Exotic Brome-Grasses in Arid and Semiarid Ecosystems of the Western US

Table 6.3

Results of univariate logistic regressions

Independent variable

No.

Values

Is widely introduced

Is a crop weed

Is a ruderal weed

Is an environmental weed

Wald Chi Sq.

Pr >Chi Sq.

Odds ratio point est.

Wald Chi Sq.

Pr >Chi Sq.

Odds ratio point est.

Wald Chi Sq.

Pr >Chi Sq.

Odds ratio point est.

Wald Chi Sq.

Pr >Chi Sq.

Odds ratio point est.

Section

147

22.0715 <0.0001

40.069

<0.0001

38.9054 <0.0001

21.2555 <0.0001

Bromus

vs.

Bromopsis

21.250 (4.386–102.951)

36.037 (10.627–124.044)

28.699 (9.104–90.466)

10.5 (2.633–41.868)

Ceratochloa

vs.

Bromopsis

15.179 (2.679–86.006)

3.890 (0.794–10.069)

4.373 (1.051–18.189)

7. 467 (1.516–36.783)

Genea

vs.

Bromopsis

127.5 (15.187–>999.999)

62.239 (9.414–411.481)

49.198 (7.834–308.977)

84 (11.696–603.298)

Bromus

vs.

Ceratochloa

1.400 (0.400–4.894)

9.333 (2.250–38.711)

6.562 (1.768–24.353)

1.406 (0.367–5.386)

Bromus

vs.

Genea

0.167 (0.029–0.965)

0.583 (0.101–3.358)

0.583 (0.101–3.358)

0.125 (0.021–0.737)

Ceratochloa

vs.

Genea

0.119 (0.018–0.795)

0.063 (0.008–0.471)

0.089 (0.013–0.621)

0.089 (0.013–0.621)

Early year

147

25.6954 <0.0001

1.042 (1.026–1.059)

30.1648 <0.0001

0.971 (0.961–0.982)

31.0694 <0.0001

0.971 (0.961–0.981)

24.5799 <0.0001

0.965 (0.952–0.979)