重要入侵植物快速扩散的多因素时空耦合互作机制及动态预测

Biological invasions is a dynamics process in nature and this process is determined by multiple factors including the biological characteristics of alien species, geography and ecology of invaded region. The recent progresses on invasion and expansion of invasive alien species, mainly focusing on the prediction of climatic suitable area based on niche modeling and simulation of single dispersal vector, can just provide us the knowledge to judge its qualitative spread tendency and thus cannot meet current requirement to develop effective early warning, prevention and control measures. Comprehensive understanding of the multiple dispersal mechanisms underlying the rapid spread of invasive species, identifying the active dispersal vectors and their coupling interaction in time and space, and quantitatively predicting its potential spread routes, direction or rate, is the latest development trends and challenges to forward current invasion biology. In respect of such challenges, we selected the three invasive plants (Ageratina adenophora,Flaveria bidentis,Solanum rostratum,Amaranthus palmeri) representing the various dispersal modes and occurred in southwest, east and north of China as our target species and planned to adopt inter-discipline methods, including GIS, spatial statistics, tempo-spatial diffusion model and other classical statistical methods, to elucidate the invasion and expansion process of alien species in this study. Firstly, we want to identify the dominant vectors and their tempo-spatial alteration of the 4 target plants and quantitatively evaluate the spatial-temporal interaction between biological, ecological and environmental factors by analyzing the known tempo-spatial diffusion dynamics. Secondly, we plan to carry out field experiment to examine the reproduction characteristics in different environmental conditions to establish demographic model for three target invasive plants, and simulated the dispersal parameters of seeds with the wind, water, animals, vehicles or specific transportation routes to develop the vector dependence dispersal kernel. Finally, we aimed to develop combined mechanistically models, which integrate spatially explicit demographic model of alien species, dispersal kernels of different vectors and coupling interaction in heterogeneous environment of invaded area to realistically predict the potential invasion and spread dynamics at large scales. The realistic prediction might provide theoretical basis and technical support for real-time dynamic monitoring of invasive species.

外来物种的传入与扩散是由其自身的繁殖扩散特性与入侵地的自然和人为等多种因素共同决定的。目前，基于气候适应性的适生区预测与单一扩散媒介的模拟研究只能判断其扩张趋势，不能预测其扩散动态。系统理解入侵物种快速扩散的多因素时空耦合机制，准确预测未来的扩散动态是当前入侵生物学研究的最新发展趋势和挑战。本研究以我国局部分布且具有不同扩散模式的四种入侵植物紫茎泽兰、黄定菊、刺萼龙葵、长芒苋为对象，拟采用GIS、扩散生态学、空间统计学、时空扩散模型等方法；首先，通过对已知分布格局的时空扩散动态分析判定主导物种扩散的关键媒介，定量评估媒介间的时空交互作用机制，其次，通过物种在不同环境条件下繁殖、扩散特性模拟实验，建立种群增长及其随不同媒介扩散的扩散核模型；最终，构建基于种群增长、繁殖体扩散的多重媒介及其时空耦合机制的机理模型，定量预测未来扩散的方向与速度，为实现入侵物种实时动态监测提供理论基础和技术支撑。

外来物种入侵后其势必会进一步的扩散蔓延并造成危害。理论上这种扩散蔓延的过程存在时空异质性。明确入侵物种蔓延的这种时空发展特性对制定早期监测预警具有重要意义。已开展适生区预测等研究不能揭示外来物种入侵后的扩散的动态过程及其异质性。外来物种入侵后其如何扩散蔓延、哪些因素是其扩散驱动力、如何预测是其潜在的扩散动态是本项目的主要目标。基于此，本项目以紫茎泽兰等近100年来入侵我国的17种入侵植物为研究对象，首先，在前期数据积累的基础上，通过系统的监测调获取了它们在我国完整入侵记录与、构建了以县级行政区为基本空间单位的时空分布数据库、重建了它们在我国时空扩散动态；首次提出并采用最小扩散速度法（Minimal Arrival Speed, MAS）定量分析了它们我国的时空扩散动态及分布格局的时空异质性、明确了它们在传入中国后的扩散蔓延的主要路线（河流、公路等路域廊道）；其次，基于17种入侵植物繁殖体扩散综合症构建了它们随不同媒介（风力、水流、车辆等）扩散的参数矩阵，并利用扩散核模型拟合了理论扩散最大值与时空动态，并通过与实际扩散动态的耦合对比分析判定了入侵植物在我国长距离扩散的主导媒介-人类活动；最后，把上述拟合的紫茎泽兰、黄顶菊、刺萼龙葵的最优模型投影到当前和未来气候变化下未入侵的潜在适生区预测了它们在我国未来的时空扩散趋势图。研究结果不仅为划定入侵物种重点监测区和扩散阻截带、构建早期监测预警网络、实现实时动态监测提供了技术支撑、同时也为创新和拓展入侵物种时空扩散动态研究方法提供了理论基础。.项目已资助发表论文10篇，其中SCI论文3篇，分别发表在植物学、生态学、地学等学科的Top期刊Journal of Ecology, Environmental Science and Technology，Water Resources Research。项目参加人在国际会议报告1次，国内会议专题报告1次。