Assessing and explaining plant invasion distribution across French Polynesian islands

This project concerns assessing and explaining the distribution of plant invasion in French Polynesian islands. The French Polynesian islands are a biodiversity hotspot, however invasive plant species which have been transported by humans to these islands are a major threat to this biodiversity. Islands are disproportionately affected by invasive alien species and are more at risk of biodiversity loss and extinction of native species, many of which are endemic.

This project will address the challenges of plant invasion in French Polynesian islands by using ecological modelling and exploring the role of socioeconomic factors in plant invasion to provide insights into how invasive plant species can be managed to protect native species.

I will use invasive plant species occurrence data in Pacific islands from the PaciFlora database together with environmental data to develop species distribution models. Species distribution models are based on the concept that ecological niches involve a collection of environmental variables, each variable having a range of values within which the species can survive.

Predictions of species presence can then be mapped to geographical areas based on their environmental suitability for the species in conjunction with knowledge of the range in which the species is currently inhabiting (species occurrence data). I will utilise ensemble modelling techniques, factoring in climate and topography, to predict invasion levels in French Polynesian islands.

These model predictions will then be compared to the actual extent of plant invasion in individual islands in order to highlight islands where the invasive species performed differently than the model predicted, indicating that other factors are involved. Previous scenario analysis has linked socioeconomic factors such as trade, population density, and agricultural practices to plant invasion.

I will carry out an in-depth analysis of the role of these socioeconomic factors in driving plant invasion to determine areas where intervention would have the greatest positive impact, thus providing guidance for future management and conservation strategies.

I will also compare the expected distributions of different invasive plant species to their actual distributions to assess their performance within their ecological niches. This will reveal which species are either underperforming in environmental conditions which they are well suited to or performing better than anticipated. I will explore the relationship between relative performance of different invasive species, their ecological niche, and society to gain insight into how plant invasion occurs and how a range of environmental factors and human activities contribute to habitat invasibility across French Polynesian islands.

In summary, this project seeks to understand the underlying driving factors of plant invasion and the distribution of invasive plant species across French Polynesian islands. Furthermore, by combining this analysis with expert opinions and research findings, and by engaging with local communities and stakeholders, this project aims to provide insights which will inform management and conservation efforts on how to better guard against and prepare for future plant invasion in French Polynesian Islands.