Functional limb anatomy in a refugee species: The endangered Patagonian huemul deer (Hippocamelus bisulcus)

Early naturalists already considered huemul rare, refuged and a stocky, short-legged mountain deer, 163 years before declared endangered (1972). Anatomically, huemul do not overlap with rock-climbers previously considered analogous, as corroborated in this paper by including additional huemul cases. Assertions that population declines are caused principally via livestock infections remain unfounded. Instead, osteopathology in multiple populations across 1,000 km, affecting 57% among dead and 86% among live specimens, may relate to micronutrient deficiencies. Historically classified a mountain deer, widespread osteopathology, micronutrient deficiencies and lack of recovery qualify huemul as a refugee species. Recovery strategies thus must include repopulating historical distribution sites.

Nutrition as an etiological factor causing diseases in endangered huemul deer

OBJECTIVES

Distinct diseases prevent endangered huemul deer (Hippocamelus bisulcus) recovery. Fundamental etiological factors include nutriments, a mayor component of habitat quality. Undernutrition affects growth, skeletal development, osteopathology, reproduction and immunocompetence: this paper amplifies data corroborating micro-nutrient deficiencies among huemul.

RESULTS

In Argentina, 57% huemul cadavers exhibited osteopathology, with new cases reported here. Recently, 86% live huemul had osteopathology: cranial lesions involved antemortem tooth loss, reducing feeding efficiency and body condition, with starvation deaths. This population had tissues well deficient compared to other cervids, averaging 0.28 ppm selenium, 4.98 ppm copper, whereas for manganese 55% were deficient (2.52 ppm) and 45% adequate (42.79 ppm). Recently, lesions in one Chilean huemul were interpreted to stem from parapoxvirus. That population also has cases with cranial osteopathologies, high disease susceptibility (parapoxvirus, parasitism, foot lesions), crippled antlers, and low density, indicative of marginal habitat and primary etiological factors like undernutrition and immunosuppression. The reported atypical symptoms attributed to parapoxvirus may relate to probable diagnostic limitations, but does support presence of nutritional deficiencies. Patagonia has selenium deficient plants and livestock, including severe muscular dystrophy, and soil levels in extant huemul areas considered very deficient. Moreover, 73% of Chilean huemul were selenium deficient and 64% severely deficient with concomitant cranial osteopathology.

The next frontier for recovering endangered huemul (Hippocamelus bisulcus): how to avoid recurrent misdiagnoses of health status and risks

Abstract Context The currently remaining 350–500 huemuls in Argentina are not recovering. We evaluated live huemuls, along with animals that died soon after confinement, or those that had died recently. Although information on the health status is highly valuable, repeated misdiagnoses of the health status indicate a need for other strategies. Aims . Discrepancies between clinical and postmortem diagnoses are critical for improving subsequent management decisions. Methods Initial clinical interpretations and risk assessments were reinterpreted on the basis of necropsies and other data. Results Two debilitated huemul individuals examined by veterinarians died soon afterwards, supposedly one being intoxicated and one being without lesions. Necropsies showed osteopathology and fluorosis (fluorine concentrations of 2209 and 2979 mg/kg). Another male was tied up, with authorities and veterinarians arriving the next day. After being sedated, and judged healthy, the animal was translocated. Because there was no reversal, this animal died 22 h post-capture. Exhumation showed severe osteopathology. Elsewhere, huemuls were considered adequate in selenium because values below the detection limit were excluded. However, when all values were included, 75% of the animals were selenium-deficient; this population had numerous cases of osteopathology. Recently, specialists went to Torres del Paine Park suspecting caseous lymphadenitis, reporting of which has been obligatory since 1937. However, many cases documented in 1999–2007 have not elicited responses since that time by health professionals. Selenium deficiency negatively affects antibody responses against caseous lymphadenitis. One province had denied huemul capture (2012 and 2013) on recommendation of scientific advisors. Because of the right for transparency, it was found out in 2016 that authorities had requested advice from only one veterinarian who assessed that darting was too risky. Another 2016 project proposed to dart the first huemul in Argentina. Two weeks earlier, that same team was called to rescue a tied-up huemul; the team opted not to involve a laboratory with drugs and radios that was only 1 h away. This huemul died and was left in the woods. Finally, the first huemul enclosure in Argentina was proposed (1995), but the permission was denied. Again, in 2000, the first huemul centre with private funding secured for 30 years was proposed. However, the Regional Delegation for Patagonian National Parks prevented aerial surveys, and advised not to provide a permit for the centre. Conclusions Future assessments should consider osteopathology. Risk assessments should be transparent and based on assessment by multiple qualified professionals. Implications Clinical misdiagnoses may reduce life expectancy, in contrast to taking individuals to enclosures, which would also allow valuable reintroductions. Not permitting captures, censusses and enclosures has resulted in unwarranted delays in conservation progress.

Elusive cranial lesions severely afflicting young endangered Patagonian huemul deer

OBJECTIVES

Most subpopulations of endangered huemul deer (Hippocamelus bisulcus) fail to recover, frequently due to osteopathology. Equivalent pathology was detected only postmortem in an additional deer 365 km further north, stressing the need to improve clinical evaluations of live huemul.

RESULTS

Captured on a farm and attended by authorities in charge of huemul, the deer was considered apt for relocation and release. Delays with attendance and lack of reversal drugs resulted in his death. The subsequent necropsy revealed severe osteopathology particularly in mandibles and maxillae. Such disease in another southern population affected 57+ % among dead adults, and 86% among live adults. The present case stems from a new subpopulation, isolated 365 km further north. Such severe pathology demands that individuals be rehabilitated, especially relevant with severely endangered species, because liberations will cause premature death and loss of reproductive lifetime. Live huemul must be examined utmost professionally especially regarding this pathophysiognomy. This incidence represents the typical situation of extant huemul, being displaced from their traditional migratory behavior to utilize fertile low-elevation habitat. This young male may have been dispersing, but reaching valleys usually leads to death due to locally intense anthropogenic activities.

Troubling disease syndrome in endangered live Patagonian huemul deer (Hippocamelus bisulcus) from the Protected Park Shoonem: unusually high prevalence of osteopathology

Objective

The last 1500 endangered Patagonian huemul deer (Hippocamelus bisulcus) exist in > 100 groups which are not recovering. Prevalence of osteopathology in dead huemul was 57+% (Argentina), whereas similar cases in Chile were accompanied by selenium deficiency. The first clinical cases from live wild huemul confirm widespread osteopathology which explains short life spans, low recruitment, and thus absence of population recovery.

Results

The first-ever radio-collaring of 3 male huemul in Argentina and 3 females, plus a fresh female carcass allowed examination of 7 huemul. Of these, 86% were diseased and clinical pathophysiognomy included lameness, affected hoof, exfoliation of 2–7 incisors, other cranial osteopathologies, and muscle atrophy. The parsimonious explanation for absent population recovery is high prevalence of osteopathology as evidenced earlier in carcasses, and now by these clinical cases. Areas currently used by huemul have reduced selenium bioavailability, very deficient soil levels, and overt selenium deficiency in local livestock and plants. These areas are known to result in primary iodine deficiency which is aggravated by selenium deficiency. The nexus to nutritional ecology of huemul likely is inaccessibility to most fertile lowlands and traditional winter ranges, elimination of migratory traditions, and concomitant elimination of source populations.

Electronic supplementary material

The online version of this article (10.1186/s13104-017-3052-4) contains supplementary material, which is available to authorized users.

The impact of recent volcanic ash depositions on herbivores in Patagonia: a review

Volcanic tephra (ejected solids) result in varied impacts on ecosystems and livestock production. The recent Puyehue (2011) and Calbuco (2015) eruptions deposited large amounts of tephra in Chile and Argentina, affecting both livestock and wildlife in several ways. Impacts from Puyehue tephra on livestock were attributed initially solely to inanition, rumen blockage, eye problems, increased mechanical tooth wear; water consumption was considered without risk for humans and animals; and toxic effects were discarded. Subsequently, wildlife exhibited pronounced clinical signs of fluorosis and bone level exceeding 10 000 ppm of fluoride by 2014. Livestock including horses, cattle and sheep also had high levels of bone fluorine and clinical fluorosis. Tephra from Calbuco and Puyehue now overlap, containing on average 548 and 352 ppm fluoride, respectively. Dryness and eolic redeposition of tephra particularly east of the continental divide continues to re-expose domestic and wild ruminants. However, fluorosis and other related impacts like hypothyroidism, anaemia, and eosinophilia in ruminants also impact wool production. Although fluoride was discarded by others as a cause for the observed reduction in wool production, the specific effect of fluorosis on reducing wool production is well recognised, and occurs in sheep with less bone fluoride than reported from the Puyehue event. The rapid accumulation of fluoride in herbivores exposed to tephra from Puyehue coincides with reports that upon exposure to fluoride, sheep bone levels increased from 160 to 2300 ppm in only 3 months. The susceptibility of ruminants to fluorosis resides in their food processing: (1) intensive mastication and tephra size reduction, (2) thorough mixing of tephra with alkaline saliva during repeated rumination cycles, (3) water-soluble extraction in the rumen, and (4) extraction in the acidic abomasum. Lastly, the fluorosis may be further exacerbated by regional iodine and selenium deficiencies. Iodine deficiency may increase the incidence of dental fluorosis and the severity of damage, whereas selenium deficiency causes secondary iodine deficiency.

Osteopathology and selenium deficiency co-occurring in a population of endangered Patagonian huemul (Hippocamelus bisulcus)

Background

About 1,000 endangered Patagonian huemul deer (Hippocamelus bisulcus) remain in Chile and 350–500 in Argentina. Most groups (>100) are not recovering, and prevalence of osteopathology in Argentina was at least 57%. Here I describe relevant cases of osteopathology from a Chilean population which, however, recently also provided data on trace mineral status, supporting the initial hypothesis that nutrition may be a primary etiologic factor. Additionally, recent data on bone chemical composition of Argentine cases and soil analyses are discussed.

Results

Fluoride levels in Argentine cases with osteopathology were low and fluorosis was discarded as an etiological factor. Selenium deficiency occurred in 73% of huemul from the Chilean population which exhibited several cases with osteopathology. The pathophysiognomy included extensive erosion; tooth loss; porosification; perforations of palate, maxillar and mandibular bone with frequent exposure of tooth roots; and fractured mandibula. Areas currently used by remaining huemul have mainly acidic volcanic soils, which reduces selenium bioavailability: mean soil selenium levels from areas typically used by extant huemul were very deficient (0.19 ppm), corroborating documented overt selenium deficiency in local livestock and plants. The area of extant huemul is known to result in primary iodine deficiency in livestock which is aggravated by selenium deficiency.

Conclusions

Currently the most parsimonious explanation for frequent osteopathology and lack of numerical recovery are the combined effects of selenium and iodine deficiencies based on: osteopathology in a population of selenium deficient huemul; selenium deficient livestock, plants and soils; acidic soils; and regional primary iodine deficiency. The nexus between mineral nutrition and population dynamics of huemul may be due to constraints on their movements to fertile lowlands, including the elimination of historic migratory traditions, and concomitant elimination of source populations.

A review of introduced cervids in Chile

We review the extent of exotic deer distributions in Chile, which are encountered in all provinces, including Tierra del Fuego, except for possibly Region III; many deer are contained in at least 107 enclosures. Red deer (Cervus elaphus) by far has the largest feral population of exotic cervids in southern South America, providing source animals that can easily cross the Andes between Chile and Argentina. Red deer was introduced from Europe to the central valley of Chile in 1928. Since the 1940s, feral populations have also expanded from Argentina into Chile, by way of easily accessible, low-elevation mountain passes of the Andes, accompanied by further direct shipments from Argentina. The area occupied by 1990 was estimated at 3400 km2, whereas an analysis in 2003 estimated an area of 7700 km2. The overall area invaded by 2003 was between 37°42′S and 54°55′S, and 73°36′W and 69°50′W (Argentina and Chile combined, although non-contiguous). Ecological impact of the red deer in Chile has been described since 1981, and red deer features in the Chilean Pest Manual. A conservative rate for the red deer expansion was estimated at 1 km/year, but likely is more rapid where habitat modifications facilitate movement. The pre-Columbian northern limit of the native cervid huemul (Hippocamelus bisulcus) was 30°S, and because red deer has occupied all habitat types currently used by huemul, it could thus spread >750 km further north. To the south, all areas are suitable for red deer. Invasion patterns will depend on additional intentional introductions and enclosures on both sides of the Andes because of the omnipresent risk of escapes. Fallow, axis and roe deer (Dama dama, Axis axis, Capreolus capreolus, respectively) also have been introduced to Chile and occur in many enclosures. Fallow deer recently escaped on Chiloé Island, became established and raised concerns because of its potential impacts on several endemic species on the island. The striking lack of information on feral deer may relate to policies and laws about firearms and restricted access to hunting areas, resulting in the apparent absence of popular hunting, which, nevertheless, could be a potential tool should the invasion continue and lead to future deer overabundance.

Variation in reproduction of a temperate deer, the southern pudu (Pudu puda)

Pudu (Pudu puda), occurring in the southern cone of Latin America, has been classified as vulnerable by the International Union for Conservation of Nature (IUCN), yet little is known about this animal in the wild, with most knowledge on the breeding behaviour coming from captive animals. For this second-smallest deer in the world, delayed implantation has been suggested to explain the two peaks in the annual cycle of male sexual hormones on the basis of the accepted tenet that the breeding period occurs only once a year, between March and June. However, in the present study, birth dates from fawns born at the Los Canelos semi-captive breeding centre in Chile and male courting behaviour revealed the possibility of two rutting periods: autumn and spring. To our knowledge, this is the first time that late-fall births (May through early June for 17% of fawns in the study population) have been recorded for the southern pudu; two of these four births were conceived by females in the wild. From zoo and captive-animal birth records (n = 97), only three fawns were born in the fall. For all births combined (n = 121), 77% occurred in spring. The roe deer (Capreolus capreolus) and Pere David deer (Elaphurus davidianus) have been considered the only two temperate cervids in which sexual activity is initiated by increasing daylength and which breed in early summer. Yet, the present results indicate a similar response from the southern pudu when under a wild or semi-captive environment, with breeding taking place in spring. These results suggest that this species may either have two reproductive periods per year or retains the capacity to be a breeder for a much more extended period of time than documented by earlier studies. Pudu, like other temperate deer, is responsive to photoperiod for timing its breeding period, but may further optimise its production of offspring by also responding to other environmental cues such as seasonal variation in food supply when climatic conditions are favourable.

Diseases of red deer introduced to Patagonia and implications for native ungulates

The red deer (Cervus elaphus) invasion in Patagonia has been continuing for nearly a century, with occurrence in all habitats between 34°S and 55°S. Their distribution, movement patterns and locally high densities raise concerns over their potential epidemiological role in maintaining disease reservoirs or transmitting diseases such as foot-and-mouth disease or tuberculosis, with potential severe health and economical impacts at the interface of humans, livestock or native wildlife. Among adult females collected by rifle and radio-collared deer that died naturally, no ectoparasites were found (n = 73). Fasciola hepatica was encountered in three surveys at prevalences ranging from 9% to 50% (n = 108). Taenia ovis krabbei was identified, and Cysticerus tenuicollis was found at a prevalence of 8% (n = 12). Ostertagia sp., Bunostomum sp. and Dictyocaulus sp. had a prevalence of 75%, 25% and 13% (n = 9), respectively. Several gastrointestinal parasites reported at low prevalence in endangered Patagonian huemul (Hippocamelus bisulcus) are common in livestock and considered commensals in domestic ruminants. Sympatry of huemul with livestock is commonplace, whereas with red deer it occurs in <2% of known populations, in which case there were 1.2 red deer, but 25.2 livestock per huemul, making livestock the determining epidemiological factor regarding disease transmission or reservoir. As red deer have been coexisting with livestock for >100 years in Argentina, both red deer and livestock play epidemiological roles for shared diseases. Research, conservation and management efforts should be directed towards livestock herd health programs or restriction of free livestock movements, particularly if diseases are shown to have an impact on recruitment of endangered natives. Livestock are routinely researched and inspected at slaughter and thus provide a proxy for diseases afflicting co-existing ungulates. Testing for antibodies to foot-and-mouth disease viral antigen was negative (n = 41). A tentative diagnosis of mycobacterial infection was based on typical visceral lesions. Antler damage occurred on 73% of shed antlers, with 36% having major breaks of tines and main beams, possibly indicating mineral imbalances. One male had both antlers, including pedicles with portions of frontal, parietal and occipital bones, broken off the skull, causing his death. The prevalence of 0.9% of campylognathia (n = 776) indicates that the disease is unlikely to be inheritable, because the founding stock of 20 animals would have had a prevalence of at least 5%. Among deer, handedness of scoliosis related significantly to the hemisphere where specimens originated (P < 0.001, n = 131). Coriolis forces are known to affect early stages of development, such as the innervation pattern of the mammalian vestibular system, or the plane of bilateral symmetry. It is, therefore, conceivable that the networks processing these environmental cues, or the mechanisms responsible for compensation, are malfunctioning and thus result in a preponderance of facial scoliosis in accordance to the earth’s rotation.

Huemul heresies: beliefs in search of supporting data. 2. Biological and ecological considerations

Scarce information from remnant huemul (Hippocamelus bisulcus) populations in marginal habitats can lead to erroneous interpretations of the species’ natural history, such as assumptions of being a highly inflexible species. We evaluated discrepancies between historical accounts and recent interpretations regarding biological and ecological traits to better understand factors preventing recovery of highly endangered huemul. Early information supports the theory that huemul are currently living under suboptimal conditions. We find variability to be the norm for huemul, as with other cervids, in regard to antler characteristics, group size and density, sexual segregation, and social and feeding behaviours. No evidence supports competition and disease from livestock or red deer as having caused declines or preventing recovery. Instead, livestock management, particularly presence of people and dogs, creates incompatibilities. Where red deer are sympatric with huemul, red deer are outnumbered by livestock by 2100%, and being regularly inspected at slaughter, livestock provide a good proxy for diseases afflicting red deer. Inadequate antipredator responses due to evolutionary absence of cursorial predators are unsupported as several Canis species coexisted with huemul, overlapping with dogs that arrived with Paleoindians. Three populations have increased despite high predator density. Age at maturity for huemul is 1 year, with evidence that fawns may also breed. Reported twinning needs confirmation, but occurs in congeneric taruca (H. antisensis) and other Odocoilines, and huemul frequently raise fawns successfully every year; life cycle calculations should apply these parameters. Like taruca, dominance group breeding systems have been described repeatedly. Although huemul bucks were recently claimed unique by displaying territoriality year-round, data do not support such behaviour. Two sole dispersal records (8 and 15.5 km) are unlikely to represent maximum dispersal capacity and do not support barriers assumed from few kilometres of unsuitable habitat. Huemul using 500 ha could predictably disperse up to 90 km, well within the ranges of other cervids. Mistakenly assuming barriers and underestimating reproductive capacity may distract from discovering the factors affecting recolonisations. Sustained recovery may depend on re-establishing source populations on more productive habitats, guided by zooarcheological and historical data.

Huemul heresies: beliefs in search of supporting data. 1. Historical and zooarcheological considerations

Patagonian huemul (Hippocamelus bisulcus) was eliminated from many former ranges before arrival of early explorers who already acknowledged its rareness. Considering huemul analogous to ungulates in mountains back home, huemul was called mountain deer, which is repeatedly cited without validation and remains the orthodox interpretation. Yet other species considered analogous also use lowlands, flatlands, deserts and grasslands, and the only congeneric, H. antisensis, uses habitat with high affinity to Patagonian grasslands. Recent comparative analyses of the post-cranial morphology show that huemul cannot be associated with rock-climbing species, but falls within ranges of other cervids. Interpretations of past human utilisation rely on one study of economic anatomy and bone remains, frequently concluding that huemul was unimportant to hunter-gatherers. However, considering only bone fat and omitting easily removable fat is erroneous. Total energy of deer in autumn–winter partitions into 53% as fat and hunter-gatherers elsewhere focussed on deer during the peak fat cycle, using all easily removable fat (>1200% more energy than in bones) and consuming fat and marrow while butchering. Natives are likely to have influenced huemul distribution and density in winter ranges due to high incentives (fat) and easiness to kill. Sparse evidence is likely the result of surveys in Patagonia having been biased towards caves, leaving out transient movements and camps. Generalist cervids passed the Panama land-bridge filter to reach South America. Considering paleoclimate, Hippocamelus dispersed east of the Andes, pushed by glaciations even to north-eastern Brazil. Hippocamelus would reach and cross Andes only after deglaciations. As a mixed feeder, huemul utilised Patagonian steppe. Hunter-gatherers arrived after the last glaciation and influenced the local distribution of Hippocamelus, especially in northern and central Chile, after early adoption of an agricultural lifestyle. Introduction of horses converted native economies through adoption of an equestrian lifestyle and arrival of millions of introduced livestock, which thus affected early writings. Only few records indicate the presence of large groups of huemul far from forests, and substantial killings. Human-caused range contractions of northern ungulates affected mainly losses at low elevations and most species persisted in the marginal periphery, including high-elevation refuges. Paleoecology, zoogeography and land-use history in southern South America indicate that mountain huemul is a secondary relict created by impacts of post-Columbian colonisation. We caution against the rigid application of modern huemul habitats in interpreting past habitat use and huemul ecology, and simply considering the few extra-Andean accounts as abnormal outliers.

Recent advances in the nutritional ecology of the Patagonian huemul: implications for recovery

Huemul (Hippocamelus bisulcus) numbers had already declined drastically by the 1800s. Only ~500 animals remain along 1800 km of the Argentine Andes between 34 and 54°S, without cases of recolonisation or numerical responses. In Chile, at least two populations have increased; the remaining populations have either decreased or are assumed to be stable. During a Chilean–Argentine meeting in 1992 several factors were hypothesised to be important for huemul recovery (cattle, exotic trees, irrational forestry, exotic animals, illegal hunting, diseases, dogs, reduced numbers), but these can be rejected as key explanations for the general lack of recovery. Each factor may play an additive role – alone or in combination – in certain populations, but none of them are likely a primary cause. Our objective is to evaluate alternative factors and several indications warrant us to postulate that nutritional ecology instead plays a central role in the general absence of recovery. A wide range of antler quality is encountered among huemul today, with well developed specimens known primarily from historic times. If antler expression in huemul is homologous to other cervids, it follows that most extant populations are under suboptimal conditions. Another important clue is a high prevalence of age-independent osteopathy among adults. We hypothesised that such generalised secondary chronic alveolar osteomyelitis, osteoarthritis and periodontitis were hypothesised to relate to nutritional ecology. Meagre antler development with frequent asymmetry, high prevalence of osteopathy, and low recruitment rates could all be related to common and limiting nutritional factors known to cause the described phenomena. Initial investigations point to several lines of evidence that support the hypothesis that deficiency in iodine and selenium (Se) might be involved. Among other things, such deficiencies impair bone growth, reproduction, neonatal development, the immune and nervous systems, and cause periodontitis in ruminants. Se deficiency directly affects iodine metabolism. Only decades ago, overt iodine deficiency in humans living in these areas was very common. For free-ranging livestock, overt Se deficiency has been described in Chile: supported by geology, pedology, topography, and climatic patterns. It is well known that valley bottoms, flood plains, and habitats downwind from glacial areas provide higher provision of iodine and Se. The nexus to the nutritional ecology of huemul likely is the inaccessibility of most traditional winter ranges, elimination of migratory traditions, and concomitant elimination of source populations. Se and iodine provisions diminish with altitude, which at the same time increases physiological needs due to hypoxia, and intensified radiations and exercise. Most extant huemul populations occur in remote high-altitude refuges, or inaccessible Pacific coastal areas. Migration, an acquired behaviour, has been eliminated through past overhunting of this population segment; huemul being very vulnerable to human predation were killed by the thousands to feed people, dogs, chicken and pigs, and their skins were used for shelters. Huemul currently dispersing from refuges are generally being killed when entering former source areas now occupied by settlers and their dogs. Other ungulates driven into mountain refuges have been shown to be deficient in these trace minerals and responded well to mitigation of the deficiency. Thus, prevention of reaching traditional winter ranges or valley bottoms might result in inadequate mineral supply to huemul.

Intraspecific variation in biology and ecology of deer: magnitude and causation

It has been noted that the search for patterns in biology to assist our understanding, often leads to over-simplification. That is, we are satisfied with statements that ‘the species as a rule does this’ or, ‘males of this species do that’. But within such generalisations are masked what are often important variations from that supposed norm and in practice there is tremendous variation in morphology, physiology, social organisation and behaviour of any one species. The focus on a supposedly mean optimal phenotype has diverted attention away from variation around that mean, which is regularly regarded as a kind of ‘noise’ stemming merely from stochastic effects, and thus irrelevant to evolution. Yet it is becoming increasingly clear that this variation is by converse extremely significant and of tremendous importance both to evolutionary biologists and to managers. Such intraspecific variation (IV) may be directly due to underlying genetic differences between individuals or populations within a species, but equally may include a degree of phenotypic plasticity whether as ‘non-labile’, traits which are expressed once in an individual’s lifetime, as fixed characteristics inherited from the parents or as more labile traits which are expressed repeatedly and reversibly in a mature individual according to prevailing conditions. Recognition of the extraordinary degree of IV which may be recorded within species has important consequences for management of cervids and conservation of threatened species. We review the extent of IV in diet, in morphology, mature bodyweight, reproductive physiology, in population demography and structure (sex ratio, fecundity, frequency of reproduction) before also reviewing the striking variation to be observed in behaviour: differences between individuals or populations in ranging behaviour, migratory tendency, differences in social and sexual organisation. In each case we explore the factors which may underlie the variation observed, considering the extent to which variation described has a primarily genetic basis or is a more plastic response to more immediate social and ecological cues.

Osteological comparisons of appendicular skeletons: a case study on Patagonian huemul deer and its implications for conservation

Early explorers described huemul (Hippocamelus bisulcus) as stocky, massive and short-legged deer of mountains, comparing them to ibex (Cabra ibex), chamois (Rupicapra rupicapra), mountain sheep (Ovis canadensis) and mountain goats (Oreamnos americanus). Subsequent key paleontological work also claimed that huemul are mountain deer. However, all these comparisons of huemul to other ungulates were done without any supporting data. These historic events lead to: (i) the continued prevailing claim that huemul are mountain deer; and (ii) that their natural range is the Andean mountains, as evidenced by the current distribution. We found that early writings about huemul generally reported their rareness, disappearance or near extinction. References to stocky and short-legged huemul were casual remarks made about deer found mainly in refuge areas. Paleontological comparisons were based on a new fossil labelled as mountain deer which, however, has been shown to be a construct and declared a ‘nomen nudum’. Behaviour like the aggressive horseshoe stance and thick long hair dissimulate stockiness by distorting body shape. Comparing leg morphometrics of huemul and 12 other ungulates revealed that huemul cannot be associated with rock climbing species. Intraspecific proportional leg length is not static and is influenced by ecogeography, nutrition, physiology and factors affecting exercise. Thus, climate, altitudinal hypoxia and locomotor pattern employed according to terrain, predation and forage affect the appendicular skeleton. Nutritional deficiencies occurring in Andean mountains are notorious for affecting bone development, causing osteopathology and altering body shape. Frequent underdeveloped huemul antlers and high incidence of osteopathology support the effect from mineral deficiencies. Skeletal proportions are affected by numerous factors, causing large intraspecific variation. Relative metapodial length varies up to 70% in better studied cervids, and populations from different environments can be clearly distinguished. Huemul morphology does not overlap with rock climbing species previously considered analogous, but falls within the range of other cervids. We caution against the rigid application of modern huemul occurrences in interpreting past habitat use. The few historic extra-Andean accounts cannot be considered abnormal outliers. Huemul ecology must be interpreted in terms of first principles rather than applying direct analogues from the present. This allows us to begin to use the past to understand the present instead of repeating the fallacy of imposing the present on the past. Current efforts to recover remaining huemul are distinctly based on the assumption that huemul foremost belong in rugged mountains, because of their supposed special adaptions and resemblance to stereotype ungulates, also erroneously believed to only occur in rugged mountains elsewhere. We conclude that the present empirical comparisons support many other lines of evidence that huemul existed in treeless habitat and colonised Andean forests and higher altitudes secondarily. Habitat breath of huemul is thus more like that found in other closely related Odocoilines, promising tremendous new opportunities for recovery efforts.

Patagonian huemul deer (Hippocamelus bisulcus) under captive conditions: an historical overview

Huemul (Hippocamelus bisulcus) is a native deer of Patagonia whose endangered status has raised concerns for several decades, and yet conservation efforts to reverse this situation have not succeeded for most populations. Captive breeding projects attempted in the past were short-lived; animals were often lost due to poor methodology or unsanitary conditions during capture, transport stresses and rudimentary husbandry, and reintroductions could not be realised. Despite inappropriate capture and transport techniques of the past, a few individuals did make it to captive centres where they managed to survive for several years, with a minimum of eight births recorded. Regardless of the successes, it is the past failures that impinge upon today’s conservation efforts. In Argentina, a recent financially backed proposal – establishing a huemul breeding centre and including an in situ reintroduction program – was prevented by the prevailing opinion that captive breeding was neither feasible nor a necessary conservation tool for huemul. In Chile, the Huilo Huilo Foundation was able to obtain government consent and to establish the only captive breeding project in the last two decades with the main objective of reintroducing individuals in the future. Here we present some of the historical accounts to demonstrate the suitability of the species to captivity. We then describe the Chilean semi-captive breeding program (begun in 2005) including capture, transport, site selection, construction design and maintenance procedures of the two centres. The first centre has grown from an initial two adults to nine individuals. The second centre, which initially served for rehabilitation of an injured male, is awaiting arrival of some females. The success of the current program demonstrates that huemul can do well in captivity, and wherever considered beneficial, could serve as a significant conservation tool for the recovery of the species, inclusive of a research program and reintroductions to qualified sites.

Blood proteins of red deer introduced to Patagonia: genetic origins and variability

A small group of European red deer (Cervus elaphus elaphus) was introduced into the foothills of the Andes in Patagonia in the early 1920s. This species adapted well to the habitat and climatic conditions in the area and presently may number over 100 000 animals. Several indices commonly used to evaluate the fitness of a species in its environment indicate that red deer thrive under very favourable conditions in Patagonia; for example, body size, antler development, reproductive rates, herd health, and longevity are near the maximum described for the species. Furthermore, some local populations occur at densities much higher than encountered in their native ranges. The objective was to examine several biological enzyme systems to test for variance in protein polymorphism in comparison to populations of red deer in other parts of the world. The protein systems examined by electrophoresis in the plasma included: post-transferrin, transferrin, vitamin D binding protein, plasminogen, and complement component; and in the erythrocytes: hemoglobin, superoxide dismutase, glucose phosphate isomerase, and diaphorase I. Variation in plasminogen was lower than is typical for red deer, and glucose phosphate isomerase showed no variation. Furthermore, some occurrences of alleles typical for North American wapiti (Cervus elaphus canadensis) indicate that the introduced deer originated from English or European deer parks which have had a history of introductions of wapiti in the past. In New Zealand, the superoxide dismutase allele typical for wapiti was found in 1% of red deer, whereas it occurred in 11% of animals in the present study. Polymorphism measured across the nine examined protein systems was 2.0 alleles per locus with an overall heterozygosity of 0.30. The low variations are likely the result of the introduction based on few individuals. However, the outstanding performance of the present population contradicts the existence of any overt impact from this founder effect. The observed large body sizes may not only be due to good environmental conditions, but also due to previous hybridisation with wapiti. Several specimens were heterozygous and one specimen was homozygous for wapiti hemoglobin.

Intraspecific phenotypic variation in deer: the role of genetic and epigenetic processes

Intraspecific phenotypic variation (PV) in deer is common, at times impressively diverse, and involves morphology, development, physiology, and behaviour. Until recently considered a nuisance in evolutionary and taxonomic studies, PV has become the primary target to study fossil and extant species. Phenotypes are traditionally interpreted to express primarily interactions of inherited genetic variants. PV certainly originates from different genotypes, but additional PV, referred to as phenotypic plasticity (PP), results from gene expression responsive to environmental conditions and other epigenetic factors. Usage of ‘epigenetics’ for PP has increased exponentially with 20 316 published papers (Web-of-Science 1990 – May 2010), yet it does not include a single paper on cervids (1900 to the present). During the ‘genomic era’, the focus was on the primary DNA sequences and variability therein. Recently however, several higher order architectural genomic features were detected which all affect PV. (1) Genes: poli-genic traits; pleiotropic genes; poli-allelic genes; gene dosage (copy number variants, CNV); single nucleotide variance in coding and gene regulatory regions; mtDNA recombinations and paternal mtDNA inheritance. (2) Gene products: pleiotropic gene products; multiple protein structures through alternative splicing; variable gene product reactions due to gene dosage. (3) Gene expression: (i) epigenetic regulation at the DNA, nucleosomal and chromosomal levels; (ii) large-scale genomic structural variation (i.e. CNV imbalance); (iii) transcription factor proteins (TF), each regulating up to 500 target genes, with TF activity varying 7.5–25% among individual humans (exceeding variation in coding DNA by 300–1000×); (iv) non-protein-coding RNA (98.5% of genome) constituting maybe hundreds of thousands RNA signals; (v) gene expression responsive to external and internal environmental variation; (vi) transgenerational epigenetic inheritance (e.g. from ubiquitous non-gametic interactions, genomic imprinting, epistasis, transgenerational gene–diet interactions); (vii) epigenetic stochasticity resulting in random PP. A unique example of labile traits in mammals is the yearly regrowth of a complete appendage, the antler in cervids. Highly complex assortments of genotypes lead to a spectrum of phenotypes, yet the same spectrum can result if a single genotype generates highly complex assortments of epigenotypes. Although DNA is the template for the DNA–RNA–protein paradigm of heredity, it is the coordination and regulation of gene expression that results in wide complexity and diversity seen among individual deer, and per-generation variety of phenotypes available for selection are greater than available genotypes. In conclusion, epigenetic processes have fundamental influences on the great intraspecific PV found in deer, which is reflected in broad ranges of environmental conditions under which they can persist. Deer management and conservation of endangered cervids will benefit from appreciating the large inherent PV among individuals and the immense contribution of epigenetics in all aspects of deer biology and ecology.

Potential existence of a sylvatic cycle of Taenia ovis krabbei in Patagonia, Argentina

Red deer (Cervus elaphus) were introduced in southern Latin America about a century ago and characteristics of the invasion raise concerns over their epidemiological role for various diseases. We report on the possible occurrence of Taenia ovis krabbei established in a sylvatic cycle in Patagonia. Hook characters, size, appearance, and location of a cysticercus from a wild red deer are consistent with Taenia ovis ovis or T. o. krabbei. Although it is not possible to differentiate between T. o. ovis and T. o. krabbei on morphological grounds with certainty, several biological characteristics indicate the cysticercus may belong to T. o. krabbei. Red deer have been reported to be refractory to T. o. ovis infection whereas other potential intermediate hosts like cattle, goats, pigs and sheep have been shown to be refractory to T. o. krabbei. Other native ungulates sympatric with red deer in Patagonia include Lama guanicoe and the endangered huemul deer (Hippocamelus bisulcus). Possible or known definitive hosts include native felids like Puma concolor, Felis colocolo, F. guigna and canids like Dusicyon griseus, D. culpaeus, and domestic dogs.

Xenobiotic biotransformation in livers and lungs of adult black-tailed deer: comparison with domestic goat and sheep

1. The capacity of liver and lung tissue of black-tailed dear (Odocoileus hemionus columbianus) to biotransform xenobiotics was compared in vitro to the domestic sheep and goat. Donor animals were all females of varying ages. Tissues from the black-tailed deer were collected in the wild. A variety of biotransformation enzymes were measured in both microsomal and cytosolic fractions. 2. Deer liver was lower in total cytochrome P450 concentration, but mono-oxygenase activities were greater compared to sheep and goat. The opposite was true for the lung. 3. Epoxide hydrolase activities were significantly different in deer vs sheep and goat. 4. In general, both hepatic and pulmonary activities were more similar between sheep and goat than either species compared to the deer, however, the magnitude of the hepatic differences did not exceed 5-fold. 5. Based on these limited results, there is no reason to discredit the sheep or goat as a toxicity testing model for deer.