Soil conditions under cormorant colonies favor for mites excepting Oribatida

Abstract

Over the last few decades, the population of the great cormorant (Phalacrocorax carbo L., 1758) in Europe has been rising. The formation of large nesting and roosting colonies in relatively small areas, their rapid metabolism and the excretion of significant amounts of guano can have a marked environmental impact. This study aimed to investigate how cormorants affect the biodiversity and density of soil mites under breeding colonies. Soil samples from three cormorant colonies located on lake islands were compared to samples from adjacent areas unaffected by birds. Soil from colonies was characterised by a higher concentration of nitrogen, phosphorus and organic matter as well as the abundance of mites (except Oribatida). The abundance and diversity of adult Oribatida in soil under the colonies were lower than in their control sites.