论文部分内容阅读
垂序商陆(Phytolacca americana)的入侵给山东省沿海防护林的生物多样性及乔木更新造成了严重的危害,为揭示其繁殖特性和扩散机制,在灵山湾国家森林公园刺槐(Robinia pseudoacacia)林下由林缘至林内60m设置5个梯度,采用机械布点法对垂序商陆的结实量、种子雨分布和扩散格局进行了调查。结果表明:1)垂序商陆的结实量与种子雨量由林缘至林内逐渐减小,分别为2273-1846和1382-621粒·m-2,不同空间种子雨密度占结实密度的60.80%-33.64%,平均为49.52%,人为搂割及动物取食是种子雨量损失的主要原因;2)种子雨始于9月中旬,林缘种子雨的发生早于林内,种子雨的平均强度由林缘至林内逐渐减小,在10月下旬和12月中旬各有一次种子雨高峰,最大强度分别为32-4和59-5粒·m-2·d-1;3)种子雨由林缘至林内散布范围逐渐减小,同时随距母株距离的增加而减小,其中最大散布距离与加权平均距离分别为210-180cm和94.32-63.03cm,整体加权平均距离为81.00cm。表明垂序商陆种子雨具有明显的时空异质性,对预测其扩散潜力及群落结构组成趋势有重要的意义。
Invasion of Phytolacca americana caused serious damage to the biodiversity and tree renewal of the coastal shelterbelts in Shandong Province. To reveal its reproductive characteristics and spreading mechanism, Robinia pseudoacacia forest Five gradients were set at 60m from the forest margin to the forest, and the investigation was conducted on the seed setting, seed rain distribution and spreading pattern of Pseudostellaria tabulaeformis by using mechanical distribution method. The results showed that: 1) The density and seed rainfall of P. falciparum decreased gradually from forest margin to forest, which were 2273-1846 and 1382-621 grains · m-2, respectively. The seed density in different space seeds accounted for 60.80% -33.64%, with an average of 49.52%. Artificial cuddling and animal feeding were the main causes of seed rainfall loss. 2) Seed rain began in mid-September. The seed rain occurred earlier than in the forest. The average intensity of seed rain was Forest edge to forest gradually reduced, in late October and mid-December each have a seed rain peak, the maximum intensity of 32-4 and 59-5 grain · m-2 · d-1; 3) Seed rain by the forest The range of dispersal decreased from the edge to the forest and decreased with the increase of the distance from the mother plant. The maximum distribution distance and weighted average distance were 210-180cm and 94.32-63.03cm respectively, and the overall average weighted distance was 81.00cm. The results showed that there was obvious temporal and spatial heterogeneity in the seed rain of Phyllostachys praecrina, which was of great significance in predicting its diffusion potential and the trend of community structure.