DOI: 10.5061/dryad.x0k6djhx5
title: The impact of gigafire on vegetation structure, terrestrial vertebrate abundance, and diel activity

description: Fire regimes are shifting around the world due to climate and land-use
 change, resulting in an increased frequency of large and severe wildfires.
 However, the impact of extreme wildfire events on animal species remains
 poorly understood. Particularly lacking is an understanding of how fire
 affects animal behaviour. By examining how distinct vertebrate groups
 respond to wildfire, we capture variations in resilience mechanisms that
 further our understanding of fire ecology and aid conservation strategies
 in increasingly fire-prone landscapes. Across an area of 180,110 ha, we
 investigated the effects of the 2019–2020 Australian ‘Black Summer’
 wildfires on vegetation structure (a proxy for vertebrate habitat), the
 number of independent detections (as an indicator of abundance), and diel
 activity of a range of terrestrial animals in Eucalypt forests of
 south-eastern Australia. We examined the influence of fire severity on
 vegetation structure, using wildlife cameras, animal species abundance,
 and how burnt or unburnt areas and fire severity affect species’ diel
 activity patterns 20 months post-fire. Areas subject to high severity
 fires (in comparison to low–moderate) had less canopy cover and leaf
 litter, and higher vegetation cover at measured (0 to &gt;2 m)
 understory heights, as well as greater abundance of logs. Fire severity
 had a limited effect on the abundance of animal species, with differences
 in abundance observed in eight of 29 species. A greater impact occurred
 following high severity fire, where 8/29 species were affected, compared
 to 3/29 in areas burnt at lower severity. However, only 4/29 species (high
 severity) and 1/29 (low severity) responded negatively, demonstrating a
 general resilience among many species to fire. Areas that burnt at high
 severity had higher introduced mammal richness and reduced native mammal
 diversity, suggesting the potential for introduced species to establish in
 severely burnt areas. The diel activity patterns in areas subject to fire
 differed for seven of 17 species with sufficient data, with these species
 concentrating their activity during specific times in burnt areas compared
 to unburnt areas. Such behavioural plasticity may facilitate species
 persistence in environments modified by fire by allowing species to
 exploit different resources or minimise predation risk. Understanding how
 fire affects animal species, including animal behaviour, will be critical
 as the world’s fire regimes continue to change.
description: # The impact of gigafire on vegetation structure, terrestrial vertebrate
 abundance, and diel activity Dataset DOI:
 [10.5061/dryad.x0k6djhx5](10.5061/dryad.x0k6djhx5) ## Description of the
 data and file structure ### File: **data\_frame\_sites\_dryad.csv** **The
 impact of gigafire on vegetation structure, terrestrial vertebrate
 abundance, and diel activity** This dataset encompasses comprehensive
 surveys of animal species across three wilderness areas affected by an
 unprecedented gigafire. It includes data on species richness, species
 diversity, and various environmental variables such as fire severity,
 vegetation types, and historical fire events. The data were collected to
 analyse the resilience of animal communities and ecosystem functions
 following large-scale fire disturbances. **Description of the Data and
 File Structure** **data_frame_sites_dryad**: This is the primary data
 frame used for analysis, containing observational data across different
 sites. **Variables in data_frame_sites_dryad** Below is a detailed
 description of the variables included in the data_frame_sites_dryad data
 frame: **Site identifiers and observation labels** ·         **site**:
 Unique identifier for each camera‐trap deployment site. ·        
 **location**: Name of the wilderness area (one of the three study regions)
 where the site is located. ·         **landscape**: Numeric code for the
 landscape unit within each study area. ·         **obs**: Label used as
 the observation‐level random effect in hierarchical models. **Deployment
 dates and camera details** ·         **start_date**: Date on which the
 camera was deployed (YYYY-MM-DD). ·         **collection_date**: Date on
 which the camera’s memory card was retrieved (YYYY-MM-DD). ·        
 **date_of_last_picture**: Date of the most recent image captured during
 that deployment (YYYY-MM-DD). ·         **deployment_days**: Total number
 of days the camera was active. ·         **camera_type**: Model of camera
 trap used at the site (e.g., Enduro Swift, Reconyx). **Site location and
 Environmental variables** ·         **latitude**: Latitude of the camera
 site in decimal degrees. ·         **longitude**: Longitude of the camera
 site in decimal degrees. ·         **topography**: Broad landform category
 at the site (e.g., ridge, valley). ·         **elevation**: Elevation at
 the site in metres above sea level. ·         **rainfall**: Mean annual
 rainfall for the site’s locale (millimetres). ·         **vegetation**:
 Dominant vegetation type at the site (e.g., shrubland, open forest).
 ·         **ndvi**: Mean Normalized Difference Vegetation Index over the
 deployment period, indicating vegetation greenness. ·        
 **terrain_ruggedness**: Terrain Ruggedness Index calculated for the area
 surrounding the site. **Fire metrics** ·         **fire_severity**:
 Categorical fire‐severity class assigned to the site (unburnt;
 low/moderate; high). ·         **fire_count**: Number of historical fires
 recorded within the site containing the site. **Biodiversity metrics**
 ·         **Total_richness**: Total number of species recorded by that
 camera across all periods. ·         **Total_native_mammal_richness**:
 Number of native mammal species detected at the site. ·        
 **Total_introduced_mammal_richness**: Number of introduced (non-native)
 mammal species detected. ·         **Shannon_diversity**: Shannon
 diversity index for all species at the site. ·        
 **Shannon_native_mammal**: Shannon diversity index calculated only for
 native mammal species. ·         **Shannon_introduced_mammal**: Shannon
 diversity index calculated only for introduced mammal species. **Species
 data** Individual species data show the sum of the number of 30-minute
 events at each site in each period. ### File:
 data\_frame\_vegetation\_dryad.csv **The impact of gigafire on vegetation
 structure, terrestrial vertebrate abundance, and diel activity** This
 dataset encompasses vegetation surveys across three wilderness areas
 affected by an unprecedented gigafire. It includes data on species
 richness, functional diversity, predator-prey interactions, and various
 environmental variables such as fire severity, vegetation types, and
 historical fire events. The data were collected to analyse the resilience
 of animal communities and ecosystem functions following large-scale fire
 disturbances. **Description of the Data and File Structure**
 **data_frame_vegetation_dryad**: This is the primary data frame used for
 analysis, containing vegetation data across different sites. **Variables
 in data_frame_vegetation_dryad** Below is a detailed description of the
 variables included in the data_frame_vegetation_dryad data frame: **Survey
 and site identifiers** * **location**: Study region (one of the three
 wilderness areas). * **survey number**: Sequential identifier for each
 survey event. * **landscape**: Numeric code for the landscape unit. *
 **site**: Unique code for each camera‐trap deployment. * **obs**:
 Observation‐level random‐effect label. **Temporal variables** * **date**:
 Date of the survey or detection (YYYY-MM-DD). * **time**: Time of the
 survey or detection (HH:MM:SS). **Spatial coordinates and positioning** *
 **landscape_position**: Position within the landscape (e.g., mid slope,
 flat, upper slope). * **latitude**: Site latitude (decimal degrees). *
 **longitude**: Site longitude (decimal degrees). **Environmental
 covariates** * **elevation**: Metres above sea level. * **rainfall**: Mean
 annual rainfall (mm). * **vegetation**: Dominant vegetation community at
 the site. * **ndvi**: Mean Normalized Difference Vegetation Index during
 the survey. * **terrain_ruggedness**: Terrain Ruggedness Index around the
 site. **Fire metrics** * **fire_severity**: Categorical class (unburnt;
 low/moderate; high). * **severity**: Continuous index of local fire
 impact. * **fire_count**: Number of historical fires in that site.
 **Habitat-structure metrics** * **canopy_species**: Dominant canopy
 species. * **Canopy cover average**: Mean percent canopy cover taken at
 three points (0m, 25m, 50m) along the vegetation transect. * **Canopy
 height average**: Mean canopy height (m) taken at three points (0m, 25m,
 50m) along the vegetation transect. * **Log volume sum**: Total fallen-log
 volume (m³) taken from their height and width within 5m on either side of
 the vegetation transect. * **Log count**: Number of fallen logs within 5m
 on either side of the vegetation transect. * **large_rocks**: Count of
 large rocks within 5m on either side of the vegetation transect. *
 **burrow_count**: Count of wombat burrows within 5m on either side of the
 vegetation transect. **Vegetation and substrate metrics** **Ground cover**
 ·         **Bare ground**: Cover of exposed soil along the vegetation
 transect. **Understorey structure cover** ·         **Ground, Low**,
 **Medium**, **High**, **Very high vegetation cover**: Cover of understory
 vegetation within each height class along the vegetation transect.
 **Leaf-litter cover** ·         **Leaf litter**, **Low/Medium/High/Very
 high leaf litter**: Cover of litter layer and its density classes along
 the vegetation transect. **Substrate feature** ·         **Rock**: Cover
 of rocks along the vegetation transect. **Plant functional groups**
 ·         **Eucalyptus adult, Eucalyptus basal, Eucalyptus dead,
 Eucalyptus epicormic, Eucalyptus juvenile**: Cover of individuals in each
 life stage along the vegetation transect. ·         **Forb, Grass, Other
 tree, Rush, Sedge, Shrub**: Cover of each functional group along the
 vegetation transect. **Tree-size metrics (DBH classes)** * **DBH alive
 5–20**, **20–50**, **51–80**, **81–120**, **121+**: Count of the live
 stems in each diameter‐at‐breast‐height (cm) class within 5m either side
 of the vegetation transect. * **DBH dead 5–20**, **20–50**, **51–80**,
 **81–120**, **121+**: Count of the standing dead stems in each DBH class
 within 5m on either side of the vegetation transect. **Note:** Variables
 ending in **A** (e.g., **Bare groundA**, **ForbA**) record the number of
 sampled grid cells in which that category was present; the corresponding
 variable without **A** gives the total count, area, or measurement for
 that category. ### **site\_images\_30min\_dryad.csv** **The impact of
 gigafire on vegetation structure, terrestrial vertebrate abundance, and
 diel activity** This dataset encompasses 30-minute event data of animal
 species across three wilderness areas affected by an unprecedented
 gigafire. It includes data on species activity and various environmental
 variables such as fire severity, vegetation types, and historical fire
 events. The data were collected to analyse the resilience of animal
 communities and ecosystem functions following large-scale fire
 disturbances. **Description of the Data and File Structure**
 **site_images_30min_dryad**: This is the primary data frame used for
 analysis, containing observational data across different sites.
 **Variables in site_images_30min_dryad** Below is a detailed description
 of the variables included in the site_images_30min_dryad data frame:
 **Event identifiers** * **event number**: Unique identifier for each
 detection event. **Site identifiers and location** * **site**: Unique code
 for each camera‐trap deployment site. * **location**: Name of the
 wilderness area (one of the three study regions) in which the site is
 situated. * **landscape**: Numeric code for the landscape unit within each
 study area. **Deployment dates and camera metadata** * **start_date**:
 Date on which the camera was deployed (YYYY-MM-DD). * **collection_date**:
 Date on which the camera’s memory card was retrieved (YYYY-MM-DD). *
 **data_of_last_picture**: Date of the most recent image captured during
 that deployment (YYYY-MM-DD). * **deployment_days**: Total number of days
 the camera was actively recording. * **camera_type**: Model of camera trap
 used at the site (e.g., Enduro Swift, Reconyx). **Site location and
 Environmental covariates** * **latitude**: Latitude of the camera site in
 decimal degrees. * **longitude**: Longitude of the camera site in decimal
 degrees. * **topography**: Broad landform category at the site (e.g.,
 ridge, valley). - **elevation**: Elevation of the site in metres above sea
 level. - **rainfall**: Mean annual rainfall for the site’s locale
 (millimetres). - **vegetation**: Dominant vegetation type at the site
 (e.g., shrubland, open forest). - **ndvi**: Mean Normalised Difference
 Vegetation Index over the deployment period, indicating vegetation
 greenness. - **terrain_ruggedness**: Terrain Ruggedness Index calculated
 around the site. **Fire metrics** * **fire_severity**: Categorical
 fire‐severity class at the camera location (unburnt; low/moderate; high).
 * **fire_count**: Number of historical fires recorded within the site.
 **Detection details** * **common_name**: Common name of the species
 detected in the event. * **DateTimeOriginal**: Original timestamp of the
 image capture (YYYY-MM-DD HH:MM:SS). * **date**: Date of the detection
 event (YYYY-MM-DD). * **time**: Time of the detection event (HH:MM:SS). *
 **number_of_objects**: Number of objects (individuals) recorded in the
 detection event (e.g., number of animals in the frame). ##
 **Sharing/Access Information** The dataset can be accessed through the
 Dryad digital repository:
 [https://doi.org/10.5061/dryad.x0k6djhx5](https://doi.org/10.5061/dryad.x0k6djhx5)