Abstract: To clarify the internal mechanisms and community succession of mix-sowed artificial grassland, the spatial patterns of main species in grassland community were measured with 5 indexes, such as dispersion index, clump index, patchiness index, Greens index and the clump intensity index of mixed plant populations in northeast China. The spatial patterns of main species (eight major species) in the mixed grassland community were from uniform distribution in 1-age to clump distribution in 3-age, while the spatial patterns of species in control were from random distribution to clump distribution. There were significant interspecific associations among 8 species of the mix-sowed artificial grassland (P<0.05). The interspecific associations were more negative in 1-age (63.6%) than in 3-age, while the community structure was not stable in 1-age. The interspecific associations were more positive in 3-age (81.8%) than in 1-age, while association coefficient (AC) in 3-age was above 0.60. In the process of community succession, the intensity of distribution pattern changed. Clump distribution promoted population invasion and inhabitation, community formation and vegetation restoration. The yield of the mix-sowed artificial grassland reached 0.46 t·hm^-2.

Key words: Mixed grassland, Community, Spatial pattern, Interspecific association

摘要： 为阐明混播草地群落内部机制及群落演替关系，在东北羊草（Leymus chinensis）退化草地建植人工混播草地，采用5项指标（扩散系数、丛生指数、负二项式K值、聚块指数、聚集强度）对建植后混播草地的植物种群进行研究。结果表明：混播草地8个主要物种的空间分布类型由生长1年时的均匀分布，均变为生长3年时的集群分布状态；非混播种物种的空间分布类型由生长1年时的随机分布状态，均变为生长3年时的集群分布状态；8个主要物种的14个种对中存在显著的种间关联（P<0.05）；生长1年的物种之间，负关联种对数量居多，占63.6%，群落结构组成不稳定，而随着生长年限的推延，种间正关联的种对数量增至81.8%，且联结强度值最高（AC≥0.60）。生长3年后，混播草地主要物种通过种内、种间作用对聚集程度进行了调整。与生长1年和2年的混播草地相比，生长3年的混播草地其物种聚集程度显著增强（P<0.05），正关联的种对增多，关联强度明显增强，混播草地干产量逐年提高，达到0.46 t·hm^-2，维持了草地种间竞争共存的暂稳状态。

关键词: 混播草地, 种群, 空间格局, 种间关联性