Table 3 Calculation methods and grading standards for ecosystem asset index.

From: Assessing the impact of human activities on ecosystem asset dynamics in the Yellow River Basin from 2001 to 2020

Indices

Method

Index grade

Excellent

Good

Medium

Poor

Bad

Ecosystem asset index

\(\:{EQ}_{i}=\frac{{\sum\:}_{j=1}^{5}({EA}_{ij}\times\:j)}{{EA}_{i}\times\:5}\times\:100\)

≥ 80

60–80

40–60

20–40

≤ 20

Comprehensive ecosystem asset index

\(\:\text{E}\text{Q}=\sum\:_{i=1}^{n}\frac{{\sum\:}_{j=1}^{5}({EA}_{ij}\times\:j)}{{\sum\:}_{i=1}^{n}{EA}_{i}\times\:5}\times\:100\)

≥ 80

60–80

40–60

20–40

≤ 20

  1. EQi is ith ecosystem asset index; EQ is comprehensive ecosystem asset index; i is ecosystem assets type, i = 1, 2, …, n; j is ecosystem asset quality grade index, that is, excellent, good, medium, poor, and bad, j = 1, 2, 3, 4, 5; EAij is area of the ith type of ecosystem assets at jth grade; and EAi is area of the ith type of ecosystem assets.
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