Soil chemical and biological responses to a sparse, early-stage black-legged kittiwake (Rissa tridactyla) colony in the Arctic mining settlement Pyramiden (Svalbard).

This study aimed to recognize the impact of a black-legged kittiwake (Rissa tridactyla) colony, located in an abandoned mining city in Svalbard, on the physical and chemical properties of nearby soil as well as abundance and diversity of soil invertebrates. Samples for physical, chemical and biological analyses were collected next to the colony,10 and 20 m apart. Deposition of black-legged kittiwakes guano significantly alters the chemistry of soils within the colony area, leading to acidification and elevated concentrations of nutrients as well as potentially toxic elements. These physical and chemical changes are largely confined to soils directly beneath the colony, reflecting the relatively small size and young age of the colony, which result in low overall guano input, as well as the flat terrain limiting horizontal transport of contaminants. Arctic soil invertebrate groups respond differently to the presence of the kittiwake colony, with no uniform response observed across taxa. Guano deposition negatively affected tardigrade density and diversity, likely as a consequence of soil acidification, while collembolan densities tended to be higher near the colony, although these differences were not statistically significant. In contrast, soil mites exhibited pronounced changes in both diversity and abundance in response to kittiwake-driven soil transformation.