Spatiotemporal Land Use/Cover Change(LUCC) Simulation In Zhejiang Province And Its Evolution Under The Background Of Climate Change

Land use and land cover change(LUCC)is a direct driving factor affecting the carbon balance of terrestrial ecosystems,and its impact on global warming is second only to that of fossil fuels and industrial emissions.The Fifth Assessment Report produced by the IPCC further noted that the emissions caused by forest reduction and land-use changes are as high as 180 billion tons of carbon,accounting for 33%of the cumulative anthropogenic CO₂ emissions.Therefore,the role of land-use plans such as reforestation in mitigating climate change has been widely recognized.However,the impact of climate change and LUCC on the temporal and spatial dynamics of forests has also received attention.Limited LUCC data cause considerable underestimations regarding the impact of LUCC on carbon emissions.The lack of spatiotemporal LUCC data under the background of the future climate is an important limitation we must overcome if we are to reveal the response of the carbon cycle of forest ecosystems to future climate change.Hence,simulating spatiotemporal LUCC data accurately under future climate scenarios and probing the spatial evolution trajectories of LUCC has important scientific significance for revealing the response of the forest ecosystem carbon cycle to LUCC.This research takes Zhejiang Province as an example.Firstly,a System dynamic model(SD)and a Markov chain(MC)were applied to predict the land-use demand of Zhejiang Province.The SD model is an optimal quantitative model to simulate demand.Secondly,a BPNN?CA model was constructed to grasp the spatial-temporal evolution of land-use.Thirdly,The BCS coupling model integrated by SD model and CA model was used to interactively simulate the spatial-temporal pattern of land-use in Zhejiang Province over the next 70 years under four development scenarios,and then the evolution of future LUCC was analyzed.Finally,the response differences of forest evolution in Zhejiang Province to different climate changes were analyzed base on the climate characteristics under future different scenarios.Through the research,the main conclusions are as follow:1.The BCS coupling model established in this study can accurately obtain the evolution law of LUCC and accurately realize the spatiotemporal LUCC simulation.(1)The accuracy of quantitative results simulated by the SD module in the BCS coupling model is high with R² of 0.99,and relative error(RE)of each land use type are within 5.21%.(2)The spatial results simulated by the BPNN?CA module in the BCS coupling model showed that the OA value was about 0.8,the Kappa coefficient was 0.75,and the FOM value was over 28%,which indicated that the spatial model could simulate the spatial distribution of land use well,and predict the consistent change of LUCC accurately.2.Based on the BCS coupling model,the future LUCC distribution was simulated,and the evolution of future LUCC will be different under different development scenarios.(1)From 2014 to2084,under different scenarios,the area of towns and bamboo forest all showed an increasing trend,and the area of cultivated land all showed a decreasing trend.Compared with the areas of 2014,towns will increase to 1.11-1.5 times,bamboo forest will increase to 1.23-1.37 times,and cultivated land will decrease to 0.72-0.82 times.The area of coniferous forest in 2084 will range from 0.85-1.13 times that of 2014.Except for the increase in the Slow Development(SD)scenario,it will decrease under other scenarios.The area of broad-leaved forest under different scenarios is between 1.01-1.06 times that of2014,with a small increase.(2)The LUCC frequency indicated that more than 20%of the area in Zhejiang Province will undergo land use type transformation,no matter which scenario the province is under.Under the SD scenario,land use protection is strong,and land use is not easily changed;while under the Fast Development(FD)scenario,land use types are prone to frequent changes.(3)In the next 70 years under different scenarios,the urban area at each municipal administrative level will show an increasing trend,while the cultivated land will show a decreasing trend.For coniferous forest,broad-leaved forest and bamboo forest,the change amplitude at each administrative level is quite different under different scenarios,and the difference reflects the strength of forest ecological protection under SD scenario to some extent.In summary,the SD scenario is the friendliest scenario to the forest ecological environment.The government can refer to the corresponding indicators for future land planning and forest resource management.3.The response of future forest evolution to different climate changes is different.In the context of appropriate temperature rise and precipitation increase,it is more conducive to the growth of forest in the future,while the excessively rapid temperature rise and precipitation decrease have a negative impact on the forest growth to a certain extent.