DOI: 10.5061/dryad.kh18932hc
title: Linear infrastructure drives biotic homogenization among bird species of a tropical dry forest

description: Linear infrastructures (LIs) such as roads, railroads, and powerlines are
 expanding rapidly around the globe. While most future developments are
 projected to take place in tropical regions, available information on
 impacts of LIs is biased towards single species studies of solely road
 impacts in temperate regions. Therefore, we investigated impacts of three
 types of LIs (road, railroad, and powerline) on the bird community of a
 tropical dry forest. Point-count surveys to record avian richness and
 abundance were conducted at 80 plots that were spatially stratified to
 include sites proximate to all possible LI combinations. Five measures of
 vegetation structure were collected at each plot as well. We then assessed
 the relationship between the bird community (i.e., richness, abundance,
 composition) and distance to each LI type while accounting for variation
 in vegetation structure. Species richness and abundance both declined
 significantly (25% and 20%, respectively) from edge habitat next to
 railroad to interior forest plots, while community composition was
 significantly altered by the distance to all three LIs. Road and railroad
 (both forms of dynamic infrastructure with moving vehicles) had similar
 effects on the bird community that contrasted with those of powerline (a
 type of static infrastructure). The resulting ordination reveled that Sri
 Lankan endemics are significantly disfavored by LI proximity, while
 species that now have naturalized populations across the globe are most
 often found proximal to LI. Our results emphasize that LI drive biotic
 homogenization by favoring these increasingly widespread species at the
 expense of unique elements of the biota.
description: <strong>Study Site</strong> The
 study was conducted in the Polonnaruwa District, North Central Province,
 Sri Lanka. The landscape consists of two protected areas: Thalapathkanda
 Forest Reserve and Minneriya National Park. The region has all three LI
 types (road, railroad, powerline) in close proximity and is scheduled for
 infrastructure expansion. <strong>Bird Survey
 Method</strong> 
 <strong>Point-count surveys conducted at 80 spatially
 stratified points.</strong> 
 <strong>Distance Categories</strong>: Plots were
 categorized based on their proximity to LI. 
 <strong>Survey Duration</strong>: Each
 survey lasted 20 minutes and was conducted between 0530 - 0800
 h. <strong>Survey
 Seasons</strong>: Dry
 season: July - August 2019 Wet
 season: December 2019 - January 2020 
 Dry season: July - August 2020 
 <strong>Vegetation Structure
 Measurements</strong> 
 <strong>Canopy cover</strong>: Percent canopy cover
 measured using ImageJ software. 
 <strong>Shrub cover</strong>: Percentage of
 understory vegetation cover measured with a white background
 board. <strong>Herb
 cover</strong>: Percentage of herbaceous cover measured via
 quadrats. <strong>Diameter
 at Breast Height (DBH)</strong>: Count of trees with DBH
 &gt;10cm. 
 <strong>Plant species richness</strong>: Number of
 tree species within each plot. 
 <strong>Data Analysis</strong> 
 <strong>Impact on Species Richness &
 Abundance</strong>: General linear models with AICc
 selection. 
 <strong>Community Composition</strong>:
 Distance-based redundancy analysis (db-RDA). 
 <strong>Software Used</strong>: R ver
 3.6.0, JMP Pro 15.
description: # Data from: Linear Infrastructure Drives Biotic Homogenization Among Bird
 Species of a Tropical Dry Forest ## General Information ### Title Linear
 Infrastructure Drives Biotic Homogenization Among Bird Species of a
 Tropical Dry Forest ### Authors Dishane K Hewavithana, Devaka K Weerakoon,
 Mayuri R Wijesinghe, Christopher A Searcy ### Date of Data Collection July
 2019 - August 2020  ### Location Polonnaruwa District, North Central
 Province, Sri Lanka (8.07°N, 80.88°E) ## Data Description ### Files
 Included * **Sri_Lanka_Bird_Matrix.csv**: Contains bird species recorded
 at each survey point, including species richness, abundance, vegetation
 structure, and distances from linear infrastructure. *
 **Bird_name_abbreviations.csv**: contains full species name for
 abbreviations used in above file ### Data Format The dataset contains the
 following key columns: * **Plot_No**: Unique identifier for each survey
 plot. * **Category**: The infrastructure type or combination influencing
 the plot (e.g., Road_Only, Rail_Only, Powerline_Only, combinations, or
 Control plots). * **Ln(Road), Ln(Rail), Ln(Power)**: Log-transformed
 distance to each linear infrastructure. * **Canopy_percentage**:
 Percentage of canopy cover at the plot. * **U_vege_cover**: Understory
 vegetation cover percentage. * **Trees10cm**: Count of trees with DBH
 &gt;10cm. * **Asn(Herb_cover)**: Herbaceous vegetation cover. *
 **Plant_species_richness**: Number of tree species with DBH &gt;10cm. *
 **Species_Richness**: Number of bird species recorded. * **Abundance**:
 Total number of individual birds recorded per plot. * **Species columns
 (e.g., WTKI, WBDR, WBSE, etc.)**: Relative abundance of each recorded bird
 species. ## Usage Notes * The dataset is intended for use in ecological
 and conservation research. * We kindly encourage users to cite this
 dataset and the related publication when using the data to support
 reproducibility and acknowledgment of the work. * Data is structured for
 compatibility with statistical analysis software. * Ethical considerations
 were followed, and data collection adhered to University of Miami IACUC
 protocol 18-160 and Sri Lankan Department of Wildlife Conservation
 regulations. ## Citation Hewavithana, D.K., Weerakoon, D.K., Wijesinghe,
 M.R., and Searcy, C.A., (2025). Linear Infrastructure Drives Biotic
 Homogenization Among Bird Species of a Tropical Dry Forest. ## Funding
 This research was supported by the National Research Council of Sri Lanka
 (16-029). ## Contact For questions about this dataset, contact: Dishane
 Hewavithana\ Email: [dkh48@miami.edu](mailto:dkh48@miami.edu)\
 Affiliation: University of Miami, Florida, USA