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/ The aim of this work is to study the invasion system constituted by the alien species Gleditsia triacanthos and the native dominant Lithraea ternifolia in montane forests of central Argentina, considering life history and demographic traits of both the alien and the native species and different site conditions for population growth (good and bad sites). Matrix models are applied to project the consequences of differences in vital rates for population growth. Analyzing these models helps identify which life cycle transitions contributed most to population growth. Obtained population growth rates are considered to assess predicted rates of spread using the reaction-diffusion (R-D) model. G. triacanthos presents many of the life history traits that confer plants high potential for invasiveness: fast growth, clonal and sexual reproduction, short juvenile period, high seed production, and high seed germinability. These traits would ensure G. triacanthos invasive success and the displacement of the slow-growing, relatively less fecund native L. ternifolia. However, since disturbance and environmental heterogeneity complicate the invasibility pattern of G. triacanthos in these montane forests, the outcome of the invasion process is not straightforward as could be if only life history traits were considered.Great variation in demographic parameters was observed between populations of each species at good and bad sites. Though both good and bad sites signified increasing or at least stable populations for G. triacanthos, for L. ternifolia bad sites represented local extinction. Analyzing the results of matrices models helps design the optimal management for the conservation of L. ternifolia populations while preventing the invasion by G. triacanthos. The predicted asymptotic rate of spread for G. triacanthos at the good site was fourfold greater than the predicted one for L. ternifolia, although the difference was much smaller considering the bad site. The usefulness of the R-D model to study this invasion system is discussed.

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Dispersal is a factor of great importance in determining a species spatial distribution. Short distance dispersal (SDD) and long distance dispersal (LDD) strategies yield very different spatial distributions. In this paper we compare spatial spread patterns from SDD and LDD simulations, contrast them with patterns from field data, and assess the significance of biological and population traits. Simulated SDD spread using an exponential function generates a single circular patch with a well‐defined invasion front showing a travelling‐wave structure. The invasive spread is relatively slow as it is restricted to reproductive individuals occupying the outer zone of the circular patch. As a consequence of this dispersal dynamics, spread is slower than spread generated by LDD. In contrast, the early and fast invasion of the entire habitat mediated by power law LDD not only involves a significantly greater invasion velocity, but also an entirely different habitat occupation. As newly dispersed individuals soon reach very distant portions of the habitat as well as the vicinity of the original dispersal focus, new growing patches are generated while the main patch increases its own growth absorbing the closest patches. As a consequence of both dispersal and lower density dependence, growth of the occupied area is much faster than with SDD. SDD and LDD also differ regarding pattern generation. With SDD, fractal patterns appear only in the border of the invasion front in SDD when competitive interaction with residents is included. In contrast, LDD patterns show fractality both in the spatial arrangements of patches as well as in patch borders. Moreover, values of border fractal dimension inform on the dispersal process in relation with habitat heterogeneity. The distribution of patch size is also scale‐free, showing two power laws characteristic of small and large patch sizes directly arising from the dispersal and reproductive dynamics. Ecological factors like habitat heterogeneity are relevant for dispersal, although its importance is greater for SDD, lowering the invasion velocity. Among the life history traits considered, adult mortality, the juvenile bank and mean dispersal distance are the most relevant for SDD. For LDD, habitat heterogeneity and changes in life history traits are not so relevant, causing minor changes in the values of the scale‐free parameters. Our work on short and long distance dispersal shows novel theoretical differences between SDD and LDD in invasive systems (mechanisms of pattern formation, fractal and scaling properties, relevance of different life history traits and habitat variables) that correspond closely with field examples and were not analyzed, at least in this degree of detail, by the previously existing models.

Occupancy of new habitats through dispersion is a central process in nature. In particular, longdistance dispersal is involved in the spread of species and epidemics, although it has not been previously related with cancer invasion, a process that involves cell spreading to tissues far away from the primary tumour.Using simulations and real data we show that the early spread of cancer cells is similar to the species individuals spread and we suggest that both processes are represented by a common spatio-temporal signature of long-distance dispersal and subsequent local proliferation. This signature is characterized by a particular fractal geometry of the boundaries of patches generated, and a powerlaw scaled, disrupted patch size distribution. In contrast, invasions involving only dispersal but not subsequent proliferation ("physiological invasions") like trophoblast cells invasion during normal human placentation did not show the patch size power-law pattern. Our results are consistent under different temporal and spatial scales, and under different resolution levels of analysis.We conclude that the scaling properties are a hallmark and a direct result of long-distance dispersal and proliferation, and that they could reflect homologous ecological processes of population selforganization during cancer and species spread. Our results are significant for the detection of processes involving long-range dispersal and proliferation like cancer local invasion and metastasis, biological invasions and epidemics, and for the formulation of new cancer therapeutical approaches.