Landscape diversity of urban greenland system in Beijing.

Landscape diversity of urban greenland system is a key matter of the study of landscape ecosystem in a city.By using landscape ecology theory,under the support of GIS,the rank,distribution and space structural measurement of urban greenland patches within the 5th ring road of Beijing were analyzed,and an integrated evaluation of the urban greenland landscape along the city gradient was carried out.The results show that there are 18 470 patches of green space within the 5th ring road,covering an area of 11 023.29 hm~2.72% of the patches are middle and small size.However,86.64% of the total area is made up of middle-large and large patches,whose areas are more than 3 000 m~2.The patch density is 167.6 ones/km~2,edge density is 2.58 m/hm~2,landscape diversity index is 1.32 and landscape evenness index is 0.82.The urban greenland landscape structure shows regular difference with the urban gradient.Overall,it manifests that with increasing human activity disturbance,accelerating landscape fragmentation and less landscape diversity,the whole landscape is controlled by a few landscapes.Acreage exerts a great impact on the whole landscape,which is well-distributed.Landscape characteristics vary greatly among the major types of landscape.With increasing human disturbance,the edge density of landscape genre is growing and fragmentating.The average patch area of the park green space is the highest,while the affiliated green space has the highest patch density and the highest complexity.Still,the park green space has the highest assembly degree.