典型草原绵羊牧食行为对放牧强度的响应

Response of Grazing Behaviors of Typical Steppe Sheep to Grazing Intensity

草地家畜的牧食行为受放牧草地供给资源量的影响,而放牧强度通过调控植物群落结构间接影响草地的植物资源供给。然而,放牧强度、牧食行为以及植物群落结构之间的相互关系和影响路径并没有得到很好的验证。本研究基于内蒙古锡林郭勒典型草原区放牧(轻度放牧、中度放牧和重度放牧)控制实验,采用人工全天追踪观察,并结合缩时拍和GPS定位,监测不同放牧强度下绵羊个体采食、反刍、站立、卧息以及游走等行为特征,探究绵羊牧食行为对不同放牧强度的响应模式。结果表明:(1)随放牧强度增加,群落总生物量降低,绵羊厌食的大针茅生物量增加,喜食的羊草和冰草等根茎型禾草以及知母等杂类草在减少。(2)随放牧强度增大,绵羊卧息和站立等保养时间显著减少,重度放牧延长了绵羊采食时间,而中度放牧降低了反刍速率;随季节推移,反刍时间减少,游走里程和采食时间大体上都经历了先减少后增加的过程。重度放牧导致草原群落物种组成的变化,地上生物量减少,优良牧草比例减少,于是绵羊会通过增加采食时间,降低卧息和站立等保养时间来确保其生存所需食物的获取。因此,在退化草地的家畜牧食行为研究中要重视群落结构的重要性,厘清这些关系有利于实施精准化的放牧管理和退化草地的快速恢复。

The grazing behavior of livestock in grassland was affected by the resource supply of grazing grassland, while grazing intensity indirectly affected the plant resource by regulating the plant community structure.However, the interrelationships and influencing pathways among grazing intensity, grazing behavior, and plant community structure have not been well verified.This study is based on control typical steppe grazing(light grazing, moderate grazing, and heavy grazing) experiments in Inner Mongolia’s Xilinhot to explore the sheep herds behavior response patterns of different grazing intensities, by artificial throughout the track observation, GPS positioning, the sheep feed individuals monitoring and travel behavior characteristics.The results showed as follows.(1) The total biomass of the community decreased with the increase in grazing intensity.The biomass of the sheep anorexic Stipa grandis increased, and the rhizome grasses such as Lymus chinensis and Agropyron cristatum,and the miscellany grasses such as Anemarhizium anemarhizae decreased.(2) The resting time and standing significantly decreased with the increase in grazing intensity.The feeding time of sheep was prolonged under heavy grazing, while moderate grazing reduces the rate of rumination.As the seasons went on, the ruminant time decreased, while the wandering distance and feeding time experienced a process of first decreasing and then increasing.Heavy grazing leads to changes in species composition of grassland communities, decreases in aboveground biomass and in the proportion of good forage grass.Therefore, the importance of community structure should be emphasized in the study of livestock grazing behavior in degraded grassland, and clarifying these relationships is conducive to the implementation of precise grazing management and the rapid restoration of degraded grassland.