Population Size and Structure of the Common Eland in Omo National Park, Southern Ethiopia

Population Size and Structure of the Common Eland in Omo National Park, Southern Ethiopia | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 7 February 2026 V1 Latest version Share on Population Size and Structure of the Common Eland in Omo National Park, Southern Ethiopia Authors : Tamirat Getachew 0000-0002-2009-4097 [email protected] and Zerihun Girma 0000-0002-2789-1881 Authors Info & Affiliations https://doi.org/10.22541/au.177046036.69580004/v1 148 views 73 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Omo National Park in southern Ethiopia harbors a critical yet increasingly threatened population of the common eland (Tragelaphus oryx), one of Africa’s largest antelopes. Facing pressures from habitat fragmentation, poaching, and agro-pastoral encroachment, this population’s ecology remains poorly understood. We conducted the first seasonally explicit assessment of eland abundance, spatial distribution, and demographics in the park using systematic line-transect distance sampling across 67 transects (totaling 402 km) during the 2024/2025 wet and dry seasons. Our results reveal a highly dynamic population driven by seasonal resource availability. Eland abundance increased significantly by 150% from the dry season (1,024 individuals; 95% CI: 674–1,555) to the wet season (2,568 individuals; 95% CI: 1,839–3,585), non-overlapping confidence intervals confirming a substantial seasonal influx. Spatially, the Sai Plain functioned as a critical dry-season refugium (61% of sightings), while Tenigne and Elilbaye experienced 4-to-6-fold increases in density during the wet season. This seasonal pulse was mirrored in demographic and social structure: the population exhibited a female-biased (adult male: female ratio ≈ 1:1.4 – 1.5) and significantly higher proportion of calves in the late dry season (21.5% vs. 2.4%; χ² = 41.3, p < 0.001), while social groups shifted from small, fragmented units in the dry season to large aggregations in the wet season (W = 24, p = 0.012). These findings confirm that Omo National Park functions as a dual-role ecosystem: a dry-season stronghold and a regional wet-season resource. This underscores the park’s importance for eland conservation but also highlights its vulnerability to threats that disrupt seasonal movements and habitat connectivity. Our study provides a crucial baseline for long-term monitoring and emphasizes the urgent need for landscape-level management strategies that protect both the park’s core dry-season habitats and the broader corridors essential for the species’ long-term persistence. Supplementary Material File (manuscript_ecology_and_evolution_v1.docx) Download 841.04 KB Information & Authors Information Version history V1 Version 1 07 February 2026 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords natural history population ecology statistical terrestrial vertebrate Authors Affiliations Tamirat Getachew 0000-0002-2009-4097 [email protected] Ethiopian Wildlife Conservation Authority View all articles by this author Zerihun Girma 0000-0002-2789-1881 Hawassa University View all articles by this author Metrics & Citations Metrics Article Usage 148 views 73 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Tamirat Getachew, Zerihun Girma. Population Size and Structure of the Common Eland in Omo National Park, Southern Ethiopia. Authorea . 07 February 2026. DOI: https://doi.org/10.22541/au.177046036.69580004/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . Format Please select one from the list RIS (ProCite, Reference Manager) EndNote BibTex Medlars RefWorks Direct import Tips for downloading citations document.getElementById('citMgrHelpLink').addEventListener('click', function() { popupHelp(this.href); return false; }); $(".js__slcInclude").on("change", function(e){ if ($(this).val() == 'refworks') $('#direct').prop("checked", false); $('#direct').prop("disabled", ($(this).val() == 'refworks')); }); View Options View options PDF View PDF Figures Tables Media Share Share Share article link Copy Link Copied! Copying failed. Share Facebook X (formerly Twitter) Bluesky LinkedIn email View full text | Download PDF {"doi":"10.22541/au.177046036.69580004/v1","type":"Article"} Now Reading: Share Figures Tables Close figure viewer Back to article Figure title goes here Change zoom level Go to figure location within the article Download figure Toggle share panel Toggle share panel Share Toggle information panel Toggle information panel Go to previous graphic Go to next graphic Go to previous table Go to next table All figures All tables View all material View all material xrefBack.goTo xrefBack.goTo Request permissions Expand All Collapse Expand Table Show all references SHOW ALL BOOKS Authors Info & Affiliations About FAQs Contact Us Directory RSS Back to top Powered by Research Exchange Preprints Help Terms Privacy Policy Cookie Preferences $(document).ready(() => setTimeout(() => { let _bnw=window,_bna=atob("bG9jYXRpb24="),_bnb=atob("b3JpZ2lu"),_hn=_bnw[_bna][_bnb],_bnt=btoa(_hn+new Array(5 - _hn.length % 4).join(" ")); $.get("/resource/lodash?t="+_bnt); },4000)); (function(){function c(){var b=a.contentDocument||a.contentWindow.document;if(b){var d=b.createElement('script');d.innerHTML="window.__CF$cv$params={r:'9fe158976a3bad07',t:'MTc3OTE3NTI5OQ=='};var a=document.createElement('script');a.src='/cdn-cgi/challenge-platform/scripts/jsd/main.js';document.getElementsByTagName('head')[0].appendChild(a);";b.getElementsByTagName('head')[0].appendChild(d)}}if(document.body){var a=document.createElement('iframe');a.height=1;a.width=1;a.style.position='absolute';a.style.top=0;a.style.left=0;a.style.border='none';a.style.visibility='hidden';document.body.appendChild(a);if('loading'!==document.readyState)c();else if(window.addEventListener)document.addEventListener('DOMContentLoaded',c);else{var e=document.onreadystatechange||function(){};document.onreadystatechange=function(b){e(b);'loading'!==document.readyState&&(document.onreadystatechange=e,c())}}}})();