African carnivore gut bacterial diversity and composition are associated with sample condition but not storage technique

Non-invasive fecal sampling is essential for molecular wildlife studies such as gut microbiome (GMB) research, yet field conditions often limit preservation options. To test the effects of preservation methods on the results of GMB community composition, we compared gut bacterial communities in paired fecal samples preserved in stabilization tubes and air-dried in paper bags collected from anesthetized African lions (Panthera leo) and spotted hyenas (Crocuta crocuta) in Etosha National Park, Namibia. Additional opportunistic samples from the ground around carnivore feeding sites that varied in moisture content were also analyzed. No differences in alpha or beta diversity were detected between preserved and dried samples, although bacterial beta diversity differed between preserved and opportunistic samples, supported by NMDS ordinations and PERMANOVA results. Core bacterial communities remained consistent across opportunistic sample conditions, indicating that host-associated taxa persist despite environmental exposure supporting the use of opportunistic samples for GMB studies in remote arid settings. However, consistent sampling protocols and future field-based desiccation studies remain critical for comparative analyses. These findings highlight that rapid air-drying offers a reliable, low-cost preservation option that maintains core microbiome patterns, expanding the feasibility of GMB research in remote or resource-limited field contexts where refrigeration and preservatives may be unavailable.