DOI: 10.5061/dryad.fttdz0957
title: Data from: Rainforest fragmentation decreases the robustness of plant-frugivore interaction networks

description: Tropical rainforests are biodiversity hotspots that provide a variety of
 ecosystem functions and services. Seed dispersal by fruit-eating birds is
 an important ecosystem process in the regeneration of tropical
 rainforests, which is increasingly threatened by widespread deforestation.
 In particular, the expansion of agricultural land often leads to forest
 fragmentation, which can have a negative impact on the interactions
 between plants and frugivores and thus on seed dispersal. However, little
 is known about how forest fragmentation affects the structure and
 robustness of plant-frugivore interaction networks. Here, we examined the
 effects of forest fragmentation on species richness of frugivorous birds
 interacting with focal tree species, and the structure and robustness of
 plant-frugivore interaction networks in the tropical lowland forests of
 northern Costa Rica. Species richness of frugivorous birds at the forest
 edges increased with fragment size and forest cover in the surrounding
 landscape, as well as with local fruit availability. Modularity and
 robustness of plant-frugivore networks increased with enhanced fragment
 size and forest cover, while network specialization (H2´) increased only
 with greater forest cover. Additionally, the three common tanager species
 (Ramphocelus passerinii, Thraupis palmarum, and Thraupis episcopus) were
 identified as key bird species for network functioning by promoting
 among-module and within-module connectivity. Conservation measures should
 therefore not only focus on threatened specialist species, but more on the
 key species that enhance network structure and consequently increase the
 robustness of these trophic interaction networks. Ultimately, our study
 demonstrates that tropical forest fragmentation simplifies network
 structure, making these interactions more vulnerable to anthropogenic
 disturbances.
description: # Data from: Rainforest fragmentation decreases the robustness of
 plant-frugivore interaction networks Dataset DOI:
 [10.5061/dryad.fttdz0957](10.5061/dryad.fttdz0957) ## Description of the
 data and file structure Between 5 October and 3 December 2023, we carried
 out 252 hours of active bird–fruit interaction observations (05:30–09:30
 AM) along fixed 300 m forest-edge transects in six old-growth rainforest
 fragments in northern Costa Rica. On three randomized days per fragment,
 three observers recorded the following data fields for every interaction
 (TABLE_S5.csv): Fragment ID; Date; Round; TreeID; Time; Tree species; Bird
 species; Bird Individuals Interacting; Tree Surrounding; Fruit amount.
 The Metadata_TABLE_S5.xlsx data file includes the description of all the
 variables.  To ensure consistency, all observations of bird-fruit
 interactions were conducted along a fixed 300 m transect at the forest
 edge of each fragment, based on accessibility and availability of
 fruit-bearing trees. Interaction frequency was defined as the number of
 individual birds pecking or swallowing a fruit. If a bird remained in the
 tree for an extended period and consumed multiple fruits, this was still
 counted as a single interaction. To be considered a new interaction by the
 same bird species, the individual had to leave the tree and return after
 at least one minute. In addition, for each observed fruit-bearing tree,
 the number of ripe fruits were estimated at the time of observation and
 additionally the tree surrounding (single standing = no other tree in 5 m
 radius; edge tree = embedded in stand of numerous trees) was classified.