Dataset DOI: 10.5061/dryad.8sf7m0d1n

Description of the data and file structure

We investigated movement responses to roads for caribou (Rangifer tarandus) in northwestern Alaska. We ran GPS telemetry data for 366 adult female caribou through a modified version of the Barrier Behavior Analysis (BaBA) tool, resulting in this dataset. The BaBA compares movement parameters near a potential barrier with those away from barriers to identify altered movement behavior. We heavily modified the original BaBA methodology for this analysis. The resulting dataset indicates interactions with roads at the encounter and altered burst scales, including information about timing and behavioral responses.

Files and variables

File: WAH_BaBA_Data_2025-05-09.csv

Description: Behavioral responses of adult female caribou of the Western Arctic Herd to roads in northwestern Alaska as indicated by our modified Barrier Behavior Analysis (BaBA). Each row of the dataset represents one burst (see definition below and in the study text) analyzed in this study. For details of how these behaviors were identified from caribou GPS telemetry data, see the Methods of this study and details in Supplementary Information 1.

Variables

• AnimalID: Unique alphanumeric identifier for each caribou analyzed in the dataset. Some AnimalIDs are completely numeric while others also include letters.
• encounter: Unique identifier for each encounter of a caribou with a road, encompassing the time from which a caribou entered a focal road buffer until it left that buffer. Encounters take the Animal_ID followed by a numeric indicator to distinguish the potential for multiple encounters per caribou.
• burstID: Unique identifier of each burst analyzed by the BaBA. Bursts represent subdivisions of an encounter, identified by a focal road being crossed or, in the event of overlapping road buffers (Red Dog – Kivalina only), the animal moving from being closer to one focal road to another while remaining within the buffers. Bursts were used to identify multiple behavioral responses to a single focal road or to multiple nearby roads with overlapping buffers. The burstID matches the encounter identifier with a possible additional numeric indicator if there were multiple bursts for a given encounter.
• start_time: The start time for the movement step in which a caribou entered a focal road buffer or started a new burst within an encounter. Times are reported here in Universal Coordinated Time (UTC) but were converted to the local Alaskan time zone (tz = "America/Anchorage") using the lubridate package in R for assignment of seasons and for the other analyses reported in our study. All telemetry location times were rounded to the nearest hour, as this was their target capture time.
• end_time: The end time for a movement step in which a caribou left a focal road buffer or ended a burst within an encounter. Times are reported here in Universal Coordinated Time (UTC) but were converted to the local Alaskan time zone (tz = "America/Anchorage") using the lubridate package in R for assignment of seasons and for the other analyses reported in our study. All telemetry location times were rounded to the nearest hour, as this was their target capture time.
• duration_hrs: The duration of the burst in hours, indicating the time between start_time and end_time.
• season: The season of the year in which the burst took place. Seasons reflect biologically relevant periods of similar caribou behavior, following Joly and Cameron 2024. Seasons included: spring migration, calving, insect harassment, late summer, fall migration, and winter. Bursts were assigned to the season which occupied the majority of the burst locations.
• road: Indication of the road with which the caribou interacted at the encounter scale. The encounter scale reflected all bursts within an encounter combined into a single representation of an interaction with a road or set of roads. We combined the Red Dog and Kivalina road responses at the encounter scale as their overlapping buffers often led to joint reactions in proximity to both roads within a single encounter. Possible roads included: Dalton, Kobuk, Nome, and Red Dog - Kivalina. Please see the Methods section of the study for descriptions of each road.
• encounter_scale: Behavioral response of the caribou at the encounter scale. Behavior was reduced to a binary of unaltered or altered movement.
  • Unaltered movement - Movements indistinguishable from season-specific movement in the absence of focal roads or for which crossing did not appear hindered. These consisted of normal movement and quick cross behaviors.
  • Altered movement - Periods where movement behavior changed near a focal road compared to seasonal average movement parameters outside of road buffers. These consisted of back-and-forth, bounce, and trace behaviors. If any of the bursts within the encounter featured altered movement, then the encounter was classified as altered.
• burst_scale: Behavioral response of the caribou at the burst scale. Each burst was assigned a movement behavior by the BaBA (details in Methods and Supplementary Information 1). Possible values included:
  • Normal movement - Movement in which movement parameters fell within seasonal average parameters or all locations in the burst were closest to the same point on the road (identifying situations where a caribou briefly dipped inside a buffer and then exited again rapidly).
  • Quick cross - Rapid, linear movement across one or more focal roads, without apparent hindrance by the road.
  • Back-and-forth - Clustered movement near a focal road, with repeated changes in movement direction leading to relatively confined space use.
  • Bounce - Movement in which a caribou approached a focal road and then bounced back away, typically without crossing.
  • Trace - Movement in which a caribou paralleled a road for a sustained amount of time.
• crossing: Binary indication of whether the caribou crossed the closest_rd during the indicated burst (1) or not (0). This corresponds to the cross_true parameter in Supplementary Fig. S1 as it  distinguished between true and false crossings by testing for locations on either side of a road. If all locations were on the same side of a road, we assumed this indicated a false crossing (i.e., when the straight line between subsequent locations might falsely indicate that a crossing occurred). Thus, crossing only takes a value of 1 when a crossing is indicated and locations occur on both sides of a road.
• closest_rd: Indication of the road with which the caribou interacted at the burst scale. At the burst scale, interactions with each road could be distinguished. Thus, possible values included: Dalton, Kivalina, Kobuk, Nome, and Red Dog. Please see the Methods section of the study manuscript for descriptions of each road.
• closest_dist_km: Numeric indicator of the distance between the closest recorded telemetry location and closest_rd, in units of kilometers. Note that this is the closest observed distance but may not reflect the closest the caribou actually came in between recorded locations. For example, any caribou that crossed the road would have an actual closest distance of 0 km. This was calculated by taking the minimum distance between the telemetry locations for a given burst and the line locations of closest_rd, using the st_distance function of the sf package in R.

Code/software

Code for running our modified Barrier Behavior Analysis (BaBA) tool is available at https://github.com/tfullman/BaBA.