Files and links (1)
CC BY V4.0, Open Access
Journal article
Estimating Total Length of Partially Submerged Crocodylians from Drone Imagery
Drones (Basel), Vol.8(3), 115
2024
Abstract
Understanding the demographic structure is vital for wildlife research and conservation. For crocodylians, accurately estimating total length and demographic class usually necessitates close observation or capture, often of partially immersed individuals, leading to potential imprecision and risk. Drone technology offers a bias-free, safer alternative for classification. We evaluated the effectiveness of drone photos combined with head length allometric relationships to estimate total length, and propose a standardized method for drone-based crocodylian demographic classification. We evaluated error sources related to drone flight parameters using standardized targets. An allometric framework correlating head to total length for 17 crocodylian species was developed, incorporating confidence intervals to account for imprecision sources (e.g., allometric accuracy, head inclination, observer bias, terrain variability). This method was applied to wild crocodylians through drone photography. Target measurements from drone imagery, across various resolutions and sizes, were consistent with their actual dimensions. Terrain effects were less impactful than Ground-Sample Distance (GSD) errors from photogrammetric software. The allometric framework predicted lengths within ≃11–18% accuracy across species, with natural allometric variation among individuals explaining much of this range. Compared to traditional methods that can be subjective and risky, our drone-based approach is objective, efficient, fast, cheap, non-invasive, and safe. Nonetheless, further refinements are needed to extend survey times and better include smaller size classes.
Details
- Title
- Estimating Total Length of Partially Submerged Crocodylians from Drone Imagery
- Authors/Creators
- Clément Aubert - Florida International UniversityGilles Le Moguédec - Université de MontpellierAlvaro Velasco - Academia Nacional de Medicina VenezuelaXander Combrink - Tshwane University of TechnologyJeffrey Lang - Madras Diabetes Research FoundationPhoebe Griffith - Leibniz Institute of Freshwater Ecology and Inland FisheriesGualberto Pacheco-SierraEtiam PérezPierre Charruau - El Colegio de la Frontera SurFrancisco Villamarín - Universidad Regional Amazonica IkiamIgor Roberto - Universidade Estadual do CearáBoris Marioni - Instituto Nacional de Pesquisas da AmazôniaJoseph ColbertAsghar MobarakiAllan Woodward - Florida Fish and Wildlife Conservation CommissionRuchira Somaweera - Stantec (United States)Marisa TellezMatthew Brien - Parks and Wildlife ServiceMatthew Shirley - Florida International University
- Publication Details
- Drones (Basel), Vol.8(3), 115
- Publisher
- MDPI
- Identifiers
- 991005651568707891
- Copyright
- © 2024 by the authors.
- Murdoch Affiliation
- School of Environmental and Conservation Sciences
- Language
- English
- Resource Type
- Journal article
UN Sustainable Development Goals (SDGs)
This output has contributed to the advancement of the following goals:
Metrics
1 File views/ downloads
38 Record Views
InCites Highlights
These are selected metrics from InCites Benchmarking & Analytics tool, related to this output
- Collaboration types
- Domestic collaboration
- International collaboration
- Citation topics
- 3 Agriculture, Environment & Ecology
- 3.35 Zoology & Animal Ecology
- 3.35.683 Reptile Ecology
- Web Of Science research areas
- Remote Sensing
- ESI research areas
- Geosciences