Consistent response of vegetation dynamics to recent climate change in tropical mountain regions

Abstract

Global climate change has emerged as a major driver of ecosystem change. Here, we present evidence for globally consistent responses in vegetation dynamics to recent climate change in the world's mountain ecosystems located in the pan-tropical belt (30°N-30°S). We analyzed decadal-scale trends and seasonal cycles of vegetation greenness using monthly time series of satellite greenness (Normalized Difference Vegetation Index) and climate data for the period 1982-2006 for 47 mountain protected areas in five biodiversity hotspots. The time series of annual maximum NDVI for each of five continental regions shows mild greening trends followed by reversal to stronger browning trends around the mid-1990s. During the same period we found increasing trends in temperature but only marginal change in precipitation. The amplitude of the annual greenness cycle increased with time, and was strongly associated with the observed increase in temperature amplitude. We applied dynamic models with time-dependent regression parameters to study the time evolution of NDVI-climate relationships. We found that the relationship between vegetation greenness and temperature weakened over time or was negative. Such loss of positive temperature sensitivity has been documented in other regions as a response to temperature-induced moisture stress. We also used dynamic models to extract the trends in vegetation greenness that remain after accounting for the effects of temperature and precipitation. We found residual browning and greening trends in all regions, which indicate that factors other than temperature and precipitation also influence vegetation dynamics. Browning rates became progressively weaker with increase in elevation as indicated by quantile regression models. Tropical mountain vegetation is considered sensitive to climatic changes, so these consistent vegetation responses across widespread regions indicate persistent global-scale effects of climate warming and associated moisture stresses.

Changes in Growing Season Vegetation and Their Associated Driving Forces in China during 2001–2012

“…In recent decades, global climate change has affected the characteristics of vegetation throughout the world [1,2]. As a key component of terrestrial ecosystems, vegetation has an irreplaceable role in regulating the carbon balance, reducing greenhouse gases, and maintaining climate stability by modifying biophysical land-surface properties and other biochemical processes [3,4].…”

Past and future influence of climate change on spatially heterogeneous vegetation activity in China

“…Studies on the relationships between vegetation activity and climate change have been carried out at different spatial scales (Krishnaswamy et al, 2014;Seddon et al, 2016). However, the specific variation in vegetation activity depends on 5 different environmental conditions and their changes.…”

Exploring Long Term Spatial Vegetation Trends in Taiwan from AVHRR NDVI3g Dataset Using RDA and HCA Analyses

“…Although these tendencies were not very strong in terms of low R 2 values, the trajectories are extremely critical while facing future climate change. In a recent study of tropical mountain regions, Krishnaswamy et al (2014) [25] found mild greening trends followed by browning trends around the mid-1990s. They also observed strong associations between vegetation with increasing temperature and temperature-induced moisture stress from their study period of .…”

“…Time series of NDVI data have proven to be an effective tool in assessing the phase of climate variability, and has been applied to worldwide geographical locations [3,[24][25][26][27][28][29]. NDVI data derived from the Advanced Very High Resolution Radiometer (AVHRR) onboard the National Oceanic and Atmospheric Administration's (NOAA) satellite series are widely used and have been considered as the best dataset available for long-term analysis of vegetation dynamics at reasonable spatial and temporal scales [30].…”