# A Novel Invertebrate Predator on an Oceanic Island: Impacts and Invasion Dynamics of Kontikia andersoni on Macquarie Island

## TL;DR

This study explores how the invasive flatworm Kontikia andersoni affects invertebrate diversity on Macquarie Island and identifies environmental factors influencing its spread.

## Contribution

The study identifies specific abiotic factors influencing the invasive flatworm's distribution and quantifies its ecological impact on native invertebrates.

## Key findings

- Presence of Kontikia andersoni at higher elevations correlates with reduced invertebrate richness.
- Slope and wind speed are key abiotic factors influencing flatworm distribution.
- Habitat suitability models identify invasion-prone areas for targeted biosecurity.

## Abstract

Sub‐Antarctic islands, characterised by high endemism and invertebrate‐dominated terrestrial ecosystems, hold significant conservation value and are vulnerable to biological invasion. On Macquarie Island, the invasive terrestrial flatworm
Kontikia andersoni
poses a threat to native biodiversity and ecosystem functioning. To determine the impacts of this invasive predator on native invertebrate communities, we examined species co‐occurrence data and community composition from multiple sites across the island. Our findings indicate that at higher elevations where
K. andersoni
is present, there are significant reductions in invertebrate richness. Additionally, of the abiotic factors tested, slope and topographically deflected wind speed explained the highest amount of variation in flatworm distribution. Habitat suitability modelling identified areas at risk of invasion, providing targets for future biosecurity surveys. This study enhances our understanding of
K. andersoni
invasion dynamics and informs conservation efforts on Macquarie Island.

This study examines the invasion dynamics of the predatory invertebrate flatworm
Kontikia andersoni
, and its impacts on the invertebrate communities of sub‐Antarctic Macquarie Island. Our findings indicate that at higher elevations where
K. andersoni
is present there are significant reductions in invertebrate richness. The abiotic factors slope and topographically deflected wind speed were found to explain the highest amount of variation in flatworm distribution.