Table 2 Applied parameters of the vulnerability index

Use frequency (N1)

N1 < 20%

20% ≤ N1 < 60%

N1 ≥ 60%

Number of uses (N2)

N2 < 2

2 ≤ N2 ≤ 4

N2 ≥ 5

Plant parts used (N3)

Leaves, latex

Fruits, branches

Wood, seeds, bark, roots, flowers

Biotope of plant (N4)

Ruderal, gardens, field

Secondary forest

Primary or undisturbed forest

Collection mode (N5)

Collection on the ground

Collection on the tree, cutting

Development stage (N6)

Old, senescent

Adult

Young

Relative frequency in the environment (N7)

Rf ≥ 2/3 Fm

1/3 Fm ≤ Rf < 2/3 Fm

Rf < 1/3 Fm