呼中林区森林景观的历史变域模拟及评价

Abstract

在大兴安岭地区呼中区,将物种的年龄和分布信息进行随机化处理后,应用空间直观景观模型LANDIS对森林景观进行长时间(2500a)模拟,取物种演替稳定时间段作为模拟历史变域的数据来源。分别在景观水平和年龄类型水平上利用景观指数空间分析、主成分分析和核密度估计方法分析景观格局历史变域的模拟结果,并在二维空间坐标内,将研究区1990年、2000年森林景观特征与之比较。结果表明,各树种面积比例在模拟900a后都达到稳定状态,可作为无干扰条件下森林景观特征的历史变域;由于长期采伐,研究区1990年景观的斑块面积和破碎化程度都偏离了该历史变域,其中,过熟林偏离最明显,其斑块面积远小于历史变域,破碎化程度非常严重;虽然1990年后的采伐管理方案比之前的更为合理,但2000年的森林景观仍旧继续偏离历史变域。;After randomizing the input information of age and distribution of forest species we simulated the long-term (2500 years) dynamic of forest landscape pattern of huzhong area in Great Xing'an Mountains using spatially explicit landscape model (LANDIS), Then we took the period when simulation results reached stable as the time range to estimate the historical range of variability (HRV). Furthermore, we analyzed the relationship between HRV and the forest landscape pattern of 1990 and 2000 using principal component analysis and kernel density estimation methods. The simulation results showed that the succession of almost all forest species arrived to their stable status at around 900th year of the simulation, and the period afterwards was utilized to estimate the HRV; as to the characteristics of forest, landscape pattern in 1990 fell out of the HRV in area of patches and the degree of landscape fragmentation, especially mature and over-mature forest deviated significantly from HRV in patch area and fragmentation; though forest harvest management was better planned after 1990, the forest landscape pattern in 2000 still deviated from the HRV.