Clipping has stronger effects on plant production than does warming in three alpine meadow sites on the Northern Tibetan Plateau

Gang Fu,Zhen Xi Shen

doi:10.1038/s41598-017-16645-2

Abstract

The relative effects of warming and clipping on vegetation growth are not fully understood. Therefore, we compared the relative effects of experimental warming and clipping on the normalised difference vegetation index (NDVI), green NDVI (GNDVI), soil-adjusted vegetation index (SAVI), aboveground biomass (AGB) and gross primary production (GPP) in three alpine meadow sites (A, B and C) on the Northern Tibetan Plateau from 2013 to 2015. There were no obvious effects of experimental warming on the NDVI, GNDVI, SAVI, AGB and GPP at the three sites, which were most likely attributed to experimental warming-induced warming and drying conditions. In contrast, clipping significantly decreased the NDVI, SAVI and AGB by 27.8%, 31.3% and 18.2% at site A, by 27.1%, 31.8% and 27.7% at site B, and by 12.3%, 15.1% and 17.6% at site C, respectively. Clipping also significantly reduced the GNDVI and GPP by 11.1% and 28.2% at site A and by 18.9% and 33.7% at site B, respectively. Clipping marginally decreased the GNDVI by 8.7% (p = 0.060) and GPP (p = 0.082) by 14.4% at site C. Therefore, clipping had stronger effects on vegetation growth than did warming in the three alpine meadow sites on the Tibetan Plateau.

Highlights

Various vegetation indices have been treated as indicators of vegetation biophysical variables[1,2,3,4,5]
Some studies found that experimental warming rather than clipping/grazing had significant effects on aboveground biomass (AGB) across all the observed years in alpine meadows on the Tibetan Plateau[31,35]
Other studies demonstrated that clipping/grazing rather than experimental warming had significant effects on AGB across all the observed years in alpine meadows on the Tibetan Plateau[34]

Summary

Introduction

Various vegetation indices (e.g., normalised difference vegetation index, NDVI; green NDVI, GNDVI; soil-adjusted vegetation index, SAVI) have been treated as indicators of vegetation biophysical variables (e.g., coverage, biomass, productivity and phenology)[1,2,3,4,5]. These findings suggest that the relative strengths of experimental warming and clipping/grazing effects on biomass production can vary over time Most of these warming and clipping/grazing experiments in alpine meadows on the Tibetan Plateau lasted less than 5 years[31,34,35]. The main objective of this study was to compare the relative strengths of experimental warming and clipping effects on the NDVI, GNDVI, SAVI, AGB and GPP in three alpine meadow sites on the Northern Tibetan Plateau

Objectives

Methods

Results

Conclusion