外来入侵植物风传扩散过程模拟模型选择

Selection of simulation models for seed dispersal of invasive plants by wind

种子扩散是外来入侵植物异地入侵的重要手段,对入侵种群扩散机制的清晰认识是有效进行入侵防治和生态管理的基础。本文在研究入侵植物风传扩散过程中的主要影响参数的基础上,分析了各参数对不同扩散过程造成的影响,总结出不同的扩散模拟过程中需要应用的影响参数,阐述了这些参数的参数化过程及相应的计算方法。对已有风传扩散模拟模型做了重点介绍,并结合入侵植物自身特征重点解析了其风传扩散过程模拟模型的选择依据。其中,对于风传扩散过程有直接、明显的影响参数是种子释放高度和水平风速。对于入侵草本、灌木植物而言,入侵区域植被高度是必须关注的影响参数。在长距离扩散研究中,以乔木和大灌木为研究对象时需要重点考虑植被叶片与水平风速垂直分布引起的冠层及冠层以上区域大气湍流所带来的影响;小灌木与草本植物则需注意由地表温度引起的温暖气团上升带来的影响。模拟模型中,2Dt模型和混合韦布尔模型可以有效描述扩散体扩散核近端与远端的扩散曲线。对更为详细的长距离扩散模拟模型选择时,需要考虑不同的大气湍流类型、扩散体大小、植被类型、扩散核维度以及模拟精度要求。

Seed dispersal is an important pathway for the invasion of alien invasive plants. A clear understanding of dispersal mechanism is the basis for more effective prevention and ecological management of invasive species. Based on the analysis of the main parameters influencing the dispersal process by wind,we examined the effects of those parameters on different diffusion processes,summed up the influencing parameters which should be chosen in the simulation process of different diffusion,and explained the calculation of these parameters. Specially,we introduced the excellent simulation models of dispersal by wind and analyzed the selection basis of simulation models of dispersal in combination with the characteristics of invasive plants. Among all the influencing parameters,the height of seed release and the horizontal wind velocity have direct and obvious effects on the dispersal process by wind. For invasive herbs and shrubs,the height of plants in the invasive area is an important parameter that must be concerned. In the study of long distance dispersal,the effects of turbulence caused by leaf and horizontal wind profile within and above the canopy should be considered for trees and large shrubs. For small shrubs and herbaceous plants,the impacts of rising warm air mass caused by surface temperature should be concerned. Among the simulation models,the 2 Dt model and the mixed Weibull model can more effectively describe the dispersal curves of the proximal and distal diffusers of the dispersal kernel. For more detailed selection of long-distance dispersal simulation models,it is necessary to consider different atmospheric turbulence types,disperser size,vegetation type,dispersal kernel dimension,and simulation accuracy requirements.