LYNCODON PATAGONICUS PDF

Lyncodon patagonicus has a distribution within the Neotropical region. Its range is from the southern and western parts of Argentina into Chile Redford and Eisenberg, There is not a lot known about the habitat of L. The little research there is on this species suggests that Patagonian weasels are found in Pampas habitats that have light-colored substrates excluding deserts Gittleman, The head and body length of Lyncodon patagonicus ranges from to mm, with the tail adding an additional 60 to 90 mm Nowak, They have very small ears that are covered by the surrounding fur.

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Mauro I. Schiaffini, Gabriel M. The Patagonian weasel Lyncodon patagonicus is one of the least known carnivores from South America, and excluding some contributions, knowledge of it seems anecdotal.

It is supposed to inhabit herbaceous and arid environments of Argentina and Chile. We also integrate some of this information, providing a historical and geographic analysis both through ecological niche modeling and biogeographic schemes of the distribution of L.

We found 2 major core areas of distribution, 1 in northwestern Argentina and another in southern Argentina i.

Patagonian weasel distribution seems to be primarily related to cold areas with marked temperature seasonality and elevations below 2, m above sea level. From LGM to the present, we observed a major retraction in potential distribution areas that might indicate the existence of a vicariance process affecting Patagonian weasel distribution. The small-sized carnivore fauna of South America, and Argentina in particular, have been poorly studied, especially in their distributional aspects.

Despite the contributions of Sielfeld and Castilla and Vianna et al. Introduced species, such as the American mink Mustela vison , despite their impact on native ecosystems, have not been properly assessed. Analyzing the distribution patterns of a given species allows us to understand its relationship with the environment, including biotic and abiotic factors Franklin In this context, the area in which L. The chorological history of L.

In this study, we aim to assess the potential distribution of the Patagonian weasel L. The study region represents the southern portion of South America, particularly Argentina and Chile, although the potential distribution of the species was evaluated at a continental scale i. Specimens from Chilean collections were not analyzed and only their geographical coordinates were used. Apart from this, no other individuals from L.

The potential distribution of L. Recent examples of the use of this software can be seen in Martin , , Torres and Jayat , and Moratelli et al. We used 2 sets of environmental variables: one for the LGM i. The 2nd data set contains elevation data; average monthly minimum, medium, and maximum temperatures; monthly precipitation; and 19 bioclimatic variables Humans et al.

The cumulative output was selected and we assigned probability values of 51— black , 26—50 dark gray , 11—25 gray , 2—10 light gray , and 0—1 white. Variable contributions were analyzed through MaxEnt's jackknife tests. We evaluated model predictions both with threshold-dependent and threshold-independent tests, using F-values of 1, 5, and 10; area under the curve AUC , and the receiver operating characteristics, respectively Phillips et al.

A further analysis was performed to somehow validate the generated models. For this, we extracted values of bioclimatic variables from the historical localities not fossil using the latest climatic database Humans et al. We then calculated the average for all points i.

We observed the same pattern in both actual and fossil variables, indicating that the same variables affect the distribution of L. Temperature bioclimatic variables in both actual and Last Glacial Maximum models. For a better representation of scale, BI04 has been eliminated. Precipitation bioclimatic variables in both actual and Last Glacial Maximum models. Because the models containing fossil localities include a broad temporal sample i. This 5th model E was generated by projecting all historical records over a new actual data set that was modified according to parameters extracted from the LGM in the following way: we generated 1, random points with Arcview 3.

In this way, we obtained a new set of modified environmental variables that reflects changes between present day and LGM times. Last, each actual not fossil locality was assigned on a geographic basis to a particular ecoregion following Olson et al. Localities recorded for L. Although 73 localities were listed, we were not able to assign an age i. Of these, 20 correspond to specimens recovered from Pleistocene and Holocene deposits and 52 to extant records Table 1 , Fig.

Interestingly, the southermost and westernmost record for the species is represented by 1 locality in southern Chile Puerto Prat, locality 8, Fig. Record localities for Lyncodon patagonicus. Record localities for Lyncodon patagonicus for Argentina and Chile organized by date see Table 1. Inset represents fossil localities. Potential distribution models are presented in Fig. This area extends into northern Chile through the western portions of San Juan, La Rioja, and Catamarca provinces in Argentina, and also includes much of the continental platform that is now under water, but was probably emerged in its majority during the LGM Rabassa et al.

Probability values are 51— black , 26—50 dark gray , 11—25 gray , 2—10 light gray , and 0—1 white. Separated from this area are several other smaller high-prediction areas in southern and western Mendoza, southern Buenos Aires Province area A, Fig. Percent contribution of each variable to the 4 models A-D are presented in Table 2. Ten variables contributed most to both LGM models, with Nineteen and 17 environmental variables contributed the most to the models with extant records, The other variables, with smaller contributions, were related to minimum temperature of coldest month and precipitation taken by quarters in the LGM models A and B , and elevation and winterAate fall minimum temperature and precipitation in the models with extant data C and D, Table 2.

Variables containing information not present in the remainder were mean temperature of coldest quarter in model A, precipitation seasonality in model B, and altitude in models C and D. Other jackknife tests i. In bold, variables with major contribution. Results of predicted areas for cumulative threshold values of 1, 5, and 10 for the 4 models A-D generated.

Model E shows a similar pattern to model C Fig. Patagonia and northwestern Argentina show extended areas at all levels of prediction; the same is true for a small area in southern Buenos Aires. Major changes are observed in temperature-related variables, indicating that cooler conditions might allow a broader distribution of L.

With an AUC value of 0. In a biogeographic context, extant records of L. Record localities black circles in a biogeographic context. Ecoregions follow Olson et al. The Patagonian weasel is distributed from Salta Argentina to the southern portion of continental South America, with most localities being found along western Argentina Fig.

Several records from eastern localities throughout its central distribution e. Some areas have a concentration of records e. In contrast, for over 70 years the species was known from fewer than 15 localities scattered mostly throughout its current known range Table 1 , Fig. Fossil records of L. The presence of L. In sum, fossil evidence indicates that the presence of L. Although potential distribution in models A and B might have some bias due to some differences between ages between localities and the temporal database i.

In this respect, variable contributions of the models show that the same variables influence the distribution of the Patagonian weasel at continental scale. A general trend can be observed when analyzing the models in a historical perspective, from LGM to Fig.

This is true for high- black shading and medium-prediction areas dark gray shading , and to a lesser extent to the areas with low prediction values light shading Fig. These patterns could be indicating a retraction in the distribution of L. Although potential distribution in models A and B. The shift from west to east, far from the Andes Mountains, might be explained by vast glacial extensions covering such areas, and the presence of extreme climatic conditions typical of periglacial environments Rabassa et al.

Also, a drop in sea level of — m during glaciations exposed much of the continental platform, adding substantial surfaces that were occupied or susceptible of being so by the biota, including L.

Even more important, during glaciations a displacement in oceanic anticyclones might also have occurred Rabassa et al.

In other words, the limits of climatic conditions typical of Patagonia cool and dry, westerly winds, and moderate temperature extended toward the northeast, covering the entire Pampa region Iriondo and Garcia Due to the sea level drop, areas of what today is Buenos Aires and eastern La Pampa provinces would have experienced a more extreme continental-like climate i.

In the context of the distribution of L. The 2 models with recent i. As pointed out above, these areas are reduced in model D Fig. Contrary to this, the area of central Chile area B, Fig.

This shift in potential distribution is consistent with projections of climate change for central Chile, which shows an increasing aridity in the area Watson et al. Both models with extant data Figs. Following this, a high-probability area is shown in southern Buenos Aires Province, though the intense human-driven modifications and an increase of precipitation in this region during the last years makes the occurrence of L. These are coincident with the supposed distribution of the 2 subspecies that have been recognized for L.

Clearly, a detailed morphological and taxonomic study is needed to clarify the status of the named subspecies. The environmental variables that appear to have the greatest influence on the potential distribution models are mostly related to minimum temperatures of the coldest months and, with smaller contributions, precipitation and elevation Table 2.

Contrary to this, a small increase in the contribution of precipitation-related values can be observed, with a maximum of Birney and Monjeau and Monjeau et al. The latter reference also relates minimum temperatures with energy availability per area. Although the distribution of L. Jackknife tests show temperature and precipitation variables as the most important, with altitude as the most important variable containing information not present in the others.

In this way, cold areas with marked temperature seasonality, spring precipitations, and altitudes below 2, m above sea level asl appear to be the best suited for the distribution of L. Recent localities are not distributed evenly, with only two of them from Chile and the rest from Argentina, mostly in Patagonian Steppe environments, followed by High Monte and Dry Chaco sensu Olson et al.

These 3 ecoregions receive less than mm of annual precipitation and are structurally composed of shrubby steppes or dry forests Burkart et al. Both high-prediction areas in models C and D Figs.

EVIS L.CARBALLOSA PDF

Patagonian weasel

The Patagonian weasel Lyncodon patagonicus is a small mustelid that is the only member of the genus Lyncodon. Its fur is whitish with black and dark brown tones mixed in. It has small ears , short legs and a bushy tail. The animal has not been thoroughly studied in the wild, and knowledge of its behavioral patterns is unsure. It reportedly has been kept as a working pet by local ranchers to destroy rodents.

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