Modelling the Spatial Invasive Range of Heracleum mantegazzianum in Europe

Abstract

The Western Caucasian plant Heracleum mantegazzianum (Giant Hogweed) is invading various parts of Europe at fast pace. This invasion is problematic, because the phytotoxic sap of Heracleum mantegazzianum can cause severe inflammations in human skin. To effectively take management actions, the potential spatial distribution of Giant Hogweed in Europe needs to be assessed. Usually, potential distribution is modelled based on parameters of the ecological niche as realised in a species native range. However, from the western Caucasus no observation data are available. This research investigates whether an environmental envelope model can reliably project the potential distribution of an invasive plant with observations from the invaded range only. Historic invaded-range observations in Europe were used to produce a time series of potential distribution maps. The results showed that the modelled area of potential distribution initially grew larger as new observations became available over time, until the area consolidated despite adding new observations. It is argued that this “point of consolidation” indicates the point in time, from when it is valid to project potential ranges of invasion with invaded-range observations only. For Giant Hogweed the potential range of invasion covers most parts of Europe and Central Russia.