DENSIDAD, ESTRUCTURA SOCIAL, ACTIVIDAD Y MANEJO DE GUANACOS SILVESTRES (Lama guanicoe) EN EL SUR DEL NEUQUÉN, ARGENTINA
ABSTRACT Los guanacos (Lama guanicoe) son los ungulados silvestres más abundantes y ampliamente distribuidos de Sudamérica, aunque su abundancia y rango de distribución disminuyó drásticamente en el último siglo. En Patagonia, la esquila en vivo de guanacos silvestres es promovida por organismos gubernamentales como una actividad complementaria a la ganadería que contribuiría a conservar sus poblaciones. La falta de estudios ecológicos sobre poblaciones que habitan campos privados dificulta la evaluación de posibles efectos negativos de esta actividad. Nuestro objetivo fue estimar la densidad, la estructura social y las actividades de una población de guanacos silvestres en un establecimiento ganadero y evaluar los efectos de un evento de manejo. Estimamos la densidad y la estructura social, dentro y fuera del área manejada, y analizamos las actividades individuales antes y después del manejo, entre invierno 2004 y verano 2005. La densidad fue similar en ambas épocas y el tamaño de grupos de machos decreció en primavera. Los grupos familiares fueron la estructura social más frecuente. La alimentación fue la actividad más común en ambas estaciones. La actividad "reposo" en verano se asoció positivamente con la temperatura. Nuestros resultados sobre efectos del manejo son limitados debido al bajo éxito de captura y que pocos ejemplares fueron esquilados; sin embargo, sugieren que la esquila no modificó la estructura social de la población manejada en el corto tiempo. La continuidad de estos estudios es esencial para evaluar la sustentabilidad de esta actividad y su valor potencial como herramienta de conservación de la especie.
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ABSTRACT: Animal Welfare 2003, 12: 387-402 A current programme of wildlife utilisation in the Andean region involves the capture of wild vicunas, their shearing, transport and, in some cases, captive farming. The effects of these interventions on the physiology, and thus welfare, of wild vicunas are unknown. As a first step to quantifying and thus mitigating any adverse welfare consequences of this harvest, we measured the immediate and longer-term physical and physiological effects of capture, shearing and transport. A sample of juvenile male vicunas was captured. Six were shorn at the capture site, six after two weeks in captivity, and the remaining seven animals were kept as controls for 39 days. In general, vicunas showed changes in blood glucose, packed cell volume, cortisol, and neutrophil:lymphocyte ratios within 4-6 h following capture. Creatine kinase was also affected by capture and transport, showing a peak plasma level 24 h after capture, which was followed by a peak plasma level of aspartate aminotransferase four days after capture and transport. After 12 days in captivity, all of the vicunas showed physiological parameters close to expected baseline values for the species. We could detect no differences in physiological parameters between animals that were captured, sheared and transported and those that were only captured and transported. Similarly, we could detect no differences in most responses of vicunas between those sheared after 12 days in captivity and a control group held under similar conditions but from which blood was sampled without shearing. A further comparison between animals sheared immediately after capture and animals sheared after 12 days in captivity revealed that creatine kinase levels were higher in the former group. During transport prior to release back into the wild, only minor injuries (lip bleeding and limb contusions) and a significant increase in rectal temperature were observed. Our results provide a basis for recommendations to improve the welfare of vicunas during the wool harvest, and provide baseline and stress-response data to serve as reference points for further studies of vicuna welfare.Animal welfare (South Mimms, England) 01/2003; 12(3). · 1.43 Impact Factor
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ABSTRACT: Animal Welfare 2003, 12: 369-385 The vicuna is mainly used in two ways: wild captured, shorn and returned to the wild; or wild captured and maintained in captivity as part of a programme of sustainable use in the Andes of South America. Farming of wild vicunas has hitherto involved no assessment of their welfare. In this study we measured a set of basic blood parameters in order to characterise baseline values in captivity, and we then characterised adrenal cortical responsiveness using an ACTH challenge. The ACTH challenge is widely used for assessing neuroendocrine responses to stress and is now increasingly being applied to studies of wild animals' welfare. Five male vicunas were injected with exogenous ACTH and their responses compared with those of a control group injected with placebo. Behavioural and haematological changes were monitored. Injection of ACTH produced a 4.5-fold increase in cortisol concentration within 1 h. Total white blood cell count almost doubled in less than 5 h. The neutrophil:lymphocyte ratio also changed, with a decrease in lymphocytes and an increase in neutrophils, suggesting that the neutrophil:lymphocyte ratio was affected by the ACTH challenge. Packed cell volume increased from 40% to 44%. Observations of individual vicunas during sampling revealed no discernible behavioural differences between treated and control animals; however, animals that had higher initial baseline cortisol concentration made more attempts to escape, and vocalised more during handling, regardless of whether they were treated with ACTH or placebo. The results reveal the different blood parameter levels associated with stress in different species and highlight the hazard of interpreting stress levels in one species on the basis of measures calibrated in another. We provide calibrated reference values for future studies of stress in vicunas.Animal welfare (South Mimms, England) 01/2003; · 1.43 Impact Factor
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ABSTRACT: We used comparative data to test functional hypotheses for 17 antipredator behaviour patterns in artiodactyls. We examined the literature for hypotheses about auditory and visual signals, defensive behaviour and group-related antipredator behaviour in this taxon and derived a series of predictions for each hypothesis. Next, we documented occurrences of these behaviour patterns and morphological, ecological and behavioural variables for 200 species and coded them in binary format. We then pitted presence of an antipredator behaviour against presence of an independent variable for cervids, bovids and all artiodactyls together using nonparametric tests. Finally, we reanalysed the data using Maddison's (1990, Evolution, 44, 539–557) concentrated-changes tests and a consensus molecular and taxonomic phylogeny. We found evidence that snorting is both a warning signal to conspecifics and a pursuit-deterrent signal, lack of evidence that whistling alerts conspecifics and indications that foot stamping is a visual signal to warn group members. Evidence suggested that tail flagging was a signal to both conspecifics and predators, that bounding, leaping and stotting were used both as a signal and to clear obstacles and that prancing functioned similarly to foot stamping. Analyses of tail flicking, zigzagging and tacking were equivocal. We confirmed that inspection occurs in large groups, freezing enhances crypticity, and species seeking refuge in cliffs tend to be small. Entering water and attacks on predators had few correlates. Finally, group living, a putative antipredator adaptation, was associated with large body size and species living in open habitats, confirming Jarman's (1974, Behaviour, 48, 215–267) classic hypothesis. Bunching and group attack apparently deter predators. Despite limitations, comparative and systematic analyses can bolster adaptive hypotheses and raise new functional explanations for antipredator behaviour patterns in general.Animal Behaviour. 01/2004;