青藏高原退化高寒草甸生长季承载力

近年来，在气候变化和人类活动的共同影响下，青藏高原部分地区草场退化严重。在青藏高原北麓河流域多年冻土区选取中度退化及未退化高寒草甸，用热红外辐射器模拟气候变暖，研究草地退化和气候变化对生长季草场数量和营养承载力（可消化蛋白承载力和代谢能承载力）的影响。结果表明：（1）退化后，莎草科植物在群落中的重要值降低，而禾本科和杂草类植物重要值逐渐增加；（2）退化对植被地上生物量无显著影响，但退化伴随着气候变暖使地上生物量在6月和9月分别显著降低了（87.17±6.93） g·m^-2和（38.89±2.23） g·m^-2；（3）退化在6月和9月使牧草粗蛋白含量分别显著降低了29.15%和33.74%，但使牧草中酸性洗涤纤维含量分别显著增加了11.68%和15.34%，牧草品质下降明显；（4）退化伴随着气候变暖使数量承载力和代谢能承载力在6月分别降低了（2.63±0.21）、（6.94±0.55）羊单位·hm^-2，在9月分别降低了（1.17±0.07）、（3.1±0.17）羊单位·hm^-2。研究区草场代谢能承载力>可消化蛋白承载力>数量承载力。研究区生长季牧草营养供给充足，适宜承载力为数量承载力

Growing Season Bearing Capacity of Degraded Alpine Meadow in the Qinghai-Tibet Plateau

In recent years, grassland has been severely degraded in parts of the Qinghai-Tibet Plateau(QTP) under the combined influence of climate change and human activities. In this study, the thermal infrared heaters were used to simulate climate warming in moderately degraded and non-degraded alpine meadows in the permafrost regions of the Beiluhe basin of the QTP to study the effects of grassland degradation and climate change on the grassland quantity and quality(digestible crude protein and metabolic energy) bearing capacity in the growing season. The result showed:(1) Degradation reduced the importance value of sedges species in the community, while that of grasses and forbs species gradually increased;(2) Degradation had no significant effect on above-ground biomass of vegetation, but degradation with climate warming reduced above-ground biomass by(87.17±6.93) g·m^-2 and(38.89±2.23) g·m^-2 in June and September;(3) Degradation reduced the content of crude protein by 29.15% and 33.74%, but increased the content of acid detergent fiber by 11.68% and 15.34% in June and September;(4) With climate warming, degradation reduced the quantity bearing capacity and metabolic energy bearing capacity by 2.63±0.21 and 6.94±0.55 sheep unit/hectare in June, and 1.17±0.07 and 3.1±0.17 sheep unit/hectare in September. The bearing capacity in the study area was in the sequence of metabolic energy bearing capacity>digestible crude protein bearing capacity>quantity bearing capacity. The nutrients supply of forage in the growing season in the study area is sufficient to livestock, and the suitable bearing capacity is the quantity bearing capacity.