甘肃马鹿冬季牧场牧草再生性对刈割的短期响应

在肃南裕固族自治县甘肃马鹿(Cervus elaphus kansuensis)不同放牧率(1.00、1.45、2.45、3.45、4.85、6.90AUM·hm-2)的冬季牧场,研究草原生产力与群落结构对牧草最佳生长期刈割的短期响应。结果表明,1)随放牧强度增加,刈割群落物种丰富度呈先增加后减少趋势,其中4.85 AUM·hm-2放牧率下的群落物种丰富度最高;刈割显著增加草地地上生物量。2)刈割群落的牧草株高和地上生物量均表现为超补偿生长,补偿指数分别以3.45、6.90AUM·hm-2放牧样地最高;各优势种变化趋势不同。3)刈割群落的Simpson优势度指数、Pielou均匀度指数在放牧较重样地最高;随放牧强度增加,群落Shannon-Wiener多样性指数呈先增加后减少趋势,以4.85 AUM·hm-2群落最高;且除4.85 AUM·hm-2群落外,刈割后的群落Shannon-Wiener多样性指数显著高于刈割前的(P0.05)。4)各功能群植物对不同放牧强度响应不同。因此,适宜放牧强度下,刈割能发挥草地最大生产潜力并维持群落结构稳定性。

Short-term effect of mowing winter pastures of Gansu wapiti on forage regeneration

The study investigated the short-term effect of mowing winter pastures of deer (Cervus elaphus kan-suens)on pasture productivity and community characteristics during the best growth period,under different stocking rates (1.00,1.45,2.45,3.45,4.85,and 6.90 AUM?hm—2).We found that:1)in mowed pastures, species richness increased with increasing stocking rate up to 4.85 AUM?hm—2and mowing significantly in-creased the above-ground biomass.2)In the mowed pastures,compensation index values indicated greater plant height and above-ground biomass.Highest compensation index was observed in the pastures grazed at 3. 45 and 6.90 AUM?hm—2,respectively.The effects of stocking rates on compensation index varied with differ-ences in the dominant plant species.3)Simpson's dominance and Pielou's evenness indices for mowed pastures were generally higher in heavily grazed pastures.The Shannon-Wiener diversity index of mowed pastures in-creased with increasing stocking rates up to 4.85 AUM?hm—2,and the difference owing to mowing of pastures at all stocking rates,except at 4.85 AUM?hm—2,were significant.4)We observed variation in responses a-mong plant functional groups to pasture mowing under different stocking rates.Therefore,we suggest that stocking rates should be considered when winter pastures are mowed for maximizing production potential and maintaining the stability of community structure.