Early and late fawn mortality in a remnant population of Arabian gazelles (Gazella arabica)

Abstract

The Arabian gazelle (Gazella arabica) population in Israel has experienced a turbulent conservation history and repeatedly faced local extinction. Low fawn survival was considered the main cause for the constant decline. In our study, we analyzed instantaneous fawn mortality rates, using a binomial coding at three different developmental stages, i.e., mortality rates to 3 months after parturition (weaning age), to 5 months after parturition (male fawns leave their mothers), and to the age of reproductive maturity, i.e., recruitment (12 months). We used a dataset obtained from 20 individually discernible mothers and their fawns (49 females and 48 males) born between June 2006 and September 2019. To explore causes for the fawn mortality rates, parental- (age of the mother at parturition) and offspring-related attributes (offspring sex), year of birth, together with one weather variable (mean monthly maximum temperature) were included as independent variables into three independent mixed effects cox regression models. Out of 97 fawns, 92 survived to weaning age, 73 to the age of 5 months and only 7 to the age of reproductive maturity. Temperature had significant effects on instantaneous fawn mortality rates, suggesting that low temperatures were detrimental to the survival of fawns after weaning (4–5 months) and male dispersal age (6–12 months). Male offspring encountered a higher instantaneous mortality rate than female offspring at the age of 6–12 months. Moreover, fawns from less experienced mother (young age at parturition) experienced higher mortality. Our results were in line with previous studies on fawn mortality observed in other desert dwelling ungulates.

Effects of season and sex on the concentrations of fecal glucocorticoid metabolites in captive and free-ranging endangered mountain gazelles (Gazella gazella)

“…), with females remaining together (matrilineal groups with a mother and her last born daughters) and completing the pregnancy process (36). This social organization mirrors the structure observed in female G. arabica groups (36). The fawning season falls between May and June.…”

“…Considering the mating season, June, July, and August are subsequent lactating periods, as lactation lasts for approximately 3 months. During this period, most females form matrilineal groups (36). Adult males are territorial and solitary throughout the year (35).…”

Reproductive biology of Gazella arabica: Predictors of offspring weight and short- and long-term offspring survival

“…At KKWRC, average mortality rates during the first year of life were around 40% (if we discount the lightest weight class, which had 100% mortality), and thus, considerably lower than mortality rates reported from wild ungulates, which can exceed 60% ( Milner-Gulland and Lhagvasuren 1998 ; Gaillard et al 2000 ; Johnstone-Yellin et al . 2009; Shalmon et al 2021 ). This discrepancy reflects the fact that most environmental stressors (such as disease, parasitism, resource shortage, and predation) are strongly reduced or even excluded at KKWRC.…”

Table_1.XLSX

“…), with females remaining together (matrilineal groups with a mother and her last born daughters) and completing the pregnancy process (36). This social organization mirrors the structure observed in female G. arabica groups (36). The fawning season falls between May and June.…”

“…Considering the mating season, June, July, and August are subsequent lactating periods, as lactation lasts for approximately 3 months. During this period, most females form matrilineal groups (36). Adult males are territorial and solitary throughout the year (35).…”