Does differential habitat selection facilitate coexistence between badgers and hedgehogs?
Data files
Jan 15, 2025 version files 331.51 KB
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Data_and_scripts_repository.zip
325.74 KB
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README.md
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Abstract
Predicting the spatial and temporal responses of species exhibiting intra-guild predation (IGP) relationships is difficult due to variation in potential interactions and environmental context. Eurasian badgers (Meles meles) are intra-guild predators of European hedgehogs (Erinaceus europaeus) and are implicated in their population decline via both direct predation and competition for shared food resources. Previous studies have shown spatial separation between these species and attributed this to hedgehogs experiencing a ‘landscape of fear’, but little is known about the potential role of differential habitat use.
We estimated the density and occupancy of both species at 22 rural study sites in England and Wales, to explore whether food availability, habitat, or the presence of badgers, explained hedgehog distributions. Hedgehog density varied significantly across major rural land uses, whereas badger density did not. Although both species co-existed at a regional (1 km²) scale, occupancy modelling showed spatial segregation at a finer (individual camera trap) scale, associated with differential habitat use. In contrast to badgers, hedgehogs were recorded near buildings, and in areas supporting lower invertebrate biomass. This is in agreement with IGP theory, whereby IG-prey may occupy sub-optimal habitat to avoid predation, however hedgehog habitat use did not vary relative to the presence of badgers. Badger and hedgehog temporal activity showed no evidence of separation. Although these findings are consistent with hedgehogs avoiding badgers via a landscape of fear, they are also indicative of differential habitat use, highlighting the need for more holistic studies considering variation in habitat selection and food availability when investigating intra-guild relationships. Future studies exploring alternative hypotheses for urban habitat selection by hedgehogs are needed to better understand how possible spatial niche partitioning may support their coexistence with badgers in some areas.
README: Does differential habitat selection facilitate coexistence between badgers and hedgehogs?
https://doi.org/10.5061/dryad.sn02v6xfn
Description of the data and file structure
Data relating to camera and invertebrate surveys that were conducted to investigate badger and hedgehog intraguild predation between April 2018 and September 2019.
Data and Scripts are stored in the zipped file 'Data_and_scripts_repository'
Files and variables
File: Data_and_scripts_repository.zip
A description of the folder structure and file contents is given below.
Activity: main folder containing data files and R scripts required to reproduce activity analysis for both study species; badger and hedgehog.
badger_small.png – silhouette image of a badger used to produce figure 5.
hog_badger_activity.csv – detection data after conversion to solar time.
hog_small.png – silhouette image of a hedgehog used to produce figure 5.
Rplot.png – copy of ‘Figure 5’ showing diel activity pattern density curves of badger and hedgehog as obtained from camera trap detections. Rplot can be reproduced by running the ‘Temporal_activity_script’.
Temporal_activity.csv – raw detection data captured by camera trapping.
Temporal_activity_script.R – R script required to reproduce activity analysis.
Occupancy: main folder containing presence/absence data and R scripts required to reproduce occupancy analysis for both study species; badger and hedgehog.
BADGER.csv – Presence/absence data for badger at each individual camera trap location included in the study. Columns S01 – S10 represent the first 10 nights of camera trapping at each individual camera trap location. A value of ‘1’ depicts the species was detected and a value of ‘0’ depicts the species was not detected.
COVARIATES.csv – Site information corresponding to the location of each individual camera trap deployed during the study. Pitfall trapping was conducted to obtain measures of macroinvertebrate abundance (PITFALL_ABUNDANCE_Z) and biomass (PITFALL_BIOMASS_Z). Relative earthworm abundance (WORM_ABUNDANCE_Z) and biomass (WORM_BIOMASS_Z) was estimated by sampling soil cores (further detail is provided in the manuscript).
HEDGEHOG.csv – Presence/absence data for hedgehog at each individual camera trap location included in the study. Columns S01 – S10 represent the first 10 nights of camera trapping at each individual camera trap location. A value of ‘1’ depicts the species was detected and a value of ‘0’ depicts the species was not detected.
Occupancy_script.R – R script required to reproduce single species, and multi-species occupancy models conducted as part of this study.
REM: main folder containing detection data (captured by camera trapping), site information and R scripts required to produce density estimates for badger and hedgehog at each study site. Density estimates were calculated from camera trapping data using the Random Encounter Model (REM).
Camera_deployment.xlsx – Deployment and collection data for individual camera locations at each study site.
Detection.xlsx – Detection data for badger and hedgehog across all study sites. Cells containing ‘n/a’ indicate data not available.
Land_use_%.xlsx – Proportion of major habitat types within the survey area of each study site.
REM_estimates.xlsx – Table of REM density estimates for badger and hedgehog at each study site.
Badger_global_activity.csv
Badger_global_activity.R
Hedgehog_global_activity.csv
Hedgehog_global_activity.R
- Site_1_badger (sub-folder of Exemplar_REM) – contains the detection data for badger at Site 1 (Brackenhurst 2018), R scripts for calculating ‘activity’ at the site level (a parameter required for REM analysis) and ‘density script’ for calculating the density estimate for badger at Site 1 using REM.
· Activity_script.R
· Brackenhurst_18.xlsx
· Brackenhurst_18_activity.csv
· Brackenhurst_18_percam.csv
· Density_script.R
- Site_1_hedgehog (sub-folder of Exemplar_REM) – contains the detection data for hedgehog at Site 1 (Brackenhurst 2018), R scripts for calculating ‘activity’ at the site level (a parameter required for REM analysis) and ‘density script’ for calculating the density estimate for hedgehog at Site 1 using REM.
· Activity_script.R
· Brackenhurst_18.xlsx
· Brackenhurst_18_activity.csv
· Brackenhurst_18_percam.csv
· Density_script.R
Chi-square.R
Chitest.csv
IGP_Density_plot.tiff – Rplot showing the relationship between badger and hedgehog densities across all study sites.
Land-use.csv
Land-use_levene.csv
Landuse.R
Linear_regression.csv
Linear_regression.R
Code/software
Scripts were run using R Studio and packages available through the CRAN R repository.
Methods
We deployed 645 camera traps across the 22 sites (mean = 29 per site), stratified by five key habitat categories: arable, amenity grassland (including residential gardens), agricultural grassland, built environment (buildings and hardstanding) and woodland (deciduous and coniferous). Twenty two rural sites (0.4 – 1.3 km²) were surveyed for badgers and hedgehogs between April - September in 2018 or 2019 (Figure 1). Camera trapping was used to estimate focal species occupancy and density, and invertebrate sampling was used to obtain an index of prey availability for both species. Rural study sites comprising either arable-dominated, pasture-dominated (where a single habitat represented ≥66.7% of the total area of a site), or mixed farming habitat were selected (Table 1), as these were considered landscapes most likely to be occupied by badgers and hedgehogs (Judge et al., 2014; Williams et al., 2018).