Mauro Lucherini

Multigene phylogeny of the Mustelidae: Resolving relationships, tempo and biogeographic history of a mammalian adaptive radiation

BackgroundAdaptive radiation, the evolution of ecological and phenotypic diversity from a common ancestor, is a central concept in evolutionary biology and characterizes the evolutionary histories of many groups of organisms. One such group is the Mustelidae, the most species-rich family within the mammalian order Carnivora, encompassing 59 species classified into 22 genera. Extant mustelids display extensive ecomorphological diversity, with different lineages having evolved into an array of adaptive zones, from fossorial badgers to semi-aquatic otters. Mustelids are also widely distributed, with multiple genera found on different continents. As with other groups that have undergone adaptive radiation, resolving the phylogenetic history of mustelids presents a number of challenges because ecomorphological convergence may potentially confound morphologically based phylogenetic inferences, and because adaptive radiations often include one or more periods of rapid cladogenesis that require a large amount of data to resolve.ResultsWe constructed a nearly complete generic-level phylogeny of the Mustelidae using a data matrix comprising 22 gene segments (~12,000 base pairs) analyzed with maximum parsimony, maximum likelihood and Bayesian inference methods. We show that mustelids are consistently resolved with high nodal support into four major clades and three monotypic lineages. Using Bayesian dating techniques, we provide evidence that mustelids underwent two bursts of diversification that coincide with major paleoenvironmental and biotic changes that occurred during the Neogene and correspond with similar bursts of cladogenesis in other vertebrate groups. Biogeographical analyses indicate that most of the extant diversity of mustelids originated in Eurasia and mustelids have colonized Africa, North America and South America on multiple occasions.ConclusionCombined with information from the fossil record, our phylogenetic and dating analyses suggest that mustelid diversification may have been spurred by a combination of faunal turnover events and diversification at lower trophic levels, ultimately caused by climatically driven environmental changes. Our biogeographic analyses show Eurasia as the center of origin of mustelid diversity and that mustelids in Africa, North America and South America have been assembled over time largely via dispersal, which has important implications for understanding the ecology of mustelid communities.

Spatially explicit inference for open populations: estimating demographic parameters from camera-trap studies

We develop a hierarchical capture-recapture model for demographically open populations when auxiliary spatial information about location of capture is obtained. Such spatial capture-recapture data arise from studies based on camera trapping, DNA sampling, and other situations in which a spatial array of devices records encounters of unique individuals. We integrate an individual-based formulation of a Jolly-Seber type model with recently developed spatially explicit capture-recapture models to estimate density and demographic parameters for survival and recruitment. We adopt a Bayesian framework for inference under this model using the method of data augmentation which is implemented in the software program WinBUGS. The model was motivated by a camera trapping study of Pampas cats Leopardus colocolo from Argentina, which we present as an illustration of the model in this paper. We provide estimates of density and the first quantitative assessment of vital rates for the Pampas cat in the High Andes. The precision of these estimates is poor due likely to the sparse data set. Unlike conventional inference methods which usually rely on asymptotic arguments, Bayesian inferences are valid in arbitrary sample sizes, and thus the method is ideal for the study of rare or endangered species for which small data sets are typical.

DIETS OF THREE SPECIES OF ANDEAN CARNIVORES IN HIGH-ALTITUDE DESERTS OF ARGENTINA

Abstract We present the 1st data on the diet of the Andean mountain cat (Leopardus jacobitus), and the 1st on the colocolo (Leopardus colocolo) and the culpeo (Lycalopex culpaeus) in high-altitude deserts of northern Argentina, based on fecal analysis. Feces of Andean mountain cats and colocolos were distinguished by DNA analysis. The Andean mountain cat (n = 57) was the most specialized, relying heavily on southern mountain vizcachas (Lagidium viscacia). The colocolo (n = 504) also was specialized, consuming mostly cricetine rodents and tuco-tucos (Ctenomys). The culpeo (n = 399) was a generalist, consuming all prey items that the cats used, and a greater variety of invertebrates. Short-tailed chinchillas (Chinchilla chinchilla) were found in 3 culpeo feces, indicating that this rodent, considered extinct in Argentina, is still present in the wild. Both southern mountain vizcachas and tuco-tucos have a patchy distribution, indicating that very large areas may be required to support populations of the cats that depend on these prey species.

Perceptions of Human–Carnivore Conflicts in the High Andes of Argentina

Abstract The Andean cat (Leopardus jacobitus), one of the worlds most threatened felids, forms part of the little-known carnivore guild occurring in the dry areas of the High Andes. Although human–carnivore conflicts are among the major causes of carnivore population decline, no data are available on this issue for the High Andes. We report here the results of the first survey of human perceptions of, and attitudes towards, carnivores in the high-altitude Andes of Argentina. Interviews with 50 adults and 226 schoolchildren revealed that pumas (Puma concolor) and foxes (Lycalopex culpaeus) are considered pests for preying upon livestock and are actively hunted by adults. Although perceptions of the Andean cat and the Pampas cat (Leopardus colocolo) were more positive, especially among schoolchildren, they are also frequently killed by local people. We suggest that, contrary to what was previously thought, hunting might be affecting the conservation status of the Andean cat and of some puma populations in the High Andes of Argentina, and that education strategies may help to improve human attitudes, particularly in the case of the endangered Andean cat.

GEOGRAPHICAL VARIATION IN THE DIET OF GEOFFROY'S CAT (ONCIFELIS GEOFFROYI) IN PAMPAS GRASSLAND OF ARGENTINA

Abstract Geoffroys cat (Oncifelis geoffroyi) is a little-known South American felid. We report here the first detailed data on its food habits and variations among 3 areas of the Argentine Pampas grassland. Analysis of 421 scat samples showed a relatively narrow trophic niche, dominated by vertebrates, especially small rodents. Despite a wide overlap in diet composition, geographical variation was found in frequency of occurrence of primary food categories, presence of secondary food items, and mean weight of vertebrate prey. These differences seem to be related to variation in food availability and suggest that Geoffroys cats are able to show a certain degree of adaptability in foraging behavior.

Influence of ancient glacial periods on the Andean fauna: the case of the pampas cat (Leopardus colocolo)

BackgroundWhile numerous studies revealed the major role of environmental changes of the Quaternary on the evolution of biodiversity, research on the influence of that period on current South-American fauna is scarce and have usually focused on lowland regions. In this study, the genetic structure of the pampas cat (Leopardus colocolo), a widely distributed felid, was determined and linked to ancient climate fluctuations on the Andean region.ResultsUsing both mitochondrial sequences and nuclear microsatellites, we inferred the existence of at least four groups of populations in the central Andes, while other three localities, with little sample sizes (n = 3), presented differences in only one of these markers. The distribution of these groups is correlated to latitude, with a central area characterized by admixture of numerous mitochondrial clades. This suggests colonization from at least three glacial refuges and a contact zone between 20 degrees and 23 degrees S following a glaciation event. The similar coalescence times of the mitochondrial haplotypes indicated that the major clades split approximately one million years ago, likely during the Pre-Pastonian glacial period (0.80 – 1.30 MYA), followed by a demographic expansion in every clade during the Aftonian interglacial period (0.45 – 0.62 MYA). Interestingly, this structure roughly corresponds to the current recognised distribution of morphological subspecies.ConclusionThe four groups of populations identified here must be considered different management units, and we propose the three localities showing differences in only mtDNA or ncDNA as provisional management units. The results revealed the influence of ancient climate fluctuations on the evolutionary history of this species. It is expected that the other species of land vertebrates with a smaller or similar mobility have been affected in the same manner by the glacial and interglacial periods in the central Andes

Estimating detection and density of the Andean cat in the high Andes

Abstract The Andean cat (Leopardus jacobita) is one of the most endangered, yet least known, felids. Although the Andean cat is considered at risk of extinction, rigorous quantitative population studies are lacking. Because physical observations of the Andean cat are difficult to make in the wild, we used a camera-trapping array to photo-capture individuals. The survey was conducted in northwestern Argentina at an elevation of approximately 4,200 m during October–December 2006 and April–June 2007. In each year we deployed 22 pairs of camera traps, which were strategically placed. To estimate detection probability and density we applied models for spatial capture–recapture using a Bayesian framework. Estimated densities were 0.07 and 0.12 individual/km2 for 2006 and 2007, respectively. Mean baseline detection probability was estimated at 0.07. By comparison, densities of the Pampas cat (Leopardus colocolo), another poorly known felid that shares its habitat with the Andean cat, were estimated at 0.74–0.79 individual/km2 in the same study area for 2006 and 2007, and its detection probability was estimated at 0.02. Despite having greater detectability, the Andean cat is rarer in the study region than the Pampas cat. Properly accounting for the detection probability is important in making reliable estimates of density, a key parameter in conservation and management decisions for any species.

Lycalopex Gymnocercus (Carnivora: Canidae)

Abstract Lycalopex gymnocercus (Fischer, 1814) is a canid commonly called the Pampas fox. A sexually dimorphic fox-like carnivore of medium size with reddish coloration on sides and white on the ventral surface, it is 1 of 6 species in the genus Lycalopex. It occurs in eastern Bolivia, western and central Paraguay, Uruguay, north and central Argentina, and southeastern Brazil. It prefers open habitats but also occurs in areas of Pampas grassland modified by extensive ranching and agriculture activities. It has been assigned to the “Least Concern” category of the International Union for Conservation of Nature and Natural Resources.

Interindividual interactions of Molina's hog-nosed skunks Conepatus chinga in the Pampas grassland of Argentina

During one year, we radiotracked two female and two male Molina’s hog-nosed skunksConepatus chinga (Molina, 1782), a little studied mephitid, in the Pampas of central Argentina, to analyze the static and dynamic interactions between individuals. Mean home range overlap was large (44.5%), but males shared a smaller proportion of their home ranges than females. The average percentage of localizations in the overlap area (39.3%) indicates that these areas were not marginal sections of individual home ranges, but this value was greater for individuals of different genders than intrasexual dyads. The Coefficient of Spatial Association confirmed that the distances between individuals of different sexes were smaller than between animals of the same sex. During simultaneous locations, females were closer than males, but reciprocal distances between individuals varied over the time. These patterns are congruent with those described as typical for mustelids and mephitids. Our results confirm that an analysis of home range overlap should not be considered complete without the study of dynamic interactions among individuals and their temporal variations, which are necessary to overcome the limitations of spatial overlap analysis.

Carnivore occurrence: do interview-based surveys produce unreliable results?

Interviews with local people have been widely used by biologists as a cost-effective approach to studying certain topics in wildlife ecology and conservation. However, doubts still exist about the validity and quality of the information gathered, especially in studies targeting cryptic or elusive species, such as carnivores. We assessed the reliability of interviews (n = 155) in detecting the presence of three species of carnivores with different characteristics, by comparing interview results with data obtained through camera trapping surveys at 52 sites in central Argentina. The degree of concordance between methods was low for Geoffroys cat Leopardus geoffroyi and especially for the puma Puma concolor . However, Geoffroys cats were detected more frequently by camera traps than interviews, whereas the opposite was true for pumas. For the pampas fox Pseudalopex gymnocercus , a less elusive species, we observed a high degree of concordance and a similar probability of occurrence between methods. Our results indicate that data obtained by interviewing local inhabitants should be used with caution because the information about species presence provided by local people may be inaccurate and biased.