Offspring sex ratio of introduced red deer in Patagonia, Argentina after an intensive drought

Red deer (Cervus elaphus) introduced to Patagonia have reached high densities in the forest-steppe ecotone. Drought conditions during 1998/99 were suspected to impact subsequent reproductive performance. Necropsies of 50 adult females during winter 1999 revealed lowered pregnancy rates and lactation in 32% of non-pregnant as opposed to 0% among pregnant females. There were no signs of fetal resorptions or abortions. The fetal sex ratio (20m:8f) deviates significantly from unity, and mothers with female or male fetuses averaged 6,7 and 5,2 years, respectively (P=0.14). However, 90% of primiparous females (2,5 years old) had males, the following age class had all females, the middle age class (5-8 years old) had all males, and older females had equally male or female fetuses. These females were at borderline of body condition allowing conception and thus were at extremely low levels of condition during breeding. The male-biased fetal sex ratio contrasts reports of other studies that only females in best condition tend to have male-biased offspring. However, ambivalent results from other studies may stem from not having evaluated body fat reserves and reproductive tracts, or studies done during environmental conditions not extreme enough. The present results also indicate that red deer populations occur at densities where they can easily become food-limited through a singular environmental phenomenon such as a drought. Although recruitment rates would be drastically reduced through such temporary food shortage, red deer will recuperate rapidly and will continue to exert intensive pressure on the flora causing subsequent damage if population densities are not lowered through hunting.Fil: Fluck, Werner Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Reservas corporales y tasa de preñez del ciervo colorado introducido en Patagonia (Argentina) después de un período de sequía

El ciervo rojo (Cervus elaphus) fue introducido en Patagonia en la década de 1920 y ha alcanzado densidades altas en ciertas áreas del ecotono entre el bosque y la estepa. Se especuló que las condiciones de severa sequía del verano-otoño de 1999 podían tener un efecto negativo sobre la reproducción del ciervo rojo. Las necropsias de 50 hembras adultas revelaron una tasa de preñez de solo 56%, comparado con un 98% en 1992–1998 o un 100% en 1996–1997 en otra población similar. La distribución de edades de hembras preñadas reflejó la importancia de no haber gestado durante el ciclo anterior. Las hembras primíparas de dos años tuvieron una tasa de preñez de 77%, mientras que ninguna de las hembras con crías lactantes estaba preñada. Normalmente, el mayor éxito reproductivo se observa en las clases de mediana edad, lo que reduce la probabilidad de preñez durante periodos de stress, lo cual se reflejó en este estudio en la distribución de edades de las hembras no-gestantes. Sin embargo, la circunferencia a la altura del pecho (como índice del tamaño corporal) no fue diferente entre las hembras gestantes y las no gestantes. Las reservas de grasa corporal estuvieron severamente agotadas en la mayoría de los animales, independientemente de su condición reproductiva. La relación entre crías y hembras adultas en el otoño siguiente fue de 30%, en comparación con 58% en 1991–1992. En la otra población, la relación fue de 28% en el otoño siguiente, indicando que el efecto de la sequía tuvo carácter regional. Los resultados sugieren que estas poblaciones de ciervo rojo tienen densidades a las cuales pueden experimentar fácilmente limitaciones de tipo nutricional debido a un fenómeno ambiental singular como un período de sequía. Aunque la tasa de reclutamiento se redujo drásticamente a través de la escasez de comida, el efecto podría ser temporario, hasta terminar la sequía, y los ciervos rojos podrían continuar ejerciendo una presión intensiva sobre la vegetación si no disminuyen las densidades de la población a través de la caza regular u otra forma de control.Red deer (Cervus elaphus) were introduced to Patagonia in the 1920´s and have reached high densities in certain areas of the forest-steppe ecotone. Severe drought conditions during summer/autumn of 1999 were suspected to have an impact on reproduction of red deer. Necropsies of 50 adult females revealed a pregnancy rate of only 56% as compared to 98% in 1992-98 or 100% in 1996/7 in a comparable population. The age distribution of pregnant females reflected the importance of not having been pregnant during the previous cycle. The primiparous  2 year-old females had a 77% pregnancy rate whereas none of  the lactating females were pregnant. Normally a higher reproductive success occurs for middle age classes, thereby reducing the chances of becoming pregnant during stress periods which was reflected in this study in the age distribution of non-pregnant females. Chest girths as an index of body size, however, were not different for pregnant and non-pregnant females. Body fat reserves were severely depleted in most animals irrespective of reproductive status. The calf-to-adult female ratio in the following autumn was 30% as compared to 58% in 1991/2. The ratio in a comparable population was 28% in the following autumn, indicating that the effect of the drought was regional. The results suggest that these red deer populations occur at densities where they can easily become food-limited through a singular environmental phenomenon such as a drought period. Although the recruitment rate was drastically reduced through such food shortage, the effect might be of short duration as the drought terminates and red deer may continue to exert intensive pressure on the flora causing subsequent damage if population densities are not lowered through continuous hunting or other control means.Fil: Fluck, Werner Thomas. Administración de Parques Nacionales. Parque Nacional ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators

Understanding population regulation of large northern herbivores like cervids has important practical and theoretical implications. Corrective measures for high densities of cervids must be based on theory and thus necessitate analysis of contradicting views of top-down and bottom-up population control. The former considers cervids incapable of self-regulation and hence that they need external factors like predation to achieve effective population regulation. The latter claims that cervids exhibit the capacity to adjust their numbers to the food supply as shown by physiological responses. However, these phenomena are not an expression of evolutionary adaption, they are a predictable physiological reaction to reduced food. In addition, studies were often done in man-modified environments or without considerations of modulating effects through predators. It is unlikely to study pristine relationships between large herbivores and predators in the future through field work, and insights from other fields need to be heeded. Considerations from evolution, thermodynamics, food webs and nutrient cycling indicate that the development of biological systems is unidirectional due to irreversible processes and leads toward optimal order and optimal accumulation of energy and nutrients. Large predators are thus not just a luxury development of evolution, but a necessary sequel to natural laws and they increase efficiency of the system to capture solar energy. It explains why analogous ecomorphs, like saber-tooth 'cats' (placental and marsupial) have re-evolved independently at least 5 times. As a group, large predators developed traits allowing self-regulation including territoriality, intra- and interspecific killing, prey-switching, and dispersal. However, in man-modified environments, herbivore densities can reach such high levels that even an intact predator community will no longer exert regulation as there is an upper limit of predator density determined by social mechanisms. As kill success rates are very low, predators also affect herbivores by largely determining spacial distribution and behavioral adaptions, all of which modify herbivore-plant interactions. Cervids on the other hand exhibit traits all indicative of absence of a capacity to self-regulate. Predictable physiological responses to reduced food intake thus operate so late that the typical population response is an irruption with subsequent major dieoff and leads to a reduction in system performance including loss of biodiversity. Therefore, the claim that there exists 'natural' regulation in such situations is an erroneous term for what is better called forced starvation. Two conclusions can be drawn: 1. Herbivore densities above a critical level will inevitably cause shifts in community functioning by altering plant and animal species composition, nutrient and energy flow patterns: the system will effectively be forced to a less complex and hence, less productive level, an evolutionary step backwards. 2. By having modified ecological parameters necessary for the welfare of herbivores, we need to take on the responsibility to guarantee their future welfare by actively replacing missing factors. For cervids it may mean implementing harvesting such that population densities permit natural plant rejuvenation and optimal biodiversity. Where the predator community is still intact, it should be protected by all means, and where still possible, predator communities should be restored. A basic tool is to disseminate the best available information, namely that large northern herbivores do not exhibit self regulation.Fil: Fluck, Werner Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Natural mortality patterns in a population of southern Argentina huemul (Hippocamelus bisulcus), an endangered Andean cervid

The huemul (Hippocamelus bisulcus), an endangered deer living in the Andes of southern South America, numbers 600-700 in Argentina, from at least 63 fragmented subpopulations. Very limited information exists on most populations, but there are indications that the distribution and population sizes continue to diminish, possibly through reduced reproductive rates, elevated mortality rates or both. This is the first analysis of the population ecology of a subpopulation in Argentina, made possible through the only existing compilation of numerous remains of dead huemul (n = 19). Surveys were conducted between 1993 and 1999 to locate and collect remains, which were found concentrated at lower elevations. The sex ratio of adults and subadults (n = 12) was 1:1, but could not be determined for fawns. Clear signs of predation was found in 37% of all deer: 50% among calves, 50% among subadults and 31% among adults. These signs occurred in 29% of adult females and 50% of adult males. Deaths occurred during winter as judged by the state of the male skulls, which indicated the phase of the antler cycle. Femur fat content of 3 deer averaged 93%. Predation signs frequently were clearly from puma (Puma concolor), which is the only natural predator of huemul. The high predation rate, high marrow fat content and no indications of deaths resulting from disease corroborate the pristine state of the of mature lenga (Nothofagus pumilio) forest. The area with a concentration of huemul carcasses appears to be the huemul's major winter habitat.Fil: Smith Fluck, Anne M.. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Departamento de Ecología; ArgentinaFil: Fluck, Werner Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Departamento de Ecología; Argentin

Severe dental fluorosis in juvenile deer linked to a recent volcanic eruption in Patagonia

The Puyehue-Cordon Caulle volcanic eruption deposited large amounts of tephra (ashes) in over 7.5 million ha of Argentina in June of 2011. Tephra were considered chemically innoxious based on water leachates, surface water fluoride levels determined to be safe, and livestock losses 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 volcanic eruption in Sept-Oct 2012. Here we show that these tephra caused severe dental fluorosis, with bone fluoride levels reaching up to 3720 ppm. Among subadults, tephra caused pathological 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 were able to conceive. Susceptibility to fluorosis among these herbivores likely resides in ruminant food processing: a) mastication and tephra size reduction, b) thorough and repeated mixing with alkaline saliva, c) water-soluble extraction in the rumen, and d) extraction in the acidic abomasum. Although initial analyses of water and tephra was 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 36-fold during the first 15.5 months of exposure to tephra. This is the first report of fluorosis in wild ungulates from volcanic eruptions. The described impact will reverberate through several aspects of the ecology of the deer, including effects on population dynamics, morbidity, predation susceptibility, as well as other components of the ecosystem like the scavenger and plant communities. We also anticipate further impact on livestock production systems, yet as of now, existence of fluorosis has not been recognized.Fil: Fluck, Werner Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata; Argentina. University Basel. Swiss Tropical and Public Health Institute; Suiza. DeerLab; ArgentinaFil: Smith Fluck, Jo Anne M.. DeerLab; Argentin

Preliminary data on movements and health condition of the first radio-collared huemul (Hippocamelus bisulcus) population study in Argentina

Aun cuando solo quedan menos de 500 ejemplares de huemul patagonico (Hippocamelus bisulcus) en Argentina, existe escasa información sobre su ecología y dinámicas poblacionales. Por primera vez en la historia de Argentina, se instalaron equipos de radio telemetría en un grupo de huemules para entender de mejor forma los factores que no han permito la recuperación de las poblaciones. Durante el invierno del 2017, se procedió a la captura de seis ejemplares en seis días (tres de cada género), al interior del parque protegido Shoonem, provincia de Chubut. Se presenta en este artículo una descripción de las condiciones particulares del clima y las características del paisaje que serán útiles considerar para mejorar el éxito de capturas de huemules, particularmente en Argentina. Aun cuando los animales capturados presentaban un aspecto sano a primera vista, durante la última evaluación (25 enero 2018), identificamos signos clínicos de enfermedad en 5 de 6 animales capturados durante el procedimiento; incluyendo renguera, pezuñas deterioradas, perdida de 2-7 incisivos y atrofia muscular. Los desplazamientos registrados desde el sitio de captura en régimen de invernada a zonas de uso estival fueron 187% mayores en las hembras comparativamente a los machos.Even though less than 500 Patagonian huemul (Hippocamelus bisulcus) remain in Argentina, information on their population ecology and dynamics is severely lacking. For the first time in Argentine history, radio-telemetry collars were placed on a group of huemul to better understand the factors behind the population?s failure to recover. Six adult huemul (3 of each gender) were captured in six days, the winter of 2017, inside Shoonem Protected Park, Chubut province. In this article, we present a description of the unique climatic conditions and characteristics of the environment that would be useful to consider in order improving the success of huemul captures, particularly in Argentina. Despite the outwardly healthy appearance of each radio-collared huemul on the last observation date (January 25, 2018), we identified clinical symptoms of disease in 5 of these 6 animals during their capture; these included lameness, affected hoof, exfoliation of 2-7 incisors, and muscular atrophy. Movement distances from the winter capture site to maximum summer distance recorded were 187% greater for females than males (n=6, p =0.05, Mann Whitney).Fil: Smith Flueck, Jo Anne. Universidad Nacional del Comahue; ArgentinaFil: Fluck, Werner Thomas. Universidad de Basilea; Suiza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Escobar Ruiz, Miguel. Fundación Shoonem; Argentin

The need to unmask lurking false friends: sustainability is a state, not a process!

Monjeau (2010, p. 117) concluded that “a possible way out from conservation crossroads might consist in being able to distinguish friends from dangerous enemies” and that conservation in Latin America is “full of Trojan horses”. This was in reference to the quantity of deceits hidden behind certain concepts, which although offered as promising solutions for conservation are also highly ambiguous. One such concept is “sustainable development”Fil: Monjeau, Jorge Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundacion Bariloche; Argentina. Universidad Atlantida Argentina. Departamento de Investigacion y Desarrollo. Instituto de Analisis de Recursos Naturales; ArgentinaFil: Smith Fluck, Jo Anne. Universidad Atlantida Argentina. Departamento de Investigacion y Desarrollo. Instituto de Analisis de Recursos Naturales; ArgentinaFil: Fluck, Werner Thomas. Universidad Atlantida Argentina. Departamento de Investigacion y Desarrollo. Instituto de Analisis de Recursos Naturales; Argentin

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 34-55°S. Their distribution, movement patterns and locally high densities raise concerns over their potential epidemiological role in maintaining disease reservoirs or transmitting diseases like foot-and-mouth disease or tuberculosis, with potential severe health and economical impact at the interface of humans, livestock or native wildlife.  Among adult females collected by rifle and radiocollared 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 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 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 unlikely is 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.Fil: Fluck, Werner Thomas. Universidad de Basilea; Suiza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Smith Flueck, Jm. Universidad Atlantida Argentina; Argentin

Marcando con radio collar un grupo del amenazado huemul patagónico por primera vez en Argentina

En Argentina quedan 350-500 huemules en peligro de extinción. Se marcaron huemules con radio-collares durante 6 días de invierno. El encuentro de un huemul cada día promedió 93 minutos (17 grupos, 37 individuos). El período de tiempo desde la detección hasta la inmovilización promedió 46 minutos; la distancia de tiro promedió 15.7 m; y desde la inmovilización hasta recuperación promedió 45.5 minutos. Se realizaron 10 intentos de captura, de los cuales seis fueron exitosos. Comparado con la única radio-marcación anterior en Argentina, esta operación requirió 96.5% menos días-hombre/animal. De los huemules marcados, 86% presentaban patologías clínicas, posiblemente por estar restringidos a áreas marginales o sumideros, es decir, trampas ecológicas. Esta operación permitió marcar por primera vez un macho y un grupo de seis huemules en Argentina.In Argentina, 350-500 endangered huemul remain. Huemul were radio-collared in Chubut during six winter days. Encountering huemul each day averaged 93 minutes (17 groups, 37 individuals). Spotting until darting an animal averaged 46 minutes; darting distance averaged 15.7 m; and darting until recovery averaged 45.5 minutes. Ten capture attempts were made, of which six were successful. Compared to the only huemul previous radio-collared in Argentina (2016), the present operation required 96.5% less man-days/animal. Of marked huemul, 86% presented clinical pathologies, best explained by restriction to marginal if not sink areas, or ecological traps. This operation allowed the first-ever marking of huemul bucks in Argentina, and a group of six huemul.Fil: Fluck, Werner Thomas. Administración de Parques Nacionales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Basilea; SuizaFil: Smith Flueck, Jo Anne M.. Universidad Nacional del Comahue; Argentin

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.Fil: Fluck, Werner Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad de Basilea; Suiza. Universidad Atlantida Argentina; Argentina. Fundación Bariloche; ArgentinaFil: Smith-Flueck, Jo Anne M.. Universidad Atlantida Argentina; Argentin