为了确定采煤沉陷区植物群落自然恢复的时间和恢复后的格局.开发了基于自然恢复的植物群落演替模拟系统,以山西大同煤峪口矿内的一处采煤沉陷区为例.模拟了植物群落自然恢复至实际植被覆盖度的演替过程,分析了自然恢复过程中植物群落的时间变化和空间分布特征.讨论了导致植物群落空间差异的关键因素.结果表明.基于归一化均方误差(ENMS)并分别从不同景观尺度(10 m×10 m.20 m×20 m,50 m×50 m,80 m×80 m,100 m×100 m)下进行的精度评价.模拟结果的植物群落格局与实际情况间误差在0.04-0.59.其中灌木植被格局误差在0.06-0.59.草本植被格局误差在0.05-0.14.整体植被格局误差在0.04-0.12.以裸地为初始条件的50次模拟结果表明.研究区通过自然恢复使草本覆盖度达到35%与55%之间且灌木覆盖度达到7%与8%水平时.平均需要10.46 a.从时间变化上看.演替前期草本植物群落恢复迅速.但随着灌木植被的增加草本覆盖度随即下降并逐渐转变为灌木植物群落,灌木群落在自然恢复3-5 a后开始出现.并随着土壤养分的累积.灌木群落的恢复速度也随之加快,而乔木植被在50次模拟中仅有2次在自然恢复10 a后出现.从空间分布上看.高程较低的沟壑区域由于地表径流成为养分和水分富集区.总是率先演替出灌木群落并向周边发展.而坡度较小的阴坡同样容易演替出灌木群落.总体来看.构建的演替模拟系统能够较好的反映植物群落自然恢复过程中实际的时空动态变化.模拟自然恢复后的植物群落格局.可以为采煤沉陷区自然恢复策略的选择提供决策工具.

simulation system for the succession of plant communities based on natural revegetation was developed to determine the duration and plant pattern of natural revegetation in mining subsidence area.The succession of plant communities in a subsidence area located in Meiyukou Mine,Datong City was simulated,and the spatial and temporal characteristics of plant succession,and key factors resulting in spatial heterogeneity of plant communities were analyzed.The results showed that the errors between simulated and actual plant patterns ranged from 0.04 to 0.59 according to normalized mean squared error (NMSE) in different landscape levels (10 m×10 m.20 m×20 m,50 m×50 m,80 m×80 m,100 m×100 m).Specifically the errors were between 0.06 and 0.59 in terms of shrub coverage,between 0.05-0.14 in terms of shrub coverage,and between 0.04 and 0.12 in terms of vegetation coverage.The results of 50 simulations with bare land as the initial vegetation condition showed it would take 10.46 years on average when the herb coverage reached between 35% and 55% and the shrub coverage reached 7% and 8% in the study area through natural revegetation.In terms of the dynamic of natural revegetation,the herb communities revegetated rapidly in the early stage of succession,while decreased and transformed into shrub communities with the developing shrub coverage.The shrub communities appeared firstly after 3-5 years of spontaneous succession,and the revegetating rate of shrub communities increased with the accumulation of soil nutrients.Only 2 out of 50 simulations of trees appeared after 10 years of natural revegetation.In terms of the distribution of vegetation pattern,the low-elevation gully area was rich in nutrients and water due to surface runoff,where shrub communities appeared firstly and spread.The shady area with a small slope was also easy to develop into a shrub community.In general,the developed simulation system in this study is able to accurately reflect the spatiotemporal dynamic of plant succession during natural revegetation,and simulate the pattern of plant communities after natural revegetation,which can serve as a tool for the selection of natural revegetation in coal mining subsidence areas.

1 研究区概况

2 植物群落演替模拟系统设计

   2.1 模拟系统总体框架

   2.2 模拟系统元胞单元设计

   2.3 模拟系统元胞邻居选择

   2.4 模拟系统元胞状态参数选取

   2.5 模拟系统元胞规则设计

   2.6 模拟区域环境条件设置

   2.7 模拟结果精度评价方法

3 结果与讨论

   3.1 模拟结果与系统精度

   3.2 植物群落演替的时间变化模拟结果

   3.3 植物群落演替的空间分布模拟结果

4 结论