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

Abstract

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.

Do the Leaves of Multiple Invasive Plants Decompose More Easily than a Native Plant’s under Nitrogen Deposition with Different Forms?

“…Invasive plants have caused serious ecological risks to native ecosystems, and invaders can especially lead to biodiversity loss [1][2][3][4]. The number of species of invasive plants in China is 515, and 92 species of these invasive plants (~17.86%) are in the Asteraceae family [5,6].…”

Changes in Community Composition and Functional Traits After Cyclones and Fire in a Pacific Rainforest

“…The high abundance of Funtumia elastica in areas that experienced both cyclones and burning (Table 2) raises serious concerns because invasive plants can change ecosystem structure and dynamics and out-compete native species to form near mono-dominant stands in rainforest (Walker and Vitousek 1991, Meyer and Florence 1996, Brown et al 2006, Dyer et al 2018, Forey et al 2023). For example, the ability to form almost mono-dominant stands in rainforests has been documented for both, Miconia calvescens DC.…”

Review of Invasive Plant Functional Traits and Management Using Remote Sensing in Sub-Saharan Africa

“…Invasive alien plants (hereafter IAPs) are considered environmental pollutants because, like other pollutants, they are threatening human well-being and livelihoods [1,2], biodiversity, and natural ecosystems [3][4][5]. They cause biodiversity loss and functional changes [6,7], endangering and/or suppressing native (local or indigenous) species [3,8], and forming novel plant communities [1,9]. They are one of the major factors inducing biotic homogenization [9], which is defined by an increase in genetic, taxonomic, or functional similarities across different sites over a predetermined period of time [10,11].…”

“…They cause biodiversity loss and functional changes [6,7], endangering and/or suppressing native (local or indigenous) species [3,8], and forming novel plant communities [1,9]. They are one of the major factors inducing biotic homogenization [9], which is defined by an increase in genetic, taxonomic, or functional similarities across different sites over a predetermined period of time [10,11]. They alter the community structure and composition of recipient environments by displacing or suppressing the abundance and/or species richness of native species [12,13].…”

“…They alter the community structure and composition of recipient environments by displacing or suppressing the abundance and/or species richness of native species [12,13]. A study conducted by Forey et al [9] in a Fijian rainforest provides evidence in favor of this, showing that IAP Pinanga coronata (Blume) Blume decreased native species richness and Shannon diversity by 50% and 33%, respectively. Another study in southern Poland by Stefanowicz et al [14] showed that IAP (Solidago gigantean Aiton) decreased soil microbe biomass and microbial activity.…”