Preference for an invasive fruit trumps fruit abundance in selection by an introduced bird in the Society Islands, French Polynesia

In the past century, our understanding of the processes driving plant invasion and its consequences for natural and anthropogenic systems has increased considerably. However, the management of invasive plants remains a challenge despite ever more resources being allocated to their removal. Often invasive plants targeted for 'eradication' are well-established, have multiple modes of reproduction, long-term seed banks, and strong associations with native and non-native mutualists that ensure dispersal and facilitate spread. The pantropical weed, Lantana camara (Lantana), is one of the most invasive woody plants globally. We illustrate that, for Lantana, eradication is an unrealistic management goal given the short-term removal approaches, irrespective of the effectiveness of removal methods. We assessed the role of dispersal by avian frugivores in the recolonization of managed areas by Lantana in the seasonally dry, tropical forests of northern and southern India. We estimated the distribution of Lantana, its dispersal potential and the proximity between managed areas and source populations. We found that Lantana was dispersed by many generalist frugivorous birds and that most managed areas were well within the median dispersal distance from source plants facilitating rapid recolonization of managed areas. We conclude that given the difficulty of eradicating long-established invasive plants, management practices should entail long-term monitoring and control in priority areas for as long as Lantana occurs in the landscape.

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“…, Spotswood et al . ). Fleshy‐fruited invasive plants are thus seldom dispersal limited (Richardson et al .…”

mentioning

confidence: 97%

Dispersal by generalist frugivores affects management of an invasive plant

et al. 2016

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“…Fruits of these species are small, round, and fleshy and are red/dark purple in color. These appear to be characteristics of preferred fruit for the red‐vented bulbul (Spotswood et al., ). All of the consumed fruit species we identified here have red fleshy diaspore, including fruit of the shrub M. rufopunctatum that occurred frequently in bulbul gut samples.…”

Section: Discussionmentioning

confidence: 99%

“…They backed this up with reference to case studies where native dispersers preferred native plant‐of‐original characteristics, while non‐native birds such as the common starling ( Sturnus vulgaris ) preferred fruits of non‐native plant species. Preference for non‐native plant species has also been postulated for the introduced red‐vented bulbul ( Pycnonotus cafer ) in French Polynesia (Spotswood, Meyer, & Bartolome, ). Preferential seed dispersal of non‐native plant species by invasive passerines highlights an urgent need for quantitative assessments of the dispersal capacity of non‐native frugivorous species, especially in areas of high conservation value such as the world's biodiversity hotspots (Mittermeier, Turner, Larsen, Brooks, & Gascon, ).…”

Section: Introductionmentioning

confidence: 97%

“…They backed this up with reference to case studies where native dispersers preferred native plant-of-original characteristics, while non-native birds such as the common starling (Sturnus vulgaris) preferred fruits of non-native plant species. Preference for non-native plant species has also been postulated for the introduced red-vented bulbul (Pycnonotus cafer) in French Polynesia (Spotswood, Meyer, & Bartolome, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…It feeds predominantly on fruits (Brooks, 2013;Islam & Williams, 2000) and can consume leaves, flowers, and fruits of a large variety of species (Thibault, Vidal, Potter, Dyer, & Brescia, 2018), leading to significant impacts on agriculture and horticulture (Cummings, Mason, Otis, Davis, & Ohashi, 1994;Vander Velde, 2002;Walker, 2008). In its alien range, it has displayed a preference for numerous non-native plant species (Sherman & Fall, 2010;Spotswood et al, 2013), and it is able to defend preferred food resources from other frugivorous avifauna (Thibault, Martin, Penloup, & Meyer, 2002). Its recent dispersal out of urbanized habitats raises questions about its potential to disperse seeds of noxious plant species along urban corridors and beyond.…”

Section: Introductionmentioning

confidence: 99%

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“Liaisons dangereuses”: The invasive red‐vented bulbul (Pycnonotus cafer), a disperser of exotic plant species in New Caledonia

Thibault

Masse

Pujapujane

et al. 2018

Ecology and Evolution

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The biodiversity hotspot of New Caledonia hosts high levels of endemism (74% of flora) that is threatened increasingly by climate change, habitat reduction, and invasive species. The fruit‐eating red‐vented bulbul (Pycnonotus cafer) is currently invading the main island of the archipelago, and its recent dispersal out of urbanized habitats raises questions about its potential to disperse noxious plant seeds along urban corridors and beyond. Indeed, the red‐vented bulbul is considered a vector of several introduced plant species in its alien range including Miconia calvescens, Lantana camara, and Schinus terebinthifolius. We conducted a quantitative assessment of the bulbul's fruits consumption by analyzing the gut contents of shot birds. We estimated gut passage times for four species of fruit found in gut contents (S. terebinthifolius, Myrtastrum rufopunctatum, Passiflora suberosa, and Ficus prolixa) and tested the effects of bird digestion on seed germination rates for two species. Finally, we monitored the movements of individual VHF radio‐tagged red‐vented bulbuls. All of the consumed fruit species we identified here have red fleshy diaspore, including fruit of the shrub M. rufopunctatum that occurred frequently (9.6%) in bulbul gut samples. Median gut passage times were short (15–41 min), corresponding to short‐distance seed transportation (77–92 m). The effect of gut passage was positive for the germination of the invasive S. terebinthifolius and negative for the endemic M. rufopunctatum, suggesting a potential bias in the contribution to the dispersal toward alien species. This study provides the first integrated assessment of mechanisms involved in the seed dispersal effectiveness of this high‐concern invasive bird species that is expected to face similar plant communities in most of its alien range in tropical islands. More generally, our results enhance knowledge of synergies between non‐native frugivores and plant species dispersal.

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The red-vented bulbul (Pycnonotus cafer): serious pest or understudied invader?

Thibault

Vidal²,

Potter

et al. 2017

Biol Invasions

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Recently, debate has flourished about inadequacies in the simplistic ''worst invasive species'' approach and its global scale. Here we investigate the status of the red-vented bulbul (Pycnonotus cafer), an Asian passerine bird. This species has been introduced widely across Pacific islands and is commonly blamed for its impacts on agriculture and biodiversity via dispersal of invasive plant seeds and competition with native fauna. This case study evaluates all available data on the impacts and management of this invasive species and identifies priorities for future research. We reviewed the scientific literature and information from three databases (ABBA, GAVIA, eBird) and highlight that the attention paid to this species by scientists and managers varied considerably between islands and contexts and was globally lower than the attention paid to other species on the IUCN-ISSG list. The red-vented bulbul has now established on 37 islands and in seven continental locations outside its native range. We show that three categories of effects are associated with this species: plant damage, seed dispersal and disturbance of fauna. We compiled lists of 110 plant species consumed, 33 plant species dispersed, and 15 species of bird that this bulbul interacts with. However, these lists were mainly made of opportunistic observations rather than specific assessments. Research outputs that focus on better ways to prevent or quantify the impacts of the red-vented bulbul remain scarce. We found very few references exploring potential positive impacts of this species, and only two examples of management actions undertaken against it. The latter are required to inform management actions, especially on sensitive tropical islands where invasions and dispersal of the red-vented bulbul are ongoing. Our analysis of the literature found no clear support for considering this species to be one of the ''world's worst'' invasive alien species.

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Preference for an invasive fruit trumps fruit abundance in selection by an introduced bird in the Society Islands, French Polynesia

Cited by 20 publications

References 17 publications

Dispersal by generalist frugivores affects management of an invasive plant

Dispersal by generalist frugivores affects management of an invasive plant

“Liaisons dangereuses”: The invasive red‐vented bulbul (Pycnonotus cafer), a disperser of exotic plant species in New Caledonia

The red-vented bulbul (Pycnonotus cafer): serious pest or understudied invader?

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