Disturbances on a shrubby steppe of the Monte phytogeographical province: changes in vegetation
We evaluated the effects of individual and joint effects of fire, mechanical removal of shrubs and grazing on natural vegetation of the eastern Monte Phytogeographical Province in Rio Negro, Argentina. Four enclosures were constructed in sites where large disturbances (fire, mechanical removal and both) had taken place. Measurements were made both inside and outside them in order to evaluate not only the grazing effects in each site, but also possible interactions between the latter and large disturbances, which have not usually been reported. Several structural characteristics (shrub density and cover, aerial biomass and basal cover of herbaceous layer, and of biological crust), plus a functional one (phenology of five grasses and two shrubs) were studied. Both the fire and the mechanical removal reduced the density and area covered by the shrubby layer, and also the biological crust cover, with the effects being larger at the site were both had taken place. Bare soil was higher in the disturbed sites respect to the control due to the disappearance of the biological crust. Fire produced a qualitative change in the floristic composition of the herbaceous layer through altering the dominance from Stipa tenuis Phil. to a more palatable species as it is Stipa papposa Nees. Grazing reduced homogeneously aboveground biomass of the herbaceous layer, but extended the vegetative period of grasses and increased the size of that budget though reducing the reproductive one. The last two effects will be beneficial for secondary production since they increase the energy flux to herbivory. Large disturbances, however, could have negative effects through the reduction of the biological crust, which plays an important role in seed germination, seedlings establishment and water balance, thus contributing to ecosystems sustainability.
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Asociación Argentina de Ecología
2007
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Kröpfl, Alicia I. Deregibus, Víctor A. Cecchi, Gustavo A. |
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Kröpfl, Alicia I. Deregibus, Víctor A. Cecchi, Gustavo A. Disturbances on a shrubby steppe of the Monte phytogeographical province: changes in vegetation |
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Kröpfl, Alicia I. Deregibus, Víctor A. Cecchi, Gustavo A. |
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Kröpfl, Alicia I. |
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Disturbances on a shrubby steppe of the Monte phytogeographical province: changes in vegetation |
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Disturbances on a shrubby steppe of the Monte phytogeographical province: changes in vegetation |
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Disturbances on a shrubby steppe of the Monte phytogeographical province: changes in vegetation |
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Disturbances on a shrubby steppe of the Monte phytogeographical province: changes in vegetation |
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Disturbances on a shrubby steppe of the Monte phytogeographical province: changes in vegetation |
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disturbances on a shrubby steppe of the monte phytogeographical province: changes in vegetation |
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We evaluated the effects of individual and joint effects of fire, mechanical removal of shrubs and grazing on natural vegetation of the eastern Monte Phytogeographical Province in Rio Negro, Argentina. Four enclosures were constructed in sites where large disturbances (fire, mechanical removal and both) had taken place. Measurements were made both inside and outside them in order to evaluate not only the grazing effects in each site, but also possible interactions between the latter and large disturbances, which have not usually been reported. Several structural characteristics (shrub density and cover, aerial biomass and basal cover of herbaceous layer, and of biological crust), plus a functional one (phenology of five grasses and two shrubs) were studied. Both the fire and the mechanical removal reduced the density and area covered by the shrubby layer, and also the biological crust cover, with the effects being larger at the site were both had taken place. Bare soil was higher in the disturbed sites respect to the control due to the disappearance of the biological crust. Fire produced a qualitative change in the floristic composition of the herbaceous layer through altering the dominance from Stipa tenuis Phil. to a more palatable species as it is Stipa papposa Nees. Grazing reduced homogeneously aboveground biomass of the herbaceous layer, but extended the vegetative period of grasses and increased the size of that budget though reducing the reproductive one. The last two effects will be beneficial for secondary production since they increase the energy flux to herbivory. Large disturbances, however, could have negative effects through the reduction of the biological crust, which plays an important role in seed germination, seedlings establishment and water balance, thus contributing to ecosystems sustainability. |
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Asociación Argentina de Ecología |
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2007 |
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https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/1411 |
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AT kropflaliciai disturbancesonashrubbysteppeofthemontephytogeographicalprovincechangesinvegetation AT deregibusvictora disturbancesonashrubbysteppeofthemontephytogeographicalprovincechangesinvegetation AT cecchigustavoa disturbancesonashrubbysteppeofthemontephytogeographicalprovincechangesinvegetation AT kropflaliciai disturbiosenunaestepaarbustivadelmontecambiosenlavegetacion AT deregibusvictora disturbiosenunaestepaarbustivadelmontecambiosenlavegetacion AT cecchigustavoa disturbiosenunaestepaarbustivadelmontecambiosenlavegetacion |
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1755912486302777344 |
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rev-ecoaus-article-14112020-11-07T23:34:01Z Disturbances on a shrubby steppe of the Monte phytogeographical province: changes in vegetation Disturbios en una estepa arbustiva del Monte: cambios en la vegetación Kröpfl, Alicia I. Deregibus, Víctor A. Cecchi, Gustavo A. fire mechanical removal grazing interactions biological crust fuego desmonte pastoreo interacciones costra biológica We evaluated the effects of individual and joint effects of fire, mechanical removal of shrubs and grazing on natural vegetation of the eastern Monte Phytogeographical Province in Rio Negro, Argentina. Four enclosures were constructed in sites where large disturbances (fire, mechanical removal and both) had taken place. Measurements were made both inside and outside them in order to evaluate not only the grazing effects in each site, but also possible interactions between the latter and large disturbances, which have not usually been reported. Several structural characteristics (shrub density and cover, aerial biomass and basal cover of herbaceous layer, and of biological crust), plus a functional one (phenology of five grasses and two shrubs) were studied. Both the fire and the mechanical removal reduced the density and area covered by the shrubby layer, and also the biological crust cover, with the effects being larger at the site were both had taken place. Bare soil was higher in the disturbed sites respect to the control due to the disappearance of the biological crust. Fire produced a qualitative change in the floristic composition of the herbaceous layer through altering the dominance from Stipa tenuis Phil. to a more palatable species as it is Stipa papposa Nees. Grazing reduced homogeneously aboveground biomass of the herbaceous layer, but extended the vegetative period of grasses and increased the size of that budget though reducing the reproductive one. The last two effects will be beneficial for secondary production since they increase the energy flux to herbivory. Large disturbances, however, could have negative effects through the reduction of the biological crust, which plays an important role in seed germination, seedlings establishment and water balance, thus contributing to ecosystems sustainability. En una estepa arbustiva del Monte oriental rionegrino se evaluó el efecto producido por la acción individual y combinada del fuego, desmonte mecánico y pastoreo doméstico sobre la vegetación que sustenta la producción ganadera de la región. Se instalaron clausuras en sitios afectados por grandes disturbios (fuego, desmonte, y ambos), y se tomaron mediciones fuera y dentro de ellas con el fin de evaluar estos disturbios. Se estudiaron diversas características estructurales (densidad y cobertura basal de los arbustos, biomasa aérea y cobertura basal del estrato herbáceo y de la costra biológica) y una funcional (fenología de las cinco gramíneas y los dos arbustos dominantes). El fuego y el desmonte redujeron la densidad y la superficie ocupada por los arbustos, y también la cobertura de costra biológica. A su vez, estos efectos se profundizaron cuando ambos disturbios actuaron en conjunto. El fuego modificó cualitativamente la composición florística del estrato herbáceo al alterar la dominancia de Stipa tenuis Phil. a favor de una especie más palatable como es Stipa papposa Nees. El pastoreo redujo de manera homogénea la biomasa aérea del estrato herbáceo, pero prolongó el período vegetativo de las gramíneas y aumentó el tamaño de ese compartimiento en desmedro del reproductivo, lo cual resultó en una mejor calidad de forraje disponible para los herbívoros. La ausencia general de interacciones entre el fuego o el desmonte con el pastoreo permitiría predecir la dirección de cambio de este sistema frente a cada disturbio en particular. Asociación Argentina de Ecología 2007-12-01 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Artículos application/pdf https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/1411 Ecología Austral; Vol. 17 No. 2 (2007); 257-268 Ecología Austral; Vol. 17 Núm. 2 (2007); 257-268 0327-5477 1667-7838 spa https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/1411/771 Derechos de autor 2020 Ecología Austral |