摘要 : Interactions between resources and abiotic conditions control local diversity and productivity, often in a complex fashion. In this study, I estimated the relative causal effects of several environmental variables known to influen... 展开 Interactions between resources and abiotic conditions control local diversity and productivity, often in a complex fashion. In this study, I estimated the relative causal effects of several environmental variables known to influence diversity and productivity in plant communities. Two sites differing in disturbance intensity (i.e. wrack deposition) were studied along a saltwater lagoon, at Iles de la Madeleine, Quebec, Canada. A larger proportion of the variance in species density (82%) and plant cover (81%) was explained by the environmental factors at the most disturbed site, while only 35% of the variance in species density and 47% of the variance in plant cover were explained at the other, less disturbed site. At the most disturbed site, environmental factors associated with distance from the shoreline (e.g. salinity, anoxia, granulometry) indirectly controlled species density through their effects on plant cover, while at the less disturbed site, environmental factors influenced both plant cover and species density. At low disturbance intensity, the species pool may be more significant than productivity per se in restricting local diversity; however, at higher intensity of disturbance, productivity (directly influenced by resources and abiotic conditions) may be more important in controlling diversity. 收起