A multi-scale modelling framework to guide management of plant invasions in a transboundary context

João Martins,Hélia Marchante,Paulo Alves,Renato Henriques,David M Richardson,Elizabete Marchante,Mirijam Gaertner,Joana R Vicente,João P Honrado

doi:10.1186/s40663-016-0073-8

Abstract

Attention has recently been drawn to the issue of transboundary invasions, where species introduced and naturalized in one country cross international borders and become problematic in neighbouring countries. Robust modelling frameworks, able to identify the environmental drivers of invasion and forecast the current and future potential distribution of invasive species, are needed to study and manage invasions. Limitations due to the lack of species distribution and environmental data, or assumptions of modelling tools, often constrain the reliability of model predictions. We present a multiscale spatial modelling framework for transboundary invasions, incorporating robust modelling frameworks (Multimodel Inference and Ensemble Modelling) to overcome some of the limitations. The framework is illustrated using Hakea sericea Schrad. (Proteaceae), a shrub or small tree native to Australia and invasive in several regions of the world, including the Iberian Peninsula. Two study scales were considered: regional scale (western Iberia, including mainland Portugal and Galicia) and local scale (northwest Portugal). At the regional scale, the relative importance of environmental predictors sets was evaluated and ranked to determine the main general drivers for the species distribution, while the importance of each environmental predictor was assessed at the local scale. The potential distribution of H. sericea was spatially projected for both scale areas. Model projections for western Iberia suggest that a large area is environmentally suitable in both Portugal and Spain. Climate and landscape composition sets were the most important determinants of this regional distribution of the species. Conversely, a geological predictor (schist lithology) was more important in explaining its local-scale distribution. After being introduced to Portugal, H. sericea has become a transboundary invader by expanding in parts of Galicia (Spain). The fact that a larger area is predicted as environmentally suitable in Spain raises concerns regarding its potential continued expansion. This highlights the importance of transboundary cooperation in the early management of invasions. By reliably identifying drivers and providing spatial projections of invasion at multiple scales, this framework provides insights for the study and management of biological invasions, including the assessment of transboundary invasion risk.

Highlights

Attention has recently been drawn to the issue of transboundary invasions, where species introduced and naturalized in one country cross international borders and become problematic in neighbouring countries
The parallel concept of transboundary invasions, where a species introduced in a given country expands into neighbouring countries has so far received much less attention, despite being discussed in recent publications (e.g. Hulme 2015; Roques et al 2016) and legislation calling for concerted action between countries (European Parliament and Council of the European Union 2014)
At local scale the prediction was obtained from the projection of the ensemble of models from biomod2

Summary

Introduction

Attention has recently been drawn to the issue of transboundary invasions, where species introduced and naturalized in one country cross international borders and become problematic in neighbouring countries. The parallel concept of transboundary invasions, where a species introduced in a given country expands into neighbouring countries has so far received much less attention, despite being discussed in recent publications Hulme 2015; Roques et al 2016) and legislation calling for concerted action between countries (European Parliament and Council of the European Union 2014) Progress in this area demands that traditional risk assessment methodologies be expanded to include multiple countries (Hulme 2015). In this paper we apply species distribution models to predict invasion patterns in a transboundary context

Methods

Results

Discussion

Conclusion