Basic and Applied Ecology 6 (2005) 367—383 Plant succession and rhizosphere microbial communities in a recently deglaciated alpine terrain Dagmar Tscherko a,Ã , Ute Hammesfahr a , Georg Zeltner b , Ellen Kandeler a ,ReinhardBo¨cker b a Institute of Soil Science and Land Evaluation, University of Hohenheim, Emil-Wolff-Straße 27, 70599 Stuttgart, Germany b Institute of Landscape and Plant Ecology, University of Hohenheim, August-von-Hartmann-Straße 3, 70599 Stuttgart, Germany Received 2 February 2004; accepted 14 February 2005 Summary This study describes how early and late successional plant species affect soil microorganisms in alpine ecosystems. We quantify the relative importance of plant species and soil properties as determinants of belowground microbial communities. Sixteen plant species were selected from six successional stages (4–14–20–43–75–135 years) within the foreland of the Rotmoosferner glacier, Austria, and at one (reference) site outside the foreland. The size, composition and function of the communities of microorganism in the bulk soil and the rhizosphere were characterized by ninhydrin-reactive nitrogen, phospholipid fatty acids and enzyme activities (b-glucosidase, b-xylosidase, N-acetyl-b-glucosaminidase, leucine aminopeptidase, acid phosphatase, sulphatase). The results show that the microbial data could be grouped according to early (up to 43 years) and late-colonizing plant species (75 or more years). In early succession, no plant species or soil age effect was detected on the microbial biomass, phospholipid fatty acids, or enzyme activity. The rhizosphere microbial community was similar to that in the bulk soil, which in turn was determined by the abiotic environmental conditions. In late succession, improved soil conditions probably mediated plant species effects on the belowground microbial community. The most pronounced rhizosphere effects were attributed to plant species of the 75- and 135-year-old sites. The microbial colonization (size, composition, activity) of the bulk soil predominantly followed changes in vegetation cover, plant life forms and soil ARTICLE IN PRESS www.elsevier.de/baae KEYWORDS Primary succession; Glacier foreland; Alpine ecosystem; Phospholipid fatty acids; Bacteria; Fungi; Enzymes; CSR model 1439-1791/$ - see front matter & 2005 Gesellschaft fu ¨r O ¨ kologie. Published by Elsevier GmbH. All rights reserved. doi:10.1016/j.baae.2005.02.004 Ã Corresponding author. Tel.: +49 7144 858999; fax: +49 711 459 3117. E-mail address: tscherko@uni-hohenheim.de (D. Tscherko).