Degradation of Tibetan grasslands

Consequences for carbon and nutrient cycles

verfasst von

Shibin Liu, Kazem Zamanian, Per Marten Schleuss, Mohsen Zarebanadkouki, Yakov Kuzyakov

Abstract

The Tibetan Plateau hosts the world's largest alpine pastoral ecosystems, dominated by the endemic sedges Kobresia pygmaea and Kobresia humilis. Owing to the very harsh environment and also to soil nitrogen (N) and phosphorus (P) limitations, these pastoral ecosystems are very sensitive to disturbances (e.g. anthropogenic activities and climate change) and recover extremely slowly. Overgrazing on the Tibetan Plateau has caused severe degradation of vegetation and soils in the last 30–50 years. For the first time, for Kobresia pastures in Tibetan Plateau, we have summarized and generalized the consequences of pasture degradation for soil organic carbon (SOC) and nutrient (N, P) stocks, and evaluated the main biotic and abiotic mechanisms of their loss. Based on 44 literature studies as well as own data, we demonstrated that 42% of SOC stocks were lost, relative to non-degraded pastures. These SOC losses are similar to the decreases in N stocks (-33%), and aboveground (-42%) and belowground (-45%) plant biomass. Although P losses are lower (-17%), its precipitation reduces its availability for plants. These losses are in fact underestimates, since undisturbed natural sites no longer exist on the Tibetan Plateau. The losses are much higher in the upper 10 cm and in some areas extend to complete removal of soil cover. This has dramatic repercussions for local livestock, human populations and river pollution. While some rehabilitation projects have shown positive outcomes, the complete recovery of degraded pastures (e.g. soil fertility, ecosystem stability) is infeasible, because of very slow pedogenic processes, slow vegetation restoration, as well as continuously increasing anthropogenic pressure and climate change. Considering the rapid losses of SOC and nutrients, and the very slow recovery potential, Tibetan pastures in some regions may disappear in the next few decades without proper and effective recovery strategies.

Externe Organisation(en)

Georg-August-Universität Göttingen
Kazan Volga Region Federal University

Typ

Übersichtsarbeit

Journal

Agriculture, Ecosystems and Environment

Band

252

Seiten

93-104

Anzahl der Seiten

12

ISSN

0167-8809

Publikationsdatum

15.01.2018

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Ökologie, Nutztierwissenschaften und Zoologie, Agronomie und Nutzpflanzenwissenschaften

Ziele für nachhaltige Entwicklung

SDG 13 – Klimaschutzmaßnahmen

Elektronische Version(en)

https://doi.org/10.1016/j.agee.2017.10.011 (Zugang: Geschlossen)