Living in the moss. Mesofaunal communities of Racomitrium lanuginosum in Icelandic rangelands
In higher latitudes, mosses (Bryophyta) represent a prominent part of the vegetation cover and contribute significantly to multiple ecological functions. The moss layer is connected with the atmosphere and the soil systems and hosts a variety of organisms, from tiny arthropods to microscopic microbes, forming an intricate web of interactions known as the bryosphere. In northern rangelands, large herbivores such as sheep and reindeer can disturb the moss layer by trampling, grazing and waste deposition. However, the effect of large herbivores on the arthropod mesofauna in the bryosphere has yet to be explored. The aim of this study is to contribute to the knowledge of the mesofaunal communities of the bryosphere of Racomitrium lanuginosum in Icelandic heathlands and assess the impact of large herbivores on the bryosphere. Moss samples were collected from an ongoing field experiment in the Icelandic highlands, where sheep grazing has been excluded for seven years. Mesofauna (mites and springtails) were extracted from the samples and compared between fenced and open control plots. Additional data from the sites showed that after the grazing exclusion period, moss depth was significantly lower in control plots that had been continuously grazed. No significant differences were found between fenced and control plots in either abundance of mites and springtails or in the overall compostion of the mesofaunal communities. These findings suggest that mesofaunal communities inhabiting Racomitrium lanuginosum might be more resilient to grazing impacts than previously thought. It is possible that more than seven years of grazing exclusion are needed to influence the abundance and composition of mesofaunal communities, and future studies should explore the longer-term effects of grazing exclusion, to explore the dynamics of invertebrates in the bryosphere and the external factors.
Náttúru- og umhverfisfræði, Mosahjúpurinn, Hraungambri, Beitilönd, Heiðarlönd, Sauðfjárbeit, Smáfána, Mítlar, Stökkmor, Bryosphere, Racomitrium lanuginosum, Rangeland, Heathland, Sheep grazing, Mesofauna, Mites, Springtails
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