高寒草甸物种多样性对藏系牧羊放牧行为的影响

为探究草原植物物种多样性对家畜放牧行为的影响及其机制，在青藏高原高寒草甸开展藏系牧羊轮牧试验，调查植被物种多样性，观察藏系牧羊采食速率、觅食速率和采食时间，并计算藏系牧羊日采食量。结果表明：两年间，植物物种丰富度与藏系牧羊采食速率呈显著正相关关系（P<0.05）；觅食速率、采食时间和日采食量对放牧率响应敏感（P<0.05），呈夏秋增冬春减的趋势。植物Shannon-Wiener指数与藏系牧羊的采食时间显著负相关（P<0.05）；在暖季或8羊/hm²放牧率下植物Shannon-Wiener指数与藏系牧羊日采食量呈显著正相关（P<0.05）。Pilelou均匀度指数与藏系牧羊采食速率和采食时间显著负相关（P<0.05）；在暖季或8羊/hm²放牧率下Pilelou均匀度指数与藏系牧羊日采食量呈显著负相关（P<0.05）。植物物种丰富度对藏系牧羊放牧行为贡献较大，且放牧藏系牧羊的采食速率和采食时间比觅食速率和日采食量对植物物种丰富度响应更敏感，以用植物物种丰富度为自变量可以更好预测藏系牧羊放牧行为。放牧管理通过影响植被物种多样性从而进一步影响了藏系牧羊放牧行为。放牧行为不仅是评价草地营养价值和家畜生产力的关键指标，也是草地健康管理的基础。因此，明确草原植物物种多样性-藏系牧羊放牧行为的互作机制有助于更好的提高藏系牧羊地生产力，维护草原生态健康。

Effects of species diversity on grazing behavior of Tibetan sheep in an alpine meadow

To investigate the effects and mechanisms of plant species diversity on grazing behavior of livestock in grassland, a Tibetan sheep rotational grazing experiment was conducted in an alpine meadow of the Tibetan Plateau. The study mainly included plant species diversity, feeding speed, foraging speed and feeding time of Tibetan sheep, and then calculated the average daily feed intake of Tibetan sheep. The results showed that species richness was significantly and positively correlated with the feeding speed of Tibetan sheep (P<0.05); foraging rate, foraging time and the average daily feed intake were sensitive to stocking rate (P<0.05), which increased in summer and autumn but decreased in winter and spring. Shannon Wiener index had a significantly negative correlation with the feeding time of Tibetan sheep (P<0.05). There was a significantly positive correlation between Shannon Wiener index and daily feed intake of Tibetan sheep in warm season or 8 sheep/hm² (P<0.05). Pilelou index was significantly negatively correlated with the feeding speed time of Tibetan sheep (P<0.05); and Pilelou index was significantly negatively correlated with the daily feed intake of Tibetan sheep in warm season or 8 sheep/hm² (P<0.05). Species richness contributed more to the grazing behavior of Tibetan sheep, and stocking rate and time of grazing Tibetan sheep were more sensitive to species diversity. Hence, species diversity was a good predictor of grazing behavior of Tibetan sheep. Grazing management influenced the grazing behavior of Tibetan sheep by affecting the plant species diversity. Grazing behavior is not only a key indicator for evaluating the nutritional value and livestock productivity of grasslands, but also a basis for grassland health management. Therefore, clarifying the interactions between species diversity and grazing behavior of Tibetan sheep can help to better improve the productivity of Tibetan sheep and maintain ecological health of grassland.