Dorcas gazelle and livestock use of trees according to size in a hyper-arid landscape

Attum, Omar; Mahmoud, Tarig E.

doi:10.1016/j.jaridenv.2011.07.002

Cited by 13 publications

(28 citation statements)

References 32 publications

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“…Due to the many provided services and goods, Acacia trees are considered keystone species in many desert ecosystems (Milton & Dean, ; Moustafa, Zaghloul & Hatab, ). Thus, the conservation of Acacia trees is important particularly in arid and hyperarid deserts for regulating microclimate, improving conditions for survival of associated plant and animal species (Attum & Mahmoud, ), providing direct benefits for local inhabitants, and for starting sustainable development (Chapman & Reiss, ).…”

Section: Discussionmentioning

confidence: 99%

“…High mortality in desert trees combined with lack of recruitment will endanger tree populations (Andersen & Krzywinsk, ) and services provided by this keystone species (Attum & Mahmoud, ). Thus, a more thorough understanding of the population structure and causes of mortality of Acacia trees is of vital importance to the conservation of the desert ecosystem.…”

Section: Introductionmentioning

confidence: 99%

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Anthropogenic effects on population structure ofAcacia tortilissubsp.raddianaalong a gradient of water availability in South Sinai, Egypt

et al. 2013

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Acacia trees in Sinai desert are suffering population decline. This study aims to explore this assumption and to determine the effects of grazing and urbanization on size structure of Acacia tortilis subsp. raddiana along a gradient of water availability in Wadi Feiran basin, South Sinai, Egypt. Size structure of 289 Acacia trees in thirteen isolated populations was analysed. Catchment area and lineament density as water availability indicators were calculated. Effects of grazing and urbanization on Acacia populations were evaluated. A strong positive correlation was recognized between tree height, crown diameter and trunk circumference. Acacia tree density and crown diameter are positively correlated with water availability indicators. Population structure of A. tortilis is characterized by absence of juveniles, clear reduction in numbers of small and large categories and increasing in medium categories. This pattern indicates very low recruitment and high mortality of small and large trees. The variation in water availability may have considerable effects on the structure of A. tortilis. Overgrazing, cutting and urbanization are the main causes of population decline of Acacia in Sinai desert. In addition, drought conditions and bruchid seed beetles aggravate the anthropogenic effect on recruitment of Acacia in South Sinai.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Anthropogenic effects on population structure ofAcacia tortilissubsp.raddianaalong a gradient of water availability in South Sinai, Egypt

et al. 2013

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“…A total of 825 pellet events were recorded for oryx (640) and gazelle (185). Of these, 65 pellet events (12 oryx and 53 gazelle) were classified as territorial clusters of feces known as middens (Attum and Mahmoud ). Middens do not reflect resource use with their location driven by territorial factors (Attum and Mahmoud ), and so were excluded from analysis, leaving 628 oryx and 132 gazelle pellet events from which density was calculated in DISTANCE 6.2 (Thomas et al.…”

Section: Methodsmentioning

confidence: 99%

Section: Indirect Distance Samplingmentioning

confidence: 99%

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Resource partitioning between ungulate populations in arid environments

Cooke

Woodfine

Petretto

et al. 2016

Ecology and Evolution

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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.

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