Where to invade next: Inaction on biological invasions threatens sustainability in a small island developing state of the tropical South Pacific

Lenz, Marie-Isabell; Galvin, Stephen; Keppel, Gunnar; Gopaul, Sunil; Kowasch, Matthias; Dyer, Michael J.; Watling, Dick; Lodhar, Sherri; Hanson, Geon C.; Erasmi, Stefan; Boehmer, Hans Juergen

doi:10.1017/9780511977961.035

Cited by 3 publications

(1 citation statement)

References 46 publications

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“…In Fiji, approximately 390 invasive alien species have been identified (Lenz et al 2022). Among these, the non-native ivory cane palm Pinanga coronata (Blume ex Mart.)…”

Section: Introductionmentioning

confidence: 99%

Alien palm invasion leads to selective biotic filtering of resident plant communities towards competitive functional traits

Forey¹,

Lodhar

Galvin

et al. 2023

Biol Invasions

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Biological invasions drive biodiversity loss and ecosystem change on tropical islands. However, we know little about the implications of species losses on the functional structure of both resident and novel communities. Herein, we examined the potential effect of a non-native palm species, Pinanga coronata, on the taxonomic and functional assemblages of understory plant species in a Fijian rainforest. We predicted that competition from this invasive species would lead to trait convergence according to the competitive hierarchy hypothesis. Using a trait-based approach, we sampled plant communities in 280 plots across a gradient of P. coronata densities. We measured five functional traits, including height and leaf traits related to nutrient acquisition. We found that an increase in P. coronata density is strongly correlated with a decrease in taxonomic diversity (i.e., about − 50% for species richness and − 33% for Shannon diversity index) and a decrease in functional richness. Community-weighted mean values of traits of resident species (i.e., excluding P. coronata) converged toward competitive strategies such as higher leaf nitrogen content (LNC), lower carbon-to-nitrogen (C:N) ratios and leaf dry matter content (LDMC), a pattern that is significantly non-random for LDMC and C:N. This study demonstrates that P. coronata might act as a strong biotic filter responsible for species loss and functional changes. Our findings suggest that in response to increasing competition with this invasive plant, resident and novel plant communities shift toward less diverse and more competitive assemblages. Nevertheless, the intensity of this filtering is habitat dependent (e.g. less filtering effect under mahogany trees). Lastly, changes in resource acquisition strategies (mainly nutrient-based) in particular in low nutrient status of rainforest soils, could lead to long-term impacts on tree regeneration, in turn causing large-scale changes in ecosystem properties.

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“…In Fiji, approximately 390 invasive alien species have been identified (Lenz et al 2022). Among these, the non-native ivory cane palm Pinanga coronata (Blume ex Mart.)…”

Section: Introductionmentioning

confidence: 99%

Alien palm invasion leads to selective biotic filtering of resident plant communities towards competitive functional traits

Forey¹,

Lodhar

Galvin

et al. 2023

Biol Invasions

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Capacity and capability of remote sensing to inform invasive plant species management in the Pacific Islands region

Chan,

Owers,

Fuller

et al. 2024

Conservation Biology

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The Pacific Islands region is home to several of the world's biodiversity hotspots, yet its unique flora and fauna are under threat because of biological invasions. These invasions are likely to proliferate as human activity increases and large‐scale natural disturbances unfold, exacerbated by climate change. Remote sensing data and techniques provide a feasible method to map and monitor invasive plant species and inform invasive plant species management across the Pacific Islands region. We used case studies taken from literature retrieved from Google Scholar, 3 regional agencies’ digital libraries, and 2 online catalogs on invasive plant species management to examine the uptake and challenges faced in the implementation of remote sensing technology in the Pacific region. We synthesized remote sensing techniques and outlined their potential to detect and map invasive plant species based on species phenology, structural characteristics, and image texture algorithms. The application of remote sensing methods to detect invasive plant species was heavily reliant on species ecology, extent of invasion, and available geospatial and remotely sensed image data. However, current mechanisms that support invasive plant species management, including policy frameworks and geospatial data infrastructure, operated in isolation, leading to duplication of efforts and creating unsustainable solutions for the region. For remote sensing to support invasive plant species management in the region, key stakeholders including conservation managers, researchers, and practitioners; funding agencies; and regional organizations must invest, where possible, in the broader geospatial and environmental sector, integrate, and streamline policies and improve capacity and technology access.

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The relationship between naturalized alien and native plant species: insights from oceanic islands of the south-east Pacific over the last 200 years

Cáceres-Polgrossi¹,

Rico²,

Parra³

et al. 2023

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Aim: The relationship between native and naturalized alien species has been widely studied, particularly across large geographic scales. However, our knowledge of the spatial and temporal variations of their relationships is still limited, particularly for remote oceanic islands such as those of the south-east Pacific and across islands and archipelagos. In this study, we aim to assess the relationships between native and naturalized alien species by analyzing their current patterns of species-area relationships at different spatial scales, in addition to temporal variations in species richness, over the last 200 years. Area: One island (Rapa Nui) and two archipelagos (Juan Fernandez and Desventuradas Islands) comprising a total of 11 oceanic islands of the south-east Pacific (OISEP). Methods: We assembled the most comprehensive dataset of the vascular flora of the OISEP from currently available island flora checklists and updated with recent publications. Each plant species was classified as being native or naturalized alien. We examined temporal changes by estimating species richness, naturalization rates and naturalized-to-native ratios over time based on the first collection year of each naturalized alien species. Then, we determined the best shape of naturalized alien species richness accumulation over time by contrasting the fit of lineal, exponential, sigmoidal and Weibull regressions. Finally, we analyzed the relationships between native and naturalized species firstly at the inter-archipelagic scale by fitting island species-area relationship models and secondly at the island scale by performing ranged major axis regression analysis on residual values. Results: The OISEP flora dataset contained 674 species of which 282 were native and 392 were naturalized alien. Native island species-area relationships were similar to those of the naturalized alien species. Naturalized alien species richness increased notably through time with two clear peaks in 1950 and 2000. A Weibull regression and an exponential shape over time were the most appropriate fits for naturalized alien species richness accumulations at the inter-archipelagic scale, which further emphasizes the notable increase in naturalized alien species richness experienced in the timeframe examined here. Main conclusions: The relationship between naturalized alien species richness and native species richness was found to be independent of the geographic scale. The number of naturalized alien species clearly exceeded the number of native species on most islands but also for the whole OISEP. The accumulation of newly detected naturalized alien species does not show any sign of saturation and it is likely that new species will arrive in the future. Increased efforts on monitoring, prevention and biosecurity are needed to halt biological invasions on these unique island ecosystems.

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Where to invade next: Inaction on biological invasions threatens sustainability in a small island developing state of the tropical South Pacific

Cited by 3 publications

References 46 publications

Alien palm invasion leads to selective biotic filtering of resident plant communities towards competitive functional traits

Alien palm invasion leads to selective biotic filtering of resident plant communities towards competitive functional traits

Capacity and capability of remote sensing to inform invasive plant species management in the Pacific Islands region

The relationship between naturalized alien and native plant species: insights from oceanic islands of the south-east Pacific over the last 200 years

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Where to invade next: Inaction on biological invasions threatens sustainability in a small island developing state of the tropical South Pacific

Cited by 3 publications

References 46 publications

Alien palm invasion leads to selective biotic filtering of resident plant communities towards competitive functional traits

Alien palm invasion leads to selective biotic filtering of resident plant communities towards competitive functional traits

Capacity and capability of remote sensing to inform invasive plant species management in the Pacific Islands region

﻿The relationship between naturalized alien and native plant species: insights from oceanic islands of the south-east Pacific over the last 200 years

Contact Info

Product

Resources

About

The relationship between naturalized alien and native plant species: insights from oceanic islands of the south-east Pacific over the last 200 years