Landscape Pattern Dynamics and Driving Forces in the Yellow River Source Area,1990-2020
The landscape pattern of the source region of the Yellow River has changed due to natural and anthropogenic factors,and the study of landscape dynamics is important for building regional ecological security.In this study,we analyzed the spatial and temporal changes of land use in the source region of Yellow River,and forces driving landscape dynamics were analyzed.The study was based on land use data collected each 5 years(1990,1995,2000,2005,2010,2015 and 2020)over a 30 year period.Land use designations included arable land,woodland,grass land,water,construction land,and un-used land.Results show that the interspersion and juxtaposition index(IJI)of arable land,water and construction land in the study area decreased significantly from the type level index,and the shapes of each type became more complex.Over the 30 year study period,the patch number(NP)of woodlands increased the most,indicating that woodlands were being gradually fragmented by other land use types.The patch landscape area density(PLAND)and cohesion of grasslands was the highest over the 30 years,with the highest dominance among landscape types and the best natural connectivity.During 1990-2005,the landscape shape index(LSI)of unused land was the highest,indi-cating that its overall landscape shape was more complex compared to other landscapes.In terms of landscape level indices,the patch density,maximum patch index,IJI and Shannon diversity index of the landscape displayed overall decreasing trends,while the perimeter-area ratio increased and the patch connectivity index changed little,indicating that overall fragmentation of the source area was low,and spatial heterogeneity decreased.Landscape pattern changes in the Yellow River source area were primarily influenced by socio-economic factors,among which economic development,popula-tion increase,and industrial restructuring were the main driving factors of land use change.Annual average temperature,annual average evaporation,and annual average precipitation were the primary natural factors affecting the landscape pattern.Our study provides a scientific basis for ecological res-toration,environmental protection and land use management in the Yellow River source area and is crucial for promoting ecologically sustainable development.
landscape patternland uselandscape leveldriving factorYellow River source region
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