Aliens will provide: avian responses to a new temporal resource offered by ornithocorous exotic shrubs

Vergara-Tabares, David L.; Toledo, Martín; García, Emiliano Hinojo; Peluc, Susana Inés

doi:10.1007/s00442-018-4207-2

Cited by 16 publications

(17 citation statements)

References 52 publications

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“…From our observations and remote camera-trap data, results support that birds are important potential seed dispersers (Díaz Vélez et al 2018, Vergara-Tabares et al 2018). This showed that bird species are effective seed dispersers of P. angustifolia.…”

Section: Discussionsupporting

confidence: 67%

Seed Dispersal by Frugivores and Germination Success of the Invasive Alien Shrub Pyracantha Angustifolia in the Eastern Free State Province, South Africa

Adams

Martin

Downs

et al. 2021

Preprint

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Invasive alien plants can use animal-plant interactions to increase their invasiveness. This study investigated the role of frugivorous birds in seed dispersal and germination of the alien plant Pyracantha angustifolia (Rosaceae) in South African high elevation grasslands. We monitored which bird species fed on the fruit of the invasive P. angustifolia in some farms in the Eastern Free State Province using camera-traps and direct surveillance. Nine bird species visited P. angustifolia shrubs to perch or feed on fruits, but only one bird (Speckled Mousebird) fed on the fruits during timed observations. To assess the effect of ingestion by avian frugivores on P. angustifolia germination, P. angustifolia fruits were fed to captive Cape White-eyes (Zosterops virens), Dark-capped Bulbuls (Pycnonotus tricolor), Purple-crested Turacos (Gallirex porphyreolophus), Red-winged Starlings (Onychognathus morio) and Speckled Mousebirds (Colius striatus). Seeds collected from bird excreta, whole fruits, and depulped fruits were grown under greenhouse conditions and germination rates recorded. All captive bird species, except for Cape White-eyes, ingested the seeds; Cape White-eyes only fed on fruit pulp that they had manually removed. Bird species with relatively larger body mass had longer seed retention times compared with the smaller bird species. Germination success of both depulped and ingested P. angustifolia seeds was high (> 80%) and that of whole fruits low (7%). Ingestion by the four avian frugivore species did not affect germination rate and success; instead, the birds facilitate the spread and germination of seeds by removing the fruit pulp and spreading the seed away from the parent shrubs.

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Section: Discussionsupporting

confidence: 67%

Seed Dispersal by Frugivores and Germination Success of the Invasive Alien Shrub Pyracantha Angustifolia in the Eastern Free State Province, South Africa

Adams

Martin

Downs

et al. 2021

Preprint

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“…2a). An additional factor that may be operating in the pattern of fruit removal, is the abundance of seed disperser birds which was shown to be similar among invasion situations in a previous study (Vergara-Tabares et al 2018a). As the increase in frugivory by birds was observed only during the overlapping period at invaded sites, the facilitation of the fruit removal of the native tree would be driven by an increase in seed dispersers in response to overall fruit supply (Gleditsch and Carlo 2011).…”

Section: Does Invasion By Fleshy Fruited Species Disrupt or Facilitate Native Seed Dispersal Mutualisms?mentioning

confidence: 74%

“…Four of the sites are invaded by Pyracantha angustifolia (Rosaceae) and Pyracantha atalantoides , species native to eastern Asia which have established mainly on stream margins but rarely on ravine slopes (Vergara‐Tabares unpubl.). Both Pyracantha species produce fruit during early autumn to late winter (September), when fruit resources from native plant species are scarce or absent (Vergara‐Tabares et al 2016, 2018a). Pyracantha covered less than 20% (hereafter ‘low invasion') in two invaded sites (Los Hornillos: 31°54′6.88″S, 64°58′35.24″W; Las Calles: 31°51′1.68″S, 64°56′18.37″W) and between 30 and 40% (‘high invasion') in other two invaded sites (La Población: 32°3′32.12″S, 64°59′57.08″W; San Javier: 32°1′36.97″S, 64°59′41.70″W).…”

Section: Methodsmentioning

confidence: 99%

Fleshy‐fruited invasive shrubs indirectly increase native tree seed dispersal

Vergara-Tabares

Blendinger

Tello

et al. 2021

Oikos

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Biological invasions are one of the main threats to biodiversity and ecosystem functioning in the Anthropocene. Fleshy-fruited invasive plants establish mutualistic interactions with native seed dispersers and may affect the mutualisms between native partners, negatively by disrupting plant dispersal through competition for seed dispersers or positively by facilitating seed dispersal via the attraction of fruit-eating animals. Moreover, the invaders' density in the neighborhood of native plants may modulate the direction and/or magnitude of such effects on natives. In mountains of central Argentina, the cessation of fruiting of the dominant native tree Lithraea molleoides overlaps with the beginning of the fruiting of invasive shrubs (Pyracantha spp.). This partial overlap allows for testing opposite predictions regarding the effect of invasive fruits on native seed dispersal. We compared frugivory by seed disperser birds on L. molleoides during non-overlapping and overlapping periods, at six sites that differed in Pyracantha shrub density (high, low and no-invasion). We counted frugivory during 2 h on 15 individuals of L. molleoides at each site and period, totaling 360 h of observation. Frugivory on the native tree was similar among sites during the non-overlapping period and remained constant in both periods at non-invaded sites. At invaded sites, frugivory increased from non-overlapping to overlapping period and was greater at highly invaded sites. The resource provided by Pyracantha did not disrupt seed dispersal of the dominant native tree. Rather, it facilitated frugivory by seed dispersers and this effect may be exacerbated with higher fruit availability of invasives. Our results provide a counterview to the prevailingly negative impacts of invasive species on the seed dispersal of native species since the fruiting of invasive plants facilitated the seed dispersal of native species in a continental region contrasts with the mutualism disruption commonly observed in insular environments.

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“…(iv) Firethorn ( Pyracantha angustifolia ) is an evergreen and thorny shrub from China whose fleshy fruits are dispersed by birds (Vergara‐Tabares et al . , ). (v) Chinaberry ( Melia azedarach ) is a deciduous tree from Southeast Asia probably dispersed by birds and bats (Mabberley ; Voigt et al .…”

Section: Methodsmentioning

confidence: 99%

“…, ; Vergara‐Tabares et al . ), with the dispersal stage overlapping with the fire season (Giorgis et al . ; Argañaraz et al .…”

Section: Introductionmentioning

confidence: 99%

Post‐burning germination responses of woody invaders in a fire‐prone ecosystem

et al. 2019

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It has been frequently recognised that there is a positive feedback between plant invasion and fire underlying invasion success in fire-prone ecosystems. Accordingly, the response of woody alien species germination to fire may have direct implications on their invasiveness in those ecosystems, particularly when fruit ripening occurs in the fire season. Here, we experimentally evaluated the germination response of some of the main woody invaders of the Chaco Serrano dry woodlands (Gleditsia triacanthos, Cotoneaster glaucophyllus, Ligustrum lucidum, Pyracantha angustifolia and Melia azedarach), which fruit in the seasons of highest fire frequency. Seeds were subjected to heat-shock treatments that simulated a range of heat intensities, and the species were classified according to their germination response as heat sensitive, tolerant or stimulated. Since Gleditsia triacanthos has indehiscent fruits that fall from the plant and might be exposed to flames, its germination response was also assessed of seeds exposed to fruit burning. Germination responses to heat varied among the invasive species. G. triacanthos seeds experienced increased germination under very low and low heat indexes; it was therefore classified as heat stimulated. The other four species showed no change in germination under very low heat indexes and were therefore considered heat tolerant. However, all species were sensitive to high heat as indicated by their significant decline in germination. G. triacanthos would have limited capacity to recruit from seeds following flaming combustion of its fruits. The prevalence of heat-tolerant rather than heat-stimulated germination responses suggests that the occurrence of frequent and seasonal fires in this subtropical savanna system might delay rather than boost the expansion of these invasive species in the system. Yet, the presence of heat-stimulated germination in one of the studied species warns against generalisation, even within the same ecosystem, and further supports the idiosyncratic nature of invasion success.Abstract in Spanish is available with online material.

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Aliens will provide: avian responses to a new temporal resource offered by ornithocorous exotic shrubs

Cited by 16 publications

References 52 publications

Seed Dispersal by Frugivores and Germination Success of the Invasive Alien Shrub Pyracantha Angustifolia in the Eastern Free State Province, South Africa

Seed Dispersal by Frugivores and Germination Success of the Invasive Alien Shrub Pyracantha Angustifolia in the Eastern Free State Province, South Africa

Fleshy‐fruited invasive shrubs indirectly increase native tree seed dispersal

Post‐burning germination responses of woody invaders in a fire‐prone ecosystem

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