华北农牧交错带不同放牧强度绵羊食性研究

Study on the Diet Composition of Grazing Sheep in the Agro-pastoral Transition Zone of North China

为探讨华北农牧交错带放牧绵羊的食性与草原退化的关系,本文以河北省张家口市塞北管理区典型草原为研究对象,于2016年7-8月运用饱和链烷技术研究羊草群落不同放牧强度下绵羊食性变化。结果表明:随牧压的增大,群落中羊草(Leymus chinensis)、花苜蓿(Medicago ruthenica)和野韭(Allium ramosum)的数量减少,克氏针茅(Stipa krylovii)、冷蒿(Artemisia frigida)和马蔺(Iris ensata)的比例增加;绵羊采食的牧草种类和比例各存在一定的差异,但绵羊优先采食羊草、野韭和花苜蓿,其次为糙隐子草(Cleistogenes squarrosa)和冷蒿,绵羊不喜食克氏针茅和阿尔泰狗娃花(Heteropappus altaicus),拒食马蔺。因此,重度放牧改变了羊草群落的植被组成,优质牧草减少,群落演替为冷蒿、克氏针茅和杂类草群落,从而导致了草地的退化。

In order to discuss the relationships of grassland degradation and the diet composition of grazing sheep in the agro-pastoral transition zone of North China,changes of diet composition of grazing sheep in the different grazing intensity were studied in June-July 2016 using n-alkane technique.The results showed that the richness of Leymus chinensis,Medicago ruthenica and Allium ramosum decreased significantly with the increase of grazing intensity,while the proportion of Stipa krylovii,Artemisia frigida and Iris ensatain the community increased at the same time.Plant species and their proportion ingested by sheep were different at different grazing intensities.L.chinensis,M.ruthenicaand A.ramosum were preferred feed,and Cleistogenes squarrosa and A.frigid were followed,however,S.krylovii and Heteropappus altaicus were pesky food for sheep,and the I.ensata was anti-feed species.In conclusion,heavy grazing in the agro-pastoral transition zone of North China changed the Leymus chinensis community into the Artemisia frigida,S.krylovii and forbs community,and this succession led to the degradation of grassland.