Onset of autumn shapes the timing of birth in Pyrenean chamois more than onset of spring

Abstract

In seasonal environments, birth dates are a central component for a species' life history, with potential long-term fitness consequences. Yet our understanding of selective pressures of environmental changes on birth dates is limited in wild mammals due to the difficulty of data collection. In a context of rapid climate change, the question of a possible mismatch between plant phenology and birth phenology also remains unanswered for most species. We assessed whether and how the timing of birth in a mountain mammal (isard, also named Pyrenean chamois, Rupicapra pyrenaica pyrenaica) tracked changes in plant growing season, accounting for maternal traits, individual heterogeneity and population density. We not only focused on spring conditions but also assessed to what extent onset of autumn can be a driver of phenological biological events and compared the magnitude of the response to the magnitude of the environmental changes. We relied on a 22-year study based on intensively monitored marked individuals of known age. Births were highly synchronized (80% of kids born within 25 days) and highly repeatable (84%; between-female variation of 9.6 days, within-female variation of 4.2 days). Individual phenotypic plasticity allows females to respond rapidly to interannual changes in plant phenology but did not prevent the existence of a mismatch: a 10-day advance in the autumn or spring plant phenology led to 3.9 and 1.3 days advance in birth dates, respectively. Our findings suggest that plant phenology may act as a cue to induce important stages of the reproductive cycle (e.g. conception and gestation length), subsequently affecting parturition dates, and stressed the importance of focusing on long-term changes during spring for which females may show much lower adaptive potential than during autumn. These results also question the extent to which individual plasticity along with high heterogeneity among individuals will allow species to cope with demographic consequences of climate changes.

Climate, female traits and population features as drivers of breeding timing in Mediterranean red deer populations

“…after rainfall; Clutton-Brock et al 1982;Douchard et al 2013). Therefore, we can only speculate that: (i) the conception advance observed might be associated with higher male activity as vocalization, smell or visualization of preferred males can advance hind ovulation (McComb 1987;Komers et al 1999); (ii) rainfall at the end of summer (September) has been described as a crucial factor for acorn maturation (García-Mozo et al 2012), allowing hinds to faster recover body condition and, hence, ovulation is advanced (Asher & Pollard 2003); and (iii) rainfall or temperature act as a predictive cue to induce estrus along with photoperiod (Fisher & Johnstone 2002;Wolcott et al 2015;Kourkgy et al 2016). Nevertheless, these hypotheses should be further explored in an experimental study.…”

Detection of tick-borne pathogens in questing Ixodes ricinus in the French Pyrenees and first identification of Rickettsia monacensis in France

“…The study area encompasses 400 ha between 1000 and 1800 m a.s.l., is mostly covered by alpine grass ( Festuca eskia ), rocks and forest (beech Fagus sylvatica and firs Abies sp. ), and is inhabited by a population of 100–130 Pyrenean chamois [ 22 ]. During the study period, the average (± SD ) annual minimum and maximum daily temperatures were 5.8 ± 5.7 °C and 15.1 ± 7.3 °C, respectively (at 910 m a.s.l.).…”

Seasonal reproductive tactics: annual timing and the capital-to-income breeder continuum

“…In some nonmigratory small mammals and birds, nutritional bottlenecks can be avoided by relying on food caches [24,76]. Although large mammals can potentially use endogenous stores to decrease their sensitivity to nutritional bottlenecks, implantation takes place long before the most energetically expensive period of lactation, which may make it more difficult to time parturition to match the seasonal peak in resource availability (but see [58,59,77]).…”

“…partial-capital) breeders use capital early in the breeding season as a mechanism to facilitate better synchrony between peaks in energy supply and demand later in the reproductive cycle [60]. For example, some ungulates that are generally regarded as being on the capital end of the spectrum, such as red deer and mountain goats (Oreamnos americanus), use capital in the lead-up to parturition, which is thought to be timed such that lactation coincides with green-up [58,60,77].…”