Litter decomposition and nutrient dynamics of typical plant species in an alpine steppe ecosystem in Northern Tibet

Litter decomposition is a key process that regulates the carbon and nutrient cycling in terrestrial ecosystems. Most previous studies were conducted in forest and temperate grassland ecosystems, while limited studies have focused on alpine steppe ecosystems. Here, we employed the litter-bag method to study the decomposition of four kinds of alpine steppe species, including Stipa purpurea, Carex moocroftii, Leontopodium pusillum, and Artemisia nanschanica. The results showed significant differences in litter mass loss among plant species and decomposition times. At the end of the experiment, the order of litter mass loss was A. nanschanica (46.69%) > S. purpurea (44.97%) > C. moocroftii (33.55%) > L. pusillum (17.05%). Additionally, the decomposition constant (k) of the four species was between 0.07 and 0.22, the half-life of the litter decomposition was between 3.14 years and 10.50 years, and the turn-over periods were between 13.59 and 45.37 years. The litter N and P dynamics during decomposition largely presented as " cumulation release” and " direct release” patterns. At the end of the experiment, the N and P remaining in the four species were in the order of L. pusillum > C. moocroftii > S. purpurea > A. nanschanica. This study will enrich our understanding of biogeochemistry cycling in alpine steppe ecosystems.