Effect of sheep grazing gradients on vegetation and soil in Peninsula Valdés, Patagonia, Argentina
The introduction of domestic livestock in the arid Patagonia produced changes in vegetation and soil that altered fundamental ecosystem processes, increasing desertification and biodiversity loss. In this region, it is common to observe gradients of decreasing animal activity from watering points where livestock impact is greatest near the watering sites, called piospheres, particularly suitable for assessing the effect of grazing on arid ecosystems. The aim of this study was to evaluate the effect of sheep-grazing intensity using piospheres on the structure of the vegetation and soil in shrubby steppes of Peninsula Valdes, Argentina. Variation of plant cover, vertical complexity of the vegetation, number and area of vegetated patches, micro-topography and soil compaction in relation to piosphere gradients were studied using Generalized Linear Mixed Models (GLMM) and multivariate analyses. Grazing intensity decreased according to increasing distance to the watering point. This fact, explaining more than 50% of the overall environmental variability, confirmed the existence of a piosphere gradient on each studied site. Such environmental changes were characterized by a gradual increase in grass and litter cover, vertical complexity of vegetation and soil microtopography at increasing distances from the watering point. Percentages of bare soil and gravel, cover of annual grasses and soil compaction showed the opposite pattern. This study demonstrates, for the first time, the existence of sheep piospheres in the shrubby steppes of Peninsula Valdes. Our results indicate that sheep-grazing intensity is associated with changes in the structure and composition of the vegetation and the soil characteristics that are compatible with degradation processes in the study region. Taking into account the importance of Peninsula Valdes in the context of biodiversity conservation, more studies of this type are required to implement effective management actions integrating livestock and conservation efforts on the terrestrial ecosystems of the region.
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Asociación Argentina de Ecología
2016
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Cheli, Germán H. Pazos, Gustavo E. Flores, Gustavo E. Corley, Juan C. |
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Cheli, Germán H. Pazos, Gustavo E. Flores, Gustavo E. Corley, Juan C. Effect of sheep grazing gradients on vegetation and soil in Peninsula Valdés, Patagonia, Argentina |
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Cheli, Germán H. Pazos, Gustavo E. Flores, Gustavo E. Corley, Juan C. |
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Cheli, Germán H. |
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Effect of sheep grazing gradients on vegetation and soil in Peninsula Valdés, Patagonia, Argentina |
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Effect of sheep grazing gradients on vegetation and soil in Peninsula Valdés, Patagonia, Argentina |
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Effect of sheep grazing gradients on vegetation and soil in Peninsula Valdés, Patagonia, Argentina |
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Effect of sheep grazing gradients on vegetation and soil in Peninsula Valdés, Patagonia, Argentina |
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Effect of sheep grazing gradients on vegetation and soil in Peninsula Valdés, Patagonia, Argentina |
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effect of sheep grazing gradients on vegetation and soil in peninsula valdés, patagonia, argentina |
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The introduction of domestic livestock in the arid Patagonia produced changes in vegetation and soil that altered fundamental ecosystem processes, increasing desertification and biodiversity loss. In this region, it is common to observe gradients of decreasing animal activity from watering points where livestock impact is greatest near the watering sites, called piospheres, particularly suitable for assessing the effect of grazing on arid ecosystems. The aim of this study was to evaluate the effect of sheep-grazing intensity using piospheres on the structure of the vegetation and soil in shrubby steppes of Peninsula Valdes, Argentina. Variation of plant cover, vertical complexity of the vegetation, number and area of vegetated patches, micro-topography and soil compaction in relation to piosphere gradients were studied using Generalized Linear Mixed Models (GLMM) and multivariate analyses. Grazing intensity decreased according to increasing distance to the watering point. This fact, explaining more than 50% of the overall environmental variability, confirmed the existence of a piosphere gradient on each studied site. Such environmental changes were characterized by a gradual increase in grass and litter cover, vertical complexity of vegetation and soil microtopography at increasing distances from the watering point. Percentages of bare soil and gravel, cover of annual grasses and soil compaction showed the opposite pattern. This study demonstrates, for the first time, the existence of sheep piospheres in the shrubby steppes of Peninsula Valdes. Our results indicate that sheep-grazing intensity is associated with changes in the structure and composition of the vegetation and the soil characteristics that are compatible with degradation processes in the study region. Taking into account the importance of Peninsula Valdes in the context of biodiversity conservation, more studies of this type are required to implement effective management actions integrating livestock and conservation efforts on the terrestrial ecosystems of the region. |
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Asociación Argentina de Ecología |
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2016 |
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https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/237 |
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rev-ecoaus-article-2372023-11-02T19:40:52Z Effect of sheep grazing gradients on vegetation and soil in Peninsula Valdés, Patagonia, Argentina Efecto de los gradientes de pastoreo ovino sobre la vegetación y el suelo en Península Valdés, Patagonia Argentina Cheli, Germán H. Pazos, Gustavo E. Flores, Gustavo E. Corley, Juan C. The introduction of domestic livestock in the arid Patagonia produced changes in vegetation and soil that altered fundamental ecosystem processes, increasing desertification and biodiversity loss. In this region, it is common to observe gradients of decreasing animal activity from watering points where livestock impact is greatest near the watering sites, called piospheres, particularly suitable for assessing the effect of grazing on arid ecosystems. The aim of this study was to evaluate the effect of sheep-grazing intensity using piospheres on the structure of the vegetation and soil in shrubby steppes of Peninsula Valdes, Argentina. Variation of plant cover, vertical complexity of the vegetation, number and area of vegetated patches, micro-topography and soil compaction in relation to piosphere gradients were studied using Generalized Linear Mixed Models (GLMM) and multivariate analyses. Grazing intensity decreased according to increasing distance to the watering point. This fact, explaining more than 50% of the overall environmental variability, confirmed the existence of a piosphere gradient on each studied site. Such environmental changes were characterized by a gradual increase in grass and litter cover, vertical complexity of vegetation and soil microtopography at increasing distances from the watering point. Percentages of bare soil and gravel, cover of annual grasses and soil compaction showed the opposite pattern. This study demonstrates, for the first time, the existence of sheep piospheres in the shrubby steppes of Peninsula Valdes. Our results indicate that sheep-grazing intensity is associated with changes in the structure and composition of the vegetation and the soil characteristics that are compatible with degradation processes in the study region. Taking into account the importance of Peninsula Valdes in the context of biodiversity conservation, more studies of this type are required to implement effective management actions integrating livestock and conservation efforts on the terrestrial ecosystems of the region. La introducción de ganado doméstico provocó modificaciones en la vegetación y en el suelo de la Patagonia extra-andina. Estos cambios alteraron procesos ecosistémicos, aumentaron la desertificación y causaron pérdida de biodiversidad. Es frecuente encontrar gradientes decrecientes de actividad animal partiendo de las aguadas (piósferas), que resultan adecuados para determinar el impacto del pastoreo sobre los ecosistemas. El objetivo de este estudio fue evaluar el efecto de la intensidad de pastoreo ovino a partir de gradientes de piósfera sobre la estructura de la vegetación y el suelo en estepas arbustivas representativas de Península Valdés, Argentina. Mediante modelos lineales generalizados mixtos (GLMM) y técnicas multivariadas se estudiaron las variaciones en la cobertura vegetal, complejidad vertical de la vegetación, número y área de parches vegetados, microtopografía del suelo y su compactación en relación con el gradiente de pastoreo. La intensidad del pastoreo disminuyó con la distancia a la aguada y explicó más de 50% de la variabilidad ambiental. Esto demuestra la existencia de efecto piósfera. La cobertura de herbáceas, mantillo, complejidad vertical de la vegetación y la microtopografía aumentaron al disminuir la presión de pastoreo en los sitios más alejados de la aguada, mientras que el porcentaje de suelo desnudo, gravas, cobertura de anuales y la compactación del suelo presentaron un patrón opuesto. Este estudio evidencia, por primera vez, la existencia de piósferas ovinas en Península Valdés e indica que la intensidad de pastoreo en la región se asocia con alteraciones ambientales compatibles con procesos importantes de degradación ecosistémica. Dada la importancia que reviste la península en el contexto de la conservación biológica de la región, se requieren más estudios de este tipo para una implementación efectiva de medidas de manejo que integren la ganadería y la conservación de los recursos naturales. Asociación Argentina de Ecología 2016-08-22 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Articles Artículos application/pdf https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/237 10.25260/EA.16.26.2.0.237 Ecología Austral; Vol. 26 No. 2 (2016): August 2016, Pages 95-211; 200-211 Ecología Austral; Vol. 26 Núm. 2 (2016): August 2016, Pages 95-211; 200-211 1667-782X 0327-5477 spa https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/237/163 Derechos de autor 2016 Ecología Austral https://creativecommons.org/licenses/by/3.0/ |