title: Resource partitioning between ungulate populations in arid environments.
abstract: Herbivores are major drivers of ecosystem structure, diversity, and function. Resilient ecosystems therefore require viable herbivore populations in a sustainable balance with environmental resource availability. This balance is becoming harder to achieve, with increasingly threatened species reliant on small protected areas in increasingly harsh and unpredictable environments. Arid environments in North Africa exemplify this situation, featuring a biologically distinct species assemblage exposed to extreme and volatile conditions, including habitat loss and climate change-associated threats. Here, we implement an integrated likelihood approach to relate scimitar-horned oryx (Oryx dammah) and dorcas gazelle (Gazella dorcas) density, via dung distance sampling, to habitat, predator, and geographic correlates in Dghoumes National Park, Tunisia. We show how two threatened sympatric ungulates partition resources on the habitat axis, exhibiting nonuniform responses to the same vegetation gradient. Scimitar-horned oryx were positively associated with plant species richness, selecting for vegetated ephemeral watercourses (wadis) dominated by herbaceous cover. Conversely, dorcas gazelle were negatively associated with vegetation density (herbaceous height, litter cover, and herbaceous cover), selecting instead for rocky plains with sparse vegetation. We suggest that adequate plant species richness should be a prerequisite for areas proposed for future ungulate reintroductions in arid and semi-arid environments. This evidence will inform adaptive management of reintroduced ungulates in protected environments, helping managers and planners design sustainable ecosystems and effective conservation programs.
authors.affiliation: Centre for Biological Sciences University of Southampton Life Sciences Building (B85) Highfield Campus Southampton SO17 1BJ UK; Marwell Wildlife Thompson's Lane Colden Common Winchester Hampshire SO21 1JH UK.
authors.forename: Robert S C
authors.identifier: 0000-0003-0601-8888
authors.initials: RS
authors.lastname: Cooke
authors.affiliation: Marwell Wildlife Thompson's Lane Colden Common Winchester Hampshire SO21 1JH UK.
authors.forename: Tim
authors.initials: T
authors.lastname: Woodfine
authors.affiliation: Marwell Wildlife Thompson's Lane Colden Common Winchester Hampshire SO21 1JH UK.
authors.forename: Marie
authors.initials: M
authors.lastname: Petretto
authors.affiliation: Centre for Biological Sciences University of Southampton Life Sciences Building (B85) Highfield Campus Southampton SO17 1BJ UK; School of Ocean and Earth Sciences National Oceanography Centre Southampton University of Southampton Southampton SO17 1BJ UK.
authors.forename: Thomas H G
authors.initials: TH
authors.lastname: Ezard
keywords: Desert; North Africa; distance sampling; dorcas gazelle; reintroduction; scimitar‐horned oryx