Unmanned aerial vehicle surveys reveal unexpectedly high density of a threatened deer in a plantation forestry landscape
The Vulnerable marsh deer Blastocerus dichotomus, the largest native cervid in South America, is declining throughout its range as a result of the conversion of wetlands and overhunting. Estimated densities in open wetlands of several types are 0.1–6.8 individuals per km2. We undertook the first unm...
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2023-01-01
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| Series: | Oryx |
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| Online Access: | https://www.cambridge.org/core/product/identifier/S0030605321001058/type/journal_article |
| _version_ | 1797754596034084864 |
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| author | Javier A. Pereira Diego Varela Leonardo J. Scarpa Antonio E. Frutos Natalia G. Fracassi Bernardo V. Lartigau Carlos I. Piña |
| author_facet | Javier A. Pereira Diego Varela Leonardo J. Scarpa Antonio E. Frutos Natalia G. Fracassi Bernardo V. Lartigau Carlos I. Piña |
| author_sort | Javier A. Pereira |
| collection | DOAJ |
| description | The Vulnerable marsh deer Blastocerus dichotomus, the largest native cervid in South America, is declining throughout its range as a result of the conversion of wetlands and overhunting. Estimated densities in open wetlands of several types are 0.1–6.8 individuals per km2. We undertook the first unmanned aerial vehicle (UAV) survey of the marsh deer to estimate the density of this species in a 113.6 km2 area under forestry management in the lower delta of the Paraná River, Argentina. During 6–8 August 2019, at a time of year when canopy cover is minimal, we surveyed marsh deer using Phantom 4 Pro UAVs along 94 transects totalling 127.8 km and 8.6 km2 (8.1% of the study area). The 5,506 photographs obtained were manually checked by us and by a group of 39 trained volunteers, following a standardized protocol. We detected a total of 58 marsh deer, giving an estimated density of 6.90 individuals per km2 (95% CI 5.26–8.54), which extrapolates to 559–908 individuals in our 113.6 km2 study area. As it has generally been assumed that marsh deer prefer open habitats, this relatively high estimate of density within a forestry plantation matrix is unexpected. We discuss the advantages of using UAVs to survey marsh deer and other related ungulates. |
| first_indexed | 2024-03-12T17:34:42Z |
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| id | doaj.art-8cb250b95c084b98bbfd72e5c02df9f6 |
| institution | Directory Open Access Journal |
| issn | 0030-6053 1365-3008 |
| language | English |
| last_indexed | 2024-03-12T17:34:42Z |
| publishDate | 2023-01-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Oryx |
| spelling | doaj.art-8cb250b95c084b98bbfd72e5c02df9f62023-08-04T12:01:30ZengCambridge University PressOryx0030-60531365-30082023-01-0157899710.1017/S0030605321001058Unmanned aerial vehicle surveys reveal unexpectedly high density of a threatened deer in a plantation forestry landscapeJavier A. Pereira0Diego Varela1https://orcid.org/0000-0003-3123-6756Leonardo J. Scarpa2https://orcid.org/0000-0002-6655-9937Antonio E. Frutos3https://orcid.org/0000-0001-5500-3637Natalia G. Fracassi4https://orcid.org/0000-0003-0350-1858Bernardo V. Lartigau5Carlos I. Piña6https://orcid.org/0000-0002-6706-5138Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”—Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, ArgentinaInstituto de Biología Subtropical, Universidad Nacional de Misiones—Consejo Nacional de Investigaciones Científicas y Técnicas, Asociación Civil Centro de Investigaciones del Bosque Atlántico, Misiones, ArgentinaCentro de Investigación Científica y de Transferencia Tecnológica a la Producción—Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencia y Tecnología, Universidad Autónoma de Entre Ríos, Diamante, Entre Ríos, ArgentinaCentro de Investigación Científica y de Transferencia Tecnológica a la Producción—Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencia y Tecnología, Universidad Autónoma de Entre Ríos, Diamante, Entre Ríos, ArgentinaEstación Experimental Agropecuaria Delta del Paraná, Instituto Nacional de Tecnología Agropecuaria, Buenos Aires, ArgentinaAsociación para la Conservación y el Estudio de la Naturaleza, Buenos Aires, ArgentinaCentro de Investigación Científica y de Transferencia Tecnológica a la Producción—Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencia y Tecnología, Universidad Autónoma de Entre Ríos, Diamante, Entre Ríos, ArgentinaThe Vulnerable marsh deer Blastocerus dichotomus, the largest native cervid in South America, is declining throughout its range as a result of the conversion of wetlands and overhunting. Estimated densities in open wetlands of several types are 0.1–6.8 individuals per km2. We undertook the first unmanned aerial vehicle (UAV) survey of the marsh deer to estimate the density of this species in a 113.6 km2 area under forestry management in the lower delta of the Paraná River, Argentina. During 6–8 August 2019, at a time of year when canopy cover is minimal, we surveyed marsh deer using Phantom 4 Pro UAVs along 94 transects totalling 127.8 km and 8.6 km2 (8.1% of the study area). The 5,506 photographs obtained were manually checked by us and by a group of 39 trained volunteers, following a standardized protocol. We detected a total of 58 marsh deer, giving an estimated density of 6.90 individuals per km2 (95% CI 5.26–8.54), which extrapolates to 559–908 individuals in our 113.6 km2 study area. As it has generally been assumed that marsh deer prefer open habitats, this relatively high estimate of density within a forestry plantation matrix is unexpected. We discuss the advantages of using UAVs to survey marsh deer and other related ungulates.https://www.cambridge.org/core/product/identifier/S0030605321001058/type/journal_articleArgentinaBlastocerus dichotomusdronemarsh deerParaná River Deltapopulation densityUAVwetland |
| spellingShingle | Javier A. Pereira Diego Varela Leonardo J. Scarpa Antonio E. Frutos Natalia G. Fracassi Bernardo V. Lartigau Carlos I. Piña Unmanned aerial vehicle surveys reveal unexpectedly high density of a threatened deer in a plantation forestry landscape Oryx Argentina Blastocerus dichotomus drone marsh deer Paraná River Delta population density UAV wetland |
| title | Unmanned aerial vehicle surveys reveal unexpectedly high density of a threatened deer in a plantation forestry landscape |
| title_full | Unmanned aerial vehicle surveys reveal unexpectedly high density of a threatened deer in a plantation forestry landscape |
| title_fullStr | Unmanned aerial vehicle surveys reveal unexpectedly high density of a threatened deer in a plantation forestry landscape |
| title_full_unstemmed | Unmanned aerial vehicle surveys reveal unexpectedly high density of a threatened deer in a plantation forestry landscape |
| title_short | Unmanned aerial vehicle surveys reveal unexpectedly high density of a threatened deer in a plantation forestry landscape |
| title_sort | unmanned aerial vehicle surveys reveal unexpectedly high density of a threatened deer in a plantation forestry landscape |
| topic | Argentina Blastocerus dichotomus drone marsh deer Paraná River Delta population density UAV wetland |
| url | https://www.cambridge.org/core/product/identifier/S0030605321001058/type/journal_article |
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