Data from: Effects of frugivore species pool and seed size on the diversity and functional composition of frugivores visiting fruiting trees
Data files
Aug 19, 2025 version files 175.40 KB
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dat_1_correl.csv
527 B
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dat_1_sampling_coverage_anamalai.csv
729 B
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dat_1_sampling_coverage_andaman.csv
695 B
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dat_1_sampling_coverage_bala.csv
1.28 KB
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dat_1_sampling_coverage_namdapha.csv
1.15 KB
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dat_1_sampling_coverage_narcondam.csv
210 B
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dat_1_sampling_coverage_pakke.csv
1.38 KB
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dat_2_td_glm.csv
25.17 KB
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dat_3_cwm_beak_hwi.csv
21.21 KB
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dat_3_envxp.csv
14.34 KB
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dat_3_FD_lm.csv
29.11 KB
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dat_4_bird_trait.csv
4.09 KB
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dat_4_site_species.csv
5.26 KB
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dat_5_nested.csv
694 B
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dat_6_visit_rate.csv
35.14 KB
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Final_Code_PRSB_Naniwadekar_EtAl.R
22.13 KB
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README.md
12.27 KB
Abstract
The relationship between biodiversity and ecosystem functioning in seed dispersal remains understudied despite its critical role in maintaining plant diversity in the tropics. Field studies on this relationship are often confounded by environmental and phylogenetic variations across species richness gradients. We examined how overall avian frugivore species richness at a site influenced the frugivore richness, visitation rates, and functional composition of two key effect traits⸺beak width and hand-wing index⸺on fruiting trees. Across six sites in tropical Asia, spanning a sevenfold gradient in frugivore species richness but with similar forest types and phylogenetically nested frugivore communities, we recorded 34,014 interactions between 134 avian frugivores and 131 plant species. Our results provide some support for the biodiversity-ecosystem functioning relationship, as higher overall frugivore species richness increased the number of frugivore species visiting individual fruiting trees but not the functional composition of frugivores. Seed size had a stronger influence on the frugivore species richness, visitation rates, and the beak size of visiting frugivores, highlighting the dominant role of morphological trait matching in influencing plant-frugivore interactions. Our findings suggest functional redundancy in certain aspects of seed dispersal effectiveness due to density compensation and the presence of key seed disperser lineages in species-poor sites.
Dataset DOI: 10.5061/dryad.hqbzkh1vw
Description of the data and file structure
The study was conducted across six sites spread across four biodiversity hotspots - Western Ghats-Sri Lanka, Eastern Himalaya, Indo-Myanmar, and Sundaland in south and south-east Asia. All the sites are tropical lowland evergreen rainforest sites below 1,200 m above sea level and receive more than 2,000 mm of annual rainfall (Fig. 1). All the sites are Protected Areas harbouring primary evergreen forests with minimal anthropogenic disturbance to fleshy-fruited plants and avian frugivores. These sites within the Oriental realm represent distinct biogeographic subunits, suggesting distinct biogeographic processes may have shaped the diversity of frugivore assemblages. The most species-poor site was the small, volcanic, oceanic island of Narcondam, which had seven avian frugivore species, while the species-rich sites in the Eastern Himalaya, Indo-Myanmar, and Sundaland regions had more than 40 species of frugivores.
We observed 544 individual fruiting trees of 131 plant species across the six sites. Fieldwork across the six sites was conducted between October 2016 and May 2024. We sampled during the non-monsoon period. The tree watches were conducted following established protocols, with two or three observers watching fruiting trees and recording species identity and the number of frugivorous birds that arrived on fruiting trees in early mornings and/or late afternoon, coinciding with activity patterns of the frugivores. Birds that visited but were not observed consuming fruits of a particular tree species were not considered frugivores. The total tree watch sampling effort was 4,246.7 hr. Across five of the six sites, the duration of the tree watch was kept fixed to six hours in the first half of the day. At the Pakke field site, we observed most individual fruiting trees over two sessions in consecutive days; the first session was between sunrise and 1100 hr, and the second was between 1100 hr and sunset. Some individual trees were observed from sunrise to sunset. The number of tree species observed at each site ranged from 13 to 48. Since we did not have precise seed width information for some species, we classified the seeds into small (< 5 mm), medium (5–15 mm), and large (> 15 mm) following existing literature.
Files and variables
File: dat_1_correl.csv
Description: data file for determining correlation between taxonomic diversity and overall species richness
Variables
- Overall_Species_Richness: Total number of avian frugivore species richness seen foraging on fruits at the site
- Site: Bala - Hala-Bala Wildlife Sanctuary (Thailand), Pakke Tiger Reserve (India), Narcondam Wildlife Sanctuary (India), Anamalai Tiger Reserve (India), Namdapha Tiger Reserve (India), Andaman (south Andaman, India)
- Seed size: three categories based on seed width: large (> 15 mm), medium (5-15 mm), small (< 5 mm)
- qD: Taxonomic Diversity value
File: dat_1_sampling_coverage_anamalai.csv
Description: data file for estimating sampling coverage for Anamalai Tiger Reserve (India)
Variables
- Species: Scientific names of avian frugivores observed during the study based on www.ebird.org/
- Large: Number of individuals seen foraging on large-seeded plants (> 15 mm seed width)
- Medium: Number of individuals seen foraging on medium-seeded plants (5-15 mm seed width)
- Small Number of individuals seen foraging on small-seeded plants (< 5 mm seed width)
File: dat_1_sampling_coverage_andaman.csv
Description: data file for estimating sampling coverage for the South Andaman site (India)
Variables
- Species: Scientific names of avian frugivores observed during the study based on www.ebird.org/
- Large: Number of individuals seen foraging on large-seeded plants (> 15 mm seed width)
- Medium: Number of individuals seen foraging on medium-seeded plants (5-15 mm seed width)
- Small: Number of individuals seen foraging on small-seeded plants (< 5 mm seed width)
File: dat_1_sampling_coverage_bala.csv
Description: data file for estimating sampling coverage for Bala Wildlife Sanctuary (Thailand)
Variables
- Species: Scientific names of avian frugivores observed during the study based on www.ebird.org/
- Large: Number of individuals seen foraging on large-seeded plants (> 15 mm seed width)
- Medium Number of individuals seen foraging on medium-seeded plants (5-15 mm seed width)
- Small: Number of individuals seen foraging on small-seeded plants (< 5 mm seed width)
File: dat_1_sampling_coverage_namdapha.csv
Description:
Variables
- Species: Scientific names of avian frugivores observed during the study based on www.ebird.org/
- Large: Number of individuals seen foraging on large-seeded plants (> 15 mm seed width)
- Medium: number of individuals seen foraging on medium-seeded plants (5-15 mm seed width)
- Small: Number of individuals seen foraging on small-seeded plants (< 5 mm seed width)
File: dat_1_sampling_coverage_narcondam.csv
Description: data file for estimating sampling coverage for Namdapha
Variables
- Species: Scientific names of avian frugivores observed during the study based on www.ebird.org/
- Large: Number of individuals seen foraging on large-seeded plants (> 15 mm seed width)
- Medium: Number of individuals seen foraging on medium-seeded plants (5-15 mm seed width)
- Small: Number of individuals seen foraging on small-seeded plants (< 5 mm seed width)
File: dat_2_td_glm.csv
Description: data file for linear modelling of taxonomic diversity as a function of overall species richness at the site and seed size
Variables
- sr: serial number
- tree_id: individual ID of each tree that was observed
- site: Name of the study site - Anamalai Tiger Reserve, Pakke Tiger Reserve, Namdapha Tiger Reserve, Narcondam Wildlife Sanctuary, South Andamans in India, and Hala Bala Wildlife Sanctuary in Thailand
- species_richness: number of species of avian frugivores seen during the tree watch
- seed_size: whether the individual tree was large-seeded (> 15 mm seed width), medium-seeded (5-15 mm), or small-seeded (< 5 mm seed width)
- tree_watch_duration: Number of hours for which the tree watch on the individual tree was conducted
- overall_sp_rich: Total number of avian frugivore species richness seen foraging on fruits at the site
File: dat_1_sampling_coverage_pakke.csv
Description:
Variables
- Species: Scientific names of avian frugivores observed during the study based on www.ebird.org/
- Large: Number of individuals seen foraging on large-seeded plants (> 15 mm seed width)
- Medium: Number of individuals seen foraging on medium-seeded plants (5-15 mm seed width)
- Small Number of individuals seen foraging on small-seeded plants (< 5 mm seed width)
File: dat_3_envxp.csv
Description: data file with individual tree ID, seed size, and overall species richness at the site where the tree was observed.
Variables
- final_tree_code: individual ID of each tree that was observed
- seed_size: three categories based on seed width: large (> 15 mm), medium (5-15 mm), small (< 5 mm)
- overall_sp_rich: three categories based on seed width: large (> 15 mm), medium (5-15 mm), small (< 5 mm)
File: dat_4_bird_trait.csv
Description: Data file of bird traits for different avian frugivore species
Variables
- species: Scientific names of avian frugivores observed during the study based on www.ebird.org/
- beak: Mean beak width of the avian frugivore species as obtained from Tobias et al. 2022. https://doi.org/10.1111/ele.13898
- hwi: Mean hand-wing index of the avian frugivore species as obtained from Tobias et al. 2022. https://doi.org/10.1111/ele.13898
File: dat_3_FD_lm.csv
Description: data file for linear modelling to examine responses of hand-wing index and beak width to overall species richness and seed size.
Variables
- final_tree_code: individual ID of each tree that was observed
- site: Name of the study site - Anamalai Tiger Reserve, Pakke Tiger Reserve, Namdapha Tiger Reserve, Narcondam Wildlife Sanctuary, South Andamans in India, and Hala Bala Wildlife Sanctuary in Thailand
- seed_size: three categories based on seed width: large (> 15 mm), medium (5-15 mm), small (< 5 mm)
- overall_sp_rich: Total number of avian frugivore species richness seen foraging on fruits at the site
- beak: community-weighted mean of beak width of birds that visited to forage on fruits for that particular tree
- hwi: community-weighted mean of the hand-wing index of birds that visited to forage on fruits for that particular tree
File: dat_4_site_species.csv
Description: List of frugivore species at each study site
Variables
- site: Name of the study site - Anamalai Tiger Reserve, Pakke Tiger Reserve, Namdapha Tiger Reserve, Narcondam Wildlife Sanctuary, South Andamans in India, and Hala Bala Wildlife Sanctuary in Thailand
- species: Scientific names of avian frugivores observed during the study based on www.ebird.org/
File: dat_5_nested.csv
Description: data file for nestedness analysis
Variables
- Family: Names of different avian frugivore species bird families
- Pakke: Number of avian frugivore species for that particular family seen at Pakke Tiger Reserve (India)
- Namdapha: Number of avian frugivore species for that particular family seen at Namdapha Tiger Reserve (India)
- Bala: Number of avian frugivore species for that particular family seen at Bala Wildlife Sanctuary (Thailand)
- Anamalai: Number of avian frugivore species for that particular family seen at Anamalai Tiger Reserve (India)
- Andaman: Number of avian frugivore species for that particular family seen at South Andamans (India)
- Narcondam: Number of avian frugivore species for that particular family seen at Narcondam Wildlife Sanctuary (India)
File: dat_6_visit_rate.csv
Description: data file for visit rates at individual trees
Variables
- site: Number of avian frugivore species for that particular family seen at Narcondam Wildlife Sanctuary (India)
- final_tree_code: individualID of each tree that was observed
- number_birds: number of birds seen on that particular individual tree
- duration_treewatch: Number of hours for which the tree watch on the individual tree was conducted
- visit_rate_hr: visitation rate of avian frugivores per hour
- visit_rate_hr_log: natural logarithm of the visit rate
- seed_size: three categories based on seed width: large (> 15 mm), medium (5-15 mm), small (< 5 mm)
- overall_sp_rich: Total number of avian frugivore species richness seen foraging on fruits at the site
File: dat_3_cwm_beak_hwi.csv
Description: data file for community-weighted mean for beak width and hand-wing index for each tree
Variables
- final_tree_code: individual ID of each tree that was observed
- beak: community-weighted mean of beak width of birds that visited to forage on fruits for that particular tree
- hwi: community-weighted mean of the hand-wing index of birds that visited to forage on fruits for that particular tree
Code/software
File: Final_Code_PRSB_Naniwadekar_EtAl.R
Description: R code used for analysis. R software (version: 4.2.3) was used to conduct the analysis. Script is included with the submission. Details of packages used can be found in the code.
Access information
Other publicly accessible locations of the data:
- NA
Data was derived from the following sources:
- The bird trait data were obtained from Tobias et al. 2022. https://doi.org/10.1111/ele.13898