Seabirds are powerful environmental modulators, generating major changes in soil properties and vegetation in areas where their breeding colonies are established. One of the largest yellow-legged gull colonies in the world is found in the Atlantic Islands of Galicia National Park. In this study, we performed seasonal monitoring, over a period of 5 years, of the flora and soil in eight subcolonies characterized by different densities of gulls. Soil nutrient concentrations differed significantly between the control site and the subcolonies, as well as between seasons; the concentrations of N-NO₃^- and bioavailable P were highest in samples obtained at the end of the breeding season. Principal Component Analysis (PCA) transformed the environmental variables into three main components following varimax rotation. The PCA components were used as potential predictors in distance-based Redundancy Analyses (db- RDA) to explain turnover and also nestedness patterns in plant assemblages. Species turnover was explained by both natural (salinity) and nutrient gradients, while none of the relationships were significant in the nestedness analysis. Floristics inventories clearly revealed ruderalization of vegetation in the densest subcolonies, which led to total replacement of the most representative vascular plant species by eutrophic and ruderal species. PERMANOVA analysis showed that seagull density in 1991, when the seagull population was at its highest, could be used to group similar plant assemblages; however, this relationship was not observed for seagull density in 2011, which was 70–90% lower than in 1991. The study findings indicate that the environmental effects of seabird colonies are long lasting and that disappearance of the birds does not lead to restoration of the previous vegetation. The gull colony has irreversibly transformed the soil and vegetation of cliffs, generating a new environmental system.

海鸟是有力的环境调节剂，可在其繁殖种群建立的地区改变土壤性质和植被。在加利西亚国家公园的大西洋群岛上发现了世界上最大的黄脚鸥殖民地之一。在这项研究中，我们进行了为期5年的季节性监测，对以不同密度的海鸥为特征的八个亚殖民地的植物区系和土壤进行了监测。对照地点和亚殖民地之间以及季节之间土壤养分浓度存在显着差异。N-NO ₃的浓度^-在繁殖季节结束时获得的样品中，P和生物利用度P最高。主成分分析（PCA）在varimax旋转后将环境变量转换为三个主要成分。PCA组件在基于距离的冗余分析（db-RDA）中用作潜在的预测因子，以解释周转率以及植物组合中的嵌套模式。物种周转率既可以通过自然（盐度）梯度来估算，也可以通过养分梯度来解释，而在巢度分析中这些关系均不显着。植物区系清单清楚地表明，在最密集的亚殖民地中，植被进行了矿化，这导致富营养和野化物种完全替代了最具代表性的维管植物。PERMANOVA分析显示，1991年的海鸥密度 当海鸥数量最高时，可用于对相似的植物组合进行分组；但是，2011年的海鸥密度没有观察到这种关系，这比1991年降低了70–90％。研究结果表明，海鸟殖民地对环境的影响是持久的，而且鸟类的消失不会导致海鸟的恢复。以前的植被。鸥群不可逆转地改变了悬崖的土壤和植被，产生了新的环境系统。研究结果表明，海鸟殖民地对环境的影响是持久的，而海鸟的消失不会导致先前植被的恢复。鸥群不可逆转地改变了悬崖的土壤和植被，产生了新的环境系统。研究结果表明，海鸟殖民地对环境的影响是持久的，而海鸟的消失不会导致先前植被的恢复。鸥群不可逆转地改变了悬崖的土壤和植被，产生了新的环境系统。