| With the rapid development of social economy,the intensity and scope of human production and life continue to increase,rapid urbanization,the large use of fossil fuels and other environmental problems caused by increasingly prominent,the sixth report of the IPCC pointed out that the current climate change,ecosystem and human society interaction is mainly negative impact,human beings are facing significant climate change risks.In recent years,extreme weather characterized by climate warming has led to significant changes in land use and land cover.Land use and land cover change(LUCC)is a direct driver of the carbon balance of terrestrial ecosystems,and LUCC is constrained by both natural and socio-economic conditions.Vegetation change is a direct representation of LUCC,and vegetation is the basic element of terrestrial ecosystems,which plays an important role in regulating carbon dioxide concentration and maintaining ecosystem balance.Vegetation NPP(Net Primary Productivity)is an indicator of vegetation activity,and previous studies have shown that vegetation activity is mainly affected by climate and land use change.Heilongjiang Province is located in the northernmost part of China and is rich in black soil resources and forest resources.In recent years,under the background of global warming,the rapid development of cities has led to obvious changes in the climate and land use pattern of Heilongjiang Province.Therefore,the study of vegetation activities in LUCC in Heilongjiang Province under the background of climate change is conducive to deepening the understanding of ecosystem function and structure in Heilongjiang Province,and has important practical significance for regional ecological management and scientific regulation of carbon cycle.In this study,Heilongjiang Province was used as the research area(excluding Jiagedaqi District),and the temporal and spatial changes of climate,LUCC and vegetation in Heilongjiang Province from 2002 to 2020 were analyzed qualitatively and quantitatively,and the impact of LUCC on vegetation activities under the background of climate change was clarified.Based on the future climate change trend in the sixth IPCC assessment report,the future climate change situation in Heilongjiang Province is predicted,and the future LUCC change characteristics of Heilongjiang Province are simulated and predicted by using FLUS software to explore the impact of LUCC on vegetation activities under the background of future climate change.The following main findings were drawn:(1)The average annual temperature of Heilongjiang Province from 2002 to 2020was between 2.58-4.43°C,and the average annual temperature showed a fluctuating increase.The northeast of Heilongjiang Province has the highest average annual temperature,followed by the southern region of Heilongjiang Province and the western region of Heilongjiang Province.The region with the lowest annual average annual temperature is located in the southeast of Heilongjiang Province,followed by the northeast and parts of the central region.The annual precipitation was between433.05-785.80mm,and the annual precipitation in Heilongjiang Province showed a fluctuating increase from 2002 to 2020.The high annual average precipitation was mainly concentrated in the northwest of Heilongjiang Province,and the areas with low annual average precipitation were located in the western part of Heilongjiang Province,followed by the northwest and southwest areas.It is predicted that the average annual temperature of Heilongjiang Province in 2026,2032 and 2038 will be between4.55-4.89°C,all of which are higher than the average annual temperature in 2020.The annual precipitation is between 535.72-785.28mm,which is lower than the annual precipitation in 2020.From 2020 to 2026,the areas with high annual average temperature change rate were mainly distributed in central Heilongjiang Province,and the areas with low annual average temperature change rate were mainly distributed in the northeast and south.The areas with high precipitation change rates are mainly distributed in the north and south,followed by the east,and the areas with low annual precipitation change rates are distributed in the west.The areas with high annual mean temperature change rates in 2020-2032 and 2020-2038 were mainly distributed in the northeast and south of Heilongjiang Province,and the areas with low annual average temperature change rates were mainly distributed in the northwest.The areas with high annual precipitation change rate from 2020 to 2032 are mainly distributed in the north,and the areas with low annual precipitation change rate are distributed in the south.From 2020 to 2038,the areas with high annual precipitation change rate were mainly distributed in the southwest,south and northeast,and the areas with low annual precipitation change rate were mainly distributed in the southeast,followed by the northwest.(2)From 2002 to 2020,Heilongjiang Province has always accounted for the largest proportion of forest land,followed by cultivated land area,and the smallest proportion is wetland area.From 2002 to 2020,the area of cultivated land,water body land and impervious land increased,and the area of forest land,grassland land,bare land and wetland decreased.The change area of impervious ground land is the largest,and the absolute dynamic value of bare land area is the largest.From 2002 to 2008,the main types of land cover transfer were cultivated land to forest land,grassland land,and impervious ground land;conversion of forest land to arable land;Grassland converted to arable land and forest land.From 2008 to 2014,the main types of land cover transfer were arable land to forest land,grassland land,and impervious ground land.Conversion of forests to arable land;Grassland converted to arable land.From 2014 to 2020,the main types of land cover transfer were arable land to forest land,grassland land,and impervious ground land;Forests are converted to arable land,and grasslands are converted to arable land.From 2002 to 2020,the main types of land cover transfer were arable land to forest land,grassland land,water body land,and impervious ground land;Conversion of forests to arable land;Grassland converted to arable land and forest land.Compared with 2020,in 2026,2032 and 2038,the area of arable land,grassland land,bare land and wetland will continue to decrease,and the area of forest land,water body land and impervious land will continue to increase.(3)From 2002 to 2020,the average annual NPP of vegetation in Heilongjiang Province showed a fluctuating and rising trend.The mean annual NPP of vegetation of forest land type in Heilongjiang Province has always been higher than that of other land use types,and the mean annual NPP of vegetation of water body land type has always been the lowest value among all land use types,followed by bare land and impervious ground land type.From 2002 to 2020,the areas with obvious annual average NPP growth trend were mainly distributed in the eastern and southern regions of Heilongjiang Province,followed by the central region.The annual mean NPP change trend in some parts of central,western and northwestern Heilongjiang Province is not obvious.(4)From 2002 to 2020,the annual average temperature and annual precipitation were not significantly weakly correlated with the changes in the area of each land use type.51.24%of the regional average temperature in Heilongjiang Province was positively correlated with the mean annual NPP,and 12.97%of the regional average temperature was positively correlated with the mean annual NPP,mainly distributed in the southeast of Heilongjiang Province.84.50%of the regional annual precipitation in Heilongjiang Province was positively correlated with the mean annual NPP,and 43.99%of the regional annual precipitation was positively correlated with the mean annual NPP,mainly distributed in the northwestern,central and western regions of Heilongjiang Province.The increase of annual precipitation and the increase of annual mean temperature are conducive to the increase of the mean annual NPP of vegetation.The future temperature change in Heilongjiang Province is conducive to the growth of vegetation and the accumulation of vegetation NPP.Future precipitation changes are not conducive to vegetation growth and affect the accumulation of vegetation NPP.(5)From 2000 to 2020,the urban expansion area of Heilongjiang Province increased by 4764.5km~2,and the total annual NPP decreased by 27.477Kg C;due to the increase of 8652.5km~2in the area of forest,grassland and wetland for ecological restoration,the total annual NPP increased by 631.363Kg C.Ecological restoration is conducive to the accumulation of total annual NPP of vegetation,while urban expansion is not conducive to the increase of total annual NPP of vegetation.From 2020 to 2026,the urban expansion area of Heilongjiang Province increased by 320.5km~2,and the ecological restoration area increased by 6187km~2.From 2020 to 2032,the urban expansion area of Heilongjiang Province will increase by 19.75km~2,and the ecological restoration area will increase by 202km~2.From 2020 to 2038,the urban expansion area of Heilongjiang Province will increase by 1062.75km~2,and the ecological restoration area will increase by 8994.75km~2.In 2026,2032 and 2038,the ecological restoration area of LUCC in Heilongjiang Province will be larger than the urban expansion area,which is conducive to vegetation growth. |
