Fernando Videla - Academia.edu (original) (raw)

Papers by Fernando Videla

Journal of Herpetology, 2001

... Hence, Li(X, ai, P) = aoi + Plxl + 2X2 + -.+ pnXn for i = 1, 2, ..., k - 1, and L(X, ati, P) ... more ... Hence, Li(X, ai, P) = aoi + Plxl + 2X2 + -.+ pnXn for i = 1, 2, ..., k - 1, and L(X, ati, P) =-(atk-+ 3iX1 + 2X2 +.. ... Eyelid granular bordered by small, protruding cili-aries: two enlarged, pointed suboculars, fol-lowed by four heavy, swollen, keeled scales. ...

Boletin De La Asociacion Herpetologica Argentina, 1985

Studies on Neotropical Fauna and Environment, 2003

The seasonal diet of Ctenomys mendocinus was determined in a habitat of the Andean Precordillera,... more The seasonal diet of Ctenomys mendocinus was determined in a habitat of the Andean Precordillera, through microhistological analyses of stomach contents and in relation to food availability. Diet included 23 genera of plants and only 6 of them were consumed with frequencies higher than 4%. The grasses Stipa and Elymus comprised about 80% of the diet. A high proportion of aerial plant material was registered throughout the year suggesting a tendency to forage on the surface. Dietary selectivity was evidenced by a preferential consumption of grasses and avoidance of shrubs. Moreover, most dietary items frequently used were eaten in proportions that differed from their availabilities. This non-opportunistic feeding behavior, specialized in a few dietary items, did not agree with the one expected for a subterranean rodent inhabiting an environment with severe climatic conditions, low food availability and patchy distribution of food resources.

Mammalian Biology - Zeitschrift für Säugetierkunde, 2007

The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its in... more The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its introduction at the end of the 19th century. Studies on hare feeding ecology are important to evaluate a potential competition with domestic and native wild herbivores. This study analyses the brown hare diet in relation to food availability, and dietary overlaps with several herbivores in northern Patagonia. Food availability was estimated by point-quadrat transects, and hare diet by microhistological analysis of faeces, carried out in five habitats in five seasonal samplings. Significant differences were detected by Kruskall-Wallis ANOVA with multiple comparisons by Tukey test. Feeding selection was detected by w 2 test, and dietary preferences by the confidence interval of Bailey. Grasses and chamaephytes were the most available plant categories, with Stipa, Panicum and Acantholippia as main species. Grasses and phanerophytes were the main dietary categories, including Poa, Panicum, Bromus, Adesmia and Prosopidastrum. The phanerophytes Prosopidastrum and Ephedra were more eaten in winter, when the main food item (Poa) presented lower availability. A higher dietary proportion of the chamaephyte Acantholippia occurred in rocky habitats, where the coarse dominant grasses were always avoided. Hares shared most food items with several wild and domestic herbivores in northern Patagonia. The lack of preference for forbs differentiates brown hares from other herbivores. However, hares exhibited important dietary similarities with plain and mountain vizcachas, goats and horses, and an interspecific competition for food is highly probable.

Mammalian Biology - Zeitschrift für Säugetierkunde, 2011

Guanaco populations face different feeding constraints along their altitudinal migrations in Ande... more Guanaco populations face different feeding constraints along their altitudinal migrations in Andean mountains. The guanaco's diet and food availability were analyzed using microhistological analysis and point-quadrat transects at four sampling sites from the summer range, and four sites from the winter range of a High Andean migratory population. Significant differences were detected with Kruskal-Wallis ANOVA, feeding selection by the 2 test, and dietary preferences by Bailey's confidence interval. Summer range was characterized by having higher plant diversity with more availability of grass-likes (Ciperaceae and Juncaceae) and forbs, compared to winter range. Sites with vegas (moist areas associated to streams and ponds, with dense hydrophytic vegetation) showed higher plant cover and diversity, also diet diversity was higher. Diet was dominated by grass-likes and grasses at sites with wetlands, only by grasses at the other sites, especially in winter. The highest diet-availability similarity occurred in the vega microhabitat, but species from slopes were also eaten at sites with wetlands. Grasses were preferred and shrubs were avoided in both seasonal ranges. The narrower guanaco's diet in winter, and the higher dietary diversity where plant cover and diversity are higher, both agree with the hypothesis of selective quality. A summer opportunistic feeding behavior shifts to a more selective behavior during winter. Winter browsing barely occurred, and grasses prevailed in the diet of both seasons. Altitudinal migration, forced by the deep snow, could favor guanacos to maintain a grazer strategy year round. Vegas and grasslands, in the summer and winter ranges, have a high feeding relevance for this guanaco population, and connectivity between both ranges is essential for their survival.

Martínez Carretero, Eduardo Ed.; Damiani, Oscar A.; Acosta, JC; Villavicencio, HJ; Marinero, JA; ... more Martínez Carretero, Eduardo Ed.; Damiani, Oscar A.; Acosta, JC; Villavicencio, HJ; Marinero, JA; García, A.; López Frese, C.; Ortiz, SG; Borghi, CE; Puig, S.; Videla, Fernando; Zambrano, JJ; Suvires, GM; Salvioli, Gerardo H.; Giannoni, SM; Márquez, J.; Pastrán, G.; Fernández, N.; Jofré, C.; Carrizo, A.; Eguaburo, A.; Cabello, H.; Martinelli, Mariana; Salmuni, G.; Garcés, G.; Rodriguez Groves, Valeria; Losada, R.; Del Valle Ruiz, L.; Dalmasso, A. ... Diversidad biológica y cultural de los altos Andes centrales de Argentina : línea de base de la reserva de biosfera San ...

Mammalian Biology Zeitschrift Fur Saugetierkunde, 1996

The structure and size of burrow systems of Ctenomys mendocinus were analysed in the present study.

Revista De La Facultad De Ciencias Agrarias Universidad Nacional De Cuyo, Jun 1, 2013

The lesser rhea (family Rheidae) is a flightless large bird of South America, threatened due to h... more The lesser rhea (family Rheidae) is a flightless large bird of South America, threatened due to habitat loss, hunting and egg collecting, with special concern in Northern Patagonia. Diet and food availability were estimated throughout the year by micro-histological analysis and point-quadrat transects in a landscape inside and another outside the Payunia Reserve, the northernmost part of the Rhea pennata pennata distribution. Significant differences were detected by Kruskall-Wallis ANOVA, food selection by Chi-square test and Bailey’s confidence interval. A strong food selection characterized the diet of lesser rheas, dominated by leaves of shrubs and forbs, complemented by dicot seeds and a few insects. This agrees with the documented low dietary overlap with other herbivores in Payunia. Dietary changes agree with the expected from the selective quality hypothesis. Food availability was better inside than outside the protected area, with probable conservation effects for lesser rhe...

Acta Theriologica, 2000

Maria 1. ROSI, M6nica 1. CONA, Fernando VIDELA, Silvia PUIG, and Virgilio G. ROIG Rosi M. 1., Con... more Maria 1. ROSI, M6nica 1. CONA, Fernando VIDELA, Silvia PUIG, and Virgilio G. ROIG Rosi M. 1., Cona M. 1., Videla F., Puig S. and Roig V. G. 2000. Architecture of Ctenomys mendocinus (Rodentia) burrows from two habitats differing in abundance and complexity of vegetation. Acta Theriologica 45: 491-505.

Acta Theriologica, 2014

ABSTRACT Wild ungulates like the guanaco are exposed to important changes in climate and plant di... more ABSTRACT Wild ungulates like the guanaco are exposed to important changes in climate and plant diversity along altitudinal gradients in the Andes Mountains, such as in the Southern Andean Precordillera where three phytogeographic provinces are present in altitudinal belts. The guanaco's diet and food availability were seasonally analyzed using microhistological analysis and point-quadrat transects at six sampling sites, representative of the phytogeographic belts along the altitudinal gradient. Plant cover and diversity decreased with growing altitude. Richness of plant species was poorer at the summit than in the lower altitudes, whereas the proportion of species eaten by guanacos increased with altitude. The diet included 77 species. Grasses were preferred and shrubs were avoided all year round. The grass Poa spp. occupied more than 50 % of the diet at all altitudes. Grasses were the main dietary item even at low altitudes, where shrubs constituted the main food available. Decreasing generalism with descending phytogeographic belts agrees with the prediction for altitudinal gradients. The increase of diversity in the diet during the winter decline of plant cover at high and middle altitudes follows that expected from the optimal foraging theory. The winter decline of vegetation and the dietary shift from grazing to browsing proved to be stronger as altitude increases and the climate become more rigorous. Plant species richness, food scarcity, and climate severity are relevant variables to explain altitudinal and seasonal changes in the diet of adaptive ungulates in mountain environments, such as the guanaco in the Southern Andean Precordillera.

Studies on Neotropical Fauna and Environment, 2003

The seasonal diet of Ctenomys mendocinus was determined in a habitat of the Andean Precordillera,... more The seasonal diet of Ctenomys mendocinus was determined in a habitat of the Andean Precordillera, through microhistological analyses of stomach contents and in relation to food availability. Diet included 23 genera of plants and only 6 of them were consumed with frequencies higher than 4%. The grasses Stipa and Elymus comprised about 80% of the diet. A high proportion of aerial plant material was registered throughout the year suggesting a tendency to forage on the surface. Dietary selectivity was evidenced by a preferential consumption of grasses and avoidance of shrubs. Moreover, most dietary items frequently used were eaten in proportions that differed from their availabilities. This non-opportunistic feeding behavior, specialized in a few dietary items, did not agree with the one expected for a subterranean rodent inhabiting an environment with severe climatic conditions, low food availability and patchy distribution of food resources.

Studies on Neotropical Fauna and Environment, 2008

Mammalian Biology - Zeitschrift für Säugetierkunde, 2007

The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its in... more The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its introduction at the end of the 19th century. Studies on hare feeding ecology are important to evaluate a potential competition with domestic and native wild herbivores. This study analyses the brown hare diet in relation to food availability, and dietary overlaps with several herbivores in northern Patagonia. Food availability was estimated by point-quadrat transects, and hare diet by microhistological analysis of faeces, carried out in five habitats in five seasonal samplings. Significant differences were detected by Kruskall-Wallis ANOVA with multiple comparisons by Tukey test. Feeding selection was detected by w 2 test, and dietary preferences by the confidence interval of Bailey. Grasses and chamaephytes were the most available plant categories, with Stipa, Panicum and Acantholippia as main species. Grasses and phanerophytes were the main dietary categories, including Poa, Panicum, Bromus, Adesmia and Prosopidastrum. The phanerophytes Prosopidastrum and Ephedra were more eaten in winter, when the main food item (Poa) presented lower availability. A higher dietary proportion of the chamaephyte Acantholippia occurred in rocky habitats, where the coarse dominant grasses were always avoided. Hares shared most food items with several wild and domestic herbivores in northern Patagonia. The lack of preference for forbs differentiates brown hares from other herbivores. However, hares exhibited important dietary similarities with plain and mountain vizcachas, goats and horses, and an interspecific competition for food is highly probable.

Mammalian Biology - Zeitschrift für Säugetierkunde, 2011

Guanaco populations face different feeding constraints along their altitudinal migrations in Ande... more Guanaco populations face different feeding constraints along their altitudinal migrations in Andean mountains. The guanaco's diet and food availability were analyzed using microhistological analysis and point-quadrat transects at four sampling sites from the summer range, and four sites from the winter range of a High Andean migratory population. Significant differences were detected with Kruskal-Wallis ANOVA, feeding selection by the 2 test, and dietary preferences by Bailey's confidence interval. Summer range was characterized by having higher plant diversity with more availability of grass-likes (Ciperaceae and Juncaceae) and forbs, compared to winter range. Sites with vegas (moist areas associated to streams and ponds, with dense hydrophytic vegetation) showed higher plant cover and diversity, also diet diversity was higher. Diet was dominated by grass-likes and grasses at sites with wetlands, only by grasses at the other sites, especially in winter. The highest diet-availability similarity occurred in the vega microhabitat, but species from slopes were also eaten at sites with wetlands. Grasses were preferred and shrubs were avoided in both seasonal ranges. The narrower guanaco's diet in winter, and the higher dietary diversity where plant cover and diversity are higher, both agree with the hypothesis of selective quality. A summer opportunistic feeding behavior shifts to a more selective behavior during winter. Winter browsing barely occurred, and grasses prevailed in the diet of both seasons. Altitudinal migration, forced by the deep snow, could favor guanacos to maintain a grazer strategy year round. Vegas and grasslands, in the summer and winter ranges, have a high feeding relevance for this guanaco population, and connectivity between both ranges is essential for their survival.

mammalia, 2000

Introduced brown hares are present across the distribution range of maras, which are endemic to A... more Introduced brown hares are present across the distribution range of maras, which are endemic to Argentina's open steppes. Food competition with exotic herbivores could be partially responsible for declines in mara populations. Diets of sympatric hares and maras were compared to detect dietary overlap according to food availability. Diets and availability were estimated using microhistological analysis and point-quadrat transects, over four seasons. Horn's index estimated dietary overlap, Kruskal-Wallis ANOVA detected significant differences, and permutational multivariate analysis of variance (Per-MANOVA) determined the multivariate response to factors. Grasses prevailed among available items and in both diets. Plant cover and richness increased in summer and forbs in spring. High dietary overlap decreased in autumnwinter, when hares ate more forbs and tall shrubs and less low shrubs than maras. Interspecific overlap was higher inside a protected area with higher food diversity, more forbs, and low shrubs. Both herbivores shifted to different foods as availability decreased. When forbs declined, they were less eaten by maras than hares. Broader habitat use allows hares to search for preferred forbs farther away than maras. The more adaptive hare could become a stronger competitor in impacted environments. Better food availability inside than outside the protected area is a feeding advantage for the coexistence of these herbivores.

Journal of Herpetology, 2001

... Hence, Li(X, ai, P) = aoi + Plxl + 2X2 + -.+ pnXn for i = 1, 2, ..., k - 1, and L(X, ati, P) ... more ... Hence, Li(X, ai, P) = aoi + Plxl + 2X2 + -.+ pnXn for i = 1, 2, ..., k - 1, and L(X, ati, P) =-(atk-+ 3iX1 + 2X2 +.. ... Eyelid granular bordered by small, protruding cili-aries: two enlarged, pointed suboculars, fol-lowed by four heavy, swollen, keeled scales. ...

Boletin De La Asociacion Herpetologica Argentina, 1985

Studies on Neotropical Fauna and Environment, 2003

The seasonal diet of Ctenomys mendocinus was determined in a habitat of the Andean Precordillera,... more The seasonal diet of Ctenomys mendocinus was determined in a habitat of the Andean Precordillera, through microhistological analyses of stomach contents and in relation to food availability. Diet included 23 genera of plants and only 6 of them were consumed with frequencies higher than 4%. The grasses Stipa and Elymus comprised about 80% of the diet. A high proportion of aerial plant material was registered throughout the year suggesting a tendency to forage on the surface. Dietary selectivity was evidenced by a preferential consumption of grasses and avoidance of shrubs. Moreover, most dietary items frequently used were eaten in proportions that differed from their availabilities. This non-opportunistic feeding behavior, specialized in a few dietary items, did not agree with the one expected for a subterranean rodent inhabiting an environment with severe climatic conditions, low food availability and patchy distribution of food resources.

Mammalian Biology - Zeitschrift für Säugetierkunde, 2007

The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its in... more The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its introduction at the end of the 19th century. Studies on hare feeding ecology are important to evaluate a potential competition with domestic and native wild herbivores. This study analyses the brown hare diet in relation to food availability, and dietary overlaps with several herbivores in northern Patagonia. Food availability was estimated by point-quadrat transects, and hare diet by microhistological analysis of faeces, carried out in five habitats in five seasonal samplings. Significant differences were detected by Kruskall-Wallis ANOVA with multiple comparisons by Tukey test. Feeding selection was detected by w 2 test, and dietary preferences by the confidence interval of Bailey. Grasses and chamaephytes were the most available plant categories, with Stipa, Panicum and Acantholippia as main species. Grasses and phanerophytes were the main dietary categories, including Poa, Panicum, Bromus, Adesmia and Prosopidastrum. The phanerophytes Prosopidastrum and Ephedra were more eaten in winter, when the main food item (Poa) presented lower availability. A higher dietary proportion of the chamaephyte Acantholippia occurred in rocky habitats, where the coarse dominant grasses were always avoided. Hares shared most food items with several wild and domestic herbivores in northern Patagonia. The lack of preference for forbs differentiates brown hares from other herbivores. However, hares exhibited important dietary similarities with plain and mountain vizcachas, goats and horses, and an interspecific competition for food is highly probable.

Mammalian Biology - Zeitschrift für Säugetierkunde, 2011

Guanaco populations face different feeding constraints along their altitudinal migrations in Ande... more Guanaco populations face different feeding constraints along their altitudinal migrations in Andean mountains. The guanaco's diet and food availability were analyzed using microhistological analysis and point-quadrat transects at four sampling sites from the summer range, and four sites from the winter range of a High Andean migratory population. Significant differences were detected with Kruskal-Wallis ANOVA, feeding selection by the 2 test, and dietary preferences by Bailey's confidence interval. Summer range was characterized by having higher plant diversity with more availability of grass-likes (Ciperaceae and Juncaceae) and forbs, compared to winter range. Sites with vegas (moist areas associated to streams and ponds, with dense hydrophytic vegetation) showed higher plant cover and diversity, also diet diversity was higher. Diet was dominated by grass-likes and grasses at sites with wetlands, only by grasses at the other sites, especially in winter. The highest diet-availability similarity occurred in the vega microhabitat, but species from slopes were also eaten at sites with wetlands. Grasses were preferred and shrubs were avoided in both seasonal ranges. The narrower guanaco's diet in winter, and the higher dietary diversity where plant cover and diversity are higher, both agree with the hypothesis of selective quality. A summer opportunistic feeding behavior shifts to a more selective behavior during winter. Winter browsing barely occurred, and grasses prevailed in the diet of both seasons. Altitudinal migration, forced by the deep snow, could favor guanacos to maintain a grazer strategy year round. Vegas and grasslands, in the summer and winter ranges, have a high feeding relevance for this guanaco population, and connectivity between both ranges is essential for their survival.

Martínez Carretero, Eduardo Ed.; Damiani, Oscar A.; Acosta, JC; Villavicencio, HJ; Marinero, JA; ... more Martínez Carretero, Eduardo Ed.; Damiani, Oscar A.; Acosta, JC; Villavicencio, HJ; Marinero, JA; García, A.; López Frese, C.; Ortiz, SG; Borghi, CE; Puig, S.; Videla, Fernando; Zambrano, JJ; Suvires, GM; Salvioli, Gerardo H.; Giannoni, SM; Márquez, J.; Pastrán, G.; Fernández, N.; Jofré, C.; Carrizo, A.; Eguaburo, A.; Cabello, H.; Martinelli, Mariana; Salmuni, G.; Garcés, G.; Rodriguez Groves, Valeria; Losada, R.; Del Valle Ruiz, L.; Dalmasso, A. ... Diversidad biológica y cultural de los altos Andes centrales de Argentina : línea de base de la reserva de biosfera San ...

Mammalian Biology Zeitschrift Fur Saugetierkunde, 1996

The structure and size of burrow systems of Ctenomys mendocinus were analysed in the present study.

Revista De La Facultad De Ciencias Agrarias Universidad Nacional De Cuyo, Jun 1, 2013

The lesser rhea (family Rheidae) is a flightless large bird of South America, threatened due to h... more The lesser rhea (family Rheidae) is a flightless large bird of South America, threatened due to habitat loss, hunting and egg collecting, with special concern in Northern Patagonia. Diet and food availability were estimated throughout the year by micro-histological analysis and point-quadrat transects in a landscape inside and another outside the Payunia Reserve, the northernmost part of the Rhea pennata pennata distribution. Significant differences were detected by Kruskall-Wallis ANOVA, food selection by Chi-square test and Bailey’s confidence interval. A strong food selection characterized the diet of lesser rheas, dominated by leaves of shrubs and forbs, complemented by dicot seeds and a few insects. This agrees with the documented low dietary overlap with other herbivores in Payunia. Dietary changes agree with the expected from the selective quality hypothesis. Food availability was better inside than outside the protected area, with probable conservation effects for lesser rhe...

Acta Theriologica, 2000

Maria 1. ROSI, M6nica 1. CONA, Fernando VIDELA, Silvia PUIG, and Virgilio G. ROIG Rosi M. 1., Con... more Maria 1. ROSI, M6nica 1. CONA, Fernando VIDELA, Silvia PUIG, and Virgilio G. ROIG Rosi M. 1., Cona M. 1., Videla F., Puig S. and Roig V. G. 2000. Architecture of Ctenomys mendocinus (Rodentia) burrows from two habitats differing in abundance and complexity of vegetation. Acta Theriologica 45: 491-505.

Acta Theriologica, 2014

ABSTRACT Wild ungulates like the guanaco are exposed to important changes in climate and plant di... more ABSTRACT Wild ungulates like the guanaco are exposed to important changes in climate and plant diversity along altitudinal gradients in the Andes Mountains, such as in the Southern Andean Precordillera where three phytogeographic provinces are present in altitudinal belts. The guanaco's diet and food availability were seasonally analyzed using microhistological analysis and point-quadrat transects at six sampling sites, representative of the phytogeographic belts along the altitudinal gradient. Plant cover and diversity decreased with growing altitude. Richness of plant species was poorer at the summit than in the lower altitudes, whereas the proportion of species eaten by guanacos increased with altitude. The diet included 77 species. Grasses were preferred and shrubs were avoided all year round. The grass Poa spp. occupied more than 50 % of the diet at all altitudes. Grasses were the main dietary item even at low altitudes, where shrubs constituted the main food available. Decreasing generalism with descending phytogeographic belts agrees with the prediction for altitudinal gradients. The increase of diversity in the diet during the winter decline of plant cover at high and middle altitudes follows that expected from the optimal foraging theory. The winter decline of vegetation and the dietary shift from grazing to browsing proved to be stronger as altitude increases and the climate become more rigorous. Plant species richness, food scarcity, and climate severity are relevant variables to explain altitudinal and seasonal changes in the diet of adaptive ungulates in mountain environments, such as the guanaco in the Southern Andean Precordillera.

Studies on Neotropical Fauna and Environment, 2003

The seasonal diet of Ctenomys mendocinus was determined in a habitat of the Andean Precordillera,... more The seasonal diet of Ctenomys mendocinus was determined in a habitat of the Andean Precordillera, through microhistological analyses of stomach contents and in relation to food availability. Diet included 23 genera of plants and only 6 of them were consumed with frequencies higher than 4%. The grasses Stipa and Elymus comprised about 80% of the diet. A high proportion of aerial plant material was registered throughout the year suggesting a tendency to forage on the surface. Dietary selectivity was evidenced by a preferential consumption of grasses and avoidance of shrubs. Moreover, most dietary items frequently used were eaten in proportions that differed from their availabilities. This non-opportunistic feeding behavior, specialized in a few dietary items, did not agree with the one expected for a subterranean rodent inhabiting an environment with severe climatic conditions, low food availability and patchy distribution of food resources.

Studies on Neotropical Fauna and Environment, 2008

Mammalian Biology - Zeitschrift für Säugetierkunde, 2007

The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its in... more The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its introduction at the end of the 19th century. Studies on hare feeding ecology are important to evaluate a potential competition with domestic and native wild herbivores. This study analyses the brown hare diet in relation to food availability, and dietary overlaps with several herbivores in northern Patagonia. Food availability was estimated by point-quadrat transects, and hare diet by microhistological analysis of faeces, carried out in five habitats in five seasonal samplings. Significant differences were detected by Kruskall-Wallis ANOVA with multiple comparisons by Tukey test. Feeding selection was detected by w 2 test, and dietary preferences by the confidence interval of Bailey. Grasses and chamaephytes were the most available plant categories, with Stipa, Panicum and Acantholippia as main species. Grasses and phanerophytes were the main dietary categories, including Poa, Panicum, Bromus, Adesmia and Prosopidastrum. The phanerophytes Prosopidastrum and Ephedra were more eaten in winter, when the main food item (Poa) presented lower availability. A higher dietary proportion of the chamaephyte Acantholippia occurred in rocky habitats, where the coarse dominant grasses were always avoided. Hares shared most food items with several wild and domestic herbivores in northern Patagonia. The lack of preference for forbs differentiates brown hares from other herbivores. However, hares exhibited important dietary similarities with plain and mountain vizcachas, goats and horses, and an interspecific competition for food is highly probable.

Mammalian Biology - Zeitschrift für Säugetierkunde, 2011

Guanaco populations face different feeding constraints along their altitudinal migrations in Ande... more Guanaco populations face different feeding constraints along their altitudinal migrations in Andean mountains. The guanaco's diet and food availability were analyzed using microhistological analysis and point-quadrat transects at four sampling sites from the summer range, and four sites from the winter range of a High Andean migratory population. Significant differences were detected with Kruskal-Wallis ANOVA, feeding selection by the 2 test, and dietary preferences by Bailey's confidence interval. Summer range was characterized by having higher plant diversity with more availability of grass-likes (Ciperaceae and Juncaceae) and forbs, compared to winter range. Sites with vegas (moist areas associated to streams and ponds, with dense hydrophytic vegetation) showed higher plant cover and diversity, also diet diversity was higher. Diet was dominated by grass-likes and grasses at sites with wetlands, only by grasses at the other sites, especially in winter. The highest diet-availability similarity occurred in the vega microhabitat, but species from slopes were also eaten at sites with wetlands. Grasses were preferred and shrubs were avoided in both seasonal ranges. The narrower guanaco's diet in winter, and the higher dietary diversity where plant cover and diversity are higher, both agree with the hypothesis of selective quality. A summer opportunistic feeding behavior shifts to a more selective behavior during winter. Winter browsing barely occurred, and grasses prevailed in the diet of both seasons. Altitudinal migration, forced by the deep snow, could favor guanacos to maintain a grazer strategy year round. Vegas and grasslands, in the summer and winter ranges, have a high feeding relevance for this guanaco population, and connectivity between both ranges is essential for their survival.

mammalia, 2000

Introduced brown hares are present across the distribution range of maras, which are endemic to A... more Introduced brown hares are present across the distribution range of maras, which are endemic to Argentina's open steppes. Food competition with exotic herbivores could be partially responsible for declines in mara populations. Diets of sympatric hares and maras were compared to detect dietary overlap according to food availability. Diets and availability were estimated using microhistological analysis and point-quadrat transects, over four seasons. Horn's index estimated dietary overlap, Kruskal-Wallis ANOVA detected significant differences, and permutational multivariate analysis of variance (Per-MANOVA) determined the multivariate response to factors. Grasses prevailed among available items and in both diets. Plant cover and richness increased in summer and forbs in spring. High dietary overlap decreased in autumnwinter, when hares ate more forbs and tall shrubs and less low shrubs than maras. Interspecific overlap was higher inside a protected area with higher food diversity, more forbs, and low shrubs. Both herbivores shifted to different foods as availability decreased. When forbs declined, they were less eaten by maras than hares. Broader habitat use allows hares to search for preferred forbs farther away than maras. The more adaptive hare could become a stronger competitor in impacted environments. Better food availability inside than outside the protected area is a feeding advantage for the coexistence of these herbivores.