In desert areas, predation risk is one of the highest costs of foraging and is a major influence ... more In desert areas, predation risk is one of the highest costs of foraging and is a major influence on animal behaviour. Several strategies are used by foragers for surviving and reproducing in desert areas. The foraging strategies of the small mammals of South American deserts are still poorly known. In this study, we investigated the foraging strategies of rodents of the Monte Desert in response to distance from seed sources to sheltered sites (i.e. shrubs) during two different seasons (wet and dry). We evaluated the relative rates of removal of two species of seeds (millet and sunflower) by rodents at two sites by establishing 80 seed sources, 40 in unsheltered microhabitats and 40 in sheltered microhabitats. We recorded both the number of caches and seed consumption for each source. We found that plant cover affected the foraging activity of rodents of the sand dunes in the Monte Desert because both consumption and numbers of caches constructed from sheltered seed sources were higher than those from unsheltered ones. Consumption of sunflower was higher in the wet season than it was in the dry season, when millet consumption increased. Sunflower was the preferred seed both from sheltered or unsheltered sources. We discuss the possible causes of the different foraging strategies used by rodents of the Monte Desert.
Linear infrastructures such as roads are among the most frequent generators of anthropogenic dist... more Linear infrastructures such as roads are among the most frequent generators of anthropogenic disturbances. Due to the expensive area that is affected along them, these great infrastructures represent a major conservation concern worldwide. Ants are an important component of natural ecosystems and are considered to be very sensitive to disturbance. The National Road Nº 150 is an important road of South America that forms part of the Central Bioceanic Corridor which will connect Brazil with Chile. In its trajectory, it crosses the Ischigualasto Provincial Park in Argentina. In order to evaluate the effects of this road on biodiversity in roadsides that run across this protected area, we compared species and functional group diversity of ants collected using pitfall traps between disturbed and undisturbed sites. In addition, we analyzed whether habitat variables, such as plant cover, gravel cover and soil hardness, explain ant species and functional group abundance in both site types. Twenty-one and 17 ant species were caught in disturbed and undisturbed sites, respectively. Roadside contained relatively more exclusives and rare species, while undisturbed sites harbored more common and dominant species. Hot climate specialists were more abundant at disturbed sites, whereas Opportunists at undisturbed sites. Ant species abundance seems to be positively in uenced by gravel cover on roadside. In the present context of land use change, roadside could have an important function as reservoir and corridor for some ant species, and thus, plays a valuable role in the conservation of ant diversity in arid ecosystems.
Several rodent species engage in group living, meaning that individuals share nests, resting plac... more Several rodent species engage in group living, meaning that individuals share nests, resting places, and range areas. Establishing how group living varies across species is critical for comparative studies to examine the origin and the adaptive value of this behavior. Comparative approaches are more powerful when a diverse array of taxonomic groups is included. We used telemetry techniques to monitor patterns of activity, resting places, and range areas at night to examine the extent of sociality of the scarcely known viscacha rats, Octomys mimax. Seven individuals were live trapped and fitted with radio-collars. Viscacha rat activity, as measured from distance moved between consecutive telemetry scans, took place mostly during the nighttime. During day, animals used from 2 to 6 putative nest places, but one was used more frequently. The sharing of resting locations by two or more radio-collared animals was never recorded. Viscacha rats showed relatively large range areas and low-to-moderate spatial overlap with neighbors. Male rats had larger range areas than females, but spatial overlap with neighbors was similar. Results suggest that viscacha rats are solitary living animals. This study supported a solitary-to-social trend from basal to more derivate forms across Octodontidae.
... by plants microtechniques and histology and their application to cottontail rabbit food habit... more ... by plants microtechniques and histology and their application to cottontail rabbit food habits. J. Wild. Manage. 13:295-298. Hansen, RM 1975. Foods of the hoary mar-mot on Kenai Peninsula, Alaska. American Mid. Nat., 94:348-353. Johansen, DA 1940. Plant microtechnique. ...
Microhistological analysis has become the most commonly used and successful method for determinin... more Microhistological analysis has become the most commonly used and successful method for determining micromammal diets. However, this technique has a number of limitations, particularly when used on fecal samples where identification of some items is difficult. This method underestimates those nearly unrecognizable plant parts in the diet, such as seed, and overestimates easily identifiable parts, such as leaf epidermis. In this note we describe a simple technique that uses a macerating solution of 17.5% NaHCO 3 for preparing reference slides of seeds. Advantages of the proposed method are discussed and compared with Jeffrey's technique.
In desert areas, predation risk is one of the highest costs of foraging and is a major influence ... more In desert areas, predation risk is one of the highest costs of foraging and is a major influence on animal behaviour. Several strategies are used by foragers for surviving and reproducing in desert areas. The foraging strategies of the small mammals of South American deserts are still poorly known. In this study, we investigated the foraging strategies of rodents of the Monte Desert in response to distance from seed sources to sheltered sites (i.e. shrubs) during two different seasons (wet and dry). We evaluated the relative rates of removal of two species of seeds (millet and sunflower) by rodents at two sites by establishing 80 seed sources, 40 in unsheltered microhabitats and 40 in sheltered microhabitats. We recorded both the number of caches and seed consumption for each source. We found that plant cover affected the foraging activity of rodents of the sand dunes in the Monte Desert because both consumption and numbers of caches constructed from sheltered seed sources were higher than those from unsheltered ones. Consumption of sunflower was higher in the wet season than it was in the dry season, when millet consumption increased. Sunflower was the preferred seed both from sheltered or unsheltered sources. We discuss the possible causes of the different foraging strategies used by rodents of the Monte Desert.
Revista Argentina de Ciencias del Comportamiento ( RACC ), 2016
ecología del comportamiento. EL ESTADO DE ALIMENTACIÓN DE RENACUAJOS MODULA LA ADQUISICIÓN DE UN ... more ecología del comportamiento. EL ESTADO DE ALIMENTACIÓN DE RENACUAJOS MODULA LA ADQUISICIÓN DE UN APRENDIZAJE.
Ramorinoa girolae Speg. (chica) is an endemic tree species which belongs to the Argentinian xerop... more Ramorinoa girolae Speg. (chica) is an endemic tree species which belongs to the Argentinian xerophyte flora. This species constitutes an appreciated forest resource for local people due to its fruits (a substantial basis of the diet of local communities) and its timber (one of the hardest woods). Moreover, chica was pointed as a vulnerable species because it is a monotypic species with low abundance and a very restricted endemism (San Juan, San Luis and La Rioja provinces). There is limited information concerning the status of genetic diversity of the species. For this, we performed an exploratory analysis to characterize the genetic diversity of a natural population located near Ischigualasto Provincial Park (San Juan, Argentina) using AFLP molecular markers in 19 individuals. The genetic data were correlated with morphometric, ecological and geographical data. Our results suggest that this population exhibited a high genetic diversity (Pj=82.3%). These values also were correlated with geographical matrices, revealing that this population exhibited a particular spatial genetic structure (SGS; Mantel Test r=0.45, P<0.001) and spatial autocorrelation. In addition, values of genetic similarity among the different analyzed individuals revealed the absence of clones, suggesting a significant contribution of genetic variability due to sexual reproduction in the studied population.
The aim of this study was to analyze and compare vigilance behavior and intermittent locomotion a... more The aim of this study was to analyze and compare vigilance behavior and intermittent locomotion at two sites (El Leoncito and Ñacuñán, Argentina) that differ in predation risk, plant structure, and plant resource availability. Subjects were lesser cavies (Microcavia australis), a social species that is semi-fossorial, diurnal, and native to South America. Continuous focal sampling was conducted during the day,
In desert areas, predation risk is one of the highest costs of foraging and is a major influence ... more In desert areas, predation risk is one of the highest costs of foraging and is a major influence on animal behaviour. Several strategies are used by foragers for surviving and reproducing in desert areas. The foraging strategies of the small mammals of South American deserts are still poorly known. In this study, we investigated the foraging strategies of rodents of the Monte Desert in response to distance from seed sources to sheltered sites (i.e. shrubs) during two different seasons (wet and dry). We evaluated the relative rates of removal of two species of seeds (millet and sunflower) by rodents at two sites by establishing 80 seed sources, 40 in unsheltered microhabitats and 40 in sheltered microhabitats. We recorded both the number of caches and seed consumption for each source. We found that plant cover affected the foraging activity of rodents of the sand dunes in the Monte Desert because both consumption and numbers of caches constructed from sheltered seed sources were higher than those from unsheltered ones. Consumption of sunflower was higher in the wet season than it was in the dry season, when millet consumption increased. Sunflower was the preferred seed both from sheltered or unsheltered sources. We discuss the possible causes of the different foraging strategies used by rodents of the Monte Desert.
Linear infrastructures such as roads are among the most frequent generators of anthropogenic dist... more Linear infrastructures such as roads are among the most frequent generators of anthropogenic disturbances. Due to the expensive area that is affected along them, these great infrastructures represent a major conservation concern worldwide. Ants are an important component of natural ecosystems and are considered to be very sensitive to disturbance. The National Road Nº 150 is an important road of South America that forms part of the Central Bioceanic Corridor which will connect Brazil with Chile. In its trajectory, it crosses the Ischigualasto Provincial Park in Argentina. In order to evaluate the effects of this road on biodiversity in roadsides that run across this protected area, we compared species and functional group diversity of ants collected using pitfall traps between disturbed and undisturbed sites. In addition, we analyzed whether habitat variables, such as plant cover, gravel cover and soil hardness, explain ant species and functional group abundance in both site types. Twenty-one and 17 ant species were caught in disturbed and undisturbed sites, respectively. Roadside contained relatively more exclusives and rare species, while undisturbed sites harbored more common and dominant species. Hot climate specialists were more abundant at disturbed sites, whereas Opportunists at undisturbed sites. Ant species abundance seems to be positively in uenced by gravel cover on roadside. In the present context of land use change, roadside could have an important function as reservoir and corridor for some ant species, and thus, plays a valuable role in the conservation of ant diversity in arid ecosystems.
Several rodent species engage in group living, meaning that individuals share nests, resting plac... more Several rodent species engage in group living, meaning that individuals share nests, resting places, and range areas. Establishing how group living varies across species is critical for comparative studies to examine the origin and the adaptive value of this behavior. Comparative approaches are more powerful when a diverse array of taxonomic groups is included. We used telemetry techniques to monitor patterns of activity, resting places, and range areas at night to examine the extent of sociality of the scarcely known viscacha rats, Octomys mimax. Seven individuals were live trapped and fitted with radio-collars. Viscacha rat activity, as measured from distance moved between consecutive telemetry scans, took place mostly during the nighttime. During day, animals used from 2 to 6 putative nest places, but one was used more frequently. The sharing of resting locations by two or more radio-collared animals was never recorded. Viscacha rats showed relatively large range areas and low-to-moderate spatial overlap with neighbors. Male rats had larger range areas than females, but spatial overlap with neighbors was similar. Results suggest that viscacha rats are solitary living animals. This study supported a solitary-to-social trend from basal to more derivate forms across Octodontidae.
... by plants microtechniques and histology and their application to cottontail rabbit food habit... more ... by plants microtechniques and histology and their application to cottontail rabbit food habits. J. Wild. Manage. 13:295-298. Hansen, RM 1975. Foods of the hoary mar-mot on Kenai Peninsula, Alaska. American Mid. Nat., 94:348-353. Johansen, DA 1940. Plant microtechnique. ...
Microhistological analysis has become the most commonly used and successful method for determinin... more Microhistological analysis has become the most commonly used and successful method for determining micromammal diets. However, this technique has a number of limitations, particularly when used on fecal samples where identification of some items is difficult. This method underestimates those nearly unrecognizable plant parts in the diet, such as seed, and overestimates easily identifiable parts, such as leaf epidermis. In this note we describe a simple technique that uses a macerating solution of 17.5% NaHCO 3 for preparing reference slides of seeds. Advantages of the proposed method are discussed and compared with Jeffrey's technique.
In desert areas, predation risk is one of the highest costs of foraging and is a major influence ... more In desert areas, predation risk is one of the highest costs of foraging and is a major influence on animal behaviour. Several strategies are used by foragers for surviving and reproducing in desert areas. The foraging strategies of the small mammals of South American deserts are still poorly known. In this study, we investigated the foraging strategies of rodents of the Monte Desert in response to distance from seed sources to sheltered sites (i.e. shrubs) during two different seasons (wet and dry). We evaluated the relative rates of removal of two species of seeds (millet and sunflower) by rodents at two sites by establishing 80 seed sources, 40 in unsheltered microhabitats and 40 in sheltered microhabitats. We recorded both the number of caches and seed consumption for each source. We found that plant cover affected the foraging activity of rodents of the sand dunes in the Monte Desert because both consumption and numbers of caches constructed from sheltered seed sources were higher than those from unsheltered ones. Consumption of sunflower was higher in the wet season than it was in the dry season, when millet consumption increased. Sunflower was the preferred seed both from sheltered or unsheltered sources. We discuss the possible causes of the different foraging strategies used by rodents of the Monte Desert.
Revista Argentina de Ciencias del Comportamiento ( RACC ), 2016
ecología del comportamiento. EL ESTADO DE ALIMENTACIÓN DE RENACUAJOS MODULA LA ADQUISICIÓN DE UN ... more ecología del comportamiento. EL ESTADO DE ALIMENTACIÓN DE RENACUAJOS MODULA LA ADQUISICIÓN DE UN APRENDIZAJE.
Ramorinoa girolae Speg. (chica) is an endemic tree species which belongs to the Argentinian xerop... more Ramorinoa girolae Speg. (chica) is an endemic tree species which belongs to the Argentinian xerophyte flora. This species constitutes an appreciated forest resource for local people due to its fruits (a substantial basis of the diet of local communities) and its timber (one of the hardest woods). Moreover, chica was pointed as a vulnerable species because it is a monotypic species with low abundance and a very restricted endemism (San Juan, San Luis and La Rioja provinces). There is limited information concerning the status of genetic diversity of the species. For this, we performed an exploratory analysis to characterize the genetic diversity of a natural population located near Ischigualasto Provincial Park (San Juan, Argentina) using AFLP molecular markers in 19 individuals. The genetic data were correlated with morphometric, ecological and geographical data. Our results suggest that this population exhibited a high genetic diversity (Pj=82.3%). These values also were correlated with geographical matrices, revealing that this population exhibited a particular spatial genetic structure (SGS; Mantel Test r=0.45, P<0.001) and spatial autocorrelation. In addition, values of genetic similarity among the different analyzed individuals revealed the absence of clones, suggesting a significant contribution of genetic variability due to sexual reproduction in the studied population.
The aim of this study was to analyze and compare vigilance behavior and intermittent locomotion a... more The aim of this study was to analyze and compare vigilance behavior and intermittent locomotion at two sites (El Leoncito and Ñacuñán, Argentina) that differ in predation risk, plant structure, and plant resource availability. Subjects were lesser cavies (Microcavia australis), a social species that is semi-fossorial, diurnal, and native to South America. Continuous focal sampling was conducted during the day,
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