Data from: City lizards are more social
Data files
Sep 08, 2025 version files 43.42 KB
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associations_data.csv
2.08 KB
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P1_attributes.csv
171 B
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P1_GBI.csv
1.08 KB
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P2_attributes.csv
465 B
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P2_GBI.csv
9.18 KB
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P3_attributes.csv
204 B
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P3_GBI.csv
1.33 KB
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P4_attributes.csv
206 B
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P4_GBI.csv
988 B
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P5_attributes.csv
124 B
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P5_GBI.csv
394 B
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P6_attributes.csv
186 B
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P6_GBI.csv
986 B
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population_density.csv
872 B
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README.md
3.72 KB
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script_Maune_etal_SNA.R
19.53 KB
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sna_data.csv
1.90 KB
Abstract
Cities are expanding globally, exposing animals to novel ecological conditions that can alter the frequency and nature of their social interactions. Urban habitat features, such as built infrastructure and patchy resource distributions, can constrain movement and promote aggregation, potentially increasing encounters among conspecifics and introducing unique social challenges. Understanding how urbanization affects social behaviour is crucial. However, these effects remain poorly understood, and studies on solitary or non-gregarious species are particularly scarce. Here, we investigate how urbanization influences social behaviour in the Common wall lizard (Podarcis muralis), a territorial species and successful urban dweller. We constructed social networks from proximity-based association data from urban and non-urban lizard populations. Urban lizards had more social connections, stronger associations, and were observed in more associations overall. These differences were not explained by variation in population density. We propose that spatial constraints and resource heterogeneity in urban habitats may enhance social tolerance. Our results reveal that urbanization can reshape social behaviour even in less gregarious species, and suggest that shifts in social strategies may facilitate persistence in urban landscapes.
Authors: Avery L. Maune, Tobias Wittenbreder, Duje Lisičić, Barbara A. Caspers, Ettore Camerlenghi, Isabel Damas-Moreira
A total of 13 data files were used to construct and analyze social networks, including:
P1_GBI.csv - P6_GBI.csv: Group-by-individual matrices
P1_attributes.csv - P6_attributes.csv: Attribute metadata
sna_data.csv: Combined dataset including calculated social metrics
Only individuals observed ≥3 times (N = 69) are included in these files.
Additional files included:
associations_data.csv: Contains data for all marked individuals (N = 94), used to analyze observation and association counts.
population_density.csv: Lizard count data from line transect surveys conducted over 10 days across all size transects, used to estimate population density.
script_Maune_etal_SNA.R: Full R script used for social network construction and statistical analysis
Data files
1. Group-by-individual matrices
Binary matrices showing individual co-occurrence in observed social groups.
Files: P1_GBI.csv, P2_GBI.csv, P3_GBI.csv, P4_GBI.csv, P5_GBI.csv, P6_GBI.csv
Details: Rows = observation events; Columns = individual lizards; 1 = present; 0 = absent
2. Attribute tables
Metadata for each individual included in the social network analysis, including id, transect, habitat, and sex. The row order corresponds to the columns in the GBI matrices.
Files: P1_attributes.csv P2_attributes.csv P3_attributes.csv P4_attributes.csv P5_attributes.csv P6_attributes.csv
3. Social network dataset
Combined data for all individuals (N = 69), including calculated social network metrics: binary_degree and weighted_degree. Social network metrics were calculate from the GBI matrices and added to the corresponding attribute tables, which were then combined into a single dataset for analysis.
File: sna_data.csv
4. Association data
Frequency of observations and associations for all marked individuals (N = 94). Includes id, transect, habitat, the total number of associations (asso_count) and total observation events (obs_count) per individual.
File: associations_data.csv
5. Population density data
Counts of lizards observed during 10 line transect surveys per site. Used to estimate population density across urban and non-urban habitats.
File: population_density.csv
6. R code
Contains all R code used in the social network construction and statistical analysis.
File: script_Maune_etal_SNA.R
Variables
| Variable | Description |
|---|---|
id |
Unique lizard identifier |
transect |
Transect ID (P1–P6) |
habitat |
Habitat type: urban or non_urban |
sex |
Sex class: F (female), M (male), or Sub (subadult) |
asso_count |
Number of associations per individual (with marked or unmarked individuals) |
obs_count |
Number of observations per individual |
no_liz |
Number of lizards counted during a single transect survey |
binary_degree |
Number of unique social connections per individual (network metric) |
weighted_degree |
Sum of edge weights per individual (network metric) |
