Climate and Spring Phenology Effects on Autumn Phenology in the Greater Khingan Mountains, Northeastern China

Yuanyuan Fu,Hong He,Jianjun Zhao,Hongyan Zhang,Michael Sunde,David Larsen,Shengwu Duan

doi:10.3390/rs10030449

Yuanyuan Fu, Hong He + Show 5 more

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https://doi.org/10.3390/rs10030449

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Abstract

Vegetation phenology plays a key role in terrestrial ecosystem nutrient and carbon cycles and is sensitive to global climate change. Compared with spring phenology, which has been well studied, autumn phenology is still poorly understood. In this study, we estimated the date of the end of the growing season (EOS) across the Greater Khingan Mountains, China, from 1982 to 2015 based on the Global Inventory Modeling and Mapping Studies (GIMMS) normalized difference vegetation index third-generation (NDVI3g) dataset. The temporal correlations between EOS and climatic factors (e.g., preseason temperature, preseason precipitation), as well as the correlation between autumn and spring phenology, were investigated using partial correlation analysis. Results showed that more than 94% of the pixels in the Greater Khingan Mountains exhibited a delayed EOS trend, with an average rate of 0.23 days/y. Increased preseason temperature resulted in earlier EOS in most of our study area, except for the semi-arid grassland region in the south, where preseason warming generally delayed EOS. Similarly, EOS in most of the mountain deciduous coniferous forest, forest grassland, and mountain grassland forest regions was earlier associated with increased preseason precipitation, but for the semi-arid grassland region, increased precipitation during the preseason mainly led to delayed EOS. However, the effect of preseason precipitation on EOS in most of the Greater Khingan Mountains was stronger than that of preseason temperature. In addition to the climatic effects on EOS, we also found an influence of spring phenology on EOS. An earlier SOS led to a delayed EOS in most of the study area, while in the southern of mountain deciduous coniferous forest region and northern of semi-arid grassland region, an earlier SOS was often followed by an earlier EOS. These findings suggest that both climatic factors and spring phenology should be incorporated into autumn phenology models in order to improve prediction accuracy under present and future climate change scenarios.

Highlights

Vegetation plays an important role in the land–atmosphere interface [1]
The centrally located mountain grassland forest (CMF) region had the earliest end of the growing season (EOS) date, which occurred on Julian day 290 on average
The average EOS dates for the grassland semi-arid region (GLS) and forest grassland region in the northwest (FGN) regions were Julian days 291 and 292, respectively, slightly later than that observed in the CMF region

Summary

Introduction

Vegetation plays an important role in the land–atmosphere interface [1]. Vegetation phenology, which refers to the growth cycle of flora in a particular region, can be seriously affected by climatic changes and is an important component of land surface process models and terrestrial carbon cycle models [2]. Xie et al [12] focused on autumn phenology from the beginning of leaf coloration through the end of leaf drop for 12 dominant deciduous tree species of northeastern USA and found that warm temperatures, drought, and heavy rainfall during the growing season could significantly affect the inter-annual variation of autumn phenology. All these findings suggest that a thorough investigation of EOS and its control factors is essential for improving autumn phenology modeling and enhancing the understanding of the impact of global climate change on the carbon cycle

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