Mathematical Problems in Engineering Landscape Ecological Security Assessment and Ecological Pattern Optimization of Inland River Basins in Arid Regions: A Case Study in Tarim River Basin

Table 2

The ratio of each ecological risk level in TRB in four periods.

Risk level	Area/km^2				Change ratio/%
	1990	2000	2010	2020	1990–2000	2000–2010	2010–2020
Low risk	105490.74	102003.28	96890.42	85162.72	−3.42	−5.28	−13.77
Relatively low risk	153342.37	151718.48	142635.10	144424.86	−1.07	−6.37	1.24
Medium risk	204713.05	206221.62	180941.32	192709.24	0.73	−13.97	6.11
Relatively high risk	231268.06	229987.72	229288.61	233568.51	−0.56	−0.30	1.83
Hight risk	338523.99	343407.11	383582.75	377472.88	1.42	10.47	−1.62