Impact of overwintering cormorants (Phalacrocorax carbo) on springtail (Hexapoda: Collembola) communities of the Azov and Black Sea coastal forests

Abstract

Nesting water bird colonies may act as important drivers of aquatic-terrestrial nutrient turnover in coastal ecosystems. Bydepositing a large amount of guano, they induce changes in the structure of soils, flora, and fauna. However, little is known abouthow nesting water bird colonies influence soil fauna, especially in a Mediterranean type of coastal landscape. In this study, focus wasplaced on how time had elapsed since the last overwintering activity of cormorant colonies, as a factor that affects the structure ofspringtail communities and edaphic parameters in the Black and Azov Sea coastal forest ecosystems. Black Sea coastal forests withactive overwintering cormorant colonies have been characterized by a decreased total abundance, genus richness, and an abundanceof certain functional groups of springtails. In contrast, in the coastal forests of the Azov Sea, where the last cormorant overwinteringactivity was observed 8 years ago, the total abundance of collembolans, and particularly epiedaphic species, had increased in comparisonwith the control sites. It was concluded that the overwintering activity of cormorants had a negative effect on springtails in previouslyundisturbed areas within the Mediterranean coastal forests. Nevertheless, the long-term absence of cormorant colonies may lead to therecovery of collembolan total abundance and genus richness in the previously affected areas.