Effects of the environmental conditions and seasonality on a population survey of the Andean condor Vultur gryphus in the tropical Andes
Background Among the New World vultures, the Andean condor is considered one of the most culturally and ecologically important species. However, their populations are declining over their entire distributional range. In response, conservation strategies have been implemented in many countries to rev...
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PeerJ Inc.
2023-01-01
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| author | Sandra Márquez-Alvis Luis Martin Vallejos Santiago Paredes-Guerrero Luis Pollack-Velasquez Gabriel Silva Santos |
| author_facet | Sandra Márquez-Alvis Luis Martin Vallejos Santiago Paredes-Guerrero Luis Pollack-Velasquez Gabriel Silva Santos |
| author_sort | Sandra Márquez-Alvis |
| collection | DOAJ |
| description | Background Among the New World vultures, the Andean condor is considered one of the most culturally and ecologically important species. However, their populations are declining over their entire distributional range. In response, conservation strategies have been implemented in many countries to reverse the increasing extinction risk of this species. The initiatives rely on extensive population surveys to gather basic information necessary to implement policies and to intervene efficiently. Still, there is a need to standardize the surveys based on seasonality and suitable environmental conditions throughout the species distribution. Here, we provide the first assessment of how daily temperature, rainfall, and seasonality influence surveys of Andean condors on a communal roost in the central Peruvian Andes. Methods Using an autoregressive generalized linear model, we associated environmental variables with visual surveys of adult and young condors at three different times of the day and three times a week between June 2014 and March 2015. Results We found that both adults and young Andean condors showed a threefold reduction in the use of the communal roost after the beginning of the rainy season. Colder and drier days (dry season) are preferable for surveying, as we expect the total number of condors using communal roosts to reduce under rainy (rainfall = −0.53 ± 0.16) and warmer days (temperature = −0.04 ± 0.02) days. Therefore, the significant variation in the use of roosts across seasons and hours should be carefully accounted for in national surveys, at the risk of undermining the full potential of the communal roost surveys. Moreover, we also found a strong bias towards immatures (about 76%) in the adult:immature ratio and a remarkable absence of Andean condors during the wet season. These results suggest that the species might be using other unknown communal roosts hierarchically. Such results provide key information for selecting priority areas for conservation and selecting the best time to survey this species in the tropical Andes. Finally, it may open a fruitful avenue for further research on the protection of the Andean condor. |
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| language | English |
| last_indexed | 2024-03-09T04:28:56Z |
| publishDate | 2023-01-01 |
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| spelling | doaj.art-97ba12f153a5440fbba55d0eca82697a2023-12-03T13:37:27ZengPeerJ Inc.PeerJ2167-83592023-01-0111e1476310.7717/peerj.14763Effects of the environmental conditions and seasonality on a population survey of the Andean condor Vultur gryphus in the tropical AndesSandra Márquez-Alvis0Luis Martin Vallejos1Santiago Paredes-Guerrero2Luis Pollack-Velasquez3Gabriel Silva Santos4CONSERVACCION, Lima, Lima, PeruPrograma de Pós-Graduação em Ecologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, BrazilReserva Nacional Pampa Galeras Bárbara D’Achille, SERNANP, Ayacucho, Ayacucho, PeruDepartamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Nacional de Trujillo, Trujillo, La Libertad, PeruInstituto Nacional da Mata Atlântica, Santa Teresa, Espirito Santo, BrazilBackground Among the New World vultures, the Andean condor is considered one of the most culturally and ecologically important species. However, their populations are declining over their entire distributional range. In response, conservation strategies have been implemented in many countries to reverse the increasing extinction risk of this species. The initiatives rely on extensive population surveys to gather basic information necessary to implement policies and to intervene efficiently. Still, there is a need to standardize the surveys based on seasonality and suitable environmental conditions throughout the species distribution. Here, we provide the first assessment of how daily temperature, rainfall, and seasonality influence surveys of Andean condors on a communal roost in the central Peruvian Andes. Methods Using an autoregressive generalized linear model, we associated environmental variables with visual surveys of adult and young condors at three different times of the day and three times a week between June 2014 and March 2015. Results We found that both adults and young Andean condors showed a threefold reduction in the use of the communal roost after the beginning of the rainy season. Colder and drier days (dry season) are preferable for surveying, as we expect the total number of condors using communal roosts to reduce under rainy (rainfall = −0.53 ± 0.16) and warmer days (temperature = −0.04 ± 0.02) days. Therefore, the significant variation in the use of roosts across seasons and hours should be carefully accounted for in national surveys, at the risk of undermining the full potential of the communal roost surveys. Moreover, we also found a strong bias towards immatures (about 76%) in the adult:immature ratio and a remarkable absence of Andean condors during the wet season. These results suggest that the species might be using other unknown communal roosts hierarchically. Such results provide key information for selecting priority areas for conservation and selecting the best time to survey this species in the tropical Andes. Finally, it may open a fruitful avenue for further research on the protection of the Andean condor.https://peerj.com/articles/14763.pdfAge rate birdConservation of carrion vertebratesConservation and planningPopulation census plansTemperature and rainfallSouth America Vultures |
| spellingShingle | Sandra Márquez-Alvis Luis Martin Vallejos Santiago Paredes-Guerrero Luis Pollack-Velasquez Gabriel Silva Santos Effects of the environmental conditions and seasonality on a population survey of the Andean condor Vultur gryphus in the tropical Andes PeerJ Age rate bird Conservation of carrion vertebrates Conservation and planning Population census plans Temperature and rainfall South America Vultures |
| title | Effects of the environmental conditions and seasonality on a population survey of the Andean condor Vultur gryphus in the tropical Andes |
| title_full | Effects of the environmental conditions and seasonality on a population survey of the Andean condor Vultur gryphus in the tropical Andes |
| title_fullStr | Effects of the environmental conditions and seasonality on a population survey of the Andean condor Vultur gryphus in the tropical Andes |
| title_full_unstemmed | Effects of the environmental conditions and seasonality on a population survey of the Andean condor Vultur gryphus in the tropical Andes |
| title_short | Effects of the environmental conditions and seasonality on a population survey of the Andean condor Vultur gryphus in the tropical Andes |
| title_sort | effects of the environmental conditions and seasonality on a population survey of the andean condor vultur gryphus in the tropical andes |
| topic | Age rate bird Conservation of carrion vertebrates Conservation and planning Population census plans Temperature and rainfall South America Vultures |
| url | https://peerj.com/articles/14763.pdf |
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