The release of captive animals through rewilding or conservation
translocation is an important strategy for the rehabilitation of
individuals and ecosystems. Assuming that wild animals are better adapted
to their environment than captive ones, comparisons between the behaviour
of released animals and their wild counterparts would allow the evaluation
of rewilding success. We compared the movement patterns of six
captive African savannah elephants, subjected to a three-year soft release
in the western Okavango Delta, Botswana, with those of two elephants
released over a decade previously and of four wild elephants. GPS fixes at
1800hrs were used to calculate daily displacement, 30-minute diurnal and
nocturnal distances, cumulative daily distances, and home ranges for all
study animals; the effects of elephant group, phase, year, and season on
these movement metrics were analysed. Captive elephants were most affected
by the phase and changed their movements after release. After release, the
movement patterns of captive elephants were less different from those of
rehabilitated elephants than wild elephants, possibly due to sample size,
which could indicate that rewilded animals may not be able to fully
approximate the behaviour of wild-born individuals. However, the captive
elephants should exhibit seasonality in movement patterns just like
rehabilitated and wild elephants. These results highlight the critical
importance of long-term monitoring of animals to allow the evaluation of
release and translocation, which is recommended for other similar
studies. The data collection was approved by the UB ethics
committee (UBR/RES/IRB/SOC/132). # Data from: Release from captivity allows African savannah elephant
movement patterns to converge with those of wild and rehabilitated
conspecifics ### Analysis Dataset and Code **General Introduction** The
project "Release from captivity allows African savannah elephant
movement patterns to converge with those of wild and rehabilitated
conspecifics" investigates the movement of rewilded African savannah
elephants (Loxodonta africana) in the western Okavango Delta, Botswana.
This study compares movement patterns of captive, previously released
(rehabilitated), and wild elephants using GPS data from collared elephants
to evaluate rewilding success. Four R scripts—30_minute_script.R,
Cumulative_Daily_Distance_script.R, Displacement_script.R, and
Home_range_script.R—analyze are saved in the zip file called
R_Scripts.zip. Four key movement metrics: 30-minute movement distances,
Cumulative daily distances, daily displacement (net displacement between
consecutive days at 18:00), and monthly 95% Kernel Density Estimation
(KDE) home range areas were analysed using these R_scripts as stated
below. These scripts fit generalized linear mixed-effects models (GLMMs)
to assess the effects of factors such as phase, season, year, day/night
(for 30-minute data), and elephant origin on movement metrics. They also
generate visualizations to compare results across groups. This work
highlights the importance of long-term monitoring in evaluating rewilding
outcomes and understanding how captive elephants adapt to wild movement
patterns. The Botswana Ministry of Environment, Natural Resources
Conservation and Tourism granted the research permission (Permit
ENT8/36/4L(43)) and the Botswana Department of Wildlife and National Parks
issued the release permit (WP SAF 16/4/1 II (1)), while the University of
Botswana Office of Research and Development provided the ethics approval
(UBR/RES/IRB/SOC/132). The R scripts were developed and tested on R
version 4.5.1 Instructions for Use 1. Place the data files
(30_min_dist.csv, daily_range.csv, last_coords_local.csv,
kde_95_monthly.csv) in your working directory. Download the Data.zip and
extract the csv files into your working directory. 2. Open the R scripts
30_minute_script.R, Cumulative_Daily_Distance_script.R,
Displacement_script.R, and Home_range_script.R in R or RStudio. 3. Update
the setwd() path in each script to match the location of your working
directory. For example: setwd("/path/to/your/directory") 4.
Install the required R packages listed below for each script. 5. Run the
scripts to preprocess data, generate visualizations, and fit GLMMs. Three
datasets are provided: * 30_min_dist.csv: 30-minute movement data\
Columns/Variables: * Column A - row number for the data. No column heading
* Column B - "CollarID", is the column for the names given to
each of the elephants in the study. Each elephant had a distinct name *
Column C - "date_timestamp_local", is the timestamp
(month/day/year hour:minutes) for the Botswana local time (+ 2 GMT) *
Column D - "seasons", is the column for the seasons of the
Okavango Delta flooding patterns. The seasons are 4 months long each *
Column E - "release_phase", is the column for the names of
different phases of the soft release. * Column F - "ele_origin",
is the column that shows the category of the elephant in this study. *
Column G - "dist_moved", is the distances measured between 2
consecutives GPS fixes in meters. * Column H - "Year", is the
column that shows the years of the data was collected with 1st December
2021 marking the beginning of year 1 of the data used in this study. *
Column I - "day_night", is the column that shows the time of day
when the data was collected. * last_coords_local.csv: Daily displacement
data\ Columns/Variables: * Column A - row number for the data. No column
heading * Column B - "CollarID", is the column for the names
given to each of the elephants in the study. Each elephant had a distinct
name * Column C - "date_timestamp_local", is the timestamp
(month/day/year hour:minutes) for the Botswana local time (+ 2 GMT) *
Column D - "seasons", is the column for the seasons of the
Okavango Delta flooding patterns. The seasons are 4 months long each *
Column E - "release_phase", is the column for the names of
different phases of the soft release. * Column F - "ele_origin",
is the column that shows the category of the elephant in this study. *
Column G - "dist_to_next_day", is the distance between GPS fixes
of consecutive 18:00 hours in meters * Column H - "Year", is the
column that shows the years of the data was collected with 1st December
2021 marking the beginning of year 1 of the data used in this study. *
Column I - "season_number", is the number allocated to each
number starting with the first season as the season when the captive
elephants were collared * Column J - "year_regular", is the
column of the Calendar year in Gregorian calendar * Column K -
"log_dist_to_next_day", is the log of the dist_to_next_day
(Column G) * kde_95_monthly.csv: Monthly 95% KDE home range data\
Columns/Variables * Column A - row number for the data written as the
95...[row number], where 95 shows the kernel density estimate 95% contour.
No column heading * Column B - "CollarID", is the column for the
names given to each of the elephants in the study. Each elephant had a
distinct name * Column C - "year_month", is the column of the
calendar year (Gregorian calendar) and month for which the kernel density
estimate (95 % contour) was generated. Month is given as a three-letter
English abbreviation * Column D - "year", is the column of the
Calendar year in Gregorian calendar * Column E - "month", is the
column of the month as a three-letter English abbreviation * Column F -
"period", is the column of the period when the elephants were
controlled (before) and when they were officially released with their
movements not controlled (after) * Column G - "ele_origin", is
the column showing the category of the elephants, whether it was captive
(elephants that were long-term captive and released during the course of
this study), rehabilitated (elephants that were previously captive and
released before this study commenced, over ten years ago), or wild (wild
elephants with no known history of captivity) * Column H -
"seasons", "seasons", is the column for the seasons of
the Okavango Delta flooding patterns. The seasons are 4 months long each *
Column I - "kde_95_area", is the column of the calculated area
of the 95% kernel density estimate (KDE) contour calculated for each
elephant in each year-month in square kilometres (km²) Analysis Scripts
30-Minute Movement Analysis Introduction script processes 30-minute
movement distances from 30_min_dist.csv to analyze fine-scale movement
patterns. It generates visualizations (histograms, bar plots) to compare
movement distances by elephant origin, period (Before vs. After), season,
and day/night. It also fits GLMMs to assess the effects of season, phase,
year, day/night, and elephant origin on movement distances, including
model diagnostics and post-hoc comparisons. CSV File 30_min_dist.csv
Requirements R packages: MuMIn (for model selection with dredge) lme4
(for generalized linear mixed-effects models), DHARMa (for model
diagnostics), dplyr (for data manipulation), lubridate (for date-time
handling), ggplot2 (for plotting), patchwork (for combining plots),
e1071 (for skewness calculation), emmeans (for post-hoc comparisons),
geosphere (for Haversine distances in preprocessing) All packages can be
installed using the code below: install.packages(c("MuMIn",
"lme4", "DHARMa", "dplyr",
"lubridate", "ggplot2", "patchwork",
"e1071", "emmeans", "geosphere")) When
running the script 30_minute_script.R, it should: * Generate histograms of
30-minute movement distances by period, overall, and for Captive, Before,
and After subsets, with density curves. * Generate bar plots of average
movement distances by elephant origin, period, season, and day/night, with
standard error bars. * Fit generalized linear mixed-effects models to
assess the effects of season, release phase, year, day/night, and elephant
origin on movement distances. * Provide summaries of the fitted
mixed-effects models and dredge results. * Provide post-hoc comparisons
using emmeans for Captive, Before, and After periods. * Generate residual
diagnostic plots using DHARMa to assess model fit. * Calculate skewness
for movement distances by period. Cumulative daily distance. This script
aggregates 30-minute movement data from 30_min_dist.csv into cumulative
daily distances, representing the total distance moved per day. It
generates visualizations (histograms, bar plots) to compare cumulative
daily distances by elephant origin, period, and season, and fits GLMMs to
assess the effects of season, release phase, and elephant origin on daily
movement distances, including model diagnostics and post-hoc comparisons.
CSV Files 30_min_dist.csv Requirements R packages: MuMIn (for model
selection with dredge) lme4 (for generalized linear mixed-effects models)
DHARMa (for model diagnostics), dplyr (for data manipulation), lubridate
(for date-time handling), ggplot2 (for plotting), patchwork (for
combining plots), e1071 (for skewness calculation), emmeans (for
post-hoc comparisons), geosphere (for Haversine distances in
preprocessing) All packages can be installed using the code below:
install.packages(c("MuMIn", "lme4",
"DHARMa", "dplyr", "lubridate",
"ggplot2", "patchwork", "e1071",
"emmeans", "geosphere")) When running the script
30_minute_script.R, it should: * Generate histograms of cumulative daily
distances by period, overall, and for Captive, Before, and After subsets,
with density curves. * Generate bar plots of average cumulative daily
distances by elephant origin, period, and season, with standard error
bars. * Fit generalized linear mixed-effects models to assess the effects
of season, release phase, and elephant origin on daily movement distances.
* Provide summaries of the fitted mixed-effects models and dredge results.
* Provide post-hoc comparisons using emmeans for Captive, Before, and
After periods. * Generate residual diagnostic plots using DHARMa to assess
model fit. * Calculate skewness for cumulative daily distances by period.
Displacement This script processes daily displacement data at 18:00 from
last_coords_local.csv, capturing net movement between consecutive days. It
generates visualizations (histograms, bar plots, boxplots) to compare
displacement by elephant origin, period, and season, and fits GLMMs to
assess the effects of season, year, release phase, and elephant origin on
displacement, including model diagnostics and post-hoc comparisons. CSV
File last_coords_local.csv Requirements R packages: MuMIn (for model
selection with dredge) lme4 (for generalized linear mixed-effects models)
DHARMa (for model diagnostics, s), dplyr (for data manipulation),
lubridate (for date-time handling), ggplot2 (for plotting), patchwork
(for combining plots), e1071 (for skewness calculation), emmeans (for
post-hoc comparisons) All packages can be installed using the code below:
install.packages(c("MuMIn", "lme4",
"DHARMa", "dplyr", "lubridate",
"ggplot2", "patchwork", "e1071",
"emmeans")) When running the script Displacement_script.R, it
should: * Generate histograms of daily displacement distances by period,
overall, and for Captive, Before, and After subsets, with density curves.
* Generate bar plots of average displacement by elephant origin, period,
and season, with standard error bars. * Fit generalized linear
mixed-effects models to assess the effects of season, year, release phase,
and elephant origin on displacement. * Provide summaries of the fitted
mixed-effects models and dredge results. * Provide post-hoc comparisons
using emmeans for Captive, Before, and After periods. * Generate residual
diagnostic plots using DHARMa to assess model fit. * Calculate skewness
for displacement distances by period. Home RangeThiss This script
processes precomputed monthly 95% KDE home range areas from
kde_95_monthly.csv, representing the spatial extent of elephant movement.
It generates visualizations (histograms, bar plots) to compare home range
sizes by elephant origin, period, and season, and fits GLMMs to assess the
effects of release phase, season, and elephant origin on home range sizes,
including model diagnostics and post-hoc comparisons. CSV File
kde_95_monthly.csv Requirements R packages: MuMIn (for model selection
with dredge) lme4 (for generalized linear mixed-effects models), DHARMa
(for model diagnostics), dplyr (for data manipulation), ggplot2 (for
plotting), e1071 (for skewness calculation), emmeans (for post-hoc
comparisons) All packages can be installed using the code below:
install.packages(c("MuMIn", "lme4",
"DHARMa", "dplyr", "ggplot2",
"e1071", "emmeans")) When running the script
Home_range_script.R, it should: * Generate histograms of monthly 95% KDE
home range areas by period, overall, and for Captive, Before, and After
subsets, with density curves. * Generate bar plots of average 95% KDE
areas by elephant origin, period, and season, with standard error bars. *
Fit generalized linear mixed-effects models to assess the effects of
release phase, season, and elephant origin on home range sizes. * Provide
summaries of the fitted GLMMs and dredge results. * Provide post-hoc
comparisons using emmeans for Captive, Before, and After periods. *
Generate residual diagnostic plots using DHARMa to assess model fit. *
Calculate skewness for home range areas by period. Reproducibility *
Ensure all required R packages are installed using the provided
install.packages() commands. * Verify that 30_min_dist.csv,
daily_range.csv, last_coords_local.csv, and kde_95_monthly.csv are in the
working directory. * Update the setwd() path in each script to point to
your working directory. * Run the scripts in R (version 4.5.1 or higher)
to reproduce the analyses. * Check for missing values or data
inconsistencies using summary() and table() functions, as outlined in the
scripts. * For home range analysis, note that kde_95_monthly.csv contains
precomputed KDE areas. To recompute these areas from raw GPS data, users
would need additional scripts and the All_elies_regular_30min.csv dataset
(not included). For questions about this dataset or scripts, please
contact: Murphy Tladi ([201000042@ub.ac.bw](mailto:201000042@ub.ac.bw) or
[murphytladi@ymail.com](mailto:murphytladi@ymail.com))