DOI: 10.5061/dryad.dv41ns21w
title: Post-weaning survival in kangaroos is high and constant until senescence: Implications for population dynamics

description: Large herbivores typically have consistently high prime-aged adult
 survival and lower, more variable, juvenile and senescent survival. Many
 kangaroo populations undergo greater fluctuations in density than other
 large herbivores, but age- and sex-specific survival of kangaroos and
 their response to environmental variation remain poorly estimated. We used
 long-term capture-mark-recapture data on 920 individuals to investigate
 the survival component of eastern grey kangaroo (Macropus giganteus)
 population dynamics. Forage availability and population density were
 monitored quarterly and included as predictors of survival in Bayesian
 Cormack-Jolly-Seber models. Annual survival probabilities were estimated
 for 5 age classes: 0 years (juveniles), 1–2 years (sub-adults), 3–6 years
 (prime-aged adults), 7–9 years (pre-senescent adults), and ≥10 years
 (senescent adults). Survival of juveniles varied widely during our 12-year
 study, ranging from 0.07–0.90 for females and 0.05–0.92 for males.
 Sub-adult survival was 0.80–0.93 for females and 0.75–0.85 for males,
 while that of prime-aged adults was ≥0.94 for females and ≥0.83 for males,
 despite large fluctuations in forage and density. The survival of
 pre-senescent adults spanned 0.86–0.93 for females and 0.60–0.86 for
 males. Senescent survival was variable, at 0.49–0.90 for females and
 0.49–0.80 for males. Male survival was significantly lower than female
 survival in prime-aged and pre-senescent adults, but not in other age
 classes. Although most models supported by WAIC selection included one or
 a combination of environmental covariates, none of these individual
 covariates had a discernable effect on survival. Temporal variability in
 overall survival was mostly due to changes in survival of juvenile and
 senescent kangaroos. Kangaroo survival patterns are similar to those of
 ungulates, suggesting a strong role of sex-age structure on population
 dynamics.
description: Descriptions of the methods used to collect, prepare, and analyse
 the data are in Bergeron et al.: Post-weaning survival in kangaroos is
 high and constant until survival: implications for population
 dynamics. Individual IDs have been replaced by
 randomised numbers.
description: <strong>Observation history</strong>
 Each row represents an individual, and each column represents a
 year, from 2008 to 2020. Represents the observation
 process of the Cormack-Jolly-Seber model used to estimate apparent
 survival. Denotes whether an individual was observed during the annual
 August-November field season or not. 0 = individual was not observed on
 the study area, 1 = individual was observed on the study area.
 obsF.csv contains female data, obsM.csv contains male
 data. <strong>State</strong>
 Each row represents an individual, and each column represents a
 year, from 2008 to 2020. Represents the state process
 of the Cormack-Jolly-Seber model used to estimate apparent survival.
 Denotes whether an individual was truly alive in a given year or not. 0 =
 individual has been found dead and is therefore certainly not alive, 1 =
 individual was observed this year or in a later year and is therefore
 necessarily alive, NA = individual was not observed, state is therefore
 not known with certainty. stateF.csv contains female
 data, stateM.csv contains male data.
 <strong>Age</strong> Each row
 represents an individual, and each column represents a year, from 2008 to
 2020. Denotes each individual's age in a given
 year, starting in the year it was first captured, from 0 to 28. For
 computational efficiency, age was always entered until the last year of
 the study, whether an individual was still alive or not. Age hence spans
 0-28 here, although no individual has lived longer than 21 years
 throughout the duration of the study. Rows of all NAs represent
 individuals which were first caught as adult and are therefore of unknown
 age. ageF.csv contains female data, ageM.csv contains
 male data. <strong>ID</strong>
 ID: each represents an individual kangaroo.
 first: represents the time step at which a given individual was
 first captured, from 2008 to 2020. 1 = 2008, 2 = 2009, and so forth, until
 13 = 2020. last: represents the time step at which an
 individual was last potentially alive, from 2008 to 2020. For any
 individual that disappeared but was never found dead, or for any
 individual that died of anthropogenic causes (mostly vehicle collisions or
 illegal shooting), this would be the last year of the study. 1 = 2008, 2 =
 2009, and so forth, until 13 = 2020. idF.csv contains
 female data, idM.csv contains male data.
 <strong>Environmental data</strong>
 Year: from 2008 to 2020. Dens and DensSD:
 population density in kangaroos/ha and associated standard deviation, from
 distance sampling model. Veg and VegSD: mean total
 palatable forage grown from October 1 of the previous year to September 30
 of the current year in g/m<sup>2</sup> and associated standard
 deviation. resDens and resDensSD: residual density and
 associated standard deviation obtained by sequential regression of
 population density in kangaroo/ha on total forage in
 g/m<sup>2</sup>. env.csv contains
 environmental data throughout the period over which survival is estimated,
 envLag.csv contains environmental data lagging the survival period by 6
 months. <strong>Nimble
 code</strong> Script used to assemble Nimble data
 and run Cormack-Jolly-Seber models to estimate apparent survival while
 accounting for imperfect detection.
 Roo_NimbleCode.R   See
 Bergeron et al. for more details.