DOI: 10.5061/dryad.hdr7sqvrz
title: Forest fragmentation effects on mutualistic interactions: Frugivorous birds and fruiting trees

description: While many effects of forest fragmentation are reasonably well understood,
 knowledge of interspecific interactions in fragmented ecosystems is much
 more limited, particularly for high-diversity tropical forests. Using
 nearly 40 years of data from the Biological Dynamics of Forest Fragments
 Project in Central Amazonia, we assessed whether forest fragment area and
 time since isolation impact mutualistic interactions between frugivorous
 birds and their food resources. We used structural equation modeling to
 analyze the complex pathways between four main variables determining these
 interactions: fruiting tree abundance, frugivorous bird abundance, forest
 fragment area, and time since fragment isolation. Our results confirm that
 fragment area alters the abundance of some tree resources, with
 successional plant families increasing in abundance with decreasing
 fragment size. However, these changes do not drive alterations in the
 abundance of frugivorous birds. We also tested if bird species with a
 greater relative diet breadth are less vulnerable to forest fragmentation
 and found that specialist frugivores are more vulnerable to forest
 fragmentation immediately after isolation but are not differentially
 impacted within the long term. Collectively, our results demonstrate the
 need to further evaluate human-driven habitat change across multiple
 timescales to fully understand its impacts on complex species
 interactions.
description: # Forest fragmentation effects on mutualistic interactions: Frugivorous
 birds and fruiting trees #### **Description of the data and file
 structure** File: “StandPlantsRawBirds” is the data we used for the SEMs
 File: “Abundance Split and Stand for Effort” is for the Diet Breadth
 portion   Specific information for: **“StandPlantsRawBirds.xlsx”** Reserve
 = Reserve number corresponding with a fragment at the Biological Dynamics
 of Forest Fragments Project (BDFFP). Time.point = Time since isolation of
 the reserve. One to two years before the BDFFP’s initial forest
 fragmentation event (time point = 0), up to four years after the initial
 fragment isolation (time point = 1), and the most recent datapoint in the
 2010s (time point = 2).  Habitat.size = The size of the forest fragment in
 hectares.  Habitat.type = a number for analysis that corresponds with a
 fragment size. Type 1 = 1 ha, type 2 = 10 ha, type 3 = 100 ha, and type 4
 = primary forest. Primary forest represents forest that has not been cut
 down or fragmented and is continuous in size. Effort = mist net effort in
 hours.  “Annonaceae”, “Arecaceae”, “Burseraceae”, “Celastraceae”,
 “Clusiaceae”, “Euphorbiaceae”, “Fabaceae”, “Lauraceae”, “Melastomataceae”,
 “Meliaceae”, “Moraceae”, “Myristicaceae”, “Myrsinaceae”, “Myrtaceae”,
 “Rubiaceae” = Plant families standardized by plot. “Lepidothrix”, “pipra”,
 “schiffornis”, “tachyphonus”, “corapipo”, “dixiphia” = abundance of
 understory frugivores.   Specific information for: **“Abundance Split and
 Stand for Effort.xlsx”** Reserve = Reserve number corresponding with a
 fragment at the BDFFP.  Species = species of bird assessed.  Change.01 =
 change in abundance (slope) from time point = 0 to time point = 1. 
 Change.12 = change in abundance (slope) from time point = 1 to time point
 = 2. Change.02 = change in abundance (slope) from time point = 0 to time
 point = 2. BDFFP.Breadth = relative diet breadth of each species.
 Fragment.size = The size of the forest fragment in hectares. 
 Fragment.type = a number for analysis that corresponds with a fragment
 size. Type 1 = 1 ha, type 2 = 10 ha, type 3 = 100 ha, and type 4 = primary
 forest.