Wen Yi-Yao, Zhu Jiang, Wang Huan, Zhang Meng-di, Lu Shun-Bao, Zheng Shu-Xia
1 College of Life Sciences, Jiangxi Normal University, Nanchang 330022, China.
2 State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Ying Yong Sheng Tai Xue Bao. 2024 Jun;35(6):1525-1533. doi: 10.13287/j.1001-9332.202406.001.
We studied the population characteristics of and related soil factors across diffe-rent stages of shrub encroachment (., light, moderate, and severe) on the Xilingol Grassland of Inner Mongolia. The results showed that the density and height of gradually increased during the process of grassland shrub-encroachment from light to moderate to severe. The density and height were increased by 196.0% and 34.5% from light to moderate stage of shrub encroachment, and were increased by 25.4% and 17.6% from moderate to severe stage. Crown size, basal diameter, tiller number per clump, and aboveground productivity of tented to decrease first and then increase, while the proportion of aboveground biomass allocation to leaves decreased across the stages of shrub encroachment. The competition between herbaceous species was strongest in the moderate encroachment stage. reduced its lateral growth (such as crown size, basal diameter, and tiller number per clump) and increased density and height to get competitive advantage. Limi-ting soil factors for varied significantly at different stages of shrub encroachment. In the light encroachment stage, soil factors had little effect on the growth of . In the moderate encroachment stage, soil moisture in the deep layer (20-50 cm) and soil pH were the key factors limiting shrub density. In the severe encroachment stage, soil moisture in the deep layer and pH limited the vertical growth of , while soil moisture of shallow layer (0-20 cm) and nutrients were the limiting factors for the lateral expansion of shrubs.
我们研究了内蒙古锡林郭勒草原不同灌木入侵阶段（即轻度、中度和重度）的[具体植物名称未给出]种群特征及相关土壤因子。结果表明，在草原从轻度到中度再到重度的灌木入侵过程中，[具体植物名称未给出]的密度和高度逐渐增加。从轻度到中度灌木入侵阶段，密度和高度分别增加了196.0%和34.5%，从中度到重度阶段分别增加了25.4%和17.6%。[具体植物名称未给出]的冠幅、基径、每丛分蘖数和地上生产力先趋于下降后上升，而地上生物量分配到叶片的比例在灌木入侵各阶段均下降。草本物种间的竞争在中度入侵阶段最强。[具体植物名称未给出]通过减少其横向生长（如冠幅、基径和每丛分蘖数）并增加密度和高度来获取竞争优势。在灌木入侵的不同阶段，限制[具体植物名称未给出]生长的土壤因子差异显著。在轻度入侵阶段，土壤因子对[具体植物名称未给出]的生长影响较小。在中度入侵阶段，深层土壤水分（20 - 50厘米）和土壤pH是限制灌木密度的关键因子。在重度入侵阶段，深层土壤水分和pH限制了[具体植物名称未给出]的垂直生长，而浅层土壤水分（0 - 20厘米）和养分是灌木横向扩展的限制因子。
