DOI: 10.5061/dryad.2jm63xsx2
title: Data from: Born in heterogenous landscapes: birth timing, body mass and growth of roe deer (Capreolus capreolus) fawns in contrasting habitats

description: Although the widespread effects of global change impact almost all
 ecosystems, we lack a detailed understanding of how wildlife that thrive
 in human-dominated environments are able to adjust their life history to
 modifications in land use of their natural habitat. In particular, spatial
 variation in environmental conditions is predicted to influence
 development during the crucial early life phase, with marked impacts on
 individual performance and population dynamics for long-lived species.
 Large herbivores such as roe deer (Capreolus capreolus), a synanthropic
 species, have increased substantially in number and distribution over the
 last half century across Europe. Roe deer have been particularly
 successful, gradually colonizing agricultural landscapes to cope with a
 global warming-driven phenological mismatch in their natural forest
 habitat. However, to date, little is known about how habitat heterogeneity
 impacts their demographic performance in this heavily human-impacted
 environment. Specifically, we predicted that fawns born in predominantly
 cultivated local habitats would achieve faster early development due to
 the food subsidies obtained by their mothers from agricultural crops.
 Contrary to our expectations, fawns in semi-natural forest habitats were
 around 10% heavier at birth than those born in more mixed (by 0.163 ±
 0.058 kg) and open (by 0.169 ± 0.006 kg) agricultural habitats. However,
 all fawns subsequently grew at a similar average rate (0.148 ± 0.058
 kg/day), irrespective of their habitat. This habitat-dependent variation
 in birth mass appeared to be driven by reproductive phenology, as i)
 early-born fawns were heavier than late-born fawns, and ii) mothers living
 in the forest gave birth around 10 days earlier than those living in the
 mixed and open habitats. As natural habitats become increasingly scarce
 and fragmented due to the activities of humans, the prospects for many
 wild populations will depend on their ability to subsist in the heavily
 modified habitats of anthropogenic landscapes.
description: <strong>Females GPS Data
 acquisition<br></strong> Each winter, from
 2007 to 2022, we caught roe deer (at least 8 months old) between January
 and March using drive netting on seven capture sites, two located in
 forest habitat, two in mixed habitat, and three in open habitat. At
 capture, the deer are immediately tranquilized and transferred to a wooden
 holding box until the end of the drive. Subsequently, each animal is
 equipped with ear tags and a GPS collar (Lotek 3300S revision 2 or GPS
 PLUS-1C Store on Board, Vectronic Aerospace) (see data CEFS 2021). Based
 on tooth wear, we distinguished juveniles (8-10 months old) from adults
 (&gt;20 months old) and then released the animal on site. Each deer
 was monitored by GPS from capture until the end of the calendar year (11
 months). Density in the mixed and open habitat of this population appears
 quite consistent over time and likely much lower than in forest habitat
 (Hewison et al. 2007) at between 5.07 (± 3.32) to 6.99 (± 4.24)
 individuals per 100 ha. <strong>Fawn capture and
 monitoring</strong> From mid-April to mid-June, 2
 or 3 pairs of 2 observers searched for fawns in the three habitat types.
 Fawns were often located by opportunistic observation of the mother during
 semi-systematic surveys of the whole study site, but we also conducted
 regular targeted observations of all adult females that had been
 previously equipped with a GPS or VHF collar during winter captures. As
 roe deer fawns adopt a hider strategy to avoid predation, their mobility
 is low during their first days of life, and thus, they can be hand-caught
 at this stage. Each caught fawn was ear-tagged, sexed, and age was
 estimated based on appearance and behaviour according to Jullien et al.
 (1992). Body mass was measured using a spring balance (Testut) which was
 calibrated at the beginning and during the season. Fawns were assigned to
 a type of habitat (open, mixed, forest) based on their capture site.
 Finally, they were equipped with a very high frequency (VHF) tag fixed to
 an expandable collar (Biotrack-Lotek UK). Their location and status were
 recorded every weekday from capture until death, or until the collar
 failed. Thus, in the following analysis, we considered age-dependent body
 mass at first capture as our proxy for early body development for the
 whole fawn sample. In total we obtained data on 359 fawns captured between
 2007 and 2022 for which we knew if they were dead or alive at the start of
 September, when weaning is almost complete.
 <strong>Birth date estimation</strong>
 For fawns caught during their first few days of life (1-20 days
 old), birth date was calculated by simply subtracting their estimated age
 from the date of capture. In addition, to increase sample size for the
 analysis of birth phenology only, we estimated parturition date of GPS
 monitored adult females for which we were unable to capture their fawn. To
 do so, we used a modified version of the method described by Marchand et
 al. (2021) to estimate parturition date for 33 females: 13 in forest
 habitat, 9 in mixed habitat, and 11 in open habitat.
description: # Born in heterogenous landscapes: birth timing, body mass and growth of
 roe deer (Capreolus capreolus) fawns in contrasting habitats.
 ## **Data:** **Data for
 body mass/habitat analyses:** We investigated the effects of habitat, sex
 and birth date on fawn's body mass during the 20 first days of their
 lives. To do so, we used the following data to perform the analyses, by
 building generalized additive models (GAM):
 *Data_gamm_models_whole_dataset.rds* We performed the same analyses with
 fawns who survived until the set of autumn only:
 *Data_gamm_models_alive_dataset.rds* **Data for phenology/parturition
 dates analyses:** Data with the birth dates, including those calculated
 from the age estimation during fawn captures, and those estimated from GPS
 monitoring of females in spring, for each habitat. *birth_date_Forest.rds*
 *birth_date_Mixed.rds* *birth_date_Open.rds* ## **Data:**
 *Script_body_mass_habitat_birth_date:* Script used to build GAM from the
 data: "Data_gamm_models_whole_dataset.rds" and
 "Data_gamm_models_alive_dataset.rds" to analyse the effects of
 habitat, sex and birth date on fawn's body mass during the 20 first
 days of life. The script also contains the code for the model selection
 using AIC. *Script_parturition_dates_analyses:* This script contains the
 code for analyses related to birth timing with the estimation of the
 median date of birth in each habitat, the building of the density plots,
 and the Mood's median test, performed to compare the median dates of
 births between the habitats. ## Description of the data and file structure
 **Data for body mass/habitat analyses:** "id": identity of the
 fawn "Capture_date": Date of capture of the fawn, in the fromat
 : *yyyy-mm-dd* "Capture_Julian_date": Date of capture of the
 fawn, in the julian date format (January 1st = 1, January 2nd =2,...)
 "Body_mass": the body mass of fawns at the date of the capture,
 measured using a spring balance (in kg) "age": estimation of the
 age of fawn at capture (in days) "birth_day": day of birth of
 the fawn, calculated from the date of capture and age estimation (in
 julian date) "sex": the sex of the fawn (Male/Female)
 "cohort": the cohort in which the fawn belongs (here, the year
 of birth) "habitat": habitat where the fawn was captured (Open,
 Mixed, Forest) **Data for phenology/parturition dates analyses:**
 "id": identity of the individual (fawn, if it is a name, in
 character / mother, if it is constituated of numbers)
 "birth_date": day of birth of the fawn, calculated from the date
 of capture and age estimation OR parturition date estimated from the GPS
 of mothers (see id to know which), format = *yyyy-mm-dd*
 "habitat": habitat where the individual was captured (Open,
 Mixed, Forest), in spring for fawns, in winter for mothers
 "birth_julian_date": day of birth of the fawn, calculated from
 the date of capture and age estimation OR parturition date estimated from
 the GPS of mothers (see id to know which), format = *Julian date* ##
 Code/Software We performed our analyses using R, and RStudio. We used the
 following packages: ***Script_body_mass_habitat_birth_date:***
 library(gamm4) library(splines) library(ggplot2) library(jtools)
 library(MuMIn) library(sjPlot) library(RColorBrewer) theme_set(theme_bw())
 library(dplyr) library(tidymv) library(viridis) library(viridisLite)
 ***Script_parturition_dates_analyses:*** library(dplyr)
 library(rcompanion) library(RVAideMemoire) library(rcompanion)