运用LANDIS Pro 7.0模型，模拟了2000—2200年小兴安岭地区10个阔叶树种地上部分生物量在当前气候条件和不同气候变化情景下的变化状况,并结合各树种的含碳率计算各树种的地上部分固碳速率.结果表明： 在模拟初始年份,水曲柳、黄檗、蒙古栎、春榆、色木槭的生物量低所占比例小,枫桦、白桦、山杨生物量较大所占比例较高.先锋树种白桦和山杨的固碳速率在模拟中后期出现先下降后上升的过程;其他阔叶树种的固碳速率变化规律较复杂,蒙古栎和紫椴的固碳速率在整个模拟阶段分别在-0.05-0.25和0.16-1.29t·hm-2·（10 a）-1范围内波动,水曲柳、春榆、色木槭和枫桦的固碳速率在模拟中后期呈先上升后下降的趋势.在模拟的第2（2050—2100年）和第4阶段（2150—2200年）,黄檗、黑桦在不同气候变化情景间的固碳速率存在显著差异,其他树种的固碳速率在不同气候条件间无显著差异.小兴安岭地区阔叶树种地上部分固碳速率对未来气候的敏感性存在差异.不同气候变化情景的不确定性对大多数森林乔木树种地上部分固碳速率不会造成显著差异,且气候对森林固碳速率的影响存在时滞效应.
Issues of scale and aggregation become important when large range of space and time scales is considered in landscape models.However,identifying appropriate levels of aggregation to accurately represent the processes and components of ecological systems is challenging.A raster-based spatially explicit forest landscape model,LANDIS,was used to study the effects of spatial aggregation on simulated spatial pattern and ecological process in Youhao Forest Bureau of the Small Khingan Mountain in Northeastern China.The model was tested over 500 simulation years with systematically increased levels of spatial aggregation.The results show that spatial aggregation significantly influences the simulation of fire disturbance,species abundance,and spatial pattern.Simulated fire regime was relatively insensitive to grain size between 30.m and 270.m in the region.Spatial aggregation from 300.m to 480.m dramatically decreased fire return interval(FRI) and increased mean fire size.Generally,species abundance and its aggregation index(AI) remained higher level over simulation years at the fine-grained level of spatial aggregation than at coarser grains.In addition,the simulated forest dynamics was more realistic at finer grains.These results suggest that appropriate levels of spatial aggregation for the model should not be larger than 270m.
