基于CA模型的上海九段沙互花米草和芦苇种群扩散动态

基于1997年以来上海九段沙栽种芦苇和互花米草种群扩散格局的多年现场调查与遥感解译分析，并结合3S技术，构建了适合滩涂盐沼植物种群动态的元胞自动机（CA）模型．结果表明：该模型能较好地模拟九段沙上芦苇和互花米草种群扩散的格局和趋势，并验证了互花米草和芦苇的空间抢先占有模型以及锋面状连续扩散格局；土著植物芦苇与外来植物互花米草占据相同的生态位，而互花米草的种群扩散速度是芦苇的3—5倍，随着九段沙的不断淤涨，互花米草种群的快速扩展还将持续．构建的CA模型有助于深入研究外来物种扩散格局与其生态学过程之间的相互关系，对湿地生物多样性保护和资源管理具有重要意义．

Population expansion of Spartina alterniflora and Phragmites australis at Jiuduansha,Shanghai based on cellular automata model

Based on the field survey and the interpretation and analysis of satellite images about the population expansion patterns of Spartina alterniflora and Phragmites australis at Jiuduansha shoals in 1997-2004,and combined with 3S techniques,a cellular automata(CA) model was built to simulate the population dynamics of plants adaptable to salt marsh.The results showed that the model could well simulate the population expansion pattern and trend of S.alterniflora and P.australis at Jiuduansha,and strongly supported the hypothesis of space pre-emption and range expansion with simple advancing wave fronts of these two species.The native species P.australis shared the same niche with the exotic species S.alterniflora,but the range expansion rate of S.alterniflora was 2-4 times faster than that of P.australis.With the accretion of the Jiuduansha shoals,a rapid range expansion of S.alterniflora was predicted to last for a long period in the future.The CA model built in this study could gain valuable insights into the relationships between population expansion pattern and its ecological processes of exotic plant species,and was of significance for wetland biodiversity conservation and resources management.