Colonies of piscivorous birds nesting in forests bring in loads of allochthonous material in amounts significantly exceeding atmospheric depositions, eventually causing major ecosystem changes. We studied the effect of increasing ornithogenic impact on ectomycorrhizal (EMF) and other root-associated fungi in a Scots pine forest affected by a colony of great cormorants. We evaluated quantitative data of ectomycorrhiza (numbers of root tips and morphotypes) and identified fungal species from pine root tips and from sporocarps collected in three designated study zones: D (zone of active nesting), E (colony margin), and G (pristine forest). Species-bearing sporocarps were absent in zone D, and their number steadily decreased in zone E and was significantly lower than in zone G. Species communities and occurrence frequencies of individual species differed significantly between the zones. Environmental factors, both directly (nutrient addition) and indirectly (changes in vegetation cover), associated with bird activity have significantly influenced fungal communities. We hypothesize that the first signs of increased avian impact on root-associated fungi are the reduced diversity of sporocarps and the low presence and diversity of boletoid fungi in root tips.

在森林中筑巢的食鱼鸟类带来了大量的外来物质，其数量远远超过大气沉积物，最终导致重大的生态系统变化。我们研究了在受大鸬鹚影响的苏格兰松林中，增加鸟类对外生菌根 (EMF) 和其他根相关真菌的影响。我们评估了外生菌根的定量数据（根尖的数量和形态类型），并从松树根尖和从三个指定研究区收集的孢子果中鉴定出真菌物种：D（活跃筑巢区）、E（菌落边缘）和 G（原始森林）。D区不存在带种孢子果，E区其数量稳步减少，明显低于G区。物种群落和单个物种的出现频率在区域之间存在显着差异。与鸟类活动相关的直接（营养添加）和间接（植被覆盖变化）环境因素对真菌群落产生了显着影响。我们假设鸟类对根相关真菌影响增加的第一个迹象是孢子果的多样性降低以及根尖中牛肝菌真菌的低存在和多样性。