Vegetation response to extreme climate events on the Mongolian Plateau from 2000 to 2010

Abstract

Climate change has led to more frequent extreme winters (aka, dzud) and summer droughts on the Mongolian Plateau during the last decade. Among these events, the 2000-2002 combined summer drought-dzud and 2010 dzud were the most severe on vegetation. We examined the vegetation response to these extremes through the past decade across the Mongolian Plateau as compared to decadal means. We first assessed the severity and extent of drought using the Tropical Rainfall Measuring Mission (TRMM) precipitation data and the Palmer drought severity index (PDSI). We then examined the effects of drought by mapping anomalies in vegetation indices (EVI, EVI2) and land surface temperature derived from MODIS and AVHRR for the period of 2000-2010. We found that the standardized anomalies of vegetation indices exhibited positively skewed frequency distributions in dry years, which were more common for the desert biome than for grasslands. For the desert biome, the dry years (2000-2001, 2005 and 2009) were characterized by negative anomalies with peak values between −1.5 and −0.5 and were statistically different (P < 0.001) from relatively wet years (2003, 2004 and 2007). Conversely, the frequency distributions of the dry years were not statistically different (p < 0.001) from those of the relatively wet years for the grassland biome, showing that they were less responsive to drought and more resilient than the desert biome. We found that the desert biome is more vulnerable to drought than the grassland biome. Spatially averaged EVI was strongly correlated with the proportion of land area affected by drought (PDSI < −1) in Inner Mongolia (IM) and Outer Mongolia (OM), showing that droughts substantially reduced vegetation activity. The correlation was stronger for the desert biome (R 2 = 65 and 60, p < 0.05) than for the IM grassland biome (R 2 = 53, Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. 1 1748-9326/13/035033+12$33.00 c 2013 IOP Publishing Ltd Printed in the UK Environ. Res. Lett. 8 (2013) 035033 R John et al p < 0.05).Our results showed significant differences in the responses to extreme climatic events (summer drought and dzud) between the desert and grassland biomes on the Plateau.

Spatio-Temporal Patterns and Climate Variables Controlling of Biomass Carbon Stock of Global Grassland Ecosystems from 1982 to 2006

“…The significant decrease trend of Agbtc in EA after 1994 could not be explained by precipitation as their correlations were not significant (Table 1 and Figure S6). Although the negative correlation between the Agbtc and temperature was not significant, the significant increased temperature may suppress grassland biomass through influencing water availability [42,44].…”

Influences of Climate Extremes on NDVI (Normalized Difference Vegetation Index) in the Poyang Lake Basin, China

“…Actually, the impacts of climate changes on vegetation growth are diverse and not constant. Numerous studies have validated the responses of NDVI to climatic changes, and concluded that they differed among vegetation types (Breda et al 2006;John et al 2013). For example, Li and Tao (2000) demonstrated that correlation between annual NDVI and annual precipitation stronger over grasslands than over areas covered with shrubs and forests.…”

Responses of Natural Vegetation to Different Stages of Extreme Drought during 2009–2010 in Southwestern China

“…The adverse effects of extreme droughts on vegetation have been widely studied using remote sensing data or drought indices [22][23][24][25][26][27][28][29]. The relationship between vegetation indices and drought indices, such as SPI [23] or PDSI [30], was found in different land cover or different seasons.…”