Wang Yalin, Geng Yuanyue, Wang Xungang, Xu Tianwei, Zhang Qian, Liu Hongjin, Zhao Na, Xu Shixiao
Northwest Institute of Plateau Biology Chinese Academy of Sciences Xining China.
University of Chinese Academy of Sciences Beijing China.
Ecol Evol. 2024 Nov 28;14(12):e70586. doi: 10.1002/ece3.70586. eCollection 2024 Dec.
Grassland carrying capacity is an indicator for measuring the stability of grassland ecosystems and can provide a basis for formulating regional sustainable grazing strategies. However, most previous studies on this have only considered annual fluctuations, but seasonal changes were ignored. In this study, the herbage yield and nutrient value of two grassland types in Yellow River Source Park (YRSP) were measured by sampling point survey method in four seasons, and the seasonal and annual grassland carrying capacity, carrying numbers of standard sheep unit (SU) were estimated based on the dry matter (DM) content, crude protein, and metabolic energy of herbage. Due to the carrying capacity being low during the yellow and wintering periods, we combined them and calculated the carrying capacity for only three periods, including the flourishing period, greening period, and withering period. The grassland pressure index (GPI) was measured by the ratio of the actual standard sheep number and the calculated number. The results showed that the herbage yield and nutrient output were higher in spring and summer, lower in autumn and winter, and showed a tendency for alpine meadows to be higher than alpine grasslands during the flourishing period ( < 0.05). The unit area carrying capacity varied significantly with the season and showed the seasonal changing characteristics of the flourishing period > greening period > withering period. The seasonal carrying number was much higher than the actual carrying number during the flourishing period and much lower than the actual carrying number during the withering period. In terms of annual carrying capacity, the GPI was balanced when considering livestock alone, while critical overloaded when considering livestock and wildlife. This study suggested the influence of seasonal change on the grassland carrying capacity should be fully considered in the grassland utilization. Meanwhile, the feeding needs of livestock and wildlife should be taken into account, and timely supplemented when forage is in short supply.
草地载畜量是衡量草地生态系统稳定性的指标，可为制定区域可持续放牧策略提供依据。然而，以往关于此的大多数研究仅考虑了年度波动，却忽略了季节变化。本研究采用样点调查法，在黄河源园区（YRSP）四季测定了两种草地类型的牧草产量和营养价值，并基于牧草的干物质（DM）含量、粗蛋白和代谢能估算了季节性和年度草地载畜量、标准羊单位（SU）承载数量。由于枯黄期和越冬期载畜量较低，我们将它们合并，仅计算了包括盛草期、返青期和枯黄期在内的三个时期的载畜量。草地压力指数（GPI）通过实际标准羊数量与计算数量的比值来衡量。结果表明，春夏季牧草产量和养分输出较高，秋冬季较低，且在盛草期高寒草甸有高于高寒草原的趋势（P < 0.05）。单位面积载畜量随季节变化显著，呈现出盛草期>返青期>枯黄期的季节变化特征。盛草期的季节承载数量远高于实际承载数量，枯黄期则远低于实际承载数量。在年度载畜量方面，仅考虑家畜时GPI平衡，而考虑家畜和野生动物时则处于临界超载状态。本研究表明，在草地利用中应充分考虑季节变化对草地载畜量的影响。同时，应兼顾家畜和野生动物的采食需求，在草料短缺时及时进行补饲。
