TY - JOUR

T1 - A functional trait-based approach to assess the impact of an alien palm invasion on plant and soil communities on a South Pacific island

AU - Forey, Estelle

AU - Lodhar, Sherri

AU - Gopaul, Sunil

AU - Boehmer, Hans Juergen

AU - Chauvat, Matthieu

N1 - Funding Information: We thank the European Commission for the attribution of the Erasmus Mundus Grant to E.F. that allowed us to establish this international research cooperation project. Lastly, we thanks the two anonymous reviewers for their suggestions and comments.

PY - 2021/4/20

Y1 - 2021/4/20

N2 - In island ecosystems, biological invasions are one of the major threats to native biodiversity and to ecosystem functioning. Invasive ornamental plants such as the alien palm tree Pinanga coronata in the Fiji islands can form mono-dominant stands in rainforests and displace native species. Using a functional trait-based approach, we investigated the impact of P. coronata on both above and belowground communities (i.e. plants and Collembola). Within a rainforest reserve on Fiji´s principal island, we sampled a total of 10 invaded and non-invaded plots and recorded five functional traits for plants and six for Collembola. We found that invasion by P. coronata led to a strong and significant decrease of native plants and Collembola taxonomic diversity. Ingress of P. coronata also induced a decrease in the functional diversity of plant communities and to a lesser extent of Collembola communities. P. coronata invasion led to a decrease of leaf carbon–nitrogen ratio (LCN), Leaf nitrogen content (LN), specific leaf area (SLA) and leaf dry matter content (LDMC) of plant communities, suggesting a change in litter properties compared to non-invaded communities. Plots with P. coronata were associated with large Collembola living at the soil surface with more trichobothria and pseudocelli, which are used as defence mechanisms. Using trait-matching, we also found that the strength of plant-soil relationships was higher (i.e. more stable) in non-invaded plots than in P. coronata-invaded plots. Lastly this study suggests that the main mechanism through which P. coronata alters soil communities is a change in plant properties rather than a change in the abiotic environment. Our trait-based approach underlines the negative impact of this alien palm invasion on native rainforest plant and soil fauna in Fiji, and the urgent need for on-the-ground action to conserve terrestrial island biodiversity in Fiji´s rainforests.

AB - In island ecosystems, biological invasions are one of the major threats to native biodiversity and to ecosystem functioning. Invasive ornamental plants such as the alien palm tree Pinanga coronata in the Fiji islands can form mono-dominant stands in rainforests and displace native species. Using a functional trait-based approach, we investigated the impact of P. coronata on both above and belowground communities (i.e. plants and Collembola). Within a rainforest reserve on Fiji´s principal island, we sampled a total of 10 invaded and non-invaded plots and recorded five functional traits for plants and six for Collembola. We found that invasion by P. coronata led to a strong and significant decrease of native plants and Collembola taxonomic diversity. Ingress of P. coronata also induced a decrease in the functional diversity of plant communities and to a lesser extent of Collembola communities. P. coronata invasion led to a decrease of leaf carbon–nitrogen ratio (LCN), Leaf nitrogen content (LN), specific leaf area (SLA) and leaf dry matter content (LDMC) of plant communities, suggesting a change in litter properties compared to non-invaded communities. Plots with P. coronata were associated with large Collembola living at the soil surface with more trichobothria and pseudocelli, which are used as defence mechanisms. Using trait-matching, we also found that the strength of plant-soil relationships was higher (i.e. more stable) in non-invaded plots than in P. coronata-invaded plots. Lastly this study suggests that the main mechanism through which P. coronata alters soil communities is a change in plant properties rather than a change in the abiotic environment. Our trait-based approach underlines the negative impact of this alien palm invasion on native rainforest plant and soil fauna in Fiji, and the urgent need for on-the-ground action to conserve terrestrial island biodiversity in Fiji´s rainforests.

KW - above-belowground interactions

KW - biodiversity

KW - biological invasion

KW - collembola

KW - functional traits

KW - Pinanga coronata

KW - plant communities

KW - rainforest

UR - http://www.scopus.com/inward/record.url?scp=85099225482&partnerID=8YFLogxK

U2 - 10.1111/aec.12995

DO - 10.1111/aec.12995

M3 - Article

AN - SCOPUS:85099225482

VL - 46

SP - 398

EP - 410

JO - Austral ecology

JF - Austral ecology

SN - 1442-9985

IS - 3

ER -