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

2021 ◽  
Author(s):  
Lehlohonolo Donald Adams ◽  
Grant D. Martin ◽  
Colleen T. Downs ◽  
Vincent Ralph Clark ◽  
Vuyisile Thabethe ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Bird Species ◽  
Camera Traps ◽  
Free State ◽  
Fruit Pulp ◽  
Frugivorous Birds ◽  
Alien Plant ◽  
Free State Province ◽  
Germination Success ◽  
Eastern Free State

Abstract 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.

scholarly journals Similar seed dispersal systems by local frugivorous birds in native and alien plant species in a coastal seawall forest

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11672
Author(s):  
Bin Liu ◽  
Guohai Wang ◽  
Yuting An ◽  
Dandan Xue ◽  
Libo Wang ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seed Dispersal ◽  
Alien Species ◽  
Plant Species ◽  
Native Species ◽  
Bird Species ◽  
Alien Plant Species ◽  
Frugivorous Birds ◽  
Alien Plant ◽  
Bird Foraging

Frugivorous birds play an important role in seed dispersal. Alien plant species’ seeds are dispersed by local birds in order to establish populations in new habitats. Alien plant species that produce fruits similar to that of native species have the potential to attract local birds, creating new mutualistic systems that are similar to the local ones. In autumn 2018 and 2019, we studied the seed dispersal systems of an alien plant species, Phytolacca americana, and a native species, Cayratia japonica, in a coastal seawall forest. Both plant species’ fruit, frugivorous bird foraging behaviors, seed germination rates, and seedling microhabitats were examined to determine whether the alien species had a similar seed dispersal system to that of the native species. Our results showed that P. americana and C. japonica had similar fruit type, color, and ripening period. There was a positive correlation between the percentage rate of fruit ripening and the percentage rate of fruit missing for both plant species, indicating that local frugivorous birds have the potential to sufficiently disperse the alien seeds to enable its spread in the coastal seawall forest (simple linear regression, P. americana: β = 0.863 ± 0.017, R2adj = 0.978, P < 0.01; C. japonica: β = 0.787 ± 0.034, R2adj = 0.898, P < 0.01). Eleven bird species consumed the fruits of the alien species or native species during the study period. Similar results were shown across alien and native species in bird foraging behavior (feeding frequency, feeding duration and first stop distance) indicating that a similar seed dispersal relationship had been established between local frugivorous and both plant species. The alien plant had a higher number of fruits carried by birds, suggesting that P. americana had a slightly higher fruit consumption than that of C. japonica (t-test, P < 0.01). Alien plant seedlings grow more abundant in forest gap microhabitat (t-test, P < 0.01). Our results confirmed that bird digestion promotes seed germination success in both plant species. Our study suggests that in a narrow coastal seawall forest, alien plant species can successfully establish their populations by relying on similar seed dispersal systems as the local species.

scholarly journals Native generalist consumers interact strongly with seeds of the invasive wild cucumber (Echinocystis lobata)

NeoBiota ◽  
2019 ◽  
Vol 53 ◽  
pp. 25-39
Author(s):  
Łukasz Dylewski ◽  
Łukasz Myczko ◽  
Dean E. Pearson
Keyword(s):  
Intraspecific Competition ◽  
Native Plants ◽  
Seedling Survival ◽  
Bird Species ◽  
Camera Traps ◽  
Invasion Success ◽  
Alien Plant ◽  
Garrulus Glandarius ◽  
Echinocystis Lobata ◽  
Survival Of Seedlings

When alien plant species arrive in a new environment, they develop novel interactions with native biota that can range from negative to positive. Determining the nature and strength of these interactions is integral to understanding why some aliens are suppressed and others become highly invasive pests. For introduced terrestrial plants, seed and seedling interactions with native biota are crucial, because most nascent populations start from seed. Herein, we explored interactions between native generalist rodent and bird consumers and seeds of the invasive wild cucumber Echinocystis lobata by conducting seed-offering experiments in Poland. We also evaluated how interspecific competition from native plants and intraspecific competition from clustering of E. lobata seed (clustering resembling consumer seed caching) affected survival of seedlings and young plants. Native consumers interacted strongly with E. lobata seeds, with rodents removing 98% of seeds from ground locations and birds removing 24% of elevated seeds. Camera and live traps indicated that striped field mice Apodemus agrarius were the predominant rodent removing seeds. Camera traps and visual observations indicated that great tits Parus major and European jays Garrulus glandarius were the primary bird species removing elevated seeds. While some level of seed removal was likely attributable to seed predation, as indicated by seed coat remains, we also observed evidence that rodents may cache E. lobata seeds and Garrulus glandarius are known to cache and disperse seeds. Monitoring of seedlings indicated that increasing cover of native plants and clustering of E. lobata seedlings both reduced survival of seedlings and young plants due to inter- and intraspecific competition, respectively. Hence, caching by generalist consumers may disperse E. lobata seeds, which are heavy and lack dispersal adaptations, but such caching may also reduce individual seedling survival rates. Fully understanding invasion success of the E. lobata will require evaluating the net effects of generalist consumers on its recruitment and dispersal.

Seed dispersal effectiveness by frugivorous birds: Identifying functional equivalent species in bird assemblages

2019 ◽  
Vol 12 (3) ◽  
pp. 103-108
Author(s):  
Facundo Xavier Palacio
Keyword(s):  
Seed Dispersal ◽  
Statistical Significance ◽  
Bird Species ◽  
Kernel Functions ◽  
Bird Conservation ◽  
Frugivorous Birds ◽  
Seed Dispersal Effectiveness ◽  
Bird Assemblages ◽  
Functional Equivalent ◽  
Dispersal Effectiveness

Seed dispersal by birds is a pivotal ecosystem function worldwide; yet, the rapid and ongoing global biodiversity loss poses a major threat to this essential ecosystem service. Seed dispersal effectiveness (SDE) is a key outcome of the interaction, represented by the product of seed dispersal quantity (number of seed dispersed) and quality (probability of recruitment of dispersed seeds). Therefore, identifying functional equivalent species in terms of SDE should become a key issue for bird conservation, since the effects of local extinctions on seed dispersal services may be weakened by remaining equivalent species. However, a method to quantitatively identify functional equivalent species in frugivorous bird assemblages is still lacking. To estimate SDE overlap between seed dispersers and assess whether two species may be functionally equivalent, I apply a novel nonparametric niche overlap index based on kernel functions and null models to test its statistical significance. For each bird species, I account for intraspecific variation in seed dispersal effectiveness to obtain a distribution of seed dispersal effectiveness values, an often neglected source of variation in seed dispersal assemblages. Non-significant differences in seed dispersal effectiveness overlap support the hypothesis that two species are functional equivalent, thus playing similar functional roles. The model proposed is applicable to any other quantity or quality component and is independent from the method or sampling design used to quantify SDE. The identification of functional equivalent species in seed dispersal assemblages adds to the theoretical framework of seed dispersal effectiveness and offers new insights into the ecology of the seed dispersal service provided by birds.

Seed-dispersing bird assemblages in riparian environments of a partially urbanized river basin, Southeastern Brazil

2020 ◽  
Author(s):  
B. F. Lessi ◽  
M. G. Reis ◽  
C. Z. Fieker ◽  
M. M. Dias
Keyword(s):  
Ecosystem Services ◽  
Seed Dispersal ◽  
Bird Species ◽  
Dry Season ◽  
Ecosystem Dynamics ◽  
Southeastern Brazil ◽  
Wet Season ◽  
Frugivorous Birds ◽  
Entire Area ◽  
Number Of Individuals

Abstract Birds play a key role in ecosystem dynamics, including urban and rural areas, bringing environmental quality improvements and ecological stability. Species contribute directly to natural regeneration of vegetation and succession processes, by offering ecosystem services as seed dispersal, an important role in human-modified areas. We studied the assemblages of fruit-eating birds in riparian environments of Monjolinho basin, central São Paulo state, southeastern Brazil. Birds were recorded in 41 points distributed in riparian ecosystems alongside waterbodies, in landscapes with five types of surrounding matrices: urban, periurban, farmland, and native vegetation. We described how assemblages are structured aiming to evaluate the possible influence of seasonality and landscape type. We recorded 39 bird species that can play a role as seed-dispersers, 32 in wet season and 32 in dry season. There were no significant differences in the diversity and dominance of species between seasons considering the entire area, indicating stability of basic assemblage structure. However, total number of individuals of all species recorded in different landscapes were influenced by seasonality. Also, the composition and abundance of species significantly changed between seasons, leading to a high dissimilarity with almost 50% of the species contributing with almost 90% of the observed variation. A higher taxonomic diversity and distinctness pointed to a wider array of possible seed dispersal services in natural areas, while the lowest values of indexes were found in human-modified areas. The higher number of non-related bird species during dry season contrasted with the higher number of individuals during wet season, indicating that there is more possible ecosystem services offered by frugivorous birds in driest period of the year, while in the rainy period the carrying capacity of the riparian environments was increased.

scholarly journals USE OF RESTORATION PLANTINGS TO ENHANCE BIRD SEED DISPERSAL AT THE ROADSIDE: FAILURES AND PROSPECTS

2015 ◽  
Vol 23 (4) ◽  
pp. 302-311 ◽  
Author(s):  
Rocío de TORRE ◽  
María Dolores JIMÉNEZ ◽  
Álvaro RAMÍREZ ◽  
Ignacio MOLA ◽  
Miguel A. CASADO ◽  
...  
Keyword(s):  
Species Richness ◽  
Seed Dispersal ◽  
Agricultural Landscape ◽  
Bird Species ◽  
Ecological Processes ◽  
Frugivorous Birds ◽  
Bird Droppings ◽  
Bird Richness ◽  
Species Richness And Abundance

Plantings are commonly used in roadside reclamation for ornamental purposes and for increasing slope stability and road safety. However, the role of these plantings in restoring ecological processes, such as seed dispersal, has received little attention. We carried out a study to assess the potential role of plantings on roadside embankments to attract frugivorous birds and to enhance seed dispersal mediated by birds from the surrounding landscape. We examined: (1) bird species richness and abundance; (2) patterns of avian spatial distribution within embankments and (3) seed dispersal mediated by birds. Bird richness and abundance did not differ between embankments with and without plantings. However, birds were not distributed randomly within embankments, with levels of species richness and abundance for facultative frugivorous between 4.8–8 times higher in areas closer to plantings. An analysis of bird droppings showed that birds only dispersed seeds of the planted species since no seeds of woody plants from matrices were detected. These results suggest that plantings acted as selective bird attractors, providing food and perches for frugivorous species. Nevertheless, the scarcity of seed-dispersing birds in the surrounding agricultural landscape prevented plantings from enhancing seed dispersal and connectivity to adjacent habitat.

scholarly journals Projected impacts of climate change on functional diversity of frugivorous birds along a tropical elevational gradient

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Irene M. A. Bender ◽  
W. Daniel Kissling ◽  
Katrin Böhning-Gaese ◽  
Isabell Hensen ◽  
Ingolf Kühn ◽  
...  
Keyword(s):  
Climate Change ◽  
Seed Dispersal ◽  
Functional Diversity ◽  
Bird Species ◽  
Elevational Gradient ◽  
Frugivorous Birds ◽  
Bird Assemblages ◽  
Functional Changes ◽  
Frugivorous Bird ◽  
Functional Dispersion

AbstractClimate change forces many species to move their ranges to higher latitudes or elevations. Resulting immigration or emigration of species might lead to functional changes, e.g., in the trait distribution and composition of ecological assemblages. Here, we combined approaches from biogeography (species distribution models; SDMs) and community ecology (functional diversity) to investigate potential effects of climate-driven range changes on frugivorous bird assemblages along a 3000 m elevational gradient in the tropical Andes. We used SDMs to model current and projected future occurrence probabilities of frugivorous bird species from the lowlands to the tree line. SDM-derived probabilities of occurrence were combined with traits relevant for seed dispersal of fleshy-fruited plants to calculate functional dispersion (FDis; a measure of functional diversity) for current and future bird assemblages. Comparisons of FDis between current and projected future assemblages showed consistent results across four dispersal scenarios, five climate models and two representative concentration pathways. Projections indicated a decrease of FDis in the lowlands, an increase of FDis at lower mid-elevations and little changes at high elevations. This suggests that functional dispersion responds differently to global warming at different elevational levels, likely modifying avian seed dispersal functions and plant regeneration in forest ecosystems along tropical mountains.

scholarly journals The role of avian frugivores on germination and potential seed dispersal of the Brazilian Pepper Schinus terebinthifolius

2010 ◽  
Vol 10 (3) ◽  
pp. 45-51 ◽  
Author(s):  
Graziele D'Avila ◽  
Antonio Gomes-Jr ◽  
Ana Carolina Canary ◽  
Leandro Bugoni
Keyword(s):  
Seed Dispersal ◽  
Seed Viability ◽  
Bird Species ◽  
Frugivorous Birds ◽  
Schinus Terebinthifolius ◽  
In Captivity ◽  
Avian Frugivores ◽  
Brazilian Pepper ◽  
Germination Experiments

Frugivorous birds play a key role in seed dispersal and establishment of a range of plant species, including invasive weeds, such as the Brazilian Pepper Schinus terebinthifolius. The potential of seed dispersal of Schinus by birds with varied feeding behaviours was studied through seed-viability tests and germination experiments using seeds obtained from birds in the field and birds kept in captivity. It was found that seeds collected after gut passage in five bird species in the field had higher proportion of germination as well as higher germination rates compared to the control seeds. Viability of seeds ingested by the Blue-and-yellow Tanager Thraupis bonariensis, which mandibulates seeds before ingesting, was significantly lower than control seeds, while reduction in viability of seeds ingested by the Creamy-bellied Thrush Turdus amaurochalinus was nonsignificant. Seeds ingested by birds in captivity germinated earlier than the control seeds, within 1-2 weeks, and had proportion and germination rates higher than controls. Probably both mechanical and chemical effects play a role in enhancing germination of seeds. In Brazil where both Schinus and avian frugivores had evolved together, the dependence of Schinus on generalist frugivores had been demonstrated in this study, similar to other countries where the invasive Schinus is dependent on native or introduced avian species for its spreading. This finding has important implications for the restoration of human-altered areas in South America, were Schinus is a native pioneer species, as well as for the management and restoration of areas invaded by Schinus elsewhere.

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