The huemul (Hippocamelus bisulcus), an endemic Patagonian deer, has been endangered for decades. Although conservation in Argentina has been directed at the 350-600 remaining huemul, the population has not recovered. In initial studies on the potential effects of diseases on huemul population dynamics, skeletal remains collected between 1993 and 2007 in the Andes (41-45 degrees S, 71.5-72 degrees W) were examined macroscopically for osteopathologic changes. Bones from six huemul were free of lesions, findings were inconclusive in 13 huemul with less than three bones, and osteopathologic processes were detected in 13 adults. Considering the limited remains/case, the prevalence of osteopathy (52%) among adults probably is conservative; 63% showed mandibular, 100% maxillary, and 78% appendicular lesions. Although predation represented the actual cause of death, the observed skeletal lesions would affect predator avoidance, possibly explaining the low average adult age (3.1 yr) and lack of population recovery. Compared with other studies in ungulates, huemul were affected at a younger age, and they had more severe pathologic changes. Due to the chronic nature of disease, low huemul population density, physiognomy, and spatiotemporal pattern of lesions, we discard senescence; gender; fulminating infections; congenital anomalies; metabolic, endocrine, genetic, or neurologic disorders; parasitism or marasmus; and fluorosis as primary etiologic factors. We hypothesize that generalized secondary chronic alveolar osteomyelitis and osteoarthritis in huemul is related to the nutritional ecology of these animals. Selenium deficiency, which impairs bone metabolism and causes periodontitis in ruminants, occurs in the region and it is more prevalent at high altitudes. Traditional winter grounds at low elevations, sometimes far from high mountains, have been converted to livestock production, which has eliminated migratory behavior and keeps huemul in remote high-elevation refuges. Although this descriptive study contributes to huemul conservation, additional approaches are needed to investigate the etiology of this osteopathy and to close other gaps in knowledge on biology and ecology of huemul.

The huemul (Hippocamelus bisulcus) is endangered, with 1500 deer split into >100 subpopulations along 2000 km of Andes. Currently occupied areas are claimed-erroneously, to be critical prime habitats. We analyzed historical spatiotemporal behavior since current patterns represent only a fraction of pre-Columbian ones. Given the limited knowledge, the first group (n = 6) in Argentina was radio-marked to examine spatial behavior. Historically, huemul resided year-round in winter ranges, while some migrated seasonally, some using grasslands >200 km east of their current presence, reaching the Atlantic. Moreover, huemul anatomy is adapted to open unforested habitats, also corroborated by spotless fawns. Extreme naivety towards humans resulted in early extirpation on many winter ranges—preferentially occupied by humans, resulting in refugee huemul on surrounding mountain summer ranges. Radio-marked huemul remained in small ranges with minimal altitudinal movements, as known from other subpopulations. However, these resident areas documented here are typical summer ranges as evidenced by past migrations, and current usage for livestock. The huemul is the only cervid known to use mountain summer ranges year-round in reaction to anthropogenic activities. Losing migratory traditions is a major threat, and may explain their presently prevalent skeletal diseases, reduced longevity, and lacking recolonizations for most remaining huemul subpopulations.

ABSTRACT:The Puyehue-Cordon Caulle volcanic eruption deposited large amounts of tephra (ashes) on about 36 million ha of Argentina in June of 2011. Tephra was considered chemically innoxious based on water leachates, surface water fluoride levels were determined to be safe, and livestock losses were attributable to inanition and excessive tooth wear. To evaluate effects on wild ungulates, we sampled wild red deer (Cervus elaphus) at 100 km from the volcano in SeptemberNovember 2012. We show that tephra caused severe dental fluorosis, with bone fluoride levels up to 5,175 ppm. Among subadults, tephra caused pathologic development of newly emerging teeth typical of fluorosis, including enamel hypoplasia, breakages, pitting, mottling, and extremely rapid ablation of entire crowns down to underlying pulp cavities. The loss of teeth functionality affected physical condition, and none of the subadults was able to conceive. Susceptibility to fluorosis among these herbivores likely resides in ruminant food processing: 1) mastication and tephra size reduction, 2) thorough and repeated mixing with alkaline saliva, 3) water-soluble extraction in the rumen, and 4) extraction in the acidic abomasum. Although initial analyses of water and tephra were interpreted not to present a concern, ruminants as a major component of this ecosystem are shown to be highly susceptible to fluorosis, with average bone level increasing over 38-fold during the first 15.5 mo of exposure to tephra. This is the first report of fluorosis in wild ungulates from a volcanic eruption. The described impact will reverberate through several aspects of the ecology of the deer, including effects on population dynamics, morbidity, predation susceptibility, and other components of the ecosystem such as scavenger and plant communities. We anticipate further impact on livestock production systems, yet until now, existence of fluorosis had not been recognized.

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.

No abstract