Diet quality and mineral status of large herbivores in West African savanna ecosystems

Ing. Lucie Stoklasová

Doctoral thesis

Abstract:

The knowledge of adequate nutritional requirements and health status of large free ranging herbivores is limited, especially in the West African region. Many studies are focused to South Africa and diet quality and mineral status of herbivores in other regions are not investigated in depth. Lack of these essential information are burning issue primarily for endangered species. The present dissertation thesis aimed to fill this gap by expanding our understanding of the diet quality and mineral status of large herbivores in West African savanna ecosystems, i.e. in semi-arid and sub-humid savannas, with special focus on the critically endangered Western Derby eland (WDE). An integral partial aim was to explore the flexibility and clarify the position of Common eland regarding its classification as “mixed feeder” feeding type, as this species was introduced into the community of large herbivores in two wildlife reserves in Senegal, regardless its South African origin. To determine mineral status and diet quality, samples of blood serum, faeces and hair were collected from Western Derby eland from semi-arid and sub-humid areas. To test whether the flexibility of Common eland to browse vs. grass diet is linked to a ‘cattle-type’ or a “moose-type” forestomach physiology by measuring the mean retention time of different digesta phases in a standard experiment on a Common eland breeding farm was done. Faecal samples for diet quality determination were collected altogether from buffalo, zebra, common eland, roan antelope and Wester Derby eland (seasonal data collection) from the same semi-arid and sub-humid areas. Mineral status of Western Derby eland was determined mainly from the blood serum since there was not found any correlation between mineral concentration in hair and faecal samples. Therefore, analysis of faeces and fur cannot stand alone for the assessment of the mineral status and the determination mineral deficiencies but may serve as useful supporting evidence. Blood mineral profile of Western Derby eland was therefore compared to other Tragelaphineae and appeared lower in almost all elements, which may reflect most likely the limited mineral background in the local environment. Nevertheless, tested individuals of WDE did not show clinical problems, which may be due to dietary adaptation of WDE to such mineral limited environment. Common eland was, based on results of our experiment, considered as ‘moose-type’. Analysis of mineral concentrations and diet quality indicators (ADF, NDF, lignin, cellulose, hemicellulose, nitrogen) from faeces of five herbivore species in two localities provided information about herbivores adaptation to semi-arid and sub-humid environment. Mixed feeders and grazers maintained the quality of their diet in most of the principal parameters, especially in the content of nitrogen and fibres, regardless the savanna ecosystem type, while browser showed significantly lower nitrogen and fibres in the semi-arid environment in comparison to the sub-humid one. The diet quality indicated by the concentration of nitrogen was higher in Derby and common elands in comparison to zebra and buffaloes at both sites. Despite the fact that all species maintained their diet quality above level of deficiency, semi-arid conditions required feeding behaviour adaptation of all species across feeding types. From conservation perspective, all feeding guilds may become threatened by changing ecosystems, even if each one by different way, if they are forced to change food resources, and a conservation-oriented ‘exit-strategy’ for species should be conceived to address these threats, including the strengthening the ecological connectivity in savanna landscapes.

Keywords

Antelope conservation, Blood serum, Faeces, Feeding type, Hair, Large herbivores, Mineral profile, Savanna ecosystem, Wildlife management

Language used: English

Date on which the thesis was submitted / produced: 4. 3. 2021

Thesis defence

• Supervisor: prof. RNDr. Pavla Hejcmanová, Ph.D.
• Reader: Milan Marounek, externi, Jiří Kamler, externi, Leoš Pavlata, Ing., externi

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Doctoral programme / field:
Agricultural Specialization / Tropical Agrobiology and Bioresource Management