Iberian Red Deer Cervus Elaphus Research Articles

Rainfall decrease and red deer rutting behaviour: Weaker and delayed rutting activity though higher opportunity for sexual selection.

In the last decades, climate change has caused an increase in mean temperatures and a reduction in average rainfall in southern Europe, which is expected to reduce resource availability for herbivores. Resource availability can influence animals' physical condition and population growth. However, much less is known on its effects on reproductive performance and sexual selection. In this study, we assessed the impact of three environmental factors related to climate change (rainfall, temperature and vegetation index) on Iberian red deer Cervus elaphus hispanicus reproductive timing and sexual behaviour, and their effects on the opportunity for sexual selection in the population. We measured rutting phenology as rut peak date, the intensity of male rutting activity as roaring rate, and the opportunity for sexual selection from the distribution of females among harem holding males in Doñana Biological Reserve (Southwest Spain), from data of daily observations collected during the rut over a period of 25 years. For this study period, we found a trend for less raining and hence poorer environmental conditions, which associated with delayed rutting season and decreased rutting intensity, but that appeared to favour a higher degree of polygyny and opportunity for sexual selection, all these relationships being modulated by population density and sex ratio. This study highlights how climate change (mainly rainfall reduction in this area) can alter the conditions for mating and the opportunity for sexual selection in a large terrestrial mammal.

Sex and age-class differences in calls of Iberian red deer during the rut: reversed sex dimorphism of pitch and contrasting roars from farmed and wild stags

Stag rutting calls differ among subspecies of red deer Cervus elaphus. Studying sex-, age-, and subspecies-related vocal variation may highlight the forces driving this evolution. This study presents the first bioacoustical comparison of oral calls produced during the rut by Iberian red deer Cervus elaphus hispanicus stags, hinds and calves and compares the acoustics of nasal and oral calls of hinds and calves. Also, it provides the first comparison of rutting roars between farmed and wild stags. Call maximum and mean fundamental frequencies (f0max and f0mean) were higher in farmed than in wild stags. Moreover, hinds had lower f0max and f0mean compared with both farmed and wild stags. The call minimum fundamental frequency (f0min) was indistinguishable between all groups of adults, irrespective of sex, farming and nasal versus oral vocal emission. In calves, but not in hinds, oral calls had higher f0max and f0mean compared with nasal calls. The higher fundamental frequencies in farmed as compared with wild stags may have resulted from emotional arousal due to human presence at recordings or from the higher body conditions of stags reared under a farm. The comparison of our results with previously published data on various subspecies of red deer suggests that there are different pathways of vocal ontogeny in eastern and western branches of Cervus elaphus and that the acoustics of stag and hind calls are more similar within the various subspecies than they are among the subspecies.

Spectrographic analysis points to source–filter coupling in rutting roars of Iberian red deer

Source–filter coupling is the rarest acoustic phenomenon not only in Iberian red deer, but in any mammal. In most mammals, sound production can be well described in the framework of source–filter theory. The vocal output is the result of combined work of the larynx (the source) and of the supralaryngeal vocal tract (the filter). The source–filter theory suggests the independence of source and filter. Thus, vocal tract filtering should not affect the fundamental frequency (f0) of the sound created in the larynx. Spectrographically, the source is mostly characterized by the f0 and its harmonics, while the filter by the vocal tract resonances, i.e., formant frequencies. Nevertheless, a non-independent (coupled) source and filter can be proposed when the vocal folds start oscillating at one of the formant frequencies. Coupling between source and filter has been found in human singers and predicted for red deer Cervus elaphus by a computer modeling approach. This study describes different modes of phonation in a natural bout of rutting calls of Iberian red deer Cervus elaphus hispanicus and the transition from a chaotic mode to a probable source–filter coupling mode. This phenomenon might be involved in the production of extremely high-frequency bugles of North American and Asian subspecies of C. elaphus.

Contrasting feeding patterns of native red deer and two exotic ungulates in a Mediterranean ecosystem

Context Ungulates have been widely introduced in multiple ecosystems throughout the world due to their value as food and for sport hunting. The identification of foraging preferences of exotic and native ungulates living in sympatry is, therefore, becoming increasingly important in order to assess potential impacts of introduced animals on the host ecosystem. Aims To describe species-specific foraging strategies and infer resource selection overlap between native and exotic ungulates. Methods We compared the trophic ecology of three sympatric ungulate species living in a Mediterranean landscape: the native Iberian red deer Cervus elaphus hispanicus, and two exotic bovids, the European mouflon Ovis orientalis musimon and the aoudad Ammotragus lervia. We simultaneously determined herbivore diet through analyses of botanical content in faeces and assessed the nutritional content of these diets. Key results Higher selection of shrubs by deer was sustained throughout the year, while bovids showed seasonal shifts in forage selection. Both bovids displayed a selective dietary strategy directed towards a higher overall nutritional quality than that of deer. Divergent exploitation patterns between the studied cervid and bovids might be related to body mass and physiological adaptations to overcome secondary defence compounds of shrubs, and were largely affected by seasonal changes in the nutritional value of available vegetation. Ecological theory suggests that diet overlap should be greater between similar-sized species. Indeed, both exotics showed similar, sometimes overlapping, dietary patterns that could lead to potential competition in the use of resources. Native red deer preferences only showed some overlap with those of exotic mouflon under constrained summer conditions. Conclusions Dietary overlap between deer and mouflon and between aoudad and mouflon during limiting summer conditions could entail a potential competitive interaction under more even densities of the study species, since a concurrent habitat overlap between those pairs of species has previously been reported. Implications The outcomes of our study suggest the need for an integration of habitat and ungulate management. Management actions in Mediterranean rangelands should be directed towards protecting habitat conditions so that biodiversity is enhanced along with the presence of sustainable communities of large herbivores. Management directed towards ungulates should maintain moderate stocking rates and monitor and control introduced and native populations.

Antler mineral composition of Iberian red deer Cervus elaphus hispanicus is related to mineral profile of diet

Previous studies have suggested that antlers are costly bone structures whose mineral composition may change depending on physiological and other factors. This study examined whether nutrition variation associated with deer management influences antler mineral composition and structural characteristics of whole antler. Mineral distribution and bone structure were examined in antlers from two groups of adult Iberian red deer Cervus elaphus hispanicus Hilzheimer, 1909. They were kept under different feeding regimes at an experimental deer farm and a game estate in southeastern Spain. Protein and mineral contents differed between the diet of captive deer and that of deer in the wild. Significant differences were found for Na, Mg, K and protein. Antler composition seems to reflect the diet, as antlers of deer differed in protein, Na, Mg and K, but not in total mineral content, Ca, Fe or Zn. Thus, management conditions related to nutrition are reflected on antler composition.

Reduced major histocompatibility complex class II polymorphism in a hunter‐managed isolated Iberian red deer population

AbstractThe major histocompatibility complex (MHC) contains the most variable functional genes described in vertebrates. Individuals from natural populations deal constantly with a diverse range of pathogens and the polymorphism at MHC loci is what determines the diversity of foreign antigens that the host immune system can recognize. Polymorphism at individual loci may result in variable MHC class II (MHC‐II) haplotypes. We characterized for the first time, the allelic diversity at the second DRB locus of the MHC‐II in the Iberian red deer Cervus elaphus hispanicus. The studied population was sampled from a fenced estate that has been managed for hunting purposes and may provide information of the effect of game management on the genetic diversity of this species. Deer presented high levels of variation at MHC‐II DRB‐2 with 18 different alleles detected in 94 individuals. However, a significant heterozygous deficiency was found for MHC‐II DRB‐2 locus (92.5% of individuals only amplified one allele), whereas genotype frequencies at three neutral microsatellite loci were according to Hardy–Weinberg equilibrium, with heterozygosity over 50%. The analysis of control Iberian red deer from different geographic locations identified two expressed DRB‐2 loci with a high degree of heterozygosis. The annual diversity index of MHC‐II DRB‐2 alleles significantly decreased along the 16‐year study period, which was confirmed with losses in microsatellite markers. Although we cannot exclude positive non‐assortative mating and/or substructured breeding (Wahlund effect) within our reference population, such unexpected apparent homozygosity at MHC DRB‐2 loci is suggestive of null alleles occurring at our population. The observed pattern could be the result of a founder effect in this recently established population. Nonetheless, the loss of MHC‐II DRB‐2 allele diversity could reflect the effects of inbreeding in this fenced population managed for hunting. These findings support the importance of immunogenetic studies to assess management decisions, especially in isolated ungulate populations.

Lactation growth influences mineral composition of first antler in Iberian red deer Cervus elaphus hispanicus

Abstract Deer antlers are bony fighting structures which are unique in that they are both easily accessible for analysis and that they are grown every year; thus, they make up good models for the study of bones. Previous studies have shown that antler bone composition is related to the external quality (antler size and weight) and the mechanical quality of the antlers, and that it reflects mineral nutrition and early growth. Because one of the main nutritional factors influencing early growth is maternal milk production and composition, and because lactation plays an important role in post-weaning growth, we set out to examine whether milk yield and composition are correlated with the mineral composition of spike antlers of 22 yearling Iberian red deer Cervus elaphus hispanicus. Total milk protein yield was positively associated with ash, Ca and P content in antler, inversely with K content, but no relationship was found for Na, Mg, Fe or Zn. This association was evidently exerted through an increase in c...

Sex-specific strategies of dentine depletion in red deer

Worn teeth in herbivore ungulates may be related to lower efficiency in mastication and hence lower performance. However, selection should favour maximal performance in terms of body mass and reproductive capacity during reproductive lifespan, when permanent teeth are already partially worn. We hypothesize that wear rate may respond to a strategy of use of tooth materials (notably dentine), which balances instantaneous wear rate and performance against tooth preservation for future performance and reproduction. In the present study, we investigated 4151 carcasses of Iberian red deer Cervus elaphus hispanicus and show that more worn molars were not related to lower performance throughout age. By comparing between sexes, tooth wear rates were smaller in females than in males, but the relationship between tooth wear and body performance also differed between the sexes: females did not show a significant relationship between tooth wear and performance but males with more worn teeth were in general heavier and had larger antlers until senile age, when more depleted teeth were related to smaller antlers. These results reveal, for the first time, sex-specific lifetime strategies of dentine expenditure: maintenance of performance ability throughout a longer reproductive lifespan in females, compared with maximizing current performance by depleting dentine reserves within a shorter lifespan in males. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 93, 487–497.

Lactation under food constraints in Iberian red deer Cervus elaphus hispanicus

The plane of nutrition in deer may affect body condition and lactation in hinds and calf growth both through long‐term density‐dependent effects and by shortterm abiotically originated falls in food supply. Our study examines the effect of low nutrient availability after calving on lactation in captive Iberian red deer Cervus elaphus hispanicus. Twelve hinds and their calves were allotted to a food restricted (50–60% daily energy requirements) or a control group just after calving. Hinds in the food‐restricted group showed a greater body mass loss, produced less milk and yield of milk fat, protein and lactose, and a different lactation curve shape, which resulted in reduced calf growth. However, the time course of lactation variables appeared to show a compensatory response up to week 4: a greater milk fat content in low‐nutrition hinds than in the control group appeared to compensate for lower milk production, as neither calf nor hind mass differed from the control group, and lactation variables in both groups showed a standard lactation pattern. In contrast, as milk fat content fell below that of the control group after week 4, the low nutrition plane overcame a standard lactation pattern and groups differed in most variables (e.g. calf and hind mass and percentage of calf growth). Our results appear to show that deer mobilise body reserves in lactation to maintain offspring growth under temporary reductions in food intake, which may be a strategy of securing investment in current offspring at the expense of reproducing the following season.