DOI: 10.5061/dryad.hqbzkh1vw
title: Data from: Effects of frugivore species pool and seed size on the diversity and functional composition of frugivores visiting fruiting trees

description: 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.
description: # Data from: Effects of frugivore species pool and seed size on the
 diversity and functional composition of frugivores visiting fruiting trees
 Dataset DOI: [10.5061/dryad.hqbzkh1vw](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 (&lt; 5 mm), medium (5–15 mm), and large (&gt; 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 (&gt; 15 mm), medium (5-15 mm), small (&lt; 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/](http://www.ebird.org/) *
 Large: Number of individuals seen foraging on large-seeded plants (&gt; 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 (&lt; 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/](http://www.ebird.org/) *
 Large: Number of individuals seen foraging on large-seeded plants (&gt; 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 (&lt; 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/](http://www.ebird.org/) *
 Large: Number of individuals seen foraging on large-seeded plants (&gt; 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 (&lt; 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/](http://www.ebird.org/) * Large: Number of
 individuals seen foraging on large-seeded plants (&gt; 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 (&lt; 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/](http://www.ebird.org/) * Large: Number of
 individuals seen foraging on large-seeded plants (&gt; 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 (&lt; 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 (&gt;
 15 mm seed width), medium-seeded (5-15 mm), or  small-seeded (&lt; 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/](http://www.ebird.org/) *
 Large: Number of individuals seen foraging on large-seeded plants (&gt; 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 (&lt; 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
 (&gt; 15 mm), medium (5-15 mm), small (&lt; 5 mm) * overall_sp_rich: three
 categories based on seed width: large (&gt; 15 mm), medium (5-15 mm),
 small (&lt; 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/](http://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](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](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 (&gt; 15 mm), medium (5-15 mm), small (&lt; 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/](http://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 (&gt; 15 mm), medium (5-15 mm), small (&lt; 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](https://doi.org/10.1111/ele.13898)