不同资源条件下刈割对植物再生能力的影响

Impact of mowing on plant regrowth under different resource conditions

以甘南地区高寒草甸中10种常见植物为对象,通过田间模拟试验,对不同生长期内的植物个体进行不同程度的刈割、施肥处理,以探讨不同资源条件下刈割对植物再生能力的影响。结果表明:多数情况下,适口性较好的植物的补偿能力较高,适口性较差的补偿能力较低。垂穗披碱草、燕麦、多枝黄芪、矮嵩草在高资源条件下的生物量补偿程度低于低资源条件,金花苜蓿、珠芽蓼、中华羊茅、獐牙菜、细叶亚菊及藏蒲公英则相反;中华羊茅、细叶亚菊、珠芽蓼在高资源条件下繁殖部分的补偿程度较高,其余7种则相反。不同资源条件下10种植物在总生物量、现存生物量方面的补偿能力排序一致,说明综合补偿指数能较好地反映刈割后植物在总生物量、现存量方面补偿能力的种间差异。本研究结果说明不同资源条件下,生存对策是影响植物再生能力的主要因素,且综合补偿指数可以更客观地反映植物的再生特点。

10 common species of subalpine meadow communities in Gannan Province were selected as experimental materials to analyze the impact of grazing on plants at different growth stages under different field resource conditions of fertilization through simulated mowing experiment. The results show positive correlation between plant palatability and compensation ability. Elymus nutans, Avena sativa, Astragalus polycladus and Kobresia humilis exhibit a relatively lower hiomass compensation capacity in high resource conditions than in low resource conditions. Medicago rythenica, Polygonum viviparvum, Festuca sinensis, Swertis bimaculata, Taraxacum tibetanum and Ajania tenuifolia exhibit the reverse response. E sinensi, A. tenuifolia and P viviparvum exhibit a relatively high reproductive compensation ability under high resource conditions while the reverse is true for the other seven plant species. The comprehensive compensation index analysis presents the biomass compensation ability order of the 10 plant species under fertilized/non-fertilized conditions is the same as that for biomass standing. This indicates that the comprehensive compensation index adequately reflects plant recovery potential. It then implies that evolutionary strategy is the most dominant factor affecting plant recovery, whereas comprehensive compensation index is a useful tool for predicting the effect of grazing on plant community dynamics.