An individual-based model trained on multiple data sources estimates population connectivity and facilitates aggregation of harvest management units
Data files
Oct 07, 2024 version files 11.85 MB
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CaptureSites_-_Anonymized.csv
2.64 KB
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GPS_Seasonal_-_SSF_points.csv
10.95 MB
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GPS_Seasonal_-_Used.csv
162.70 KB
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Harvests_-_Harvested_Birds_-_anonymized.csv
15.34 KB
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Nest_Monitoring_-_Nest_Info.csv
33.89 KB
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README.md
7.56 KB
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SeasonShifts.csv
4.75 KB
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Spring_Movement_Timestamps.csv
1.37 KB
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Telemetry_Data_-_Telemetry.csv
546.43 KB
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Trapping_-_Data.csv
126.34 KB
Abstract
Management boundaries are often delimited by political and social factors, whereas animal movements are affected by ecological and geophysical constraints. Thus, understanding connectivity among distinct management units is of considerable importance, particularly for harvested species, where quotas set in ignorance of connectivity may fail to meet management goals. Our goal was to construct an individual-based model (IBM) to better understand Wild Turkey movements at large scales, benefiting from multiple data sources that are often available for harvested species. We built an IBM describing spring seasonal movements of Wild Turkeys, using data from ringed, radio-, and GPS-marked turkeys captured in Maine, USA. Our IBM accommodated variation in individual turkey response to landscape connectivity metrics and identified emergent migratory connectivity dynamics among harvest management regions. We calculated a low degree of connectivity among wildlife management districts (WMD) which, in combination with the substantial number of boundary crossings observed, indicated a more diffuse distribution of turkeys among WMDs. Nevertheless, the number of turkeys moving between districts provided a clear delineation of where immigration was strongest, identifying which WMDs should be managed as singular population units. This approach has widespread utility for any species or system where harvest management decisions are made at finer spatial scales than the movement dynamics affecting population processes.
https://doi.org/10.5061/dryad.s4mw6m9gg
Missing data: In cases where data was not recorded, we report NA instead. In trapping datasets, many NAs resulted from the fact that not all animals received the same marking, some were not sampled for blood or other individual-specific cases. In telemetry data, many NAs were produced for second and third location checks for triangulation, as it was not often necessary for general project purposes.
Files and variables
File: CaptureSites_-_Sheet1.csv
Description: Location information for captures of Wild Turkey
Variables
- Study.Area: General Region
- Town: Town Name
- Latitude: Decimal Degrees
- Longitude: Decimal Degrees
File: GPS_Seasonal_-_Used.csv
Description: Location information for Wild Turkeys capture near Bangor Maine
Variables
- BirdID: Individual bird indicator
- location.lat: Decimal Degree
- location.long: Decimal Degree
- timestamp: DateTime in GMT for Wild Turkey locations
File: Harvests_-_Harvested_Birds.csv
Description: Location information
Variables
- Season: Whether harvest occurred in spring or fall hunting season.
- Year: Year of harvest
- Alum Band ID: ID number of aluminum butt end leg band if present
- Rivet ID: ID number of aluminum rivet bands if present
- Color Band ID: ID number of color band if present
- Pat Tag ID: ID number for patagial tag if present
- MissingButt: If there was a missing leg band
- VHF Trans: If there was a VHF transmitter on the bird
- Sex: Sex of animal harvested
- Capture Date: Date of original banding.
- Town of Capture: Town where the animal was originally captured and banded
- Date of Harvest: Date of harvest, as indicated by hunter self-reporting
- Town of Harvest: Location of harvest, as indicated by hunter self-reporting and correspondence with a hunter if ambiguous
- Harvest WMD: Location of harvest, identified via town information and correspondence with a hunter if ambiguous
- Time of Harvest: Approximate time of harvest as indicated by hunter, self-reporting
- Reported Online: Y/N Method of reporting as indicated by hunter, self-reporting
- Reported to Phone: Y/N Method of reporting as indicated by hunter, self-reporting
- Reported by Check Station: Y/N Method of reporting as indicated by hunter, self-reporting
- Reported Via Other method: Y/N Method of reporting as indicated by hunter, self-reporting
File: Nest_Monitoring_-_Nest_Info.csv
Description: Information on the nesting behavior of Wild Turkeys marked with VHF and GPS transmitters
Variables
- Year: Year in which the nest occurred
- Alum Band ID: Common ID among datasets
- Frequency: VHF frequency of transmitter
- Nest Attempt: 1st, 2nd, or 3rd nest attempt within a nesting season
- Bird Capture Site: Original location where the bird was captured and marked.
- NestID: Individual identifier for nest
- FlagLat: Decimal Degree flagging location for checking if hens were on the nest.
- FlagLong: Decimal Degree flagging location for checking if hens were on the nest.
- FlagBear: Direction in degrees from the flagging location for checking if hens were on the nest.
- NestLat: Location of the nest, confirmed. Decimal degrees.
- NestLong: Location of the nest, confirmed. Decimal degrees.
- Nest Description: Brief description of nesting locations
- Clutch Size: Number of eggs in clutch when counted
- Date Counted: Date counted
- FloatA: Estimated age from floating eggs
- FloatB: Estimated age from floating eggs
- FloatC: Estimated age from floating eggs
- FloatD: Estimated age from floating eggs
- FloatAverage: Average estimated age of floating eggs
- Est.Laying.Initiation: Estimated laying initiation date, calculated based on egg floating and number of eggs present
- EstimatedHatch: Estimated hatch date, calculated based on the estimated initiation date
- Fate: Final fate of the nest, successful or failed
- Comments: Relevant information
File: SeasonShifts.csv
Description: Estimates of seasonal shifts in movement behaviors of individual birds
Variables
- BirdID: Common ID number across datasets, AlumBandID
- Year: Year of movements
- Season: Season names
- Start: Start of behavioral phase
- End: End of behavioral phase
File: Spring_Movement_Timestamps.csv
Description:
Variables
- BirdID: Common ID for bird
- Start: DateTime Start of spring movement
- End: DateTime End of spring movement
- WNSame: Whether Winter and Nesting season overlap
File: GPS_Seasonal_-_SSF_points.csv
Description: Post-Data management SSF use-available locations. Inputs for SSF.
Variables
- ID: Bird_Year ID
- x1_: UTM19 EPSG 32619 Starting Location Longitude
- x2_: UTM19 EPSG 32619 Ending Location Longitude
- y1_: UTM19 EPSG 32619 Starting Location Latitude
- y2_: UTM19 EPSG 32619 Ending Location Latitude
- sl_: Step Length in meters
- ta_: Turning angle in radians
- t1_: DateTime for the starting location
- t2_: DateTime for the end location
- case_: Whether used or available location
- step_id_: Individual step identifier, linking used and available
- Year: Year data collected
- BirdID: bird ID
File: Trapping_-_Data.csv
Description: Details about animal trapping and marking
Variables
- Study.Area: General region of capture
- Location: Name of capture location
- Town: Town of capture location
- WMD: Wildlife management district
- Region: Management region
- Date: Date of capture
- AlumBand: ID Number if marked
- Rivet Band: ID Number if marked
- TransFreq: Transmitter fruency
- Trans.Type: Backpack, Necklace, or GPS
- GPS ID: If GPS, ID number
- Color Band: ID Number if marked
- Pat Tag: ID Number if marked
- Recapture: If previously capture
- Tier Init: Name of the person who tied the transmitter
- Trans On?: Was the transmitter confirmed on
- Sex: Sex of bird
- Age: relative age of bird at capture, either adult (>1) or juvenile
- Bld Red: Was blood draw collected in a red tube
- Bld Purp: Was blood draw collected in a red tube
- ClclSwb: Was cloacal swab collected
- CapTube: Was blood collected via a capillary tube
- Weight (lbs): Weight of bird
- Spur: Spur length in inches (unit of measurement used by hunters)
- Beard: Beard length cm
- Tarsus: Tarsus (leg) length cm
- Time.Fired: Time net was released/fired
- Release Time: Time bird was released
- Hematoma: Whether an animal obtained a hematoma during blood collection
- Flock.Size: Approximate number of birds present when net-fired
- Comments: comments
- Comments 2: more comments
File: Telemetry_Data_-_Telemetry.csv
Description: Details on VHF telemetry checks of marked birds
Variables
- AlumBand: Common Bird ID
- TransFreq: Transmitter frequency
- Date: Date of check
- Fate: Fate of bird, live/dead, when checked
- Lat1: Decimal Degree Latitude
- Long1: Decimal Degree Longitude
- Bear1: Bearing in Degrees
- Lat2: Decimal Degree Latitude
- Long2: Decimal Degree Longitude
- Bear2: Bearing in Degrees
- Lat3: Decimal Degree Latitude
- Long3: Decimal Degree Longitude
- Bear3: Bearing in Degrees
- Notes: note
- Recovered: If dead, was the transmitter recovered
- Downloaded: If GPS, was data downloaded
Code/software
R
Access information
Other publicly accessible locations of the data:
- Movebank for GPS data
We captured 890 turkeys from December through March of 2018-2020 and marked each with one or two unique leg rings imprinted with information for reporting recovered birds. From late April to early June of 2018-2020, Maine allowed the recreational harvest of bearded turkeys in most management districts. When ringed turkeys were reported, we asked hunters to identify the town of harvest, which we used to define the locations of recoveries. Of captured turkeys, we fit a subset of females with either a GPS or VHF transmitter to monitor seasonal movements and nesting activity. We programmed GPS transmitters to record one nighttime roost location and hourly daylight locations each day from November 1 through July 31 each year. We relocated radio-marked turkeys from April through July of 2018-2020 to identify nests following methods in Gonnerman, Shea, et al. (2022).
We classified movement between winter and spring home ranges by comparing capture locations to either harvest or nest locations for the same turkey in the year of capture, as data collected in the following years included additional seasons of movement. We defined a seasonal movement as any instance where a harvested or nesting turkey was observed greater than 5.5km from its given capture location, which corresponds to the radius of the circle of area equal to the average Maine town. This was chosen to correspond with the most coarse observational scale at which harvest data was collected and while conservative ensured that all potential behaviors were captured.