ABSTRACT: Great cormorant Phalacrocorax carbo sinensis populations in the Baltic Sea have rapidly expanded since the 1990s, raising concerns about their ecosystem impacts. Nutrient runoff from colonies, as well as cormorant predation on fish, can affect surrounding producer communities. Past studies have found cormorant impacts on producers in the immediate vicinity of colonies, but the importance of cormorants over a larger spatial scale is unknown, especially compared to other environmental variables. We used an extensive underwater vegetation inventory dataset (~18000 data points along the Finnish coast) to determine the effects of cormorant colonies on macroalgae and plants. We compared community structure and species abundance/occurrence in near-colony (<5 km from a colony) and control (>10 km from a colony) points, and determined the importance of cormorant influence (using an index incorporating colony size and distance from the colony) in near-colony sites. We found no significant differences in community structure between near-colony and control points in most habitats, and adding the cormorant index only infinitesimally improved statistical models after incorporating other environmental factors. However, the abundance of several species did differ; in particular, the foundation species bladderwrack Fucus vesiculosus and eelgrass Zostera marina were either less likely to occur in near-colony points or were negatively correlated with cormorant index, possibly due to the effects of nutrient enrichment from colonies. Our findings confirm that cormorants can have effects on some producer species, but highlight that these effects are negligible when taking into account the scale and magnitude of other bottom-up and top-down processes occurring in the Baltic Sea.

中文翻译：

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bent对底栖植被群落的海景规模影响可忽略不计

摘要：大Great中华car自1990年代以来，波罗的海的人口迅速增长，引发了对其生态系统影响的担忧。殖民地的营养径流以及鱼类cor的捕食会影响周围的生产者社区。过去的研究已经发现cor对殖民地附近生产者的影响，但是but在更大的空间范围内的重要性尚不明确，尤其是与其他环境变量相比。我们使用了广泛的水下植被清单数据集（沿芬兰海岸约有18000个数据点）来确定of殖民地对大型藻类和植物的影响。我们比较了近殖民地（距殖民地<5 km）和对照（距殖民地> 10 km）点的群落结构和物种丰度/发生率，并确定了在近殖民地地点cor影响力的重要性（使用结合了殖民地大小和与殖民地的距离的指数）。我们发现在大多数生境中，近殖民地和控制点之间的群落结构没有显着差异，并且在结合其他环境因素后，仅将cor指数添加到能够无限改进的统计模型中。但是，几种物种的丰度确实有所不同。特别是基础物种 几种物种的丰度确实有所不同；特别是基础物种 几种物种的丰度确实有所不同；特别是基础物种墨角榕和鳗Z带状疱疹不太可能在近菌落处发生，或者与negative指数呈负相关，这可能是由于菌落营养富集的影响。我们的发现证实that可以对某些生产者产生影响，但强调指出，考虑到波罗的海其他自下而上和自上而下过程的规模和大小，这些影响可以忽略不计。