ObjectiveIn this paper, the vegetation change and its response to climate change in Hunan Province of southern China was studied in order to provide a scientific guidance for ecological protection in Hunan Province.
MethodBased on the SPOT-VGT NDVI, vegetation types and meteorological data from 2000 to 2015, combined with the least squares trend analysis and correlation analysis, this paper discusses the characteristics of vegetation growth change in Hunan Province and analyzes the response of different vegetations to climate change from different time scales respectively.
ResultThe results showed that:(1)in recent 16 years, vegetation NDVI in most areas of Hunan Province showed an increasing trend, but the spatial distribution was quite different. The large value of NDVI was found in the northwest and southwest of Hunan Province, while the vegetation cover in the middle and north of Hunan Province was poor. (2)From 2000 to 2015, the growth rate of NDVI in Hunan Province reached 0.004 5/ year and the brush reached 0.005 1/ year, while swamp showed the smallest increase trend, only 0.002 6/ year. (3)The positive and negative correlations between NDVI and temperature and precipitation is coexisting, and the correlation between NDVI and temperature was better. According to different types of vegetation, the area of positive correlation between NDVI and temperature was the most, the area of positive correlation between NDVI and precipitation was larger in shrub and coniferous forest, while the area of grass, meadow and swamp NDVI was negative correlated with precipitation. The area with positive or negative correlation between broadleaved forest and cultivated vegetation and precipitation was about half of each area. (4)The time lag analysis showed that the vegetation response to rainfall had two-month lag, and the correlation between July NDVI and June rainfall, September NDVI and the rainfall in the same period was significant, but the correlation between monthly NDVI and the temperature in the first 0-3 months was not significant.
ConclusionIn recent 16 years, the vegetation cover in Hunan Province has been increasing, but the spatial distribution is quite different and different vegetations have different degrees of responses to climate change.