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

162

Table 6.2

(continued) Factor

Hypothesis

Basis/rationale

Independent variables

Comments based on analyses

11

Climate

Ability to grow in arid regions is correlated with invasiveness

Ability to adapt to extreme environmental conditions may provide competitive advantages

Minimum precipitation, Maximum precipitation

Lower minimum precipitation and higher maximum precipitation were correlated with wide introduction and weediness

12

Climate

Ability to adapt to varying precipitation levels is associated with invasiveness

Ability to adapt to extreme environmental conditions may provide competitive advantages

Precipitation range

Wider precipitation range was correlated with wide introduction and weediness

Variables used for analyses and comments are provided for each hypothesis

S.Y. Atkinson and C.S. Brown