Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported

Autores
Travaini, Alejandro; Zapata, Sonia Cristina; Bustamante, Javier; Pedrana, Julieta; Zanón Martínez, Juan Ignacio; Rodriguez, Alejandro
Año de publicación
2015
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Background: Guanacos (Lama guanicoe) are thought to have declined in Patagonia mainly as a result of hunting and sheep ranching. Currently accepted estimates of total population size are extrapolated from densities obtained through strip transects in local studies. We used road surveys (8,141 km) and distance sampling to estimate guanaco density and population size over major environmental gradients of Santa Cruz, a large region in southern Patagonia. We also calculated the survey effort required to detect population trends in Santa Cruz. Results: We found considerable spatial variation in density (1.1 to 7.4 ind/km2), with a mean value of 4.8 ind/km2, which is more than twice the mean value guessed for central and northern Patagonia. Consequently, guanaco numbers in Santa Cruz were estimated at 1.1 million individuals (95% CI 0.7 to 1.6), which almost doubles current estimates of guanaco population size in South America. High guanaco abundance was found in arid lands, overgrazed and unable to support profitable sheep stocks. Detecting a 50% change in guanaco population size over a 10-year period requires substantial monitoring effort: the annual survey of between 40 and 80 30-km transects, which becomes up to 120 transects if trends are to be detected over 5 years. Conclusions: Regional patterns in guanaco density can only be detected through large-scale surveys. Coupling these surveys with distance sampling techniques produce robust estimates of density and its variation. Figures so obtained improve currently available estimates of guanaco population size across its geographic range, which seem to be extrapolated from strip counts over small areas. In arid lands degraded by sheep overgrazing, sustainable use of guanaco populations would help harmonize guanaco conservation, socio-economic progress of rural areas, and eventually the restoration of shrub-steppes.
Fil: Travaini, Alejandro. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Zapata, Sonia Cristina. Universidad Nacional de la Patagonia Austral; Argentina
Fil: Bustamante, Javier. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; España
Fil: Pedrana, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Instituto Nacional de Tecnología Agropecuaria; Argentina
Fil: Zanón Martínez, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina
Fil: Rodriguez, Alejandro. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; España
Materia
DISTANCE SAMPLING
GUANACO
LIVESTOCK
MONITORING
PATAGONIA SHRUB-STEPPE
SUSTAINABLE USES
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/44673
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/44673
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reportedTravaini, AlejandroZapata, Sonia CristinaBustamante, JavierPedrana, JulietaZanón Martínez, Juan IgnacioRodriguez, AlejandroDISTANCE SAMPLINGGUANACOLIVESTOCKMONITORINGPATAGONIA SHRUB-STEPPESUSTAINABLE USEShttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1Background: Guanacos (Lama guanicoe) are thought to have declined in Patagonia mainly as a result of hunting and sheep ranching. Currently accepted estimates of total population size are extrapolated from densities obtained through strip transects in local studies. We used road surveys (8,141 km) and distance sampling to estimate guanaco density and population size over major environmental gradients of Santa Cruz, a large region in southern Patagonia. We also calculated the survey effort required to detect population trends in Santa Cruz. Results: We found considerable spatial variation in density (1.1 to 7.4 ind/km2), with a mean value of 4.8 ind/km2, which is more than twice the mean value guessed for central and northern Patagonia. Consequently, guanaco numbers in Santa Cruz were estimated at 1.1 million individuals (95% CI 0.7 to 1.6), which almost doubles current estimates of guanaco population size in South America. High guanaco abundance was found in arid lands, overgrazed and unable to support profitable sheep stocks. Detecting a 50% change in guanaco population size over a 10-year period requires substantial monitoring effort: the annual survey of between 40 and 80 30-km transects, which becomes up to 120 transects if trends are to be detected over 5 years. Conclusions: Regional patterns in guanaco density can only be detected through large-scale surveys. Coupling these surveys with distance sampling techniques produce robust estimates of density and its variation. Figures so obtained improve currently available estimates of guanaco population size across its geographic range, which seem to be extrapolated from strip counts over small areas. In arid lands degraded by sheep overgrazing, sustainable use of guanaco populations would help harmonize guanaco conservation, socio-economic progress of rural areas, and eventually the restoration of shrub-steppes.Fil: Travaini, Alejandro. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zapata, Sonia Cristina. Universidad Nacional de la Patagonia Austral; ArgentinaFil: Bustamante, Javier. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; EspañaFil: Pedrana, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Zanón Martínez, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Rodriguez, Alejandro. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; EspañaSpringer2015-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/44673Travaini, Alejandro; Zapata, Sonia Cristina; Bustamante, Javier; Pedrana, Julieta; Zanón Martínez, Juan Ignacio; et al.; Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported; Springer; Zoological Studies; 54; 23; 1-2015; 1-121810-522XCONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1186/s40555-014-0097-0info:eu-repo/semantics/altIdentifier/url/https://zoologicalstudies.springeropen.com/articles/10.1186/s40555-014-0097-0info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:54:25Zoai:ri.conicet.gov.ar:11336/44673instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 09:54:25.453CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported
title Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported
spellingShingle Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported
Travaini, Alejandro
DISTANCE SAMPLING
GUANACO
LIVESTOCK
MONITORING
PATAGONIA SHRUB-STEPPE
SUSTAINABLE USES
title_short Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported
title_full Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported
title_fullStr Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported
title_full_unstemmed Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported
title_sort Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported
dc.creator.none.fl_str_mv Travaini, Alejandro
Zapata, Sonia Cristina
Bustamante, Javier
Pedrana, Julieta
Zanón Martínez, Juan Ignacio
Rodriguez, Alejandro
author Travaini, Alejandro
author_facet Travaini, Alejandro
Zapata, Sonia Cristina
Bustamante, Javier
Pedrana, Julieta
Zanón Martínez, Juan Ignacio
Rodriguez, Alejandro
author_role author
author2 Zapata, Sonia Cristina
Bustamante, Javier
Pedrana, Julieta
Zanón Martínez, Juan Ignacio
Rodriguez, Alejandro
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv DISTANCE SAMPLING
GUANACO
LIVESTOCK
MONITORING
PATAGONIA SHRUB-STEPPE
SUSTAINABLE USES
topic DISTANCE SAMPLING
GUANACO
LIVESTOCK
MONITORING
PATAGONIA SHRUB-STEPPE
SUSTAINABLE USES
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Background: Guanacos (Lama guanicoe) are thought to have declined in Patagonia mainly as a result of hunting and sheep ranching. Currently accepted estimates of total population size are extrapolated from densities obtained through strip transects in local studies. We used road surveys (8,141 km) and distance sampling to estimate guanaco density and population size over major environmental gradients of Santa Cruz, a large region in southern Patagonia. We also calculated the survey effort required to detect population trends in Santa Cruz. Results: We found considerable spatial variation in density (1.1 to 7.4 ind/km2), with a mean value of 4.8 ind/km2, which is more than twice the mean value guessed for central and northern Patagonia. Consequently, guanaco numbers in Santa Cruz were estimated at 1.1 million individuals (95% CI 0.7 to 1.6), which almost doubles current estimates of guanaco population size in South America. High guanaco abundance was found in arid lands, overgrazed and unable to support profitable sheep stocks. Detecting a 50% change in guanaco population size over a 10-year period requires substantial monitoring effort: the annual survey of between 40 and 80 30-km transects, which becomes up to 120 transects if trends are to be detected over 5 years. Conclusions: Regional patterns in guanaco density can only be detected through large-scale surveys. Coupling these surveys with distance sampling techniques produce robust estimates of density and its variation. Figures so obtained improve currently available estimates of guanaco population size across its geographic range, which seem to be extrapolated from strip counts over small areas. In arid lands degraded by sheep overgrazing, sustainable use of guanaco populations would help harmonize guanaco conservation, socio-economic progress of rural areas, and eventually the restoration of shrub-steppes.
Fil: Travaini, Alejandro. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Zapata, Sonia Cristina. Universidad Nacional de la Patagonia Austral; Argentina
Fil: Bustamante, Javier. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; España
Fil: Pedrana, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Instituto Nacional de Tecnología Agropecuaria; Argentina
Fil: Zanón Martínez, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina
Fil: Rodriguez, Alejandro. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; España
description Background: Guanacos (Lama guanicoe) are thought to have declined in Patagonia mainly as a result of hunting and sheep ranching. Currently accepted estimates of total population size are extrapolated from densities obtained through strip transects in local studies. We used road surveys (8,141 km) and distance sampling to estimate guanaco density and population size over major environmental gradients of Santa Cruz, a large region in southern Patagonia. We also calculated the survey effort required to detect population trends in Santa Cruz. Results: We found considerable spatial variation in density (1.1 to 7.4 ind/km2), with a mean value of 4.8 ind/km2, which is more than twice the mean value guessed for central and northern Patagonia. Consequently, guanaco numbers in Santa Cruz were estimated at 1.1 million individuals (95% CI 0.7 to 1.6), which almost doubles current estimates of guanaco population size in South America. High guanaco abundance was found in arid lands, overgrazed and unable to support profitable sheep stocks. Detecting a 50% change in guanaco population size over a 10-year period requires substantial monitoring effort: the annual survey of between 40 and 80 30-km transects, which becomes up to 120 transects if trends are to be detected over 5 years. Conclusions: Regional patterns in guanaco density can only be detected through large-scale surveys. Coupling these surveys with distance sampling techniques produce robust estimates of density and its variation. Figures so obtained improve currently available estimates of guanaco population size across its geographic range, which seem to be extrapolated from strip counts over small areas. In arid lands degraded by sheep overgrazing, sustainable use of guanaco populations would help harmonize guanaco conservation, socio-economic progress of rural areas, and eventually the restoration of shrub-steppes.
publishDate 2015
dc.date.none.fl_str_mv 2015-01
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/44673
Travaini, Alejandro; Zapata, Sonia Cristina; Bustamante, Javier; Pedrana, Julieta; Zanón Martínez, Juan Ignacio; et al.; Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported; Springer; Zoological Studies; 54; 23; 1-2015; 1-12
1810-522X
CONICET Digital
CONICET
url http://hdl.handle.net/11336/44673
identifier_str_mv Travaini, Alejandro; Zapata, Sonia Cristina; Bustamante, Javier; Pedrana, Julieta; Zanón Martínez, Juan Ignacio; et al.; Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported; Springer; Zoological Studies; 54; 23; 1-2015; 1-12
1810-522X
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1186/s40555-014-0097-0
info:eu-repo/semantics/altIdentifier/url/https://zoologicalstudies.springeropen.com/articles/10.1186/s40555-014-0097-0
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
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dc.publisher.none.fl_str_mv Springer
publisher.none.fl_str_mv Springer
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
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reponame_str CONICET Digital (CONICET)
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instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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score 13.070432

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