DOI: 10.5061/dryad.wm37pvmzp
title: Tree composition mitigates the negative effects of urbanization on specialist and generalist forest moth communities

description: Changes at local and landscape scales impact forests embedded in urban and
 urbanizing landscapes. In the Northeast USA, urban forest fragments are
 characterized by smaller sizes, low connectivity, and novel plant
 assemblages relative to intact natural areas. Disruptions of connectivity
 from landscape-scale development can negatively impact habitat suitability
 and colonization by terrestrial insects, but managing local tree
 compositions may offset negative impacts, especially for phytophagous taxa
 specialized to host plants. Here, we surveyed nocturnal moth community
 diversity using light traps deployed within forest fragments that varied
 in surrounding urban development, tree floristics, and tree structure. We
 found that local and landscape-scale factors interact to affect temperate
 forest moth communities. In most cases, impervious surface (as a proxy for
 urbanization) negatively impacted moth communities, whereas the basal area
 of Lepidoptera-rich host plants positively affected moth communities.
 However, the magnitude of benefits of Lepidoptera-rich host trees were
 most apparent at low levels of urbanization and most substantial for
 specialists over generalists. Practical Implication: These
 results provide evidence that forest management approaches prioritizing
 tree species that support a high richness of species interactions can
 offset the adverse effects of fragmentation on vital insect taxa at
 different levels of urban development. However, at high levels of urban
 development, other urban-associated mechanisms, such as artificial light,
 pesticides, and reduced dispersal, may inhibit sustainable populations of
 sensitive moth species.   
description: # Tree composition mitigates the negative effects of urbanization on
 specialist and generalist forest moth communities R script, JAGS model,
 and data used to test relationships between moth community metrics,
 urbanization and forest characteristics in Delaware and Pennsylvania, USA.
 Missing data is indicated by NA. Description of the data and file
 structure File 1: JAGS_moth_analysis.txt- * JAGS model used to test
 relationships between moth community metrics, urbanization, and forest
 characteristics. File 2: JAGS_moth_specializationDistance_analysis.txt *
 JAGS model used to test relationships between moth specialization
 distance, urbanization, and forest characteristics. File 3:
 JAGS_moth_richness_rarefied.txt * JAGS model used to test relationships
 between moth rarefied richness, urbanization, and forest characteristics.
 File 4: moth_bayesian_analysis.Rmd * R script that loads datasets and
 formats data for the JAGS model. Has code for summarizing and visualizing
 posterior distributions. File 5: site_summary.csv - site-level summaries
 of moth abundance, moth biomass, impervious surface, basal area, genus
 richness and Lepidoptera-rich tree basal area. site_format: character
 string, site name plot: numeric, plot ID year: numeric, year
 specialist_abundance: numeric, abundance of genus-specialist moths
 generalist_abundance: numeric, abundance of genus-generalist moths
 other_abundance:numeric, abundance of other moths total_abundance:numeric,
 total abundance of moths specialist_biomass: numeric, biomass (in mg) of
 genus-specialist moths generalist_biomass: numeric, biomass (in mg) of
 genus-generalist moths other_biomass: numeric, biomass (in mg) of other
 moths total_biomass:: numeric, biomass (in mg) of all moths
 specialist_family_abundance: numeric, abundance of family-specialist moths
 generalist_family_abundance: numeric, abundance of family-generalist moths
 other_family_abundance: numeric, abundance of other moths
 total_family_abundance: numeric, abundance of all moths
 specialist_family_biomass: numeric, biomass (in mg) of family-specialist
 moths generalist_family_biomass: numeric, biomass (in mg) of
 family-generalist moths other_family_biomass: numeric, biomass (in mg) of
 other moths total_family_biomass: numeric, biomass (in mg) of all moths
 total_basal: numeric, total basal area of trees genera_richness:numeric,
 total genera richness of trees keystone_basal:numeric,total basal area of
 keystone trees productivity_index: numeric, productivity value (basal area
 * lepidoptera richness supported) productivity: numeric, productivity
 value (basal area * lepidoptera richness supported) lat_fixed: latitude
 long_fixed: longitude imperv_1km_mean: numeric, mean proportion of
 impervious surface within 1km imperv_500m_mean: numeric, mean proportion
 of impervious surface within 500m prop_keystone: numeric, proportion of
 keystone tree biomass year_factor: numeric, year as a factor rep: unique
 ID scaled_imperv: numeric, scaled value of impervious surface
 scaled_basal: numeric, scaled value of basal area scaled_genera: numeric,
 scaled value of genera richness scaled_keystone: numeric, scaled value of
 keystone basal area year_binary: binary, 2018=1 File 6:
 allmoths_traits_12feb2024_format.csv - Individual species and counts for
 each sampling event with associated traits. Site: Character string, site
 name plot: numeric, plot ID date: Date, date of sampling count: numeric,
 total number of moth individuals species: character string, moth
 scientific name species_good: character string, moth scientific name
 foodtype_broad: category, food type foodtype_specific: category, food type
 hostplants_genera: numeric, number of host plant genera
 hostplants_family:numeric, number of host plant families wing_low:
 numeric, minimum wing measurement wing_high: numeric, maximum wing
 measurement exotic: binary, exotic to the United States, yes=1
 specialization_distance: phylogenetic distance among host plant genera
 specialization_notes: character string, notes about specialization
 gbif_totalCount: Number of gbif observations sampleSize: Number of gbif
 observations area_km2: numeric, area in km2 of all gbif observations
 (minimum convex polygon) minFlight: numeric, earliest month observed in
 gbif records maxFlight: numeric, latest month observed in gbif records
 lengthFlight: numeric, range of flight from min to max gbif_notes: notes
 date_format: date, formatted date year: numeric,year of sampling month:
 numeric, month of sampling specialist: category, specialist or generalist
 at the genus level specialist_family: category, specialist or generalist
 at the family level File 7: moth_rareifiedRichness_specialists.csv -
 Rarefied richness of genus specialist moths Assemblage: character string,
 unique assemblage (plot + year) Diversity: category string, estimate type
 Observed: numeric: observed number of species Estimator: numeric:
 estimated number of species s.e.: numeric, standard error LCL: numeric,
 lower confidence limit UCL: numeric, upper confidence limit variance:
 numeric, variance estimate ID: numeric, plot ID site_format: character
 string, site name plotID: numeric, plot ID year: numeric,year
 scaled_imperv: scaled variable, impervious surface scaled_basal:scaled
 variable, basal area all trees scaled_genera: scaled variable, number of
 plant genera scaled_keystone:scaled variable,basal area of keystone trees
 Site: character string, site name year_factor: numeric, year as a factor
 rep: numeric, unique ID year_binary: binary, year where 2018 = 1 File 8:
 moth_rareifiedRichness_generalists.csv - Rarefied richness of genus
 generalist moths (output from iNext) Assemblage: character string, unique
 assemblage (plot + year) Diversity: category string, estimate type
 Observed: numeric: observed number of species Estimator: numeric:
 estimated number of species s.e.: numeric, standard error LCL: numeric,
 lower confidence limit UCL: numeric, upper confidence limit variance:
 numeric, variance estimate ID: numeric, plot ID site_format: character
 string, site name plotID: numeric, plot ID year: numeric,year
 scaled_imperv: scaled variable, impervious surface scaled_basal:scaled
 variable, basal area all trees scaled_genera: scaled variable, number of
 plant genera scaled_keystone:scaled variable,basal area of keystone trees
 Site: character string, site name year_factor: numeric, year as a factor
 rep: numeric, unique ID year_binary: binary, year where 2018 = 1 File 9.
 leps_withplants.csv moth species, counts, and basal area of host trees at
 each plot plot: numeric, plot ID mothID: character string, moth scientific
 name mothID_format:character string, moth scientific name count: numeric,
 count of moth individuals total_basal_all: numeric, basal area of all
 known host plants planttype: category, plant type woody (wood)
 num_hostplants: numeric, number of known host genera category: specialism
 category (generalist or specialist) File 10. final_foodplant_analysis.Rmd
 * Rscript to run GLMM of Host plant relationships with the abundance of
 individual species. File 11. rlq_data.RDS * Data file of matrices for RLQ
 and Fourth Corner Analysis. File 12. rlq_data_justHerbivores.RDS * Data
 file of matrices for RLQ and Fourth Corner Analysis for just herbivores.
 File 13. moth_data.csv ID: numeric, unique ID plot: numeric, plot number
 year: numeric, year specialist_abundance: numeric, abundance of
 genus-specialist moths generalist_abundance: numeric, abundance of
 genus-generalist moths other_abundance:numeric, abundance of other moths
 total_abundance:numeric, total abundance of moths specialist_richness:
 numeric, richness of genus-specialist moths generalist_richness: numeric,
 richness of genus-generalist moths other_richness: numeric, richness of
 other moths total_richness: numeric, total richness of moths
 specialist_biomass: numeric, biomass (in mg) of genus-specialist moths
 generalist_biomass: numeric, biomass (in mg) of genus-generalist moths
 other_biomass: numeric, biomass (in mg) of other moths total_biomass::
 numeric, biomass (in mg) of all moths specialist_family_richness
 generalist_family_richness other_family_richness total_family_richness
 specialist_family_abundance: numeric, abundance of family-specialist moths
 generalist_family_abundance: numeric, abundance of family-generalist moths
 other_family_abundance: numeric, abundance of other moths
 total_family_abundance: numeric, abundance of all moths
 specialist_family_biomass: numeric, biomass (in mg) of family-specialist
 moths generalist_family_biomass: numeric, biomass (in mg) of
 family-generalist moths other_family_biomass: numeric, biomass (in mg) of
 other moths total_family_biomass: numeric, biomass (in mg) of all moths
 plotID: numeric, plot number site: character, site name siteID.x: numeric,
 plot number total_basal: numeric, total basal area of trees
 genera_richness:numeric, total genera richness of trees
 keystone_basal:numeric,total basal area of keystone trees
 productivity_index: numeric, productivity value (basal area * lepidoptera
 richness supported) productivity: numeric, productivity value (basal area
 * lepidoptera richness supported) siteID.y: character, site and plot name
 site_name: character: site name lat_fixed: latitude long_fixed: longitude
 imperv_1km_mean: numeric, mean proportion of impervious surface within 1km
 imperv_500m_mean: numeric, mean proportion of impervious surface within
 500m imperv_100m_mean: numeric, mean proportion of impervious surface
 within 100m imperv_50m_mean: numeric, mean proportion of impervious
 surface within 50m prop_keystone: numeric, proportion of keystone plants
 site_format: character, formatted site name