渤海湾贝壳堤湿地芦苇种群与蒙古蒿种群空间分布格局和种间关系

Spatial Pattern and Interspecific Relationship of Phragmites australis and Artemisia mongolica Populations in Chenier Wetlands in Bohai Bay

采用扩散系数、丛生指数、聚块指数和聚集强度,研究了渤海湾贝壳堤湿地两种优势植物芦苇(Phragmites australis)和蒙古蒿(Artemisia mongolica)种群的空间分布格局;采用关联系数和χ~2检验方法,分析两者之间的关联性和联接强度,利用Ochiai指数、Dice指数和Jaccard指数,检测种对(芦苇和蒙古蒿)相伴随出现的机率。研究结果表明,在小尺度上,芦苇种群和蒙古蒿种群聚集分布尤为明显;向海侧区域、向陆侧区域采样地芦苇种群聚集分布尺度小于蒙古蒿种群;随着研究尺度的增加,蒙古蒿种群与芦苇种群的关联程度逐渐增加。χ~2检验表明,研究尺度的变化对向海侧区域和向陆侧区域采样地芦苇种群与蒙古蒿种群的种间关联程度的影响不大,在6.25 cm及以下栅格尺度,两者的种间联结系数都为-1,达到显著水平(p<0.05),Ochiai指数、Dice指数和Jaccard指数都为0,说明在此尺度以下蒙古蒿种群和芦苇种群几乎处于完全独立状态;而在滩脊地带,在较小的尺度(2.5 cm)上,芦苇种群和蒙古蒿种群即显著正相关。由此可见,贝壳堤湿地芦苇种群和蒙古蒿种群的空间分布格局和种间关系的尺度转换效应随生境而呈不同趋势,在未来需要加深不同生境下两种植物种间关系机制的研究,从而为因地制宜地制定相应的植物保护和恢复策略提供基础数据。

In this paper, using the diffusion coefficient, clumping index, patch index and gather strength, the spatial pattern of two dominant plants, Phragrnites australis and Artemisia mongolica, in Chenier wetlands in Bohai Bay were studied, χ2-test and interspeeific association coefficient were used to analysis the relevance and coupling strength between the two populations. The associated presence probability of two populations was studied using Ochiai index, Dice index and Jaccard index. The results showed that Phragmites australis and Artemisia mongolica populations clustered particularly at smaller scale. In addition to the beach ridges, the turning point of spatial patterns of Phragmites ausstralis population was less than that of Artemisia mongolica population. With research scale increasing, the interspecific association coefficient was from negative to posi- tive and the degree of association increased. The result of χ2-test showed that little difference between the sea side and towards landside according to the populations relative correlations and scale. At 6.25 cm scale and be- low, the correlation coefficient between the two species was -1 which was significant （p〈0.05）, while Ochiai index, Dice index and Jaccard index was 0. However, it was a smaller scale （2.5 cm） that significant positive correlation between Phragmites australis and Artemisia mongolica populations could be found in the shell ridge. Thus, population spatial pattern and interspecific relationship between Phragmites australis and Artemis- ia mongolica in chenier wetlands in Bohai Bay in different sites was different. Deepen study in the future on the mechanism of interspecific relationship between the two species, such as resources utilization, space occu- pying, and population regeneration in different habitats as well as the intensity was needed.