Grazing and grazing exclusion along a resource gradient in magellanic meadows of tierra del fuego

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Although Magellanic meadows have been subject to ungulate herbivory for a long time; they have suffered severe grazing by domestic sheep since the end of the 19th century. We hypothesized that, if protected from grazing, the present dominant dwarf forms would be replaced by taller competitive forms,...

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Autores principales: Collantes, M.B., Escartín, C., Braun, K., Cingolani, A., Anchorena, J.
Formato: JOUR
Lenguaje:English
Materias:
Equilibrium
Plant Community Dynamics
Plant-Animal Interactions
Riparian Ecology
State-And-Transition
community composition
correspondence analysis
dominance
environmental response
floristics
grass
grazing
herbivory
meadow
restoration ecology
ungulate
wetland
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_15507424_v66_n6_p688_Collantes
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_15507424_v66_n6_p688_Collantes
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spelling todo:paper_15507424_v66_n6_p688_Collantes2023-10-03T16:23:30Z Grazing and grazing exclusion along a resource gradient in magellanic meadows of tierra del fuego Collantes, M.B. Escartín, C. Braun, K. Cingolani, A. Anchorena, J. Equilibrium Plant Community Dynamics Plant-Animal Interactions Riparian Ecology State-And-Transition community composition correspondence analysis dominance environmental response floristics grass grazing herbivory meadow restoration ecology ungulate wetland Although Magellanic meadows have been subject to ungulate herbivory for a long time; they have suffered severe grazing by domestic sheep since the end of the 19th century. We hypothesized that, if protected from grazing, the present dominant dwarf forms would be replaced by taller competitive forms, mainly grasses. We then monitored floristic composition along a gradient of soils over periods of 5 to 16 yr on seven meadow sites under grazing and, in five, also on exclosures. Initial and final floristic samples were classified with TWINSPAN and ordinated with Detrended Correspondence Analysis (DCA). We also tracked cover changes in life-forms (grasses, dwarf sedges/rushes, rhizomatous helophytes, and cushion shrubs). At the end of the study, we assessed floristic similarity between paired grazed and exclosed treatments, and compared their life-form cover, diversity, biomass, and soil compaction with Student's t and Mann-Whitney's tests. Temporal displacements of composition in ordination space showed the effect of a long drought (DCA axis 1) and of grazing removal (DCA axis 2). Grazing exclusion had a much greater impact in wet meadows-where grasses became the dominant life-form-than in dry meadows. The effect of drought was shown in 1) the expansion of the cushion shrub Azorella trifurcata (Gaertn.) Pers. in both grazed and nongrazed treatments of the drier wetlands; 2) the decrease in Caltha sagittata Cav. in riparian meadows, and its encroachment under grazing in the wettest spring meadow; and 3) the large increase in Poa pratensis L. in exclosed wet meadows. Despite this strong response to environmental conditions, overall results supported the idea that these wetlands are equilibrium systems. Although the drier meadows have crossed an irreversible threshold, the Caltha-encroached wet meadows returned to a grass state in about 4 yr when protected from grazing. Their resilience suggests that they could be partly restored with rest-rotation grazing. © 2013 The Society for Range Management. Fil:Braun, K. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Cingolani, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR English info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_15507424_v66_n6_p688_Collantes
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
language English
orig_language_str_mv English
topic Equilibrium
Plant Community Dynamics
Plant-Animal Interactions
Riparian Ecology
State-And-Transition
community composition
correspondence analysis
dominance
environmental response
floristics
grass
grazing
herbivory
meadow
restoration ecology
ungulate
wetland
spellingShingle Equilibrium
Plant Community Dynamics
Plant-Animal Interactions
Riparian Ecology
State-And-Transition
community composition
correspondence analysis
dominance
environmental response
floristics
grass
grazing
herbivory
meadow
restoration ecology
ungulate
wetland
Collantes, M.B.
Escartín, C.
Braun, K.
Cingolani, A.
Anchorena, J.
Grazing and grazing exclusion along a resource gradient in magellanic meadows of tierra del fuego
topic_facet Equilibrium
Plant Community Dynamics
Plant-Animal Interactions
Riparian Ecology
State-And-Transition
community composition
correspondence analysis
dominance
environmental response
floristics
grass
grazing
herbivory
meadow
restoration ecology
ungulate
wetland
description Although Magellanic meadows have been subject to ungulate herbivory for a long time; they have suffered severe grazing by domestic sheep since the end of the 19th century. We hypothesized that, if protected from grazing, the present dominant dwarf forms would be replaced by taller competitive forms, mainly grasses. We then monitored floristic composition along a gradient of soils over periods of 5 to 16 yr on seven meadow sites under grazing and, in five, also on exclosures. Initial and final floristic samples were classified with TWINSPAN and ordinated with Detrended Correspondence Analysis (DCA). We also tracked cover changes in life-forms (grasses, dwarf sedges/rushes, rhizomatous helophytes, and cushion shrubs). At the end of the study, we assessed floristic similarity between paired grazed and exclosed treatments, and compared their life-form cover, diversity, biomass, and soil compaction with Student's t and Mann-Whitney's tests. Temporal displacements of composition in ordination space showed the effect of a long drought (DCA axis 1) and of grazing removal (DCA axis 2). Grazing exclusion had a much greater impact in wet meadows-where grasses became the dominant life-form-than in dry meadows. The effect of drought was shown in 1) the expansion of the cushion shrub Azorella trifurcata (Gaertn.) Pers. in both grazed and nongrazed treatments of the drier wetlands; 2) the decrease in Caltha sagittata Cav. in riparian meadows, and its encroachment under grazing in the wettest spring meadow; and 3) the large increase in Poa pratensis L. in exclosed wet meadows. Despite this strong response to environmental conditions, overall results supported the idea that these wetlands are equilibrium systems. Although the drier meadows have crossed an irreversible threshold, the Caltha-encroached wet meadows returned to a grass state in about 4 yr when protected from grazing. Their resilience suggests that they could be partly restored with rest-rotation grazing. © 2013 The Society for Range Management.
format JOUR
author Collantes, M.B.
Escartín, C.
Braun, K.
Cingolani, A.
Anchorena, J.
author_facet Collantes, M.B.
Escartín, C.
Braun, K.
Cingolani, A.
Anchorena, J.
author_sort Collantes, M.B.
title Grazing and grazing exclusion along a resource gradient in magellanic meadows of tierra del fuego
title_short Grazing and grazing exclusion along a resource gradient in magellanic meadows of tierra del fuego
title_full Grazing and grazing exclusion along a resource gradient in magellanic meadows of tierra del fuego
title_fullStr Grazing and grazing exclusion along a resource gradient in magellanic meadows of tierra del fuego
title_full_unstemmed Grazing and grazing exclusion along a resource gradient in magellanic meadows of tierra del fuego
title_sort grazing and grazing exclusion along a resource gradient in magellanic meadows of tierra del fuego
url http://hdl.handle.net/20.500.12110/paper_15507424_v66_n6_p688_Collantes
work_keys_str_mv AT collantesmb grazingandgrazingexclusionalongaresourcegradientinmagellanicmeadowsoftierradelfuego
AT escartinc grazingandgrazingexclusionalongaresourcegradientinmagellanicmeadowsoftierradelfuego
AT braunk grazingandgrazingexclusionalongaresourcegradientinmagellanicmeadowsoftierradelfuego
AT cingolania grazingandgrazingexclusionalongaresourcegradientinmagellanicmeadowsoftierradelfuego
AT anchorenaj grazingandgrazingexclusionalongaresourcegradientinmagellanicmeadowsoftierradelfuego
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