Decreasing nutrient concentrations in soils and trees with increasing elevation across a treeline ecotone in Rolwaling Himal, Nepal

Author(s)
Simon Drollinger, Michael Müller, Timo Kobl, Niels Schwab, Jürgen Böhner, Udo Schickhoff, Thomas Scholten
Abstract

At a global scale, tree growth in alpine treeline ecotones is limited by low temperatures. At a local scale, however, tree growth at its upper limit depends on multiple interactions of influencing factors and mechanisms. The aim of our research was to understand local scale effects of soil properties and nutrient cycling on tree growth limitation, and their interactions with other abiotic and biotic factors in a near-natural Himalayan treeline ecotone. Soil samples of different soil horizons, litter, decomposition layers, and foliage samples of standing biomass were collected in four altitudinal zones along three slopes, and were analysed for exchangeable cations and nutrient concentrations, respectively. Additionally, soil and air temperature, soil moisture, precipitation, and tree physiognomy patterns were evaluated. Both soil nutrients and foliar macronutrient concentrations of nitrogen (N), magnesium (Mg), potassium (K), and foliar phosphorus (P) decrease significantly with elevation. Foliar manganese (Mn) concentrations, by contrast, are extraordinarily high at high elevation sites. Potential constraining factors on tree growth were identified using multivariate statistical approaches. We propose that tree growth, treeline position and vegetation composition are affected by nutrient limitation, which in turn, is governed by low soil temperatures and influenced by soil moisture conditions.

Organisation(s)
Department of Geography and Regional Research
External organisation(s)
Eberhard Karls Universität Tübingen, Universität Hamburg
Journal
Journal of Mountain Science
Volume
14
Pages
843 - 858
No. of pages
16
ISSN
1672-6316
DOI
https://doi.org/10.1007/s11629-016-4228-4
Publication date
05-2017
Peer reviewed
Yes
Austrian Fields of Science 2012
105401 Biogeography, 105402 Soil geography, 105405 Geoecology, 106050 Vegetation science
Keywords
ASJC Scopus subject areas
Geography, Planning and Development, Earth-Surface Processes, Geology, Nature and Landscape Conservation, Global and Planetary Change
Portal url
https://ucrisportal.univie.ac.at/en/publications/1d4e65df-3ff0-4c1b-a7c4-e9d5ae60f932