Evidence of reproductive senescence of released individuals in a reinforced bird population

Long lasting breeding performance differences between wild-born and released females in a reinforced North African Houbara bustard (Chlamydotis undulata undulata) population: a matter of release strategy

“…In the particular cases of translocated individuals originating from captive-breeding, any impairments of vital rates in translocated individuals can result either from translocation conditions (i.e., post-release effects per se), captivity conditions (including genetic and non-genetic issues), or the interaction of translocation and captivity conditions. However, disentangling the various sources of demographic variation in translocated populations (and in particular those related to the translocation protocol from other sources of variation) is challenging because (1) the comparison between translocated and wild-born animals requires the monitoring of wild-born individuals; a difficult task often hindered by several methodological and ethical issues, and (2) changes of vital rates over time in translocated individuals can be confounded by other longitudinal sources of demographic heterogeneity, such as age effects (Bacon et al 2017a), or by inter-individual heterogeneity (e.g., apparent improvement of survival due to the selection of the best survivors).…”

Genetic assessment of a conservation breeding program of the houbara bustard (Chlamydotis undulata undulata) in Morocco, based on pedigree and molecular analyses

“…For example, the study of the socio‐sexual system of the species (Hingrat, Saint Jalme, Chalah, Orhant, & Lacroix, 2008; Lesobre, Lacroix, Le Nuz, et al, 2010; Vuarin et al, 2019) allows adjusting management in captivity while knowledge of the genetic status of the free‐ranging population (e.g. population genetic structure; Lesobre, Lacroix, Caizergues, et al, 2010), its spatial structure (Hingrat et al, 2004), and the fate of individuals released into the wild (Bacon, Hingrat, & Robert, 2017; Bacon, Robert, & Hingrat, 2019; Hardouin et al, 2014; Hardouin, Hingrat, Nevoux, Lacroix, & Robert, 2015) provide useful information on the spatial scale to sample founders and on the expected genetic relationship amongst them and with the existing captive population.…”

“…The houbara is a promiscuous bird with an "exploded-lek" mating system (Hingrat et al, 2004), historically distributed from North Mauritania to Egypt. As a consequence of unregulated hunting, poaching, and habitat degradation (Azafzaf, Sande, Evans, & Collar, 2005;Goriup, 1997), the species has suffered a sharp population decline since the 1990s with an estimated population decline of 25% between 1984(BirdLife International, 2018 www.houbarafund.org), aiming to restore sustainable free-ranging populations of houbara (Lacroix, Seabury, Al Bowardi, & Renaud, 2003). This program is managed as a captive-free-ranging system with regular exchanges between captive and free-ranging populations through supplementation of wild populations with captive-bred individuals along with regular additions of founders using egg collections in the wild.…”

Reproductive performance in houbara bustard is affected by the combined effects of age, inbreeding and number of generations in captivity

“…The results corroborate those of previous studies in houbara conducted in captivity at the phenotypic level 38 – 40 and the genetic level 37 . In addition, a recent study of the reproductive parameters of captive-bred individuals released into the wild showed that the deleterious effects of senescence translated into free-ranging population reproductive success parameters, such as nest survival (i.e., the probability that at least one egg remains in the nest at a given time interval) or clutch size 36 . Although our study did not explore the physiological mechanisms underpinning the senescence patterns found in reproductive parameters, the results are consistent with previous studies that highlighted variations in endocrine components of reproduction with age as well as decreases in reproductive behavior and gonadal functions 67 – 69 .…”

“…The study model was a large captive population of North African houbara bustard Chlamydotis undulata undulata (Jacquin 1784, hereafter houbara) that have been maintained in captivity and managed to maximize the maintenance of genetic diversity for 24 years 31 , 32 . Our study is at the interface of previous research on houbara that have highlighted (1) a negative effect of inbreeding on behavioral phenotypes 33 , 34 , hatching success, post hatching mortality and growth 35 ; (2) the senescence of reproductive parameters in the free-ranging population 36 but also in the captive population 37 – 40 ; (3) the efficient maintenance of genetic diversity and minimization of inbreeding within the captive population 32 ; and (4) intergenerational variations in reproductive parameters 41 , 42 . Within this framework, we were particularly interested in (1) quantifying the relative effects of age, inbreeding and number of generations in captivity on reproductive performance and (2) assessing their potential interactions.…”