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

Abstract

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.

Review of Historical and Zooarchaeological Data to Trace Past Biogeographic Distribution of Endangered Huemul (Hippocamelus bisulcus) to Enhance Conservation Strategies

“…The huemul has been classified as a mixed feeder [83,85] and, also as a user of nonforested areas [82,87]. This is corroborated by its anatomy showing limb adaptations to open unforested habitats [29], and having spotless fawns, as with the taruca [148][149][150]. This coincides with the sympatric findings of it with the guanaco, as recorded in archaeological sites and by historical and current observations.…”

“…We predict that historical records of huemul distribution on lowlands, in addition to behavioral and morphological adaptations to cope with a grassier diet and local predators, support its ability to thrive in lowland and open ranges. Aside from the previously used literature (see Supplementary Table S1) to describe the past distribution and ecology of huemuls [22,28,29,31], additional sources of information presented here allow us to reinforce these prior conclusions [22], indicating that many extant huemul populations have lost their migratory traditions and no longer exist in typical winter ranges used historically, which likely explains the lack of the species' recovery in numbers and spatial extent.…”

“…Later on, a chapter about huemuls also concurred that they were once present in the Patagonian steppe at 140-200 km from the nearest forests; that it had reached the Atlantic Ocean; and that their grass consumption reached 16% in forested mountains [26,27]. Several subsequent articles also treated historical data based on their 167 citations [15,22,28,29]. Given the importance of historical distribution ranges in allowing the recovery of this endangered species [13,28,30], we provide additional sources to substantiate and strengthen prior observations, with historical sources ranging from 1779 onward (Tables 1 and 2), to support our hypothesis that the current huemul distribution is an artifact of its past and ongoing interactions with humans [4,5,13,17,19].…”

Loss of Migratory Traditions Makes the Endangered Patagonian Huemul Deer a Year-Round Refugee in Its Summer Habitat

“…Moreover, huemul limb morphology does not overlap with species considered mountain specialists, but falls within the range of other cervids, with some populations of Rangifer spp. and even Odocoileus virginianus having much shorter legs than huemul: these findings contradict the long-standing assertion that attributed the apparent short stature of huemul to be an adaptation to mountainous terrain [74,75]. Moreover, stable isotope analyses of archeological samples reveal that huemul's diet from open environments cannot be differentiated from that of steppe guanaco [76].…”

A Protocol to Assess the Welfare of Patagonian Huemul (Hippocamelus bisulcus) in Conservation Centers

“…To maintain normal physiological functions, wild ungulates often seek sources of salt [10]. Due to the habitat conditions of the Patagonian huemul, some studies de-scribe micronutrient deficiencies (essential minerals e.g., Se, Cu, Mn, and others) in this species, which affect their growth, skeletal development, reproduction, and immunocompetence [26][27][28]. In addition, it has been observed that Patagonian huemuls that can access blocks of mineral salts have better coat and antler conditions, and females give birth to heavier offspring [29].…”