载畜率对内蒙古荒漠草原冷蒿种群资源分配格局的影响

研究植物的资源分配格局以揭示其对环境变化的响应机制有重要的生态学意义。以内蒙古短花针茅(Stipa breviflora)草原冷蒿(Artemisia frigida)种群为研究对象,设置4个载畜率水平的随机区组试验,由冷蒿地上、地下及各构件生物量的变化入手,探讨了载畜率对该种群资源分配格局的影响规律,为退化草地的恢复及合理的放牧管理提供参考。结果表明:(1)冷蒿种群的高度随载畜率的增大而显著降低(P0.05),中度与重度放牧显著降低了该种群的盖度(P0.05),轻度放牧使该种群密度显著增加(P0.05);(2)地上、地下生物量及总生物量均随载畜率的增加而显著降低(P0.05),3a的年际效应及载畜率与年际的互作效应对总生物量、地上和地下生物量的影响差异均显著(P0.05);(3)生物量分配的总体格局是根茎叶花/果,且各构件的生物量均随着载畜率的增加而减少;(4)各构件的生物量分配比例对载畜率的响应不同,中度与重度放牧显著增大了生物量在根的分配(P0.05),茎的生物量分配在轻度放牧显著增加,重度放牧显著降低(P0.05),轻度与中度放牧显著促进了叶的生物量分配(P0.05),花/果的生物量分配随载畜率的增加而显著降低(P0.05);(5)随着载畜率的增大,冷蒿的有性繁殖能力减弱,而无性繁殖能力增强。

Stocking rates affect the resource allocation patterns of Artemisia frigida in the inner mongolian desert steppe

Studying the patterns of plant resource allocation is of crucial ecological significance, as well as investigating how these patterns respond to environmental change. This study intends to provide a reference for grassland degradation and restoration, as well as grassland grazing management. Therefore, we investigated the biomass distribution of Artemisia frigida in the Stipa breviflora desert steppe in Inner Mongolia under different stocking rates. A randomized block experiment that included four different stocking rates was set up in the field. From these treatments, the total biomass, above- and belowground biomass, and biomass from different plant parts were collected and analyzed. Our results indicated that:(1) the height of A. frigida significantly decreased with the increase in stocking rates (P < 0.05), and A. frigida cover significantly decreased by moderate and heavy grazing (P < 0.05), although its density increased remarkably under light grazing (P < 0.05). (2) The above- and belowground biomass and total biomass of A. frigida significantly decreased with increasing stocking rates (P < 0.05), and the influence of 3-year interannual effects, stocking rates, and interannual interactions on total biomass and above- and belowground biomass was significant (P < 0.05). (3) The biomass was differentially distributed in A. frigida segments, with the highest values measured in the roots, and lower values in the stem, leaf, and flowers or fruits, respectively. Furthermore, the biomass per plant part significantly decreased with increasing stocking rates (P < 0.05). (4) The biomass distribution ratio per A. frigida plant part was different under various stocking rates, with root biomass distribution increasing with moderate and heavy grazing (P < 0.05), and biomass accumulation in the stem significantly increasing with light grazing and significantly decreasing heavy grazing (P < 0.05). In addition, light and moderate grazing enhanced leaf biomass accumulation (P < 0.05), whereas and fruit biomass significantly decreased with increasing stocking rates (P < 0.05). (5) Finally, increasing stocking rates reduced the sexual reproduction ability of A. frigida, and promoted its asexual propagation ability.