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Naturalized alien floras still carry the legacy of European colonialism


The redistribution of alien species across the globe accelerated with the start of European colonialism. European powers were responsible for the deliberate and accidental transportation, introduction and establishment of alien species throughout their occupied territories and the metropolitan state. Here, we show that these activities left a lasting imprint on the global distribution of alien plants. Specifically, we investigated how four European empires (British, Spanish, Portuguese and Dutch) structured current alien floras worldwide. We found that compositional similarity is higher than expected among regions that once were occupied by the same empire. Further, we provide strong evidence that floristic similarity between regions occupied by the same empire increases with the time a region was occupied. Network analysis suggests that historically more economically or strategically important regions have more similar alien floras across regions occupied by an empire. Overall, we find that European colonial history is still detectable in alien floras worldwide.

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Fig. 1: Zeta diversity decline and retention rate for each empire.
Fig. 2: Drivers of alien species turnover in the different European empires.
Fig. 3: Networks of the four empires with nodes placed at the region centroids and edges (links) between the regions.

Data availability

All driver datasets used in the study are openly available and provide spatially explicit, gridded information and the aggregated data are provided in Supplementary Table 5. The GloNAF database together with the shapefile that was used to produce the maps have been published in a data paper35. All data and code are available on Zenodo and can be found here:

Code availability

All code is available on Zenodo and can be found here:


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P.P. and J.P. were supported by EXPRO grant no. 19-28807X (Czech Science Foundation) and long-term research development project RVO 67985939 (Czech Academy of Sciences). M.v.K. and M.W. were supported by the German Research Foundation DFG (M.v.K., 264740629; M.W., FZT118, 202548816). H.S. acknowledges support through the 2017–2018 Belmont Forum and BiodivERsA joint call for research proposals, under the BiodivScen ERA-Net COFUND programme and with the funding organization BMBF (AlienScenarios 16LC1807A). A.S. acknowledges funding from the Austrian Science Foundation FWF (grant no. I3757).

Author information

Authors and Affiliations



B.L. and F.E. designed the study. B.L. performed the analysis with input from G.L. B.L. led the writing with significant input from F.E. and S.D. Species data were provided by the GloNAF core team (F.E., M.v.K., M.W., W.D., P.P., J.P., H.K. and P.W.). All other authors (including A.S., H.S. and Q.Y.) contributed to the discussion and writing.

Corresponding author

Correspondence to Bernd Lenzner.

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Nature Ecology & Evolution thanks Nussaïbah Raja and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

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Extended data

Extended Data Fig. 1 Conceptual overview of the analyses performed in the study.

Conceptual overview of the analyses performed in the study. For each analysis, an interpretation of the metrics is provided (a-i; b-i; c-i) and the expectation based on the formulated hypotheses (a-ii & a-iii; b-ii & b-iii; c-ii & c-iii). ‘Random empire’ (a-ii & a-iii) relates to a hypothetical empire associated with a colonial power that has the same number of mainland and island regions in total and per UN geospatial region as the observed empire of that colonial power. ‘Sites’ refers to the respective spatial unit used in the analysis and can be a country or subnational region (for example, county or island).

Extended Data Fig. 2 Maximum extent of the four European Empires under consideration independent of the temporal dimension.

Maximum extent of the four European Empires under consideration independent of the temporal dimension. All regions have been included at some point in the respective empire. Regions with an area < 50000 km2 are additionally highlighted by a circle. Saturation of the colour indicates the total time in years the region was occupied by the respective empire. The bar graph shows the extent of the European Empires (that is, number of regions) over time from 1492-2010.

Supplementary information

Supplementary Information

Supplementary Figs, 1–13 and Tables 1–3, 6 and 7.

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Supplementary Table

Supplementary Tables 4 and 5.

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Lenzner, B., Latombe, G., Schertler, A. et al. Naturalized alien floras still carry the legacy of European colonialism. Nat Ecol Evol 6, 1723–1732 (2022).

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