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Assessment of diet composition of free-ranging addax antelopes (Addaxnasomaculatus) by the combination of microhistological procedures and n-alkanes and long-chain alcohols as fecal markers

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Canadian Journal of Zoology
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Understanding herbivore foraging behaviour is crucial for adequate wildlife management decisions. This study assessed the diet composition of free-ranging addax antelope (Addaxnasomaculatus (de Blainville, 1816)). Samples collected during the spring season were analyzed using microhistological procedures along with n-alkanes and long-chain alcohols as fecal markers. Twelve animals were monitored and fresh fecal samples were collected daily during a 7-day period. Diet composition estimates obtained by both methods were similar and indicate that Stipagrostis pungens (Desf.) De Winter was the main diet component followed by Fagonia glutinosa Delile, Helianthemum kahiricum Delile, and Hammada schmittiana (Pomel.) Botsch. Data showed that addax have mixed diets composed of perennial woody and herbaceous plant species depending on their availability. The four species most selected by the animals were also the most abundant species in terms of plant cover. In contrast, species that accounted for less than 5% of the plant cover were not present in the fecal samples. Results of this study represent a single grazing season, and for that reason, further studies are required to fully understand how the grazing behaviour of addax varies with seasonal changes in vegetation cover.
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Assessment of diet composition of free-ranging addax
antelopes (Addax nasomaculatus) by the combination of
microhistological procedures and n-alkanes and long-chain
alcohols as fecal markers
Hicham Seri, Mohsen Chammem, Severiano Silva, Miguel Rodrigues, Touhami Khorchani,
and Luis Ferreira
Abstract: Understanding herbivore foraging behaviour is crucial for adequate wildlife management decisions. This study
assessed the diet composition of free-ranging addax antelope (Addax nasomaculatus (de Blainville, 1816)). Samples collected during
the spring season were analyzed using microhistological procedures along with n-alkanes and long-chain alcohols as fecal
markers. Twelve animals were monitored and fresh fecal samples were collected daily during a 7-day period. Diet composition
estimates obtained by both methods were similar and indicate that Stipagrostis pungens (Desf.) De Winter was the main diet
component followed by Fagonia glutinosa Delile, Helianthemum kahiricum Delile, and Hammada schmittiana (Pomel.) Botsch. Data
showed that addax have mixed diets composed of perennial woody and herbaceous plant species depending on their availability.
The four species most selected by the animals were also the most abundant species in terms of plant cover. In contrast, species
that accounted for less than 5% of the plant cover were not present in the fecal samples. Results of this study represent a single
grazing season, and for that reason, further studies are required to fully understand how the grazing behaviour of addax varies
with seasonal changes in vegetation cover.
Key words: diet composition, addax, Addax nasomaculatus, Jbil National Park, n-alkanes, long-chain alcohols.
Résumé : La compréhension des comportements d’alimentation des herbivores est d’importance cruciale pour les décisions
d’aménagement de la faune. L’étude évalue la composition du régime alimentaire d’addax (Addax nasomaculatus (de Blainville,
1816)) en liberté. Des échantillons prélevés au printemps ont été analysés par des procédures microhistologiques combinées à
l’usage de n-alcanes et d’alcools à longue chaîne comme marqueurs fécaux. Douze animaux ont fait l’objet d’une surveillance, et
des échantillons fécaux frais ont été prélevés quotidiennement durant une période de 7 jours. Les estimations de la composition
du régime alimentaire obtenues par les deux méthodes sont semblables et indiquent que Stipagrostis pungens (Desf.) De Winter
était la principale composante du régime alimentaire, suivi de Fagonia glutinosa Delile, Helianthemum kahiricum Delile et Hammada
schmittiana (Pomel.) Botsch. Des données montrent que les addax ont des régimes alimentaires mixtes composés d’espèces de
plantes ligneuses et herbacées pérennes, selon leur disponibilité. Les quatre espèces les plus choisies par les animaux sont
également les espèces les plus abondantes de la couverture végétale. En comparaison, les espèces qui représentent moins de 5 %
de la couverture végétale n’étaient pas présentes dans les échantillons fécaux. Les résultats de l’étude représentent une seule
saison de broutage, de sorte que d’autres études sont nécessaires pour bien comprendre les variations du comportement de
broutage de ces antilopes en fonction des variations saisonnières de la couverture végétale. [Traduit par la Rédaction]
Mots-clés : composition du régime alimentaire, addax, Addax nasomaculatus, parc national de Jbil, n-alcanes, alcools à longue chaîne.
Introduction
Knowledge on herbivore grazing behaviour is important to un-
derstand the foraging ecology of these species and is crucial to
establish adequate wildlife management programs. Season is widely
recognized as a major possible factor determining diet selection
(Pavlù et al. 2006) because it influences forage quality and quantity
(Schut et al. 2009). Seasonal differences in the timing of vegetation
growth and dormancy could affect the amount of forage produced.
The use of plant-wax markers, namely n-alkanes, long-chain fatty
acids, and long-chain alcohols (LCOH), has drawn considerable inter-
est as methods to estimate herbivore diet composition (Dove and
Mayes 2006). Diet composition is determined by comparing the
marker concentration profiles in the animal feces with those of pos-
sible diet sources (i.e., plant species that are available to the animals).
Results from previous studies (Dove and Mayes 2005;Lin et al. 2009;
Ferreira et al. 2015) showed that both n-alkanes and LCOH are incom-
pletely recovered in the feces of ruminant species. As a result, fecal
marker concentrations should be corrected for incomplete recovery
prior to diet composition estimation.
Initially, only n-alkanes were used as diet composition markers,
but further studies have shown the benefits of combining them
Received 7 November 2017. Accepted 29 March 2018.
H. Seri, M. Chammem, and T. Khorchani. Laboratoire d’Elevage et de la Faune Sauvage, IRA–Médenine, Médenine, Tunisia.
S. Silva. CECAV Animal Science Department, University of Trás-os-Montes and Alto Douro, 5000-801, Vila Real, Portugal.
M. Rodrigues and L. Ferreira. CITAB Centre for the Research and Technology of Agro-Environment and Biological Sciences, University of Trás-os-Montes
and Alto Douro, 5000-801, Vila Real, Portugal.
Corresponding author: Hicham Seri (email: hichamseri98@gmail.com).
Copyright remains with the author(s) or their institution(s). Permission for reuse (free in most cases) can be obtained from RightsLink.
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Can. J. Zool. 96: 1284–1289 (2018) dx.doi.org/10.1139/cjz-2017-0320 Published at www.nrcresearchpress.com/cjz on 24 August 2018.
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