From salmon to salmonberry: the effects of salmon-derived nutrients on the stomatal density of leaves of the nitriphillic shrub Rubus spectabilis

Background and Aims: Nutrients derived from the carcasses of Pacific salmon have been shown to have wide-ranging effects on riparian systems. These include changes in community species composition and an increase in leaf nitrogen concentration, with the latter effect pronounced in the nitriphilic shrub Rubus spectabilis (salmonberry). Experimental work with other species has shown that leaf stomatal density increases in response to nitrogen fertilization. Therefore, we predicted that the stomatal density of salmonberry leaves would vary directly with the density of spawning salmon in salmonberry leaves collected from 16 streams in the vicinity of Bella Bella, on British Columbia’s central coast. We estimated the stomatal density along each stream, and quantified stream characteristics, including the number of spawning salmon (Oncorhynchus spp.), canopy cover, stem density and soil moisture.
Key results: We found that salmon have both direct and indirect effects on stomatal density, ...

研究背景与目的：太平洋鲑鱼尸体所携带的营养物质已被证实会对河岸生态系统产生广泛影响，具体包括群落物种组成改变与叶片氮浓度提升，其中后者在嗜氮灌木大花悬钩子（Rubus spectabilis，俗称三文鱼莓salmonberry）上表现尤为显著。针对其他物种的实验研究表明，叶片气孔密度会随氮肥施用而升高。据此，我们提出预测：在不列颠哥伦比亚省中部海岸贝拉贝拉附近16条溪流采集的三文鱼莓叶片，其气孔密度将与对应溪流内产卵鲑鱼的种群密度呈正相关。为此，我们对每条溪流周边的叶片气孔密度进行了测定，并量化了多项溪流相关特征，包括产卵鲑鱼（Oncorhynchus spp.）的种群数量、林冠覆盖率、茎秆密度以及土壤含水量。
主要研究结果：本研究发现，鲑鱼对气孔密度兼具直接与间接影响，……