks on ecosystem functions in grasslands remains unclear. To address this issue, we established a yak grazing experiment in an alpine meadow, including summer supplementary feeding grazing (FG), traditional heavy grazing (TG), and grazing prohibition (NG). Our results indicated that summer supplementary feeding alleviated the decline in plant α-diversity caused by traditional grazing. Both summer supplementary feeding and traditional grazing reduced plant biomass. The traditional grazing had lower surface soil pH and nitrate nitrogen compared to grazing prohibition, while summer supplementary feeding weakened these effects. Summer supplementary feeding significantly decreased soil organic carbon in the 20-30 cm soil but increased total phosphorus content in the surface soil. The study suggests that summer supplementary feeding grazing has the potential to reduce the pressure of traditional grazing and provides important scientific evidence for the protection and management of alpine ecosystems in the Qinghai-Tibetan Plateau.