Closely related invasive species may be controlled by the same demographic life stages

Invasive species that are closely related to each other may have similar population dynamics and, therefore, be controlled by targeting life stages. We studied two invasive knapweed species, spotted (Centaurea stoebe subsp. micranthos) and the hybrid meadow complex ( Centaurea × moncktonii ) in New York, USA, determine their individual growth rates (λ) across several sites over three years. Both had were greater than 1 (spotted λ ranged from 1.005–1.440; 1.541–2.408), but there was high variability between years sites. One study of composed primarily individuals black ancestry C. nigra ), a that, while introduced, is not invasive. For this population, projected stable (λ approximately 1). Elasticity analysis showed flowering-to-flowering stage contributed most rate for six seven additional transitions also influential four knapweed: seedling-to-vegetative stage, vegetative-to-flowering flowering-to-seedling stage. simulated how increasing vital would affect found both followed same pattern. The established seedlings maturing flowering plants greatest effect on growth, survival new seedlings. In all cases, responses non-linear, with small initial changes having large effect. Increases later stages tended positive rate, effects more modest. Although sensitivity indicated early largest these practical management. Rather, reducing older or delaying maturation vegetative effective. similarity contributes provides support protocols developed one should effective caveat any biological control agent directly tested target before being utilised.