Table 2 Species richness (number of species m⁻²) and absolute abundance (numbers in m⁻²) of herbaceous vegetation and bare ground (%) under three invasion levels of Senna obtusifolia (L.) (non-invaded, lightly invaded, and heavily invaded) at two locations in northern Ethiopia, with statistical results of the GLM (F, P, R² values)

 Non-invaded

9.9 ± 2.1^a

65.9 ± 1.0^a

0.0 ± 0.3^c

 Lightly invaded

6.5 ± 1.5^b

29.7 ± 1.8^b

8.2 ± 0.9^b

 Heavily invaded

3.5 ± 1.6^c

20.1 ± 1.5^b

16.7 ± 1.3^a

 Non-invaded

7.7 ± 1.8^a

57.1 ± 0.8^a

0.0 ± 0.2^c

 Lightly invaded

5.2 ± 2.0^b

25.3 ± 2.2^b

6.1 ± 1.3^b

 Heavily invaded

5.1 ± 2.4^c

31.2 ± 1.6^b

22.4 ± 1.5^a

  F (df = 1156)

3.89

0.09

1.38

  P

0.050

0.770

0.243

  F (df = 2156)

75.28

1378.67

65.85

  P

< 0.0001

< 0.0001

< 0.0001

  F (df = 2156)

13.54

6.75

6.51

  P

< 0.0001

0.0015

0.012

  R²_adjusted values

0.538

0.581

0.415