National Hulunbuir Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
National Hulunbuir Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
Sci Total Environ. 2023 Sep 1;889:164191. doi: 10.1016/j.scitotenv.2023.164191. Epub 2023 May 17.
Livestock-grassland interactions are among the most important relationships in grazed grassland ecosystems, where herbivores play a crucial role in plant community and ecosystem functions. However, previous studies primarily have focused on the responses of grasslands to grazing, with few focussing on the effects of livestock behaviour that in turn would influence livestock intake and primary and secondary productivity. Through a 2-year grazing intensity experiment with cattle in Eurasian steppe ecosystem, global positioning system (GPS) collars were used to monitor animal movements, where animal locations were recorded at 10-min intervals during the growing season. We used a random forest model and the K-means method to classify animal behaviour and quantified the spatiotemporal movements of the animals. Grazing intensity appeared to be the predominant driver for cattle behaviour. Foraging time, distance travelled, and utilization area ratio (UAR) all increased with grazing intensity. The distance travelled was positively correlated with foraging time, yielding a decreased daily liveweight gain (LWG) except at light grazing. Cattle UAR showed a seasonal pattern and reached the maximum value in August. In addition, the canopy height, above-ground biomass, carbon content, crude protein, and energy content of plants all affected cattle behaviour. Grazing intensity and the resulting change in above-ground biomass and forage quality jointly determined the spatiotemporal characteristics of livestock behaviour. Increased grazing intensity limited forage resources and promoted intraspecific competition of livestock, which induced longer travelling distance and foraging time, and more even spatial distribution when seeking habitat, which ultimately led to a reduction in LWG. In contrast, under light grazing where there were sufficient forage resources, livestock exhibited higher LWG with less foraging time, shorter travelling distance, and more specialized habitat occupation. These findings support the Optimal Foraging Theory and the Ideal Free Distribution model, which may have important implications for grassland ecosystem management and sustainability.
家畜-草地相互作用是放牧草地生态系统中最重要的关系之一，其中食草动物在植物群落和生态系统功能中起着至关重要的作用。然而，以前的研究主要集中在草地对放牧的响应上，很少关注家畜行为的影响，而家畜行为反过来又会影响家畜的摄食量以及初级和次级生产力。通过在欧亚草原生态系统中进行为期两年的放牧强度实验，使用全球定位系统 (GPS) 项圈来监测动物的运动，在生长季节期间，以 10 分钟的间隔记录动物的位置。我们使用随机森林模型和 K-均值方法对动物行为进行分类，并量化了动物的时空运动。放牧强度似乎是家畜行为的主要驱动因素。觅食时间、行进距离和利用率区域比 (UAR) 都随着放牧强度的增加而增加。行进距离与觅食时间呈正相关，除了轻度放牧外，每日活体重增加 (LWG) 都会减少。牛 UAR 呈现季节性模式，在 8 月达到最大值。此外，冠层高度、地上生物量、碳含量、粗蛋白和能量含量都会影响牛的行为。放牧强度以及由此引起的地上生物量和饲料质量的变化共同决定了家畜行为的时空特征。增加的放牧强度限制了饲料资源，促进了家畜种内竞争，导致在寻找栖息地时行进距离和觅食时间延长，空间分布更加均匀，从而导致 LWG 减少。相比之下，在有足够饲料资源的轻度放牧下，家畜表现出更高的 LWG，觅食时间更短，行进距离更短，对栖息地的占用更具专业性。这些发现支持最优觅食理论和理想自由分布模型，这可能对草地生态系统管理和可持续性具有重要意义。
