Age-specific feeding cessation in male red deer during rut

Tactics for resource-use involve both using stored reserves (capital breeding) and feeding while reproducing (income breeding). In polygynous ungulates, males often use an income breeding strategy when young and shift to a capital breeding tactic at prime age. Little is known regarding why prime-aged males stop or largely reduce eating during rut but still remain inactive for as much time as before rut. A detailed exploration of how rumen content correlates with age and date may shed light on the ultimate causes of why some males stop eating. We provide quantitative empirical data on rumen content from red deer Cervus elaphus during the rutting season in Norway. In male red deer, rumen content declined with age, up to around 6 years of age. Above this age, rumen content was low and stable. A time-of-year effect on rumen content was best described with a second-order polynomial term, as rumen fill was lowest during mid-October when the mass loss of males and the ovulation rate of females both peak. We present two new hypotheses related to why males reduce eating ( physical rest and parasite hypotheses). Two related patterns need to be explained and better documented: (1) why are resting times stable before, after and during rut, and (2) why do non-prime-aged males eat more between rutting activities?     

Variable extent of hybridization between invasive sika (Cervus nippon) and native red deer (C. elaphus) in a small geographical area

Instances of hybridization between endemic and alien species pose a threat to species integrity but also provide us with an opportunity to study the dynamics of gene flow between two species as they first meet. Here, we used variation at 22 highly differentiated microsatellite loci and one mitochondrial DNA (mtDNA) marker in a sample of 735 individuals, to investigate the genetic consequences of an introduction of Japanese sika deer ( Cervus nippon ) for native red deer ( C. elaphus ) on the Kintyre Peninsula in Scotland. We investigated population structure, estimated null-allele frequency and assigned individual hybrid scores using a Bayesian clustering algorithm implemented in structure 2.2. The dataset clearly divided into two clusters and generally, introgression into red and sika was low. However at one site, West Loch Awe, 43% of individuals were hybrids. MtDNA introgression indicated that hybridization was occurring between red-deer hinds and sika-deer stags. We argue that the pattern of differential introgression across the study area is primarily due to the rarity of hybridization events between the two species and the limited time the two species have been in contact (< 120 years). This contrasts with the causes of classic mosaic hybrid zones (selection induced by habitat variability). Currently, it seems possible that, in time, the level of hybridization found at West Loch Awe could also be found across the whole of the peninsula.     

Estimating selection on neonatal traits in red deer using elasticity path analysis

Van Tienderen recently published a method that links selection gradients between a phenotypic trait and multiple fitness components with the effects of these fitness components on the population growth rate (mean absolute fitness). The method allows selection to be simultaneously estimated across multiple fitness components in a population dynamic framework. In this paper we apply the method to a population of red deer living in the North Block of the Isle of Rum, Scotland. We show that (1) selection on birth date and birth weight can operate through multiple fitness components simultaneously; (2) our estimates of the response to selection are consistent with the observed change in trait values that we cannot explain with environmental and phenotypic covariates; (3) selection on both traits has fluctuated over the course of the study; (4) selection operates through different fitness components in different years; and (5) no environmental covariates correlate with selection because different fitness components respond to density and climatic variation in contrasting ways.     

The impact of red deer on liverwort-rich oceanic heath vegetation

Background: There is concern about increasing numbers of large herbivores including red deer (Cervus elaphus), but little is known about their impact on bryophytes.

Aims: This study set out to determine the effect of different localised densities of red deer on the internationally important Northern Atlantic hepatic mat, characteristic of oceanic heath vegetation, at four locations in the Scottish Highlands where sheep have been absent for decades.

Methods: Thirty 7 m × 7 m plots were randomly located in each study area. The standing crop dung pellet group count method was used to estimate red deer density. Species richness, diversity and cover of hepatic mat liverworts were obtained from 1 m × 1 m quadrats placed at random within the sample plots. Calluna vulgaris cover, ericoid height, rock cover, gradient and altitude were also recorded.

Results: Model simplification in analysis of covariance revealed a consistent pattern of decreasing cover of hepatic mat and Calluna with increasing red deer density at all four study areas. Northern Atlantic hepatic mat cover, diversity and species richness were positively correlated with Calluna cover.

Conclusions: The data suggest that Calluna cover is reduced (through trampling and browsing) at high local densities of red deer which has had cascading effects on the Northern Atlantic hepatic mat. Alternative explanations are discussed.     

Short- and long-term effects of winter and spring weather on growth and survival of red deer in Norway

Populations of red deer (Cervus elaphus) in Norway have increased continuously over the last decades. We tested the possible effects of climate and increase in population size on the survival rates and body condition of individuals in one of the northernmost populations of red deer in Europe. Based on 678 individuals of known age marked between 1977 and 1995, we estimated annual survival rates, the probabilities of being harvested and the recapture probability according to sex, age, year, winter and spring weather, population size, and, body weight and body condition, using capture-mark-recapture models. Winter harshness negatively influenced the body weight of yearlings and the survival of calves of both sexes. Spring weather influenced the survival of males in all age classes. A negative trend during the study period was detected in body weight and condition of calves and yearlings, but not in any age- or sex- specific survival rates. No significant gender differences in mean survival were shown in any age class. Moreover, there was little (male) or no (female) detectable between-year variation in survival rates for yearlings and adults. Winter weather acts as a limiting factor on population growth through a short-term effect on first-year survival and a long-term effect on body weight. We discuss the surprising low sex differences in natural survival rates and the differential effects of winter harshness on body weight, body condition and survival in relation to life history characteristics of red deer. Received: 10 November 1997 / Accepted: 2 June 1998     

Polygyny can increase rather than decrease genetic diversity contributed by males relative to females: evidence from red deer

Polygyny is expected to erode genetic variability by reducing the diversity of genetic contribution of males to the next generation, although empirical evidence shows that genetic variability in polygynous populations is not lost as rapidly as expected. We used microsatellite markers to study the genetic variability transmitted by mothers and fathers to offspring during a reproductive season in wild populations of a polygynous mammal, the red deer. Contrary to expectations, we found that males contributed more genetic diversity than females. Also, we compared study populations with different degrees of polygyny to find that polygyny was not related to a decrease in genetic diversity contributed by males. On the contrary, when population genetic diversity was relatively low, polygyny associated with higher genetic diversity of paternal lineage. Our results show that sexual selection, by favouring heterozygote individuals, may compensate the potential reduction of effective population size caused by polygyny, thus contributing to explain why genetic diversity is not depleted in polygynous systems.     

The relationship between tooth wear, habitat quality and late-life reproduction in a wild red deer population

1. Molar tooth wear is considered an important proximate mechanism driving patterns of senescence in ungulates but few studies have investigated the causes of variation in molar wear or their consequences for reproductive success. 2. In this study, we assessed molar tooth wear at death among red deer Cervus elaphus of known age on the Isle of Rum, Scotland. 3. First molar height showed a decelerating decline with age. In females, the rates of molar wear with age varied with location of home range and individuals experiencing low resource competition showed reduced molar wear. We suggest that this spatial variation in molar wear is related to differences in the availability of high-quality grazing habitat and levels of resource competition. 4. There was no evidence that females with more heavily worn molars had reduced reproductive performance late in life or that first molar height was associated with reproductive senescence.     

Mitochondrial DNA evidence for a genetic distinction of the native red deer of Mesola, northern Italy, from the Alpine populations and the Sardinian subspecies

Native red deer of Mesola Wood, northern Italy, were compared with the Sardinian subspecies and with some populations from the Italian Alps and Austria using the analysis of restriction fragment length polymorphism (RELP) of mitochondrial (mt) DNA segments. The results highlight the existence of four main genetic lineages, and provide evidence for a structuring of populations according to their geographic occurrence. Two mitochondrial lineages, although highly distantly related, are shared between the populations from the centre-eastern Alps of Italy and Austria, while the other two lineages characterize the Sardinian and Mesola red deer, respectively. The exclusive haplotype found in the Mesola population appears as being an offshot of one of the two main Alpine lineages, suggesting a presumed origin of these deer from a panmictic population which dwelt in mid-southern Europe, prior to the fragmentation of populations caused by human activities and manipulations. Considering their distinctiveness in morphologic and genetic traits, as well as their historical background and biogeographical value, these native deer should be regarded as a national conservation priority. The Sardinian red deer is highly divergent from both Mesola and Alpine populations. However, the controversial question of the phylogeographic origin of this subspecies remains unresolved. The utility of RELP analyses of mtDNA segments as a tool to discriminate among red deer populations as well as to develop effective strategies for their conservation and management.

Zusammenfassung

Mitochondrien-DNA-Daten zur genetischen Unterscheidung der autochthonen Rothirsche von Mesola, Norditalien, von jenen aus alpinen Populationen und von der Unterart auf SardinienAutochthone Rothirsche aus dem Mesola-Waldgebiet in Norditalien wurden mittels Restriktionsfragmentlängenpolymorphismen (RFLPs) von Abschnitten der mitochondrialen (mt)DNA mit Rotwild der sardischen Unterart und Tieren aus alpinen Populationen verglichen. Die Ergebnisse weisen auf die Existenz von vier genetischen Hauptlinien hin und belegen auch eine Strukturierung der Populationen gemäβ ihrer geographischen Herkunft. Zwei entfernt verwandte mtDNA-Linien wurden in Beständen aus dem Zentral- und Ostalpenbereich von Italien und Österreich gefunden. Die beiden anderen Linien waren jeweils charakteristisch für Rotwild auf Sardinien und Rotwild in Mesola. Der exklusive Haplotyp der Mesola-Population scheint ein Abkömmling einer der beiden alpinen Hauptlinien zu sein. Dies legt eine Abstammung der Mesola-Rothirsche von einer groβen, panmiktischen Population nahe, wie sie vor der anthropogen bedingten Fragmentierung und Isolation von Beständen im Bereich von Mittel- und Südeuropa existiert haben sollte. Sowohl nach der Eigenständigkeit in morphologischen und molekularen Merkmalen als auch im Hinblick auf die Bestandsgeschichte und den biogeographischen Wert sollte der letzten autochthonen Rotwildpopulation in Mesola eine nationale Priorität im Rahmen von Arterhaltungsprogrammen zugebilligt werden. Das sardische Rotwild unterschied sich in hohem Maβ von den alpinen Beständen und der Mesola-Population. Die phylogeographische Herkunft bleibt allerdings unklar. Die Brauchbarkeit von mtDNA-RFLPs zur Abgrenzung von Rothirschbeständen sowie zur Entwicklung von Arterhaltungs- und Management-Konzepten wird diskutiert.     

Benefits for dominant red deer hinds under a competitive feeding system: food access behavior, diet and nutrient selection

Social dominance is widely known to facilitate access to food resources in many animal species such as deer. However, research has paid little attention to dominance in ad libitum access to food because it was thought not to result in any benefit for dominant individuals. In this study we assessed if, even under ad libitum conditions, social rank may allow dominant hinds to consume the preferred components of food. Forty-four red deer hinds (Cervus elaphus) were allowed to consume ad libitum meal consisting of pellets of sunflower, lucerne and orange, and seeds of cereals, corn, cotton, and carob tree. The meal was placed only in one feeder, which reduced accessibility to a few individuals simultaneously. During seven days, feeding behavior (order of access, time to first feeding bout, total time spent feeding, and time per feeding bout) were assessed during the first hour. The relative abundance of each meal component was assessed at times 0, 1 and 5 h, as well as its nutritional composition. Social rank was positively related to the amount of time spent feeding during the 1(st) h (P = 0.048). Selection indices were positively correlated with energy (P = 0.018 during the 1(st) h and P = 0.047 from 1(st) to 5(th)) and fat (only during the 1(st) h; P = 0.036), but also negatively with certain minerals. Thus, dominant hinds could select high energy meal components for longer time under an ad libitum but restricted food access setting. Selection indices showed a higher selectivity when food availability was higher (1(st) hour respect to 1(st) to 5(th)). Finally, high and low ranking hinds had longer time per feeding bout than mid ones (P = 0.011), suggesting complex behavioral feeding tactics of low ranking social ungulates.     

贺兰山马鹿冬季取食和卧息生境选择

2007 年12 月至2008 年1 月,在贺兰山地区,利用痕迹检验法和直接观察法对马鹿阿拉善亚种的冬季取食和卧息生境选择进行研究。通过在选定的15 条沟段里进行调查,共测定了72 个取食利用样方,59 个卧息利用样方和131 个对照样方的18 种生态因子。结果表明,马鹿在冬季偏好的取食地为平滑起伏坡,以酸枣、柳为优势乔木、混合型树林或空地,乔木高大稀疏、间距较远,灌木密度大,草本盖度较高,位于< 15°的半阴半阳坡的下坡位,距裸岩远,隐蔽度高;偏好的卧息地在山地疏林草原带的平滑起伏坡上,以酸枣、柳为优势乔木、混合型树林或空地,乔木高大稀疏,灌木矮小、稀疏且距离较远,草本盖度较高,位于< 15°阳坡的下坡位,远离裸岩,隐蔽程度高。马鹿冬季的取食和卧息生境在草本盖度和隐蔽度上差异极显著。相对于卧息生境,马鹿冬季的取食生境对草本盖度和隐蔽度要求更低一些。马鹿冬季取食地的资源选择函数为1.155 - 0.149 × 乔木高度- 0.066 × 草本盖度+ 0.190 × 坡度,模型的正确判别率为86.8% ;马鹿冬季卧息地的资源选择函数为- 30.936
+ 0.494 × 乔木高度+ 0.257 × 坡度-0.002 × 海拔高度+ 0.387 × 隐蔽度,模型的正确判别率为95.8% 。食物、隐蔽条件以及贺兰山的独特地形特征是影响马鹿冬季取食和卧息生境选择的主要因素。     

基于线粒体Cty b基因的西藏马鹿种群遗传多样性研究

西藏马鹿(Cervus elaphus wallichi) 为我国特有物种,仅分布在西藏东南部的桑日县,目前关于西藏马鹿的研究报道很少。因此,深入了解西藏马鹿各地理单元内种群的遗传变异,可以为我们制定保护管理策略提供依据,进而使其种群得到有效的保护和管理。本文对54个不同西藏马鹿个体（来自3个不同地点）的线粒体DNA Cty b基因进行了测定和群体分析,获得了731bp的片断,并检测到24个变异位点,占分析长度的3.28%,且这24个变异位点皆为碱基置换,并未出现碱基插入或缺失的现象,并定义了14种单倍型,核苷酸多样性平均值为0.02781,种群总体遗传多样性较高。从Tajima′s D和Fu and Li′s D值的估算结果来看, 这3个马鹿种群相对于中性进化的歧异度并没有明显的偏离(P>0.1),没有明显的证据显示这3个西藏马鹿种群间存在很强的平衡选择。分子变异分析表明3个群间基因流(5.36>Nm>1.87)均大于1,说明这3个马鹿种群间存在着丰富的基因流,并建议将三个地区的西藏马鹿作为一个管理单元进行保护和管理。     

Sex-ratio variation and reproductive costs in relation to density in a forest-dwelling population of red deer (Cervus elaphus)

For dimorphic species in which the variance in reproductivesuccess of males is more pronounced than that of females, theoriesof adaptive variation in sex ratio predict that mothers shouldinvest more heavily in sons than in daughters. By using harvestdata from a forest-dwelling red deer population that experienceda marked reduction in population density we tested the hypothesisthat adaptive sex-ratio variation should occur only when populationsare much below carrying capacity. More specifically, we testedwhether at low density, females in better than average conditionwere more likely to produce male offspring and to invest inindividual sons rather than were females in poorer than averagecondition. We also investigated female reproductive costs arisingfrom a decrease either in body mass or in reproduction. We didnot find any support for a biased sex ratio or investment towardmale calves by high-quality mothers at any population density.Costs of reproduction in terms of body mass and pregnancy rateswere only detectable for females that reproduced as yearlingsand not for those that reproduced as adults. Our results thereforedo not support the hypothesis of adaptive sex-ratio variationin a population living below carrying capacity. The four-folddifference in party sizes (defined as the number of deer aggregatein the same party in which no individual was more than 50 mfrom any other) observed in our population living in a closedforest habitat compared with populations living in more openhabitats previously studied might account for such a discrepancy.We suggest that a smaller party size may decrease the intensityof sexual selection and could be the proximal cause for thelack of adaptive sex-ratio variation we report for the populationstudied here.