Soil Macroinvertebrate Distribution Along a Subalpine Land Use Transect

Abstract

Little is known about the complex processes within the soil ecosystem and especially about soil animals and their role in supporting and sustaining ecosystem functioning in alpine soils. Currently, environmental and socioeconomic changes, such as climate change and the cessation of traditional cultivation, are influencing mountain ecosystems. Epi- and endogeic animals play an essential role in litter decomposition, humus formation, and pedogenesis and in improving resistance to natural hazards. Therefore, knowledge about the diversity of soil macroinvertebrates is of immediate importance. To test the effect of different management techniques on soil macroinvertebrates, we took 144 soil monoliths from 4 different land use types (with 3 replicates each) in a subalpine area. The land use types were (1) extensively grazed dry pastures, (2) intensively used hay meadows, (3) larch forests, and (4) spruce forests. All sites were comparable in terms of bedrock and exposition. Additionally, we measured pH, organic matter content, and C and N content, as well as soil temperature and soil moisture. We found the highest abundances of macroinvertebrates on the intensively used hay meadows, followed by larch forests, spruce forests, and dry pastures. Diptera larvae and Lumbricidae were predominant in hay meadows, while we found the highest number of Coleoptera larvae, Araneae, and Symphyla in larch forests. In comparison to the other land use types, the dry pastures harbored the most Gastropoda individuals. No unique taxa were observed in the spruce forests. At species level, larch forests had the highest number of species (73), followed by hay meadows (44), spruce forests (42), and dry pasture (36). Despite showing lower biodiversity, we found more rare and specialist species in the extensive dry pastures compared to the more generalist species assemblages in the other habitats, supporting the high conservation value of extensively managed alpine landscapes.

Keywords

• climate change
• european alps
• ltser
• soil biodiversity
• south tyrol
• traditional low-input land use