Dynamic Research On Landscape Pattern Of Rhododendron Shrubland In Northwestern Guizhou Based On GIS

The purpose of this study was to explore the evolution process of rhododendron shrub landscape pattern in northwest Guizhou.This study uses remote sensing images of Baili Dujuan Nature Reserve in 1992,2005 and 2015 as the data source,and use remote sensing technology to make the multi-temporal landscape pattern distribution map,vegetation coverage grade map,topographic factor grade map and calculate the landscape pattern index of the study area.The change of landscape pattern of Rhododendron shrub in different periods and its relationship with topographic factors,meteorological factors,vegetation coverage were analyzed.The main results are as follows:(1)In 1992,2005 and 2015,the distribution of rhododendron shrub in the elevation grade was more consistent.The rhododendron shrub in the three years were mainly distributed at the altitude of 1600-1800 m,accounting for 77.03%,78.90%and78.99%of the total area,respectively.The area of rhododendron shrub at the altitude of 1600-1700 m was the largest,accounting for 39.59%,45.96%and 49.41%,respectively.Under the slope grade,the distribution of Rhododendron shrub at the slope of 7-15°was the largest,and the area ratio is 46.85%,52.20%and 54.97%,respectively,followed by the area of 3-7°area,the area ratio is 22.25%,22.93%,and31.90%,respectively.(2)The distribution of Rhododendron shrub under different aspect grades is slightly different.Among them,In 1992,Rhododendron shrub were mainly distributed on the west slope,accounting for 16.74%of the total area of Rhododendron.followed by the southwest slope,accounting for 13.99%of the total area of Rhododendron;In2005,Rhododendron shrub were mainly distributed on the southwest slope,accounting for 15.75%of the total area of Rhododendron,followed by the southern slope,accounting for 14.64%of the total area of Rhododendron;In 2015,Rhododendron shrub were mainly distributed on the western slope,accounting for22.08%of the total area of Rhododendron,followed by the southeast slope,accounting for 17.51%of the total area of Rhododendron.(3)The flowering area of rhododendron shrub in different years was affected by different meteorological factors,and the influence of temperature and sunshine duration was significant.Due to the little difference of precipitation in the three periods,precipitation had no obvious effect on the flowering of rhododendron shrub.(4)There was no obvious correlation between the area of Rhododendron shrub and fractional vegetation cover in different years,but it was consistent with the area of high fractional vegetation cover,showing an increasing trend.(5)Fragstats4.2 software was used to analyze the landscape of Rhododendron shrub in different years.It shows that the area of Rhododendron shrub in 1992,2005and 2015 were 752.40 hm~2,826.11 hm~2,and 1071.12 hm~2,respectively,showing an increasing trend;The fragmentation of the landscape first increases and then decreases.Landscape dominance has been increasing.In conclusion,remote sensing technology was used to study the distribution characteristics and area changes of rhododendron shrub flowering area in the study area.To provide scientific support for the effective development,management and protection of rhododendron shrub resources in Guizhou Baili Rhododendron Nature Reserve.It also provides a theoretical basis for revealing the formation mechanism of rhododendron shrub landscape in northwest Guizhou,and provides basic data for further exploring the evolution process of rhododendron shrub in northwest Guizhou.