Applications to the Invasion Success of Weeds

To illustrate the applicability (7.57), we compare it with published data of three different invasive weed species in their native and exotic ranges. In the exotic range, species can exhibit invasive behavior. The model should show that predicted 7nii values are higher than the actual plant fecundities in the native range and lower than actual plant fecundities in the exotic range. Although the three species studied show 

This is an annual plant native to the western Mediterranean basin which was introduced and became invasive in pastures in Australia. In [172] the authors compared its population dynamics in Evora, Portugal, where this plant is native, with Canberra, Australia, where this plant is exotic. From the published data we accurately estimated the parameters needed to evaluate T. As E. plantagineum is an annual, all surviving plants produce seed once at age 1 yr and die. This presents the case in (7.63) with n = 1. To estimate the parameters Y and Oq, we average the data published in [172] over all the populations considered. If one assumes that seeds produced can survive in the seedbank up to 6 yr [172], then 

This leguminous shrub is native to western Europe and has become an invasive weed in some Australian ecosystems, suppressing native species and increasing fire risk [212], We compare the population dynamics of this species in a native habitat in southern France [344] with those from an invasive population in Australia [396], 

Finally, one can estimate the germination distribution using that 18% of the flowering plants produced seeds in their first flowering year (at 3 yr of age), as noted in [396]. Assuming that after the second flowering year all surviving plants (they can survive up to 20 yr) could produce seeds, we obtain a PDF for seed production over time of the form 

The estimated values of Y and Y j for the native and exotic range in Table 7.4 are as expected for noninvasive and invasive populations, respectively, except for the SC subpopulation in the native range, which our T and Tmin estimates suggest should exhibit invasive behavior. However, the SC subpopulation relates to a disturbed treatment, and survival was very different from that found in other subpopulations in the same study. We conclude that this case is not representative of the characteristic behavior of C. scoparius in its native range. 

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