Abstract Wetlands dominated by shrubs are ubiquitous features in the Great Lakes Region of North America, yet little is known about the interactions between plants and the environmental conditions of these ecosystems. We measured the response of seven common wetland shrub species and two forbs to soil moisture treatments over a growing season. Average soil moisture content across three treatments ranged from 75%. These soil moisture differences produced a measurable effect on plant growth for six of the nine species tested. While Rosa palustris and Spiraea alba preferred the highest soil moisture treatments, Salix interior, Sambucus nigra, and Solidago uliginosa had higher biomass from moderate soil moisture, with no effect observed for Cornus sericea, Salix discolor, and Viburnum lentago. Most of the growth differences were from aboveground portions of the plants. A significant difference in root-to-shoot ratio (R:S) was found for eight of the species, with contrasting directions of change between the soil moisture treatments. New growth was compared to mean stomatal conductivity to determine an estimated water use efficiency (WUEe), which demonstrated a montonal relationship for six of the species across the measured soil moisture regime. Only the upland goldenrod, Solidago altissima, demonstrated the expected increase in WUEe with decreasing soil moisture, which suggests wetland shrubs are inefficient at low soil moisture. The results of this study provide quantitative data on the range of responses to soil moisture of common species of shrub wetlands, which can be used by wetland managers to improve restoration success.

中文翻译：

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灌丛沼泽物种对土壤湿度水平的响应：对恢复的影响

摘要 以灌木为主的湿地是北美五大湖区普遍存在的特征，但对植物与这些生态系统环境条件之间的相互作用知之甚少。我们测量了七种常见湿地灌木物种和两种杂草在生长季节对土壤水分处理的反应。三个处理的平均土壤水分含量为 75%。这些土壤水分差异对测试的九个物种中的六个物种的植物生长产生了可测量的影响。虽然 Rosa palustris 和 Spiraea alba 更喜欢最高土壤湿度处理，但 Salix internal、Sambucus nigra 和 Solidago uliginosa 具有较高的来自中等土壤湿度的生物量，对 Cornus sericea、Salix discolor 和 Viburnum lentago 没有观察到影响。大多数生长差异来自植物的地上部分。发现八个物种的根茎比（R：S）存在显着差异，土壤水分处理之间的变化方向相反。将新的生长与平均气孔传导率进行比较，以确定估计的用水效率 (WUEe)，这表明在测量的土壤水分状况中，六个物种之间存在单调关系。只有高地一枝黄花表明 WUEe 随土壤湿度降低而预期增加，这表明湿地灌木在低土壤湿度下效率低下。本研究的结果提供了有关灌木湿地常见物种对土壤水分响应范围的定量数据，湿地管理者可以利用这些数据来提高恢复成功率。