Tardigrada in Svalbard lichens: diversity, densities and habitat heterogeneity

Krzysztof Zawierucha,Michał Węgrzyn,Paulina Wietrzyk,Marta Ostrowska

doi:10.1007/s00300-016-2063-2

Krzysztof Zawierucha, Michał Węgrzyn + Show 2 more

Open Access

https://doi.org/10.1007/s00300-016-2063-2

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Abstract

Tardigrades in lichens have been poorly studied with few papers published on their ecology and diversity so far. The aims of our study are to determine the (1) influence of habitat heterogeneity on the densities and species diversity of tardigrade communities in lichens as well as the (2) effect of nutrient enrichment by seabirds on tardigrade densities in lichens. Forty-five lichen samples were collected from Spitsbergen, Nordaustlandet, Prins Karls Forland, Danskøya, Fuglesongen, Phippsøya and Parrøya in the Svalbard archipelago. In 26 samples, 23 taxa of Tardigrada (17 identified to species level) were found. Twelve samples consisted of more than one lichen species per sample (with up to five species). Tardigrade densities and taxa diversity were not correlated with the number of lichen species in a single sample. Moreover, the densities of tardigrades was not significantly higher in lichens collected from areas enriched with nutrients by seabirds in comparison to those not enriched. The incorporation of previously published data on the tardigrades of Spitsbergen into the analysis showed that tardigrade densities was significantly higher in moss than it was in lichen samples. We propose that one of the most important factors influencing tardigrade densities is the cortex layer, which is a barrier for food sources, such as live photosynthetic algal cells in lichens. Finally, the new records of Tardigrada and the first and new records of lichens in Svalbard archipelago are presented.

Highlights

Terricolous lichens are one of the main components of the vegetation of polar regions (Węgrzyn et al 2011)
Guil et al (2009) reported that Echiniscus species are more abundant in mosses and lichens collected from rocks than in leaf litter or in mosses and lichens collected from trees in the Sierra de Guadarrama, Central Spain
We show that the effect of seabird nutrients on tardigrade abundance in lichens was not significant and tardigrades were more abundant in mosses than in lichens

Summary

Introduction

Terricolous lichens are one of the main components of the vegetation of polar regions (Węgrzyn et al 2011). Some of them have the ability to assimilate atmospheric nitrogen, which allows them to colonize areas completely devoid of vegetation due to a lack of nutrients in the soil (Millbank 1978; Rychert et al 1978; Belnap 2002; Węgrzyn and Wietrzyk 2015). Lichens provide an important habitat for various invertebrates including water bear species (Ramazzotti and Maucci 1983; Nelson 2002; Nelson et al 2015). Terrestrial tardigrades inhabit mosses, lichens, hepatics, rosettetype higher plants, algae, leaf litter and soil, while aquatic species inhabit either freshwater or marine habitats (e.g., Ramazzotti and Maucci 1983; Dastych 1988).

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