Skip to main content
×
Home
    • Aa
    • Aa

Abundance and spatial distribution of Greater Rhea Rhea americana in two sites on the pampas grasslands with different land use

  • Paola F. Giordano (a1), Laura M. Bellis (a2), Joaquín L. Navarro (a1) and Mónica B. Martella (a1)
Abstract
Summary

In Argentina the original landscape structure of the pampas grasslands has changed rapidly due to intensified and specialized agricultural practices. The conversion of grasslands into croplands has been suggested as a threat to Greater Rhea Rhea americana populations. The main goals of this study were to estimate the abundance of Greater Rheas and to analyse the species' spatial distribution at two sites of the pampas region with different land use: agro-ecosystem and grassland. The former was mainly devoted to crop production whereas the latter was mostly used for livestock grazing. Data were collected through 14 aerial surveys from 1998 to 2001, and in 2004. Each survey consisted of six strip-transects per site, spaced at regular intervals. The total area surveyed represented 4% of each study site (113 km2 in the grassland and 95 km2 in the agro-ecosystem). Greater Rhea density (±SE) was significantly higher in the grassland (from 0.22 ±0.11 to 0.86 ± 0.24 ind. km−2) than in the agro-ecosystem (from 0.05 ± 0.05 to 0.12 ± 0.08 ind. km−2). Greater Rheas occupied 51% of the study area in the grassland but less than 5% in the agro-ecosystem. They showed a wide and uniform spatial distribution in the former area, whereas in the latter individuals occurred in small and isolated clusters. These results raise concern about the future of the species because, over recent years, land has been increasingly used for crop production. Hence, if the current rate of change in land use continues, the conservation status of this species will be seriously affected.

Resumen

En Argentina, la estructura original de los pastizales pampeanos ha sufrido profundos cambios debido a la intensificación y especialización de las prácticas agrícolas. El reemplazo de pastizales por cultivos ha sido sugerido como una amenaza para las poblaciones silvestres de ãandú común Rhea americana. Los objetivos principales de este estudio fueron estimar la abundancia del ãandú común y analizar la distribución espacial de la especie en dos sitios de la región pampeana con diferente uso de la tierra: un agroecosistema y un pastizal. El primer sitio se caracteriza principalmente por la producción de cultivos mientras que la actividad predominante del segundo es la cría de ganado. Los datos fueron recolectados mediante 14 recuentos aéreos entre 1998 y 2001, y en 2004. Cada muestreo consistió en seis transectas de faja por sitio, colocadas a espacios regulares. El área muestreada representó el 4% del área total en cada sitio de estudio (113 km2 en el pastizal y 95 km2 en el agroecosistema). La densidad de los ãandúes (±ES) fue significativamente mayor en el pastizal (entre 0.22 ± 0.11 y 0.86 ± 0.24 ind. km−2) que en el agroecosistema (entre 0.05 ± 0.05 y 0.12 ± 0.08 ind. km−2). Los ãandúes ocuparon el 51% del área de estudio en el pastizal aunque menos del 5% en el agroecosistema. Los individuos presentaron una distribución espacial amplia y uniforme en el pastizal mientras que en el agroecosistema los ãandúes se encontraron en grupos pequeãos y aislados entre sí. Estos resultados resultan preocupantes para el fururo de la especie porque durante los últimos aãos, la tierra ha sido utilizada de manera creciente para la producción de cultivos. En consecuencia, si la tasa actual de cambio en el uso de la tierra continúa, el estado de conservación de esta ratite se verá seriamente afectado.

    • Send article to Kindle

      To send this article to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Abundance and spatial distribution of Greater Rhea Rhea americana in two sites on the pampas grasslands with different land use
      Available formats
      ×
      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about sending content to Dropbox.

      Abundance and spatial distribution of Greater Rhea Rhea americana in two sites on the pampas grasslands with different land use
      Available formats
      ×
      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about sending content to Google Drive.

      Abundance and spatial distribution of Greater Rhea Rhea americana in two sites on the pampas grasslands with different land use
      Available formats
      ×
Copyright
Corresponding author
*Author for correspondence; e-mail: pgiordano@com.uncor.edu
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Bird Conservation International
  • ISSN: 0959-2709
  • EISSN: 1474-0001
  • URL: /core/journals/bird-conservation-international
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Metrics

Altmetric attention score