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This is the first morpho‐histological comparison of guanaco ovaries between reproductive (long‐days) and non‐reproductive (short‐days) seasons, and oestrogen receptor‐alpha (ERα) and beta (ERβ) detection. Different stages of follicle development were found in the cortical area, but no corpus luteum was detected. The size and frequency of antral follicles and large atretic follicles were higher in long‐day ovaries than short‐days, consistent with ovarian activity in this season. Differential expression of ERα and ERβ was observed in follicles at different stages of development between short and long days. These data reveal histological and molecular differences between reproductive and non‐reproductive seasons of guanaco ovaries. [ABSTRACT FROM AUTHOR]

Understanding competitive interactions is essential to properly inform management strategies, in particular in the context of livestock‐wildlife conflict across a degraded land, such as the case of wild guanacos in Patagonia. Guanacos are historically perceived by ranchers as livestock's main competitors, and there is a growing demand for reducing their numbers. However, both competition theory and available evidence suggest a more complex interaction than the one assumed by the current management approach. This study aimed to test the occurrence of competitive exclusion of guanacos by domestic sheep at intra‐ranch scale. We assessed the spatial segregation of guanacos and sheep and compared guanaco occupancy patterns within a sheep ranch with those recorded within an adjacent protected area free from livestock. The probability of a group of herbivores being sheep instead of guanacos increased in bottom valleys and smaller paddocks and decreased as the distance to water increased. These results agree with the expected patterns of sheep habitat use resulting from physiological restrictions and grazing behaviour. Occupancy patterns within the ranch showed a higher proportion of guanacos in ridges, away from water sources and in larger paddocks, opposing those observed in the sheep‐free area where guanacos occupied mostly bottom valleys, irrespective of the distance to water. Areas used consistently by guanacos showed a higher per cent cover of preferred forage and basal‐plant cover, indicating a better range condition than those used predominately by sheep. Our results add to the solid body of evidence on spatial segregation of these species at coarser spatial scales, support the competitive exclusion of guanacos by sheep and suggest that intra‐ranch coexistence is possible because guanacos occupy areas underused or inaccessible to sheep. Under these conditions, it is unlikely that guanaco culling will improve sheep production and the empirical verification of the assumptions underlying current management initiatives becomes crucial. [ABSTRACT FROM AUTHOR]

Previous attempts to address the presence of interspecific competition between domestic livestock and wild ungulates have focused largely on habitat or dietary overlaps. Although overlaps in habitat or diet create opportunities for competition to occur between species, competition only results from such overlap if it affects one or both species negatively. Less attention has been afforded to possible behavioural modifications induced in wildlife by competition with domestic livestock. Here, we investigated the effects of the presence of livestock on feeding behaviour of guanaco (Lama guanicoe) in southern Patagonia, using focal sampling of individuals during foraging bouts, with instantaneous scan samples to estimate group behavioural budgets. We recorded guanaco bite and step rates, used as proxies of foraging intake and selectivity, from four different study sites over eight consecutive seasons. We also estimated sheep and guanaco densities per site, along with vegetation biomass availability. As in other ungulates, bite rates of guanaco appear to be highly flexible and generally increased with vegetation biomass availability. However, as sheep densities and thus additional grazing pressure increased, guanaco foraging strategy compensated by increasing bite rates when foraging vegetation was scarce, indicating further likelihood of competition. Additionally, scan samples indicated that the probability of guanaco feeding occurring at any one time was higher in areas shared with domestic sheep compared to national parks, suggesting guanaco have to focus more on feeding than other behaviours when sheep are present. [ABSTRACT FROM AUTHOR]

Most food web models fail to account for the full complexity of interactions within a community, particularly where microbes are involved. Carcasses are microbe‐rich resources and may represent a common nexus for the macrobiome and microbiome, effectively uniting autotrophs, consumers, predators and microbiota.We evaluated the role of carcasses as multitrophic resources and explored dietary partitioning for a sexually dimorphic obligate scavenger known for its hierarchical social system. This study was set in a well‐studied community of camelids Vicugna, Lama guanicoe, pumas Puma concolor and Andean condors Vultur gryphus in the Andes. We hypothesized that condors, by feeding on trophically distinct dietary substrates within any given carcass, would have highly variable trophic position (TP) values. Furthermore, we expected that the microbial consumers within the carcass would inflate TP values in both, the carrion and the condors. Thus, we expected that the trophic heterogeneity within a carcass could facilitate sex‐based dietary partitioning in condors.We used a multifaceted approach to assess the foraging of Andean condors, using regurgitated pellet and bulk isotopic analyses, and also quantified the TP of the entire community of graminoids, camelids, camelid carrion, pumas, and female and male condors employing compound‐specific stable isotopes analysis of amino acids.Our analysis of condor pellets and bulk isotopes revealed non‐trivial plant consumption, close to 10% of condor diet. Isotope analysis of amino acids revealed that condors had highly variable TPs (2.9 ± 0.3) compared to pumas (3.0 ± 0.0) and camelids (2.0 ± 0.1), likely representing 'trophic omnivory', wherein the condors consume plants (TP = 1.0 ± 0.1) and microbe‐colonized carrion (2.3 ± 0.1). Female condors exhibited a TP (2.8 ± 0.2) lower than strict carnivory, suggesting that they consume more plant biomass in a carcass, while males (TP = 3.1 ± 0.3) are likely consuming more of the microbe‐rich animal tissue.Our study highlights that carcasses represent a trophically heterogeneous resource and that vertebrate scavengers can feed across trophic groups within the carcass, from autotrophs to secondary consumers, and from both the macrobiome and microbiome. Thus, integration of microbes in macroecological contexts can help to resolve trophic identity, and better characterize the importance of microbes in detritivorous and omnivorous species. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

The present study examined the effects of different photoperiods and melatonin treatment on plasma prolactin concentrations in guanacos, a South American camelid, in captivity. Fourteen adult female guanacos, not gestating or lactating and isolated from males, were studied. The control group was exposed to natural daylight, during short days (N = 7, 10L:14D) and long days (N = 7, 16L:8D). The treatment group (N = 7, 10L:14D) received melatonin implants every 23 days for 6 weeks during long days. Blood samples were taken at intervals of 1 week for 3 weeks, starting the third week of treatment. Prolactin concentrations were measured using competitive ELISA. Plasma concentrations of prolactin in non‐lactating female guanacos have seasonal changes, with a higher concentration (p <.001) in short days (3.50 ± 2.24 ng/ml) than long days (1.10 ± 0.91 ng/ml). Melatonin treatment significantly decreases (p <.05) plasma concentrations of prolactin on the 21st day after the treatment. These findings are the first report of an endogenous circannual rhythm of plasma prolactin concentration and the action of melatonin treatment on prolactin secretion in this wild camelid. [ABSTRACT FROM AUTHOR]

In a recently published paper, Oliva et al. concluded that domestic grazing pressure across Patagonian rangelands approached carrying capacity due to decades of stock adjustment, but that guanaco overpopulation may have altered that balance. The authors argued that unless guanaco numbers are controlled, they will reduce forage available for domestic stock and will negatively affect rangelands. We consider that the herbivore‐stock analysis presented is inaccurate and deserves revision, and that the stated conclusions lack empirical support.When the spatial distribution of herbivores is accounted for in the Oliva et al. analysis, domestic stock is far above carrying capacity, indicating that domestic overgrazing continues.Theoretical and empirical evidence on bottom‐up regulation and competitive exclusion challenges the supposed guanaco overpopulation and the hypothetical reduction of forage available for livestock.Even if guanaco numbers are reduced, grassland degradation and production losses will continue because their main drivers, domestic overstock and heterogeneous grazing, are still operating.Synthesis and applications. Oversimplified models with poor ecological insight can lead to erroneous conclusions and misguide management decisions. The incorrect inference that Patagonian domestic stock is adjusted to carrying capacity could help to consolidate current domestic overgrazing by reducing incentives to improve livestock management practices. Regarding guanacos, a controversial species in an unfavourable context, control‐oriented harvest without a clear justification threatens populations' viability and genuine attempts of productive diversification. Addressing relevant ecological processes, such as niche partitioning, competitive exclusion and population regulation, is essential to correctly assess joint carrying capacity in multi‐herbivore systems, as well as to identify the true factors driving degradation processes and to optimize rangeland use on a sustainable basis. [ABSTRACT FROM AUTHOR]

This paper presents the results of the taphonomic analysis of the micromammal bone remains recovered from Nutria Mansa 1 (NM1), an archaeological site located in the Pampean plains, Argentina. This campsite was occupied by hunter‐gatherers that processed and consumed Lama guanicoe during the Late Holocene. In NM1, there are taxa from different environments: mammals from arid and semiarid environments (Patagonic Phytogeographic Province) and humid and temperate environments (Pampean Phytogeographic Province). The main objective of the present study was to evaluate how the recorded small mammal species were incorporated into the archaeological site and which of them were exploited by humans. The micromammal assemblage shows traces of post mortem agents such as weathering, chemical action of sediments, and probably some evidence of predation. The micromammal bones in the archaeological record offer no clear evidence of human modification, and their presence can be the result of predation or other postdepositional agents such as the action of water on the flood plain. [ABSTRACT FROM AUTHOR]

The guanaco (Lama guanicoe) was the most relevant species in hunter‐gatherer subsistence of the Argentine Pampas during the Quaternary. An early Late Holocene (3,184 ± 50 14C years bp) guanaco assemblage with evidence of exploitation, coming from Cerro del Águila site, Buenos Aires Province, is analysed herein. The assemblage is composed by three perinatal individuals; the estimated age at the moment of death ranges from a few weeks before birth to a few weeks old. Cerro del Águila is interpreted as a site where activities of procurement and processing of perinatal individuals were performed. The available information allows raising a discussion on the hunting and exploitation strategies of guanaco in a regional context. [ABSTRACT FROM AUTHOR]

The analysis of factors that determine the distribution of top‐scavengers at large scales can provide clues to understanding important ecological processes and may be useful in establishing conservation and management strategies. Here, we conducted a large‐scale survey to study the distribution of the threatened Andean Condor Vultur gryphus in relation to environmental factors in southern Patagonia. This area has undergone the settlement of livestock and the introduction of exotic wildlife, although to a lesser extent than in the distribution of Condors in northern Patagonia. The aim of this study was to determine the relevance of different factors such as the availability of food resources, the availability of suitable nesting and roosting places and the presence of humans on large‐scale condor distribution. Our results show that the presence of meadows was the primary factor shaping Andean Condor distribution, despite the fact that this habitat occupies only 4% of the Patagonian landscapes. However, this habitat has a high probability of herbivore presence, so Condors seem to optimize their searching. The availability of nesting and roosting cliffs also contributed to explaining the observed distributions. Our results suggest that Condor distribution in southern Patagonia is a compromise between the spatial locations of two low‐frequency habitats – meadows and cliffs. A successful Condor conservation strategy in southern Patagonia should include the protection of these habitats and the regulation of farming expansion, including the recovery of meadows. [ABSTRACT FROM AUTHOR]

Abstract: Grouping behavior of social ungulates may depend on both predator occurrence and perceived predation risk associated with habitat structure, reproductive state, and density of conspecifics. Over 3 years, we studied grouping behavior of guanaco (Lama guanicoe) families in Chilean Patagonia during the birthing season and determined their response to variation in predator occurrence and perceived predation risk (habitat structure, calf/adult rate, and density of conspecifics). We considered the effect of two predators, puma (Puma concolor) and culpeo fox (Lycalopex culpaeus). We measured two common (family group size and vigilance) and one novel (family group cohesion) behavioral responses of guanaco. Our results show that guanaco family groups adapted their grouping behavior to both predator occurrence and perceived predation risk. Larger family groups were found in open habitats and areas with high puma occurrence, while guanacos stayed in small family groups in areas with high shrub cover or low visibility. Group cohesion increased in areas with higher occurrence of pumas and culpeo foxes, and also increased in smaller family groups and in areas with low guanaco density. Vigilance (number of vigilant adults) was mainly related to group size and visibility, increasing in areas with low visibility, while residual vigilance (vigilance after removing the group‐size effect) did not vary with the explanatory variables examined. Our results suggest that a mix of predator occurrence and perceived predation risk influences guanaco grouping behavior and highlights the importance of evaluating different antipredator responses together and considering all predator species in studies aimed at understanding ungulate behavior. [ABSTRACT FROM AUTHOR]

Contents The wild South American camelids developed a strategy of seasonal reproduction during spring and summer with singleton birth. The photoperiod is one of the factors that may modulate this seasonality where light would be translated into a hormonal signal. This study evaluated the influence of changes in daily light intensity on melatonin concentration in captive guanacos under a long-day photoperiod (16 hr light/8 hr dark; 33 '28′S). Mean melatonin concentration was 28.3 ± 20.3 pg/ml, with a maximum of 52.14 ± 17.19 pg/ml at 23:30 and minimum of 14.29 ± 6.64 pg/ml at 08:30 ( p < .001). There was a negative association between light intensity and melatonin concentration ( r = −0.57; p < .001). The results indicate that guanacos respond to variation in daily environmental light with a hormonal response and point to a circannual rhythm as a function of the photoperiod. [ABSTRACT FROM AUTHOR]

Contents This study evaluated ovarian activity in late gestation and post-partum in guanacos in captivity. Follicular dynamics was monitored every second day from 40 days before and other 40 after delivery by transrectal sonography and by plasma steroids concentrations. Seven out of eight (87.5%) of gestating females presented ovarian follicular activity under progesterone levels >3 nmol/l with maximum follicular size of 8.42 ± 0.83 mm from days 23 to 1 before delivery. After delivery, all females have follicular wave development from day 0 to 38, with larger follicular size and longer follicular wave phases and interwave interval when compared with pre-partum data. During post-partum period, there was a close relationship between follicle size and estradiol-17 β concentration, with r = 0.69 at the beginning of growth phase and r = 0.86 in association with the largest dominant follicle. Plasma estradiol-17 β concentration varied from 11.92 to 198.55 pmol/l. Plasma estrone sulfate, free estrone and progesterone returned to baseline concentrations during peripartal period and remained basal thereafter. The results described follicular activity during late gestation and early post-partum period. These findings provide relevant information to understand physiological changes occurring during this reproductive key period in seasonal breeders with long gestation duration as New and Old World camelids. [ABSTRACT FROM AUTHOR]

ABSTRACT We study the isotopic variability of modern social groups of guanacos ( Lama guanicoe) and discuss the implications of these results for the analysis of archaeofaunas from archaeological sites of Patagonia. The aim of this work is to evaluate whether the study of the isotope composition of carbon and nitrogen from collagen (δ13C and δ15N) is a methodology that allows the discussion of hunting strategies - individual versus mass - carried out by human populations in this particular case of the guanaco from southern Patagonia. Samples come from five modern assemblages of guanacos located in the west margin of the Cardiel Lake and are the result of a catastrophic mortality episode produced by winter stress. The isotopic variability of these samples is compared with that of a mesoregional attritional assemblage built from multiple sites and chronologies. The results indicate, in the first place, that there is no differentiation between males and females, second, that the offspring show no increase of signals when compared to the other age categories and finally, juveniles recorded the lowest δ15N values. In relation to the main purpose of this research, measurements of variability from modern assemblages and the attritional groups have been compared. The three assemblages with lower variability are modern ones. However, the two remaining modern assemblages record a variability higher than or equal to the attritional groups. Thus, for southern Patagonian guanacos, the hypothesis that proposes that the isotopic variability of a herd would be lower than the one obtained from multiple populations and different hunting events is rejected. Finally, we analyze the possible causes for these results together with situations in which δ13C and δ15N can be used in the study of the guanaco hunting strategies in southern Patagonia. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper presents an isotopic characterization (δ13C and δ15N) of modern huemul from Patagonian Andean forest. This deer is considered an endemic species, now inhabiting the sub-Antarctic forest of Chile and Argentina. We analyse if the isotopic signals of the modern huemuls can be used as geographic markers on two distinct spatial scales. Firstly, on the intra-forest level, we analyse the relation between the δ13C and δ15N of the huemul and the annual precipitation in the place in which the sample was collected. Secondly, on the inter-environmental level, we evaluate to what extent the huemul's isotopic signal differs from that of the guanaco ( Lama guanicoe), an herbivore that occupies Patagonia's continental steppe. The results reveal that, on the one hand, there is no relation between the isotopic values of modern huemules and precipitation levels, whereas on the other hand, the modern huemul is different from the guanaco in both isotopes. We believe that this difference between the herbivores is associated with the isotopic signals at the base trophic chain, which is influenced by the precipitation gradient. In this way, even though for now, these isotopic markers turn out not to be useful for differentiating between huemuls coming from sectors of the forest with marked differences in precipitation, it is possible to distinguish herbivores coming from the forest and steppe of continental Patagonia, enabling the use of δ13C and δ15N as geographic markers. The isotopic characterization of δ13C and δ15N of the modern huemuls and its relation to the Patagonian Andean forest has strong implications for paleoecological and archaeological aspects of this environment, including the biogeographical history of the huemul, and in order to the test the models of use and exploitation of the forest by hunter-gatherers in the past. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT This article explores the levels of fragmentation and fracture patterns in archaeofaunal assemblages from the lower basin of the Colorado River (Argentina) following Outram's methodology. Remains of ungulates (guanaco) have suffered, in these assemblages, a high degree of fragmentation probably caused during the processing of the carcasses. The presence of helical debris and shaft fragments indicates that fragmentation would respond to processing tasks for the consumption of marrow and possibly bone grease. The results of the application of this methodology that were obtained from the analysis of three late Holocene sites (La Primavera, Loma Ruiz 1 and El Tigre) are presented. These results provide new evidence not only for patterns of marrow and bone grease consumption but also for dealing with the subsistence model proposed for the study area. In this sense, the intensification processes already proposed during the final late Holocene (1000-250 bp) are discussed. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Habitat can constrain and shape successful ecological and physiological strategies, thus providing the context for the evolution of life-history traits. However, unpredictable challenges, such as storms, natural disasters, and human activities can also have great effects on stress. Glucocorticoids (GCs) are adrenal steroid hormones that play an important role in how vertebrates cope with these predictable and unpredictable environmental challenges. Although assessing GCs levels can have many applications in the study of wildlife and/or captive animals, with or without capturing individuals, it requires a species-specific complete validation (analytical and biological) before its use. In this work, our aim was to: (a) validate a radioimmunoassay (RIA) for measuring GCs levels in L. guanicoe serum; (b) assess cortisol and corticosterone levels (if present) in serum of wild L. guanicoe individuals; and (c) compare the response to acute stressors (handling, shearing, and release). Our results successfully: (a) validated RIA for asses GCs levels in wild ungulates; (b) confirmed the presence for cortisol and corticosterone and showed that both GCs are differently affected by environmental stimuli in L. guanicoe; and (c) showed that GCs exhibit different patterns in the field and in response to acute stressors, making these camelids an interesting endocrinological model when seeking the adaptive functions of a given variation and further emphasizing the complexity of GC physiology in wild mammals. J. Exp. Zool. 319A: 539-547, 2013. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper provides a detailed analysis of thorn lesions found in lower limb elements of a modern osteological collection of guanaco ( Lama guanicoe). Four types of lesions were recorded: (1) thorns visible on the bone surface, (2) bony reaction with relief, (3) small negative scars and (4) medium negative scars. The methods used to recognise, record and quantify these lesions are presented. As a result, 35 of the 36 individuals analyzed contained one or more types of lesions. The highest concentrations of lesions were recorded on the anterior view of the metacarpal shafts. All the age ranges were affected by lesions; however, individuals between the ages of 1 and 3 years were the most affected, whereas those between the ages of 0 and 1 year contained the least amount of lesions. To provide examples of how thorn lesions can be identified and used as a paleoenvironmental proxy in the fossil record, we analyzed two archaeological sites from different phytogeographic provinces: Bajo de la Quinta (Monte phytogeographic province) and Calera (Pampa phytogeographic province). Results found that 25% of the elements from the Bajo de la Quinta site contained lesions, whereas none of the elements from the Calera site showed evidence of lesions. When detectable in the fossil record, thorn lesions can provide an indirect approximation of the paleoenvironment. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A comprehensive study of the phylogeography and population genetics of the largest wild artiodactyl in the arid and cold-temperate South American environments, the guanaco ( Lama guanicoe) was conducted. Patterns of molecular genetic structure were described using 514 bp of mt DNA sequence and 14 biparentally inherited microsatellite markers from 314 samples. These individuals originated from 17 localities throughout the current distribution across Peru, Bolivia, Argentina and Chile. This confirmed well-defined genetic differentiation and subspecies designation of populations geographically separated to the northwest ( L. g. cacsilensis) and southeast ( L. g. guanicoe) of the central Andes plateau. However, these populations are not completely isolated, as shown by admixture prevalent throughout a limited contact zone, and a strong signal of expansion from north to south in the beginning of the Holocene. Microsatellite analyses differentiated three northwestern and 4-5 southeastern populations, suggesting patterns of genetic contact among these populations. Possible genetic refuges were identified, as were source-sink patterns of gene flow at historical and recent time scales. Conservation and management of guanaco should be implemented with an understanding of these local population dynamics while also considering the preservation of broader adaptive variation and evolutionary processes. [ABSTRACT FROM AUTHOR]

According to current theory, anti-predator benefits promote group formation in open-dwelling ungulates. An inverse relationship between vigilance effort and group size has been documented frequently and thought to reflect the consequent decrease in perceived predation risk as group size increases. In contrast, competition costs are supposed to set the upper limit to the number of individuals that can forage together. As anti-predator behavior is no longer functional in the absence of predation and competition costs might be affected by resource distribution, the net benefit of aggregation will depend on the particular combination of predation risk and habitat structure experienced by the individual. To test this hypothesis, group-size effects on female time allocation and within-group aggression rate were compared between two guanaco populations exposed to contrasting levels of puma predation. Habitat structure within both sites consisted of mosaics of shrublands and grasslands, and group-size effects were also compared between these habitat types. Females under predation risk showed a strong reduction in vigilance as the number of adults in the group increased, whereas females from the predator-free population showed overall low levels of vigilance, regardless of group size. These results emphasize the anti-predator significance of the group-size effect on female vigilance, as well as guanaco plasticity to adjust time allocation to local conditions. On the other hand, within-group aggression rate increased with the number of adults in the group. Aggression rate was almost null within groups located in grasslands but was significantly higher in shrublands, regardless of predation risk, suggesting that the more heterogeneous distribution of shrubs increases the interference competition level. These results strengthen the notion of predation pressure and habitat structure as major determinants of the balance between costs and benefits of group living, and highlight the potential of individual behavioral patterns to make qualitative predictions about group-size variation within territorial ungulates. [ABSTRACT FROM AUTHOR]

Predatory interactions involving large carnivores and their ungulate prey are increasingly recognized as important in structuring terrestrial communities, but such interactions have seldom been studied in the temperate Neotropics. Here, the large carnivore guild is limited to a single species, the puma Puma concolor, native prey populations have been drastically reduced and lagomorphs and ungulates have been introduced. We examined puma dietary patterns under varying abundances of native camelid prey – guanacos and vicuñas – in protected areas of northwestern Argentina. We collected puma feces from seven protected areas, and sampled each area for the relative abundance of camelids using on-foot strip and vehicle transects. In one area, where longitudinal studies have been conducted, we examined the remains of vicuñas and guanacos for evidence of puma predation in 2004–2006. We compared our results with a study conducted in 1978–1983, and contrasted the frequency of carcasses showing signs of puma predation with estimates of camelid abundance. Across sites, we observed a positive and significant relationship between camelid consumption by pumas and camelid abundance, with pumas about nine times more likely to consume camelids where the latter were most abundant. The temporal variation in predation rates on camelids differed by species. Guanacos, which did not change in abundance between periods, showed a slight decrease (1.5 times) in the relative frequencies of individuals killed by pumas. Conversely, vicuñas increased in abundance by a factor of ∼7 between periods, coinciding with an c. 3.4 times increase in individuals showing evidence of puma predation. Some protected areas of northwestern Argentina are conserving the trophic interaction between pumas and native camelid prey. This interaction may be the basis of the far-reaching community effects described for analogous systems on other continents. It also has implications for the possible recovery of or reintroduction of camelids to areas with high puma densities, where predation losses can be expected to be high, and possibly prohibitive. [ABSTRACT FROM AUTHOR]

Females in several ungulates transfer milk to non-filial (NF) offspring, in a process known as allonursing. This behavior is less common in monotocous species, including most ungulates, and it has been associated with parasitic behavior of calves or mothers who have lost their own offspring. To examine whether the calves ‘steal’ milk from the females or whether females fail to discriminate their own calves in guanacos, allonursing behavior was observed. If milk theft drives allonursing, mothers should reject NF offspring, they should search for their own calves, and calves attempting to suckle from alien mothers should adopt parallel (as opposed to the anti-parallel) position during allonursing. Alternatively, if allonursing is caused by mothers unable to discriminate own offspring, mothers are not expected to reject NF offspring, and alien calves should use parallel and antiparallel position similarly when allonursing. Allonursing was investigated during the first 3 mo of lactation in two groups of captive guanacos composed of 15 and 14 mother-calf pairs, respectively. While 40% and 62.5% of mothers in groups 1 and 2 performed allonursing, high individual variation prevailed; some females exhibited this behavior infrequently (4.1% and 6.5 % in groups 1 and 2). The rejection rate to NF nursing attempts was threefold higher than the rejection rate to filial nursing attempts. The occurrence of nursing to NF was associated to a parallel posture by the calves. Our findings suggest that ‘milk theft’ is a more plausible hypothesis to explain allonursing in guanacos than ‘misdirected parental care’. [ABSTRACT FROM AUTHOR]

We conducted focal observations of territorial guanacos, a highly polygynous and social mammal, to compare time budgets between sexes and test the hypothesis that the differences in reproductive interests are associated with differential group size effects on male and female time allocation patterns. In addition, we used group instantaneous sampling to test the hypothesis that grouping improves detection capacity through increased collective vigilance. We fit GLM to assess how group size and group composition (i.e., presence or absence of calves) affected individual time allocation of males and females, and collective vigilance. As expected from differences in reproductive interests, males in family groups devoted more time to scan the surroundings and less to feeding activities compared to females. Both sexes benefited from grouping by reducing the time invested in vigilance and increased foraging effort, according to predation risk theory, but the factors affecting time allocation differed between males and females. Group size effects were significant when females were at less than five body-lengths from their nearest neighbour, suggesting that grouping benefits arise when females are close to each other. Female time budgets were also affected by season, topography and vegetation structure. In contrast to our expectation, males reduced the time invested in vigilance as the number of females in the group increased, supporting the predation risk theory rather the intrasexual competition hypothesis. The presence of calves was associated with an increase in male individual vigilance; and vegetation type also affected the intensity of the group size effect over male time allocation. In closed habitats, collective vigilance increased with the number of adults but decreased with the number of calves present. Although male and female guanacos differed in their time allocation patterns, our results support the hypothesis that both sexes perceive significant antipredator benefits of group living. [ABSTRACT FROM AUTHOR]

1. We review the status of the four currently recognized guanaco Lama guanicoe subspecies, and provide information about their taxonomy and distribution. The success of guanaco in inhabiting open habitats of South America is based mainly on the flexibility of their social behaviour and ecophysiological adaptations to harsh environments. 2. Lönnberg described the first subspecies, L. g. cacsilensis, at the beginning of the 20th century. Forty years later Krumbiegel described L. g. voglii, based on skull measurements and pelage colouration. The other two subspecies, L. g. huanacus and L. g. guanicoe, were classified as subspecies by Krumbiegel based on pelage colouration and body size, while maintaining the original Latin names and descriptors. 3. Further guanaco populations have been incorporated into each of these subspecies, based on their proximity to the type locality but without attention to the homogeneity of phenotype or habitat and only limited consideration of Bergmann’s rule based on scarce skulls. Two alternative geographical ranges were proposed in the middle and towards the end of the 20th century. Discrepancies occur in the geographical range of each subspecies. 4. Molecular studies based on mitochondrial DNA cytochrome b sequences recognized only two subspecies: the Peruvian L. guanicoe cacsilensis and the rest of the populations grouped in the clade recognized as L. g. guanicoe. We conclude that the evolutionary biology of L. guanicoe requires a significant revision with respect to biogeography. Phylogeographical data hold particular value in developing conservation strategies, particularly for some of the reduced and marginal populations and/or subspecies and will support IUCN (The World Conservation Union) Red List classification. [ABSTRACT FROM AUTHOR]

Genotype data from 14 microsatellite markers were used to assess the genetic diversity and differentiation of four guanaco populations from Argentine Patagonia. These animals were recently captured in the wild and maintained in semi-captivity for fibre production. Considerable genetic diversity in these populations was suggested by the finding of a total of 162 alleles, an average mean number of alleles per locus ranging from 6.50 to 8.19, and He values ranging from 0.66 to 0.74. Assessment of population differentiation showed moderate but significant values of FST = 0.071 ( P = 0.000) and RST = 0.083 ( P = 0.000). An amova test showed that the genetic variation among populations was 5.6% while within populations it was 94.4%. A number of 6.6 migrants per generation may support these results. Unambiguous individual assignment to original populations was obtained for the Pilcaniyeu, Las Heras and La Esperanza populations. The erroneous assignment of 18.75% Rio Mayo individuals to the Las Heras population can be explained by the low genetic differentiation found between these two populations. Thirty-nine of 56 loci per population combinations were in Hardy–Weinberg disequilibrium because of guanaco heterozygote deficiency, which may be explained by population subdivision. The high level of genetic diversity of the guanacos analysed here indicates that the Patagonian guanaco constitutes an important genetic resource for conservation or economic utilization programmes. [ABSTRACT FROM AUTHOR]

To address the biogeographical enigma of why guanacos (Lama guanicoe) are in the Falkland Islands we investigated the following questions: (1) What was the origin of the introduced guanacos? (2) What were the initial population sizes? (3) Why are they found only on one island? and (4) Who was John Hamilton and what role did he play?The Falkland Islands are located in the South Atlantic Ocean 600 km east of Patagonia at the southern end of South America. While dominated by East and West Falkland Islands, the archipelago is composed of some 750 islands. Sedge and Staats Islands, two small outlying islands of West Falkland, are the focus of this paper.Historical information was collected from known relevant documents housed at the Falkland Islands Government Archives in Stanley, and personal interviews conducted with past and present residents of West Falklands. Research expeditions were made to Staats Island in 1999, 2002 and 2003 to assess the guanaco population size, distribution and social structure.Guanacos were unsuccessfully introduced in 1862 to East Falkland south of Mt Pleasant where Prince Alfred hunted them in 1871. John Hamilton, Scottish immigrant to the Falklands and Patagonia of southern Argentina and Chile, was the driving force in the introduction of guanacos from the region of Rio Gallegos, Argentina during the 1930s. The guanaco was one of several wildlife species he introduced, however, only the guanaco, Patagonia grey fox (Dusicyon griseus) and perhaps the sea otter (Lutra felina) survive. Hamilton's acting agent, Jimmy Miller, imported four shipments totalling 26 guanacos from 1934 to 1939. In 1934 the Falkland Government authorized Miller to introduce guanacos to Sedge Island, all 11 of which disappeared. Whether intentional or accidental, 15 guanacos were taken to Staats Island, an islet of 500 ha on the western edge of the archipelago. Historically, guanacos are unexpected on Staats Island because documentation authorizing their introduction is unknown. Guanaco numbers have fluctuated widely on Staats Island for 65 years primarily due to culling. In 1959 the population was dangerously close to extirpation, but today 400 thrive there. A severely reduced gene pool and genetic bottlenecking were suggested by recent field studies, revealing preliminary evidence of deleterious consequences of inbreeding.John Hamilton, spirited and visionary Scottish immigrant to the Falklands in the early 1880s, was responsible for the introduction of guanacos into the Falkland Islands. While there are some gaps in the historical events, the enigma of how and why guanacos were introduced to a single island in the South Atlantic Ocean is understood. Today, Staats Island, as a closed system, is a rare natural experiment in progress. It offers unique opportunities for addressing advanced questions in ungulate population, behavioural and genetic ecology. The population potentially also represents breeding stock for farming the guanaco's highly valuable wool on other islands. Thus, among his many efforts to practice land stewardship and promote economic diversity through the introduction of Patagonian wildlife, a remaining legacy of John Hamilton to the Falkland Islands is unmistakably the guanacos of Staats Island. [ABSTRACT FROM AUTHOR]

Guanacos (Lama guanicoe) are the largest native Artiodactyl in South America and the most widely distributed. In arid Patagonia, densities are low and negatively related to domestic sheep numbers in space and time consistent with interspecific competition theory. Although guanacos and domestic sheep have been described as intermediate feeders sharing food resources, no studies have been conducted to compare their diets in sympatric conditions and explore whether the potential exists for direct interspecific competition. We assessed the diet of both species across 9 different sites and 2 seasons by microhistological analysis of fecal samples. We found that (1) guanacos and sheep are generalist herbivores feeding on a wide range of plant species; (2) both are intermediate feeders able to include both monocotyledoneous and dicotyledoneous plants in their diet; (3) both are able to change their diets seasonally; and (4) food niche overlap is high, particularly in summer when food resources are more scarce than in spring. We conclude that the potential for competition between guanacos and sheep is high and could have played a major role in the demise of guanacos. Consequently, current management practices focused on maximizing sheep numbers are not compatible with the recovery of guanaco populations. [ABSTRACT FROM AUTHOR]

The effect of three different vertical structures of a perennial ryegrass-dominated sward, defined by pseudostem heights (cm) — 1·3 low (L), 2·5 medium (M) and 3·5 high (H) — on the bite depth and selection of plant parts within the grazed horizon of the sward by sheep and guanacos was studied. The bite depth (cm) was similar between sheep and guanacos across the different swards (L, 1·5; M, 3·6; H, 3·8) and was related to pre-grazing sward surface height rather than to pseudostem height. There were differences in diet composition between species that were related to differences in selection for plant parts. Sheep had a higher proportion of green leaf in the diet than did guanacos in L (0·84 vs. 0·71, P < 0·05) and M (0·75 vs. 0·59, P < 0·05) swards, and possibly selected this plant part in H swards in which the proportion of green leaf in the grazed horizon was low (0·45–0·50). Guanacos had a higher proportion of dead leaf and sheath in the diet than did sheep in L (0·23 vs. 0·09, P < 0·05) and M (0·30 vs. 0·18, P < 0·05) swards, and possibly selected this plant part on these swards, in which the proportion of green leaf in the grazed horizon was high (0·70–0·95). The proportion of pseudostem in the diet of sheep and guanacos was similar across all swards (0·03) and was generally much lower than that in the grazed horizon (0·01–0·18). Guanacos had a higher proportion of dead stem in the diet than did sheep (0·06 vs. 0·02, P < 0·05) across all swards, but the proportion was similar to that in the grazed horizon of each sward. [ABSTRACT FROM AUTHOR]

The aggressive behaviour of free-ranging guanacos and vicuñas, living in sympatry in Catamarca Andes, Argentina, was analysed in relation to their social organisations. These organ/rations include territorial family units, solo males (territorial or not), and bachelor groups. In both guanacos and vicunas, family groups tended to have higher rates of agonistic interactions than bachelors and to be frequently involved in aggressive en- counters, whereas bachelor groups showed the opposite tendencies. Encounters between family groups and solo males were more frequent than expected. Bachelors acted almost exclusively as recipients of aggressive interactions, whereas solitary and family males frequently initiated encounters. Family groups adopted different behaviours towards bachelors in the two camelids. In guanacos, the latter were simply ignored, whereas in vicuñas {where they tend to compete for food with families) bachelors were consistently attacked by families. The behaviour of solitary males showed the main difference between the two species. Guanaco solo males had a much more aggressive attitude than vicuñas counterparts, Their proportion in guanaco population was also unexpectedly high. These results suggest that, in the less rigid organisation of guanaco society, the behaviour of solitary males is adopted by a number of adult males in an attempt to breed. [ABSTRACT FROM AUTHOR]

Assesses progress made and challenges to sustained-yield management of guanacos in Chile. Potential as economic resource; Plans of Chile to sell guanacos internationally with proper host-country permits; Breeding of guanacos in captivity; Biological basis for use of wild populations.

Describes the development and characteristics of microsatellite primers designed for the guanaco, Lama guanicoe and their utility for the South American camelids. Isolation of microsatellite loci using a modified non-radioactive capture-hybridization method; Annealing of the biotinylated capture probe to the linkered DNA.

The article describes a case of systemic candidosis in a guanaco kept in captivity. It is noted that the postmortem findings in reported cases of disseminated candidosis include the enlargement of lymph nodes, nephritis and hepatitis. The case elaborates that systemic candidosis should be considered after ineffective antibiotic treatment in captive, stressed animals.

The article reports the revisions of the statutory list of dangerous wild animals in Great Britain. It says that the Department for Environment, Food and Rural Affairs (DEFRA) has announced that following an independent review of the Dangerous Wild Animals Act 1976, the list was revised. It is now limited to those species that the experts agree, present a genuine risk to the public. The cat hybrids, raccoons and guanaco are among the species that have been removed from the list.

Discusses the efforts of the Chilean Agricultural and Livestock to keep the guanaco, a wild relative of the llama, from disappearing from the Andes mountains in central Chile. Comments by Jurgen Rottman of the Forestry Science Department, University of Chile, on guanacos; Result of the analysis of puma droppings in central Chile; Advantage of the existence of protected open areas near Santiago, according to Cristian Bonacic, director of the wildlife conservation research group Fauna Australis.

Summary 1. The Chilean National Forestry and Park Service is striving to implement a guanaco management programme of sustained-yield use. To achieve this, the rate, variation and causes of juvenile guanaco mortality must be understood thoroughly. Therefore, we monitored the survival of 409 radio-collared juvenile guanacos in Torres del Paine National Park, Chile, from 1991 to 1996. 2. The Kaplan–Meier product limit estimator of survival for staggered entry was calculated, and survival rates between juvenile males and females and among years were compared using the lifetest procedure in SAS. The Cox proportional hazards model was used to relate mortality rate to explanatory variables such as juvenile sex, birth weight, adult female aggression towards researchers during the capture and tagging of newborns, population density, and mean monthly winter snowfall. 3. Mean juvenile survival rate (ŝ) was 0·38, but varied between 0·31 and 0·55. Survival rates between the sexes were not significantly different, although male survival was lower than that of females. Mortality rate was highest during the first 14 days after birth. Most deaths occurred between birth and 7 months of age. 4. The risk of mortality increased by almost 6% with every 1 cm increase in winter snowfall, whereas the risk of mortality decreased by almost 24% as adult female aggression increased towards researchers. 5. Current management objectives are aimed at the implementation of a rational harvest of guanacos on the Chilean side of the island of Tierra del Fuego. Our results provide improved and updated estimates of juvenile guanaco survival and will aid in the modelling of harvest rates of guanacos in southern Chile. Future proposed harvests from wild populations in southern Chile need to consider the rate and variation of this critical life-history parameter. [ABSTRACT FROM AUTHOR]