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. By depositing a large amount of guano, they induce changes in the structure of soils, flora, and fauna. However, little is known about how nesting water bird colonies influence soil fauna, especially in a Mediterranean type of coastal landscape. In this study, focus was placed on how time had elapsed since the last overwintering activity of cormorant colonies, as a factor that affects the structure of springtail communities and edaphic parameters in the Black and Azov Sea coastal forest ecosystems. Black Sea coastal forests with active overwintering cormorant colonies have been characterized by a decreased total abundance, genus richness, and an abundance of certain functional groups of springtails. In contrast, in the coastal forests of the Azov Sea, where the last cormorant overwintering activity was observed 8 years ago, the total abundance of collembolans, and particularly epiedaphic species, had increased in comparison with the control sites. It was concluded that the overwintering activity of cormorants had a negative effect on springtails in previously undisturbed areas within the Mediterranean coastal forests. Nevertheless, the long-term absence of cormorant colonies may lead to the recovery of collembolan total abundance and genus richness in the previously affected areas.