Fig. 1
From: Demographic amplification is a predictor of invasiveness among plants
Projections of stable and transient population dynamics of two thistle species. Cirsium pitcheri (blue) is a non-invasive species whose life cycle in the native range is discretised into three life-stages (1 = seedling, 2 = rosette, 3 = flowering adult)33 and measured as annual rates of per-capita transition among them. Cirsium arvense (red) is invasive (life-stages 1 = seed, 2 = rosette, 3 = flowering adult)34. Predicted population dynamics (polygons) are initiated at initial population size of 1 and projected for twenty years. Solid central lines project dynamics of a population initiated at stable stage structure. Polygons capture the envelope of amplification and attenuation achieved by non-stable initial stage structures. Polygon boundaries are functions of time (t), stable rate of increase (λ), and demographic inertia (\(\bar \rho _\infty\) and ρ∞ describing amplification and attenuation, respectively). C. pitcheri, the non-invasive species, increases slowly and has a narrow envelope of amplification and attenuation. C. arvense, the invasive species, increases rapidly and has a wide envelope of amplification and attenuation. We ask, across plant species, can stable growth rates or demographic inertia, measured in the native range, predict the invasiveness of plants in their naturalised range?.
