Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported
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) an...
| Autores principales: | , , , , , |
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| Formato: | info:ar-repo/semantics/artículo |
| Lenguaje: | Inglés |
| Publicado: |
Springer
2019
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| Materias: | |
| Acceso en línea: | https://link.springer.com/article/10.1186/s40555-014-0097-0 http://hdl.handle.net/20.500.12123/4558 https://doi.org/10.1186/s40555-014-0097-0 |
| _version_ | 1855035344847634432 |
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| author | Travaini, Alejandro Zapata, Sonia Cristina Bustamante, Javier Pedrana, Julieta Zanón Martínez, Juan Ignacio Rodriguez, Alejandro |
| author_browse | Bustamante, Javier Pedrana, Julieta Rodriguez, Alejandro Travaini, Alejandro Zanón Martínez, Juan Ignacio Zapata, Sonia Cristina |
| author_facet | Travaini, Alejandro Zapata, Sonia Cristina Bustamante, Javier Pedrana, Julieta Zanón Martínez, Juan Ignacio Rodriguez, Alejandro |
| author_sort | Travaini, Alejandro |
| collection | INTA Digital |
| 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. |
| format | info:ar-repo/semantics/artículo |
| id | INTA4558 |
| institution | Instituto Nacional de Tecnología Agropecuaria (INTA -Argentina) |
| language | Inglés |
| publishDate | 2019 |
| publishDateRange | 2019 |
| publishDateSort | 2019 |
| publisher | Springer |
| publisherStr | Springer |
| record_format | dspace |
| spelling | INTA45582019-03-08T13:34:46Z Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported Travaini, Alejandro Zapata, Sonia Cristina Bustamante, Javier Pedrana, Julieta Zanón Martínez, Juan Ignacio Rodriguez, Alejandro Guanaco Población Animal Vigilancia Sostenibilidad Muestreo Guanacos Animal Population Monitoring Sustainability Sampling Región Patagónica 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. EEA Balcarce 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. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina Fil: Bustamante, Javier. Consejo Superior de Investigaciones Científicas (CSIC). Estación Biológica de Doñana. Department of Wetland EcologyRemote Sensing and GIS Lab; España Fil: Pedrana, Julieta. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina Fil: Zanón Martínez, Juan Ignacio. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. 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. Centro para el Estudio y Conservación de las Aves Rapaces en Argentina; Argentina Fil: Rodriguez, Alejandro. Consejo Superior de Investigaciones Científicas (CSIC). Estación Biológica de Doñana. Department of Conservation Biology; España 2019-03-08T13:33:43Z 2019-03-08T13:33:43Z 2015-12 info:ar-repo/semantics/artículo info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion https://link.springer.com/article/10.1186/s40555-014-0097-0 http://hdl.handle.net/20.500.12123/4558 1810-522X https://doi.org/10.1186/s40555-014-0097-0 eng info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-sa/4.0/ Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) application/pdf Springer Zoological Studies 54 : 23 (December 2015) |
| spellingShingle | Guanaco Población Animal Vigilancia Sostenibilidad Muestreo Guanacos Animal Population Monitoring Sustainability Sampling Región Patagónica Travaini, Alejandro Zapata, Sonia Cristina Bustamante, Javier Pedrana, Julieta Zanón Martínez, Juan Ignacio Rodriguez, Alejandro 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 |
| 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_short | 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 |
| topic | Guanaco Población Animal Vigilancia Sostenibilidad Muestreo Guanacos Animal Population Monitoring Sustainability Sampling Región Patagónica |
| url | https://link.springer.com/article/10.1186/s40555-014-0097-0 http://hdl.handle.net/20.500.12123/4558 https://doi.org/10.1186/s40555-014-0097-0 |
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