Individual and temporal variation in movement patterns of wild alpine reindeer and implications for disease management
Cite this dataset
Hjermann, Tilde Katrina Slotte et al. (2024). Individual and temporal variation in movement patterns of wild alpine reindeer and implications for disease management [Dataset]. Dryad. https://doi.org/10.5061/dryad.h18931zt3
Abstract
Animal behaviour is important for prevalence and outbreaks of infectious diseases, for instance by affecting individual interactions. Increasing the knowledge of individual movement patterns can provide better insight into disease prevalence and spread, helping to target efforts to minimise disease outbreaks. Chronic wasting disease (CWD) is a fatal prion disease affecting cervids. CWD is transmitted by animal-to-animal contact and through the environment, thus individual variation in space use and social associations may influence disease transmission patterns and infection risk. CWD was detected in Norwegian alpine reindeer (Rangifer tarandus) in 2016, and eradication of the infected population was implemented. A 3:1 infection rate between males and females suggests sex-specific behavioural drivers. We utilised an extensive individual-based dataset of 149 GPS-marked wild reindeer to investigate individual variation in movement patterns in terms of inter- and intra-annual home range size and site fidelity, and variation in home range overlap and distances between individuals. We aimed to identify patterns which could indicate higher potential disease risk. Females had larger annual and seasonal home ranges than males, except during calving and rut. Greater home range overlaps and shorter between-individual distances were found between same-sex individuals than different-sex individuals, except during the rut. Accordingly, the rut season stands out with greater male home ranges, greater home range overlap and shorter distances between males and between males and females, which could indicate that this season is critical for disease transmission. Measures to prevent disease spread should lower contact rates, e.g., by reducing the abundance of adult males before they mix with other groups during the rut. This can be achieved for instance by allowing earlier hunt on adult males when they are distributed in small male groups, to reduce the transmission risk and keep disturbance of other individuals low.
README: Norwegian alpine reindeer home range size, overlap, and between-individual distances
https://doi.org/10.5061/dryad.h18931zt3
Description of the data and file structure
The datasets included here provide data from Norwegian wild alpine reindeer for analysing the following:
- Seasonal home range sizes (dataset is named "Seasonal_HR_size_data")
- Annual home range sizes (dataset is named "Annual_HR_size_data")
- Inter-individual overlap (dataset is named "overlaptable_between_individuals")
- Intra-individual home range overlap, i.e., site fidelity (datasets are named "site_fidelity_NF", "site_fidelity_SH", and "site_fidelity_SR", split into study populations)
- Daily distance between nearest male and female individual.
The files for the home range, between-individual overlap and distance analyses contain data from three populations of Norwegian wild alpine reindeer, whereas the files for the site fidelity analyses are separated into population-specific files (NF = Nordfjella, SH = Snøhetta, SR = Setesdal Ryfylke).
The data files all contain multiple columns. In the datasets for the annual and seasonal home ranges:
- RegNr: Registration number, unique to each individual.
- area: home range area (either annual or seasonal depending on the dataset).
- HRyear: home range year. We defined a home range year with the start in the calving season (May 1st) and end after the winter season (March 15th). This means that for the majority of the calendar year, the home range year will be the same, except between January 1st and May 1st.
- Sex: the sex of the individual. 1 = male, 2 = female.
- NrDays: Number of days tracked during the home range year (HRyear) or season, depending on the dataset (seasonal or annual home range).
- Population: study population. NF = Nordfjella, SH = Snøhetta, SR = Setesdal Ryfylke.
- Season: the season, defined as in the corresponding article.
- id: a combination of the columns RegNr, HRyear, Season (only for the seasonal home range dataset), Sex, and NrDays (separated by a space between each).
For the distance dataset (column names that are not already similar to the ones mentioned above are presented):
- FK_SexCode: the sex of the unique individuals. 1 = male, 2 = female.
- date: the date for the day the distance is calculated.
- Month, Year and Day: the month, day and year (calendar year) the distance was calculated.
- DayNr: the day of the year of the given date. Janueary 1st = day 1.
- iddist: a combination of the columns RegNr, date, Season, Sex, and Population (separated by a space between each).
- All columns starting with "i.": similar to the columns not starting with this, but for the other individual the distance is calculated between.
- distance: the distance between the two individuals (in m).
- sex.pair: a vector with the sex of the two individuals the distance is calculated between, separated by "-". 1-1 = male-male, 1-2 = male-female (or female-male), and 2-2 = female-female.
- sqrt.dist: the square root of the distance.
For the overlap between individuals dataset (column names that are not already similar to the ones mentioned above are presented):
- from: the id (a combination of the columns RegNr, HRyear, Season (only for the seasonal home range dataset), Sex, and NrDays (separated by a space between each) of the first individual the overlap is calculated between.
- to: similar to from (see above), but for the other individual the overlap is calculated between).
- include: a binomial column with 1 if to be included in the analyses, and 0 if not.
- all columns starting with either "from." or "to.": similar to columns with similar names (except the prefix) found in the seasonal home range datasets (see above).
- overlap.BA.T: the home range overlap between the given individuals (the given season and year).
- overlap.bin: binomial column. 1 = overlap >= 0.1, and 0 = overlap < 0.1.
For the site fidelity analyses (column names that are not already similar to the ones mentioned above are presented):
- All columns are similar to the ones found in the dataset for overlap between individuals. However for the site fidelity data, both the "from" and "to" individuals are the same individuals, but either different year (inter-annual site fidelity), or different season within the same year (intra-annual site fidelity).
- SeasonsPair: the pair of seasons the site fidelity is calculated between.
Methods
This information is available in the Materials and Methods section in the associated article (DOI: 10.1111/ecog.06957).
Funding
The Research Council of Norway, Award: 223257
Norwegian Environment Agency, Award: 19SB7177