Dynamic of Mycobacterium avium subspecies paratuberculosis infection in a domestic-wildlife interface: Domestic sheep and guanaco as reservoir community.

Natural herbivore populations have experienced uninterrupted pressures from direct and evident domestic-wildlife interactions and competition, to indirect or less obvious ones such as pathogen transmission. Thus, pathogen spillover between wild and domestic animals is a constant concern because the domestic-wildlife interface represents the ecological frontier in which pathogen transmission takes place in both directions. In Patagonian steppe communities, extensive sheep ranching and guanaco (Lama guanicoe) populations coexist, and guanaco have shown to be infected by pathogens such as Mycobacterium avium subspecies paratuberculosis (MAP) likely transmitted from livestock. MAP causes chronic enteritis and affects mostly domestic ruminants. We evaluated MAP prevalence and pathogen shedding in both species' faeces collected in non-shared and shared sites according to presence/absence of sheep and guanaco along a year, in four different seasons (autumn, winter, and spring 2018, and summer 2019). Our results indicate that MAP circulates in both sheep and guanaco populations with self-sustained transmission; however, both species differ in their levels of competence. We detected higher pathogen shedding in sites occupied by sheep, suggesting that sheep populations may be the main source of infection for susceptible animals due to their large numbers which drive MAP dynamics.

Behavioural Indicators of Intra- and Inter-Specific Competition: Sheep Co-Grazing with Guanaco in the Patagonian Steppe.

In extensive livestock production, high densities may inhibit regulation processes, maintaining high levels of intraspecific competition over time. During competition, individuals typically modify their behaviours, particularly feeding and bite rates, which can therefore be used as indicators of competition. Over eight consecutive seasons, we investigated if variation in herd density, food availability, and the presence of a potential competitor, the guanaco (Lama guanicoe), was related with behavioural changes in domestic sheep in Chilean Patagonia. Focal sampling, instantaneous scan sampling, measures of bite and movement rates were used to quantify behavioural changes in domestic sheep. We found that food availability increased time spent feeding, while herd density was associated with an increase in vigilant behaviour and a decrease in bite rate, but only when food availability was low. Guanaco presence appeared to have no impact on sheep behaviour. Our results suggest that the observed behavioural changes in domestic sheep are more likely due to intraspecific competition rather than interspecific competition. Consideration of intraspecific competition where guanaco and sheep co-graze on pastures could allow management strategies to focus on herd density, according to rangeland carrying capacity.

Partially Reversible Immobilization of Free-Ranging Huemul Deer (Hippocamelus bisulcus) with Medetomidine-Ketamine and Atipamezole.

A combination of intramuscular medetomidine and ketamine was used to immobilize 46 free-ranging huemul deer (Hippocamelus bisulcus) with a remote drug delivery system in Chilean Patagonia for tagging and biological sampling. Captures occurred in May-October of 2005-09 between fall and early spring in the southern hemisphere. An initial dose of 6.6 mg medetomidine and 185 mg ketamine was adjusted after 17 captures to 3 mg and 200 mg, respectively, in the 29 remaining deer. Mean±SD adjusted dose was 0.042±0.012 mg/kg of medetomidine and 2.929±0.427 mg/kg of ketamine. Inductions were calm and the mean±SD time to sternal recumbency was 10.3±10.1 min. Palpebral reflex and jaw tone were present during immobilization. Atipamezole at 5 mg/mg of medetomidine was administered intramuscularly for reversal after 55.3±18.8 min procedure time. Recoveries were smooth and mean±SD time to standing was 10.2±3.3. All immobilized animals were hypoxemic by pulse oximetry (blood oxygen saturation approximately 81%). Three animals that developed apnea were resuscitated through chest compression and atipamezole administration, another regurgitated during capture, and all developed tachypnea. The combination of medetomidine-ketamine and atipamezole can be used for partially reversible immobilization of huemul, but supplemental oxygen should be administered, blood oxygenation should be monitored, and equipment for intubation and manual ventilation should be available.

Extinction risk assessment of a Patagonian ungulate using population dynamics models under climate change scenarios.

Climate change affects population cycles of several species, threatening biodiversity. However, there are few long-term studies on species with conservation issues and restricted distributions. Huemul is a deer endemic to the southern Andes in South America and it is considered endangered mostly due to a 50% reduction of its distribution over the last 500 years. To assess environmental variables potentially affecting huemul population viability and the impact of climate change, we developed population dynamics models. We used a 14-year survey data from Bernardo O'Higgins National Park, coastal Chilean Patagonia. We used Ricker models considering winter and spring temperatures and precipitation as variables influencing huemul population dynamics. We used the Bayesian information criterion (BIC) to select models with the greatest predictive power. The two best models (ΔBIC < 2) included winter temperature and density-dependence population growth drivers. The best model considered a lateral effect, where winter temperature influences carrying capacity and the second best a vertical effect with winter temperature influencing Rmax and carrying capacity. Population viability was evaluated using those models, projecting them over a 100-year period: (a) under current conditions and (b) under conditions estimated by Global Climate Models for 2050 and 2070. The extinction risk and quasi-extinction were estimated for this population considering two critical huemul abundance levels (15 and 30 individuals) for persistence. The population is currently in a quasi-extinction process, with extinction probabilities increasing with climate change. These results are crucial for conservation of species like huemul that have low densities and are threatened by climate change.

Protected areas' effectiveness under climate change: a latitudinal distribution projection of an endangered mountain ungulate along the Andes Range.

BACKGROUND: Climate change is one of the greatest threats to biodiversity, pushing species to shift their distribution ranges and making existing protected areas inadequate. Estimating species distribution and potential modifications under climate change are then necessary for adjusting conservation and management plans; this is especially true for endangered species. An example of this issue is the huemul (Hippocamelus bisulcus), an endemic endangered deer from the southern Andes Range, with less than 2,000 individuals. It is distributed in fragmented populations along a 2,000 km latitudinal gradient, in Chile and Argentina. Several threats have reduced its distribution to <50% of its former range. METHODS: To estimate its potential distribution and protected areas effectiveness, we constructed a species distribution model using 2,813 huemul presence points throughout its whole distribution range, together with 19 bioclimatic layers and altitude information from Worldclim. Its current distribution was projected for years 2050 and 2070 using five different Global Climate Models estimated for scenarios representing two carbon Representative Concentration Routes (RCP)-RCP4.5 and RCP6.0. RESULTS: Based on current huemul habitat variables, we estimated 91,617 km2 of suitable habitat. In future scenarios of climate change, there was a loss of suitable habitat due to altitudinal and latitudinal variation. Future projections showed a decrease of 59.86-60.26% for the year 2050 and 58.57-64.34% for the year 2070 according to RCP4.5 and RCP6.0, respectively. Protected areas only covered only 36.18% of the present distribution, 38.57-34.94% for the year 2050 and 30.79-31.94% for 2070 under climate change scenarios. DISCUSSION: Modeling current and future huemul distributions should allow the establishment of priority conservation areas in which to focus efforts and funds, especially areas without official protection. In this way, we can improve management in areas heavily affected by climate change to help ensure the persistence of this deer and other species under similar circumstances worldwide.

Blood mineral concentrations in the endangered huemul deer (Hippocamelus bisulcus) from Chilean Patagonia.

Concentrations of calcium, magnesium, copper, zinc, and selenium were measured in plasma from 11 huemul (Hippocamelus bisulcus) from Chilean Patagonia. Except for zinc and copper, concentrations of these minerals were similar to those of other deer species.

Evidence of bovine viral diarrhea, but absence of infectious bovine rhinotracheitis and bovine brucellosis in the endangered huemul deer (Hippocamelus bisulcus) in Chilean Patagonia.

We screened 18 endangered Chilean huemul (Hippocamelus bisulcus) for antibodies to infectious agents. We detected no antibody to bovine herpesvirus-1 (BHV-1) or Brucella abortus (BA); two huemul had antibody to bovine viral diarrhea virus (BVDV). Cattle (n=35) had antibody to BVDV and BHV-1 but not BA.

First records of the louse Solenopotes binipilosus (Insecta: Phthiraptera) and the mite Psoroptes ovis (Arachnida: Acari) from wild southern huemul (Hippocamelus bisulcus).

Two species of Phthiraptera, Bovicola caprae (Ischnocera: Bovicolidae) and Solenopotes binipilosus (Anoplura: Linognathidae), and one species of mite, Psoroptes ovis (Acari: Psoroptidae), were recorded on huemul (Hippocamelus bisulcus) in Chile. The sucking louse S. binipilosus and the mite P. ovis are reported for the first time from this host.

Application of DNA forensic techniques for identifying poached guanacos (Lama guanicoe) in Chilean Patagonia*.

Guanaco (Lama guanicoe) is a protected and widely distributed ungulate in South America. A poacher, after killing guanacos in Valle Chacabuco, Chilean Patagonia, transported and stored the meat. Samples were retrieved by local police but the suspect argued that the meat was from a horse. Mitochondrial cytochrome b gene (774 pb), 15 loci microsatellites, and SRY gene were used to identify the species, number of animals and their population origin, and the sex of the animals, respectively. Analysis revealed that the samples came from a female (absence of SRY gene) Patagonian guanaco (assignment probability between 0.0075 and 0.0282), and clearly distinguishing it from sympatric ungulates (E-value = 0). Based on the evidence obtained in the field in addition to forensic data, the suspect was convicted of poaching and illegally carrying fire arms. This is the first report of molecular tools being used in forensic investigations of Chilean wildlife indicating its promising future application in guanaco management and conservation.