{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,8,21]],"date-time":"2025-08-21T18:33:44Z","timestamp":1755801224795,"version":"3.44.0"},"reference-count":69,"publisher":"Public Library of Science (PLoS)","issue":"8","license":[{"start":{"date-parts":[[2025,8,21]],"date-time":"2025-08-21T00:00:00Z","timestamp":1755734400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"WWF-UK","award":["NA"],"award-info":[{"award-number":["NA"]}]},{"DOI":"10.13039\/501100022422","name":"WWF Nepal","doi-asserted-by":"publisher","award":["NA"],"award-info":[{"award-number":["NA"]}],"id":[{"id":"10.13039\/501100022422","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:p>Drone-based aerial monitoring can play a pivotal role in scaling up efforts to monitor species at risk. In this study, we assessed the population size, occupancy, and spatial interactions of gharials and muggers in the Eastern Rapti River and its tributaries within Chitwan National Park, complying with national regulations. Using a Wingtra Tail-Sitter Vertical Take-Off and Landing fixed-wing drone, we surveyed a 73-km river stretch during the species\u2019 basking period. The drone captured 24,129 photographs across 27 flight missions, covering 702.66 km and 44.68 km\u00b2, of which 153 contained dorsal images of gharials (77) and muggers (76). An experienced image analyst identified and counted 323 crocodiles (205 gharials and 118 muggers) from the images. The encounter rates were 14.33 gharials and 9.95 muggers detections per 1 hour of drone flight time. To measure habitat-use through an occupancy framework, we divided the 73-km river stretch into 809 grid cells of 0.04 km\u00b2 each. The site-level probabilities of habitat-use were 0.47 for gharials and 0.24 for muggers. As anticipated, both species co-occurred spatially along the Eastern Rapti River during the winter season, with a spatial interaction factor (SIF) of 1.94. This study demonstrates the effectiveness of drones in collecting high-resolution ecological data\u2014both spatial and temporal\u2014for assessing population parameters and monitoring threatened crocodile species at scale. Drones offer a cost-effective and less labor-intensive (~US$ 0.61 per km) alternative to traditional ground-based surveys (~US$ 21 per km). Integrating machine learning with drone surveys for automated image analyses has significant potential to further reduce costs and increase efficiency and could strengthen conservation efforts across South Asian River system.<\/jats:p>","DOI":"10.1371\/journal.pone.0330350","type":"journal-article","created":{"date-parts":[[2025,8,21]],"date-time":"2025-08-21T17:23:51Z","timestamp":1755797031000},"page":"e0330350","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Eyes in the sky: Drone monitoring of the largest gharial and mugger populations in the East Rapti River, Chitwan National Park"],"prefix":"10.1371","volume":"20","author":[{"given":"Gokarna Jung","family":"Thapa","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3838-2804","authenticated-orcid":true,"given":"Kanchan","family":"Thapa","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shashank","family":"Poudel","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dil Bahadur Purja","family":"Pun","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0594-1331","authenticated-orcid":true,"given":"Sujita","family":"Shrestha","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Prem","family":"Poudel","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0974-372X","authenticated-orcid":true,"given":"Hari Bhadra","family":"Acharya","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bal Kumar","family":"Lamsal","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rajesh","family":"Sada","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Serge A.","family":"Wich","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"340","published-online":{"date-parts":[[2025,8,21]]},"reference":[{"issue":"5","key":"pone.0330350.ref001","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1002\/fee.1281","article-title":"Unmanned aircraft systems in wildlife research: current and future applications of a transformative technology","volume":"14","author":"KS Christie","year":"2016","journal-title":"Front Ecol Environ"},{"issue":"11","key":"pone.0330350.ref002","doi-asserted-by":"crossref","first-page":"685","DOI":"10.1016\/j.tree.2015.08.008","article-title":"Emerging Technologies to Conserve Biodiversity","volume":"30","author":"SL Pimm","year":"2015","journal-title":"Trends Ecol Evol"},{"key":"pone.0330350.ref003","doi-asserted-by":"crossref","DOI":"10.1093\/oso\/9780198850243.003.0001","article-title":"Conservation and technology: an introduction","volume":"1","author":"AK Piel","year":"2021","journal-title":"Conserv Technol"},{"key":"pone.0330350.ref004","volume-title":"Camera traps in animal ecology: methods and analyses","author":"KU Karanth","year":"2011"},{"issue":"4","key":"pone.0330350.ref005","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1111\/mam.12046","article-title":"Are unmanned aircraft systems (UASs) the future of wildlife monitoring? 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Dinerstein","year":"2003"},{"issue":"1","key":"pone.0330350.ref040","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1017\/S0030605313000471","article-title":"Estimating the abundance of Nepal\u2019s largest population of tigers Panthera tigris","volume":"49","author":"JB Karki","year":"2013","journal-title":"Oryx"},{"issue":"12","key":"pone.0330350.ref041","doi-asserted-by":"crossref","first-page":"3069","DOI":"10.1016\/j.biocon.2008.09.013","article-title":"Factors associated with human-killing tigers in Chitwan National Park, Nepal","volume":"141","author":"B Gurung","year":"2008","journal-title":"Biol Conserv"},{"issue":"10","key":"pone.0330350.ref042","doi-asserted-by":"crossref","DOI":"10.1016\/j.cub.2016.04.001","article-title":"Best practice for minimising unmanned aerial vehicle disturbance to wildlife in biological field research","volume":"26","author":"JC Hodgson","year":"2016","journal-title":"Curr 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Choudhary","year":"2018","journal-title":"Aquat Conserv Mar Freshw Ecosyst"},{"key":"pone.0330350.ref046","doi-asserted-by":"crossref","first-page":"593","DOI":"10.1007\/s10531-016-1260-1","article-title":"Prey and tigers on the forgotten trail: high prey occupancy and tiger habitat use reveal the importance of the understudied Churia habitat of Nepal","volume":"26","author":"K Thapa","year":"2017","journal-title":"Biodivers Conserv"},{"issue":"5","key":"pone.0330350.ref047","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0216504","article-title":"Elephant (Elephas maximus) temporal activity, distribution, and habitat use patterns on the tiger\u2019s forgotten trails across the seasonally dry, subtropical, hilly Churia forests of Nepal","volume":"14","author":"K Thapa","year":"2019","journal-title":"PLoS One"},{"key":"pone.0330350.ref048","doi-asserted-by":"crossref","first-page":"640338","DOI":"10.3389\/fmars.2021.640338","article-title":"A novel method for using small 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PRESENCE2-Software to estimate patch occupancy and related parameters. Httpwww Mbr-Pwrc Usgs Govsoftwarepresence Html. 2006."},{"key":"pone.0330350.ref051","doi-asserted-by":"crossref","first-page":"912","DOI":"10.2307\/3803155","article-title":"Avoiding pitfalls when using information-theoretic methods","author":"DR Anderson","year":"2002","journal-title":"J Wildl Manag"},{"issue":"3","key":"pone.0330350.ref052","doi-asserted-by":"crossref","first-page":"546","DOI":"10.1111\/j.0021-8790.2004.00828.x","article-title":"Investigating species co\u2010occurrence patterns when species are detected imperfectly","volume":"73","author":"DI MacKenzie","year":"2004","journal-title":"J Anim Ecol"},{"issue":"4","key":"pone.0330350.ref053","doi-asserted-by":"crossref","first-page":"902","DOI":"10.1111\/1365-2664.13318","article-title":"A view from above: Unmanned aerial vehicles (UAV s) provide a new tool for assessing liana infestation in tropical forest canopies","volume":"56","author":"CE Waite","year":"2019","journal-title":"J Appl Ecol"},{"issue":"2","key":"pone.0330350.ref054","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1002\/aqc.960","article-title":"Basking site and water depth selection by gharial Gavialis gangeticus Gmelin 1789 (Crocodylia, Reptilia) in National Chambal Sanctuary, India and its implication for river conservation","volume":"19","author":"SA Hussain","year":"2009","journal-title":"Aquat Conserv Mar Freshw Ecosyst"},{"key":"pone.0330350.ref055","doi-asserted-by":"crossref","unstructured":"Basyal C, Neupane B, Dhami B, Adhikari B, Nishan KC, Poudel S, et al. 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Vashistha","year":"2021","journal-title":"Sci Rep"},{"issue":"1","key":"pone.0330350.ref059","doi-asserted-by":"crossref","first-page":"5","DOI":"10.3390\/drones5010005","article-title":"Quantifying Waterfowl Numbers: Comparison of Drone and Ground-Based Survey Methods for Surveying Waterfowl on Artificial Waterbodies","volume":"5","author":"SJ Dundas","year":"2021","journal-title":"Drones"},{"key":"pone.0330350.ref060","doi-asserted-by":"crossref","first-page":"176528","DOI":"10.1016\/j.scitotenv.2024.176528","article-title":"Monitoring macroplastics in aquatic and terrestrial ecosystems: Expert survey reveals visual and drone-based census as most effective techniques","volume":"955","author":"L Gallitelli","year":"2024","journal-title":"Sci Total Environ"},{"issue":"12","key":"pone.0330350.ref061","doi-asserted-by":"crossref","first-page":"13571","DOI":"10.1007\/s13762-022-04739-y","article-title":"Hybrid drone-based survey of riverine habitat and crocodiles in complex 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