Study on Ecological Risk Evaluation and Optimum Selection of Desert Expressway Schemes Based on the Two-Dimensional Cloud Model

Table 1

Classification of index factors.

Indexes	I	II	III	IV
Disturbance of living environment of wild animals and plants (U1)
Destruction of the original vegetation along the expressway, U11	Minor impact	Short-term damage	Long-term damage	Total loss
Self-recovery ability of natural vegetation, U12	Excellent	Good	General	Poor
Wildlife corridor partition, U13	Almost no	A few parts	Many parts	Completely
Disturbance of wild animal living environment, U14	Very weak	Weak	General	Severe
Destruction of natural ecological landscape (U2)
Loss of integrity of natural landscape, U21	Slight	Small	Large	Severe
Damaged land occupied by construction, U22	Very weak	Weak	General	Severe
Restoration methods of landscape ecology, U23	No repair	Natural repair	Artificial repair	Irreparable
Pollution of water and soil resources (U3)
Number of surface water crossings along the line, U31	0	1	2	>2
Pollution degree of water source, U32	Very weak	Weak	Medium	Strong
Cause the severity of soil erosion, U33	Very few	Small area	Multiarea	Whole line area
Degree of soil structure change, U34	Very weak	Weak	Medium	Strong
Development and utilization of natural resources (U4)
Development of solar energy resources, U41	Abundant natural resources, no impact on the ecological environment	Adequate natural resources, with little impact on the ecological environment	Adequate natural resources, with greater impact on the ecological environment	Insufficient natural resources, with greater impact on the ecological environment
Development of wind power resources, U42
Development of characteristic tourism resources, U43
Sand fixation of plants and subsequent maintenance (U5)
Effect of sand fixation on original ecology, U51	Very beneficial	Beneficial	General	Harmful
Annual loss rate of ecological protection effect, U52	<2%	2∼3%	3∼5%	>5%
Available water source for plant irrigation, U53	Very sufficient	Sufficient	Average	Insufficient
Maintenance cycle, U54	>10a	8–10a	5-8a	<5a