Paulo Corti

Feeding Ecology of the Black-necked Swan Cygnus melancoryphus in Two Wetlands of Southern Chile

The diet of Black-necked swans, Cygnus melancoryphus (Anatidae), was studied in two southern Chilean wetlands in 1993–1995; the Cruces River Sanctuary and the Chihuao-Pichoy River, both near Valdivia. The diet of swans was analyzed by using microhistologic techniques of cell remains in feces collected in the field. The analysis showed that swans were eating predominantly the most abundant submerged aquatic plant, Brazilian waterweed, Egeria densa (Hydrocharitaceae), at both Cruces River (91.9% of diet) and Chihuao-Pichoy River (71.7%). The foraging action of this species was estimated using four forage exclosures in the Chihuao-Pichoy River wetland free from swan grazing, which were compared with foraged controls. Aquatic plant biomass taken in the exclosures was significantly higher (p < 0.05) than biomass sampled outside the exclosures. Cygnus melancoryphus might play an important role as a regulator of aquatic plant biomass, thus contributing to cause a delay in ecological succession. The potential impact of this slowing down is discussed in terms of a natural ecological process in wetland environments.

Learning to count: adapting population monitoring for Endangered huemul deer Hippocamelus bisulcus to meet conservation objectives.

Considerable efforts have been invested in recent years to improve methods for both data collection and analyses required for population monitoring. Where historical or current estimates of population size are not adjusted for detection probabilities they may be too inaccurate to provide meaningful estimates of trends and thus monitoring methods need to be adapted. Here, we use data from the Endangered huemul deer Hippocamelus bisulcus to outline a framework to develop accurate robust estimates of detection probabilities that can be incorporated into new surveys in a cost-effective way and applied to existing survey data sets. In particular, by retroactively estimating detection probabilities for surveys of huemul, we show that current survey methods for huemul are inadequate to determine population trends reliably. Based on these results we propose a new monitoring method for the huemul and discuss the importance of estimating accuracies of historical survey data to ensure that changes in the abundance of the species reflect real population trends and are not an artefact of variation over time in the accuracy of survey data.

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.

Predicting the potential distribution of the Endangered huemul deer Hippocamelus bisulcus in North Patagonia

Habitat loss is one of the main threats to wildlife, particularly large mammals. Estimating the potential distribution of threatened species to guide surveys and conservation is crucial, primarily because such species tend to exist in small fragmented populations. The Endangered huemul deer Hippocamelus bisulcus is endemic to the southern Andes of Chile and Argentina. Although the species occurs in the Valdivian Ecoregion, a hotspot for biodiversity, we have no information on its occupancy and potential distribution in this region. We built and compared species distribution models for huemul using the maximum entropy approach, using 258 presence records and sets of bioclimatic and geographical variables as predictors, with the objective of assessing the potential distribution of the species in the Valdivian Ecoregion. Annual temperature range and summer precipitation were the predictive variables with the greatest influence in the best-fitting model. Approximately 12,360 km 2 of the study area was identified as suitable habitat for the huemul, of which 30% is included in the national protected area systems of Chile and Argentina. The map of potential distribution produced by our model will facilitate prioritization of future survey efforts in other remote and unexplored areas in which huemul have not been recorded since the 1980s but where there is a high probability of their occurrence.

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

Abstract 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.

Muzzle morphology and food consumption by pudu (Pudu puda Molina 1782) in south-central Chile

The southern pudu (Pudu puda) is one of the smallest living deer of the world. It inhabits the temperate rainforest of Chile and Argentina, where it is considered vulnerable due to decreasing populations. To improve the existing information concerning its feeding ecology, we performed morphometric measurements on skulls and jaws (n = 22), and observed feeding behavior on individual deer (n = 14). The pudu presented an oral morphology adapted to select specific parts of plants, and a brachyodont molar type, which is consistent with the selective browsing style and consumption of primarily dicotyledonous plants. This information can be used to infer habitat relationships and needs of the pudu during the growth season.

Interpretation of plasma selenium data in huemul: response to Flueck et al.

Flueck et al. (2014) expressed several misconceptions about the huemul plasma micronutrient data we provided (Chihuailaf et al. 2014). We expressed selenium (Se) plasma values as mean, median, ranges, and intervals for comparison with those reported for other deer species, which were mostly raw values. We did not refer to the Se values as a ‘‘reference interval’’ but as an ‘‘interval calculated.’’ Perhaps we should have used a different term to avoid confusion. Our data do not meet the requirements of a reference interval according to the American Society of Veterinary Clinical Pathology (Friedrichs et al. 2012). Similarly, Se values reported by McDowell et al. (1995) did not receive the statistical treatment required to be considered a reference interval; they provided only a data range expressed as maximum and minimum values found by the authors for one species in one area. There is no single definition for ‘‘healthy population’’ for either wild or domestic animals. Therefore, building reference intervals requires safeguards for selection of sampling animals (Friedrichs et al. 2012). Also, appropriate statistical analysis of the data is required. The American Society of Veterinary Clinical Pathology suggests removal of outlier values to minimize error when establishing reference intervals, so a large sample of healthy animals is needed (Friedrichs et al. 2012). These conditions are more easily met in domestic livestock than in wild animals. It is also important to identify values that may indicate a deficient, marginal, or sufficient status for a given micronutrient, implying that we know the requirement criteria (Suttle 2010). This issue has been discussed for domestic livestock where each production system, geographic area, and breed, among several other factors, requires a separate reference value for each micronutrient; but it also is a growing necessity for wildlife and their ecosystems. For example, Se requirements for livestock in the US are higher than those reported for New Zealand (Suttle 2010). This implies that a trace mineral reference interval developed for one species in one geographic area or ecosystem is likely insufficient to categorize other species in other habitats. Furthermore, if we attempt to equate requirements of wild species with those for production livestock, which are subject to additional metabolic pressure to maintain productive efficiency, we would introduce an error in biologic data interpretation. If huemul deer (Hippocamelus bisulcus) inhabited North America, where acid rain produces soils low in Se, Flueck et al. (2014) might be correct in their comments, but southern South America lacks chronic atmospheric pollution (Huygens et al. 2008). It is important to consider that the data provided by Chihuailaf et al. (2014) only suggest a condition that should be further investigated. After all, huemul have survived since the Pleistocene (Marin et al. 2013) in habitats dominated by volcanic soils lacking in Se (reviewed by Chihuailaf et al. 2014).

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.

Evidence of Mycobacterium avium subsp. paratuberculosis (MAP) infection in huemul deer (Hippocamelus bisulcus) in Patagonian fjords

espanolRESUMEN: En el Parque Nacional Bernardo O’Higgins de la Patagonia chilena se recolectaron catorce muestras de heces de huemul para deteccion de Mycobacterium avium subsp. paratuberculosis. Seis de las muestras resultaron positivas, pero solo una mostro un patron molecular similar al patron mas comun de cepas aisladas de bovinos en Chile. EnglishABSTRACT: In the Chilean coastal Patagonia, fourteen wild deer huemul faecal pellet samples were collected and cultured for Mycobacterium avium subsp. paratuberculosis detection. Six samples were positive, but only one was able to show a molecular type similar to the most common strain reported for cattle in Chile.

Development of eight microsatellite loci from the endangered huemul ( Hippocamelus bisulcus ) and cross-species amplification in six other ungulate species

We developed eight polymorphic microsatellite loci for the huemul (Hippocamelus bisulcus) and tested for cross-species amplification in six other ungulate species. Microsatellite loci were typed in 58 individuals from the Lago Cochrane National Reserve, Chile. Two to five alleles were observed per locus (mean 3.4) and observed heterozygosity ranged from 0.29 to 0.60 (mean 0.53). One to five loci amplified in other ungulate species. These markers will be used to refine studies of population structure and allow for more accurate pedigree reconstruction in the huemul.