| Land is the carrier of human activities.As social and economic development shifts from high speed to high quality development and urbanization level continues to rise,land ecological problems and regional sustainable development issues are constantly receiving attention,land ecosystem research is gradually becoming a hot spot.Land use landscape pattern is closely related to ecosystem services value.Under the influence of human activities superimposed on natural factors,the land use landscape pattern evolves drastically,which leads to different degrees of changes in ecosystem service value.Taking the Karst-Coastal Zone in Southwest Guangxi as an object,the spatial and temporal patterns of land use landscape patterns and their ecosystem service value in the study area from 1990 to 2019 were analyzed in depth by using the landscape pattern index method and the ecosystem service value measurement method.The correlation between landscape pattern index and ecosystem service value was measured by the gray correlation method,so as to explore the influence of land use landscape pattern evolution on the change of ecosystem service value.Finally,relevant landscape pattern optimization measures were proposed to improve the ecosystem service value and regional sustainable development level in the study area.The conclusions are as follows:(1)From 1990 to 2019,the land use of Karst-Coastal Zone in Southwest Guangxi had changed significantly.Land use was in rapid change;the scale of urban and rural construction land kept expanding,with an average annual increase of 2962.73 hm~2 in construction land and a dynamic degree of up to 9.06%,the fastest growth rate;cultivated land shrank seriously,with an average annual decrease of 3283.67 hm~2;forest land was relatively stable;water area grew in general,but continued to decline after 2010;grassland area was declining year after year.(2)From 1990 to 2019,the landscape pattern of Karst-Coastal Zone in Southwest Guangxi changed significantly,with different evolutionary characteristics of landscape fragmentation degree,edge and shape complexity degree,aggregation degree and diversity level depending on the differences of land types and regions.The landscape fragmentation degree was low in the northwest and high in the southeast,with an overall decreasing trend and a narrowing of the area difference between patches,while the fragmentation degree increased in the northwest and southwest and remained at a high degree in the southeast;the fragmentation level of patches of cultivated land,forest land,grassland,water and other land decreased,while the patches of construction land became more fragmented.The complexity of landscape edge and shape was low in the northwest and high in the southeast,with an overall decreasing trend,with the northwest becoming more complex and the southeast and southwest becoming simpler and more regular;the edge and shape of cultivated land,forest land,grassland and other land tended to be simpler and more regular,while the edges of water area tended to be more complex but it’s shape more simple and regular,and the edge and shape of construction land became more complex.The level of aggregation and connectivity was high in the northwest and low in the southeast,the level of separation was low in the northwest and high in the southeast,the overall level of aggregation increased,the level of connectivity and separation decreased,the level of landscape connectivity and aggregation decreased in the northwest,the level of separation did not change significantly,the level of aggregation,connectivity and separation increased in different degrees in the southeast and middle;the probability of the existence of other types around the patches of cultivated land,grassland and water area increased,and the agglomeration effect was enhanced.The patches of construction land and forest land were more and more agglomerated,and the probability of other types of patches around them decreased.The patches of other land became more dispersed,and the probability of other types of patches around them increased.Diversity level fluctuated growth,with a low level in the northwest and a high level in the southeast.The level of diversity in the northwest continued to rise,and the level of diversity in the central region decreased dynamically.The southeast and southwest did not change much.(3)From 1990 to 2019,the ESV in the study area showed an overall upward trend.The increase and decrease of ESV in various categories and individual service functions were quite different in time and space.The ESV increased by 2.15385 billion yuan,with an average annual increase of 74.27 million yuan.The ESV of cultivated land,grassland and other land showed a downward trend.Among them,the ESV of grassland had a larger decline,and the ESV of other land had a smaller decline;the ESV of forest land and water area showed an increasing trend,among which,the ESV of water area increased the most,but it continued to decrease after 2010.The ESV of the adjustment service accounted for the largest proportion,and the ESV of the cultural service accounted for the smallest;the ESV of the supply service,the adjustment service and the cultural service increased by 186.09 million yuan,2.00340 billion yuan and 24.1 million yuan respectively;the support service ESV decreased by 59.74 million yuan.The ESV of food production decreased;the ESV of the five functions of raw material production,gas regulation,climate regulation,soil conservation,and biodiversity decreased first and then increased;the ESV of water supply,hydrological regulation,environmental purification and aesthetic landscape increased by 328.69 million yuan,3.59082 billion yuan,40.95 million yuan and 0.515 billion yuan respectively;ESV maintaining nutrient cycle services continued to decrease by 182.7million yuan.The central,northern and southeastern regions were the low-value ESV agglomeration distribution areas;the northwest and southwest were the high-value ESV agglomeration areas;the proportion of the high-value areas in the northwest decreased,and the proportion of the central,southeastern and northern ESV low-value areas decreased,and the proportion of the low-high and high-low agglomeration area was small,with little change.(4)The evolution of the land use landscape pattern in Karst-Coastal Zone in Southwest Guangxi has a greater impact on the change of ESV.The correlation level between the landscape pattern index and ESV is generally above the medium level.The degree of landscape aggregation has the greatest influence on ESV,and the comprehensive correlation between them was the highest(0.7460),followed by the degree of landscape fragmentation,and the level of landscape diversity had the least impact on ESV changes,and the comprehensive correlation level was weak(0.1490).CONTAG had the strongest effect on ESV,with a strong correlation degree of 0.9410,while SHDI and SHEI had the weakest effect on ESV,with a weak correlation degree of 0.1684 and 0.1296.To improve the level of ESV and regional sustainable development,land use allocation should be guided by planning and management;adhere to high-quality and sustainable two-way development;base and revitalize the existing construction land;build a landscape ecological corridor with the new western land-sea corridor as the axis. |
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