Speed Presentation 2024 Australian Marine Sciences Association Annual Meeting combined with NZMSS

Quantifying and Predicting Spatial Extent of Invasions (#320)

Kyle Hilliam 1 2 , Oliver Floerl 3 , Ian Davidson 1 , Simone Stevenson 2 , Abraham Growcott 4 , Eric A Treml 5
  1. Biosecurity Team, Cawthron Institute, Nelson, New Zealand
  2. Deakin Marine Research and Innovation Centre & School of Life and Environmental Sciences, Deakin University, Melbourne, Victoria, Australia
  3. LWP Ltd, Christchurch, Canterbury, New Zealand
  4. Aquatic Biosecurity Surveillance, Ministry for Primary Industries , Wellington, New Zealand
  5. Marine Ecology & Biosecurity, Australian Institute of Marine Science, Perth, Western Australia, Australia

Understanding the drivers of spread for marine nonindigenous species is an important topic in invasion ecology and for effective marine pest management. Previous research has highlighted species traits, environmental factors, and duration as important variables, but explicit inclusion of transport pathway dynamics is often overlooked. We used data from two spatial repositories for marine invasive distributions to quantify invader spread patterns through relativised linear spread and total extent (area) annually and cumulatively across their invasions. These data were then tied to a quantitative network framework of nationwide recreational and commercial vessel movements. Increases in annual coastal invasion distance per species ranged from tens to thousands of kilometres. Vessel traffic volume, connection strength, and directionality were higher for invaded locations than for uninvaded locations. The location of initial incursion and vessel pathways contribute to the extent of invasions over time. This modelling framework can help us understand the spatial patterns of marine invasions and inform risk assessment and resource allocation for implementing biosecurity measures.