Its all about connections: hubs and invasion in habitat networks

Authored by Thibaut Morel-Journel, Claire Rais Assa, Ludovic Mailleret, Elodie Vercken

Date Published: 2019

DOI: 10.1111/ele.13192

Sponsors: European Union

Platforms: R

Model Documentation: Other Narrative

Model Code URLs: https://datadryad.org/stash/dataset/doi:10.5061/dryad.1g3gp03

Abstract

During the early stages of invasion, the interaction between the features of the invaded landscape, notably its spatial structure, and the internal dynamics of an introduced population has a crucial impact on establishment and spread. By approximating introduction areas as networks of patches linked by dispersal, we characterised their spatial structure with specific metrics and tested their impact on two essential steps of the invasion process: establishment and spread. By combining simulations with experimental introductions of Trichogramma chilonis (Hymenoptera: Trichogrammatidae) in artificial laboratory microcosms, we demonstrated that spread was hindered by clusters and accelerated by hubs but was also affected by small-population mechanisms prevalent for invasions, such as Allee effects. Establishment was also affected by demographic mechanisms, in interaction with network metrics. These results highlight the importance of considering the demography of invaders as well as the structure of the invaded area to predict the outcome of invasions.

Tags

Individual-based model Simulation Social networks Evolution connectivity Infection Diversity Network Landscape connectivity Conservation Dispersal invasion Spread Establishment Gypsy-moth Allee effect Hub Microcosm Patches