Effects of food supplementation and helminth removal on space use and spatial overlap in wild bank vole populations
Data files
Feb 15, 2024 version files 181.82 KB
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fulltrap21_volecapturedata.csv
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README.md
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site_trts.csv
Abstract
Animal space use and spatial overlap can have important consequences for population-level processes such as social interactions and pathogen transmission. Identifying how environmental variability and inter-individual variation affect spatial patterns and in turn influence interactions in animal populations is a priority for the study of animal behavior and disease ecology. Environmental food availability and macroparasite infection are common drivers of variation, but there are few experimental studies investigating how they affect spatial patterns of wildlife. Bank voles (Clethrionomys glareolus) are a tractable study system to investigate spatial patterns of wildlife and are amenable to experimental manipulations. We conducted a replicated, factorial field experiment in which we provided supplementary food and removed helminths in vole populations in natural forest habitats and monitored vole space use and spatial overlap using capture-mark-recapture methods. Using network analysis, we quantified vole space use and spatial overlap. We compared the effects of food supplementation and helminth removal and investigated the impact of season, sex, and reproductive status on space use and spatial overlap. We found that food supplementation decreased vole space use while helminth removal increased space use. Space use also varied by sex, reproductive status, and season. Spatial overlap was similar between treatments despite up to three-fold differences in population size. By quantifying the spatial effects of food availability and macroparasite infection on wildlife populations, we demonstrate the potential for space use and population density to trade off and maintain consistent spatial overlap in wildlife populations. This has important implications for spatial processes in wildlife including pathogen transmission.
README: Effects of food supplementation and helminth removal on space use and spatial overlap in wild bank vole populations
https://doi.org/10.5061/dryad.r4xgxd2mp
Capture-mark-recapture data for experimental field study of wild bank vole (Clethrionomys glareolus) populations in southern Finland. This dataset documents the capture locations of uniquely identified individual voles in standardized trapping grids (100 x 100m; 61 traps) at 12 independent study sites in boreal forest. A replicated field experiment was conducted in which study sites were assigned to food supplementation, helminth removal, both food supplementation and helminth removal, or no manipulation. Trapping was conducted for 48 hours (traps checked every 12 hours) once per month from June - October 2021. Sex and reproductive status (reproductive or non-reproductive) was also recorded for all voles once per month. These data are used in a study investigating the effects of food supplementation and helminth removal on wild rodent space use and spatial overlap and the implications for pathogen transmission.
Description of the data and file structure
Vole capture data file: "fulltrap21_volecapturedata.csv"
This file includes all the capture data for over 700 individual voles. Each row is a capture event of an individual and columns provide information on when the vole was captured, the type of site it was at, where on the grid it was captured, and the vole's sex and reproductive status.
column name | data R class | description |
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year | numeric | year of data collection; all data collected in 2021 |
month | factor (levels: June, July, Aug, Sept, Oct) | month of data collection; possible values (June, July, August, September, October) |
season | factor (levels: summer, fall) | season of data collection; summer if month=June, July, August; fall (autumn) if month=September, October |
occ.sess | character | combination of the occasion and session numbers as "occasion.session" such that occasion 3 includes occ.sess 3.1, 3.2, 3.3, and 3.4 |
occasion | numeric | trapping occasion number when data was collected; one occasion per month (2=June, 3=July, 4=August, 5=September, 6=October) |
session | numeric | trapping session number when data was collected; each occasion has four (1,2,3,4) sessions spaced 12 hours apart when traps were checked |
site | character | site name where vole was trapped; n=12 sites; possible values (asema, hevonen, helmipollo, janakkala, ketunpesa, kiirastuli, kuoppa, mustikka, puro, radio, talo, vaarinkorpi) |
trt | factor (levels: unfed-control, unfed-deworm, fed-control, fed-deworm) | experimental treatment pairing conducted at the site; possible values (unfed-control, unfed-deworm, fed-control, fed-deworm) |
food_trt | factor (levels: unfed, fed) | food treatment conducted at the site; possible values (unfed, fed) |
helm_trt | factor (levels: control, deworm) | helminth removal treatment conducted at the site; possible values (control, deworm) |
tag | character | PIT tag number of unique vole; 6-digit number |
firstcap | factor (1-first capture, 0-subsequent capture) | binary indicating if this capture was the first capture of an individual vole or a subsequent capture |
trap | character | trap ID where vole was captured; combination of a letter A-K (column) and number 1-6 (row) |
x | character | x coordinate of the trap location in the trapping grid indicating the column 1-11 |
y | character | y coordinate of the trap location in the trapping grid indicating the row 1-11 |
sex | factor (0-female, 1-male) | vole sex |
season_breeder | factor (levels: non-reproductive, reproductive) | vole reproductive status, summarized across all months in a given season; a vole that had testes (male) or any of a perforate vagina, visible nipples, or was pregnant (female) in any month of a season was considered reproductive in that season |
Site names and their experimental treatment pairing: "site_trts.csv"
This file is used as metadata to support spatial overlap network data generated in the associated R code from the analysis of the capture data.
column name | description |
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site | site name where vole was trapped; n=12 sites; possible values (asema, hevonen, helmipollo, janakkala, ketunpesa, kiirastuli, kuoppa, mustikka, puro, radio, talo, vaarinkorpi) |
food_trt | food treatment conducted at the site; possible values (unfed, fed) |
helm_trt | helminth removal treatment conducted at the site; possible values (control, deworm) |
Associated Code
These data feed into a series of R scripts used to conduct social network analyses and estimate bank vole space use and spatial overlap between individual voles in each population. All the R code detailing these analysis and workflow needed to run the scripts is available on GitHub (https://github.com/jmistrick/vole-spatial-manuscript) and has been archived with Zenodo <a href="https://zenodo.org/doi/10.5281/zenodo.10603001"><img src="https://zenodo.org/badge/580540737.svg" alt="DOI"></a>
Methods
These data were collected during field sampling of wild bank voles at our experimental study sites. Voles were longitudinally monitored using capture-mark-recapture methods on standardized trapping grids over 48 hours (traps checked 4x in 48 hours) once a month from June to October 2021. Sites were randomly assigned to one of four treatment pairings (food supplementation only, helminth removal only, both food supplementation and helminth removal, no manipulation). Captured voles were marked with a unique passive integrated transponder (PIT tag) for identification. The capture location (trap number) was recorded for each vole at each capture. The sex and reproductive status of captured voles were assessed once per month. Data was collected in the field by hand, digitized, and cleaned for quality control. The capture data here represents all captures in 2021 where sex and reproductive status data were recorded. These data were then used in social network analyses in program R to estimate space use of bank voles and spatial overlap between individuals in each population.