L’autruche d’Afrique du Nord (Struthio camelus camelus) communément appelée autruche à cou rouge a disparu à l’état naturel au Niger depuis 2004. Le présent article est une contribution au processus de réintroduction de cette espèce, qui vise à caractériser la végétation du site dénommé « Tchillala » dans le Koutous, site pilote pour le pré-lâché de l’autruche. Les relevés phytosociologiques ont été effectués à l’aide de la méthode sigmatiste d’abondance-dominance de Braun-Blanquet dans 42 placettes de 1000 m² (50 m × 20 m). Dans chaque placette, la coupe de la phytomasse herbacée a été réalisée dans des carrés de rendement de 1 m². Au total, soixante-six (66) espèces réparties en cinquante un (51) genres et vingt-huit (28) familles ont été recensées. La classification hiérarchique ascendante des relevés a permis d’individualiser trois groupements végétaux : le groupement à Acacia tortilis et Tribulus terrestris, le groupement à Balanites aegyptiaca et Zornia glochidiata et le groupement à Leptadenia pyrotechnica et Echinochloa colona. La richesse spécifique de ces groupements végétaux varie de quarante un (41) à soixante-deux (62) espèces. L’indice de diversité de Shannon varie de 4,01 à 3,16 bits et l’indice d’équitabilité de Piélou de 0,56 à 0,67. La productivité moyenne de la phytomasse herbacée des trois groupements est de 0,48±0,17 tonnes de matière sèche par hectare et une capacité de charge moyenne de 0,07±0,02 UBT/ha/an. Les spectres biologiques des groupements montrent une dominance des thérophytes. Quant aux spectres phytogéographiques, ils montrent une dominance des espèces paléotropicales. Ce site possède un potentiel floristique pour faire le pré-lâchage des autruches.Mots clés : Struthio camelus camelus, phytosociologie, productivité, réintroduction, Koutous, Niger   English Title: Phytodiversity and herbaceous productivity of the future site of pre-release ostrich of North Africa (Struthio camelus camelus L.) in Koutous, Niger The North African ostrich (Struthio camelus camelus), commonly known as the Red-necked Ostrich, which has been extirpated from Niger since 2004. This article is a contribution to the reintroduction process of this species; aims to characterize the vegetation of the site called "Tchillala" in the Koutous, pilot site for the ostrich pre-release. The phytosociological surveys were carried out using the Braun-Blanquet sigmatism abundance-dominance method in 42 plots of 1000 m² (50 m × 20 m). In each plot, herbaceous phytomass was cut in yield squares of 1 m². A total of sixty-six (66) species divided into fifty-one (51) genera and twenty-eight (28) families were identified. The ascending hierarchical classification of the surveys has shown three plants groups such as Acacia tortilis and Tribulus terrestris group, Balanites aegyptiaca and Zornia glochidiata group and Leptadenia pyrotechnica and Echinochloa colona group. The species richness of these plant groups varies from 62 to 41 species. The Shannon diversity index varies from 4.01 to 3.16 bits and Piélou's equitability index from 0.56 to 0.67. The average productivity of the herbaceous phytomass of the three groups is 0.48 ± 0.17 tonnes of dry matter per hectare and an average carrying capacity of 0.07±0.02 TLU/ha/year. The biological spectra of the groups show a dominance of therophytes. As for phytogeographic spectra, they show a dominance of paleotropical species. This site has a floristic potential to pre-release the individuals of ostrich.Keywords: Struthio camelus camelus, phytosociology, productivity, reintroduction, Koutous, Niger.

The North African Ostrich (Struthio camelus camelus), also known as the red-necked ostrich, disappeared from Niger 15 years ago but preliminary work completed in 2011 has shown that the species has not vanished from the collective memory in the Koutous. Using a Participatory Action Research (PAR) approach, this study combines the results of questionnaire surveys and local market monitoring conducted between October 2017 and January 2020, in order to document the ethnozoological knowledge of the communities living in the surroundings of the ostrich breeding centre of Kellé (Zinder). It fits within the wider framework of the species reintroduction program. A total of 120 people were interviewed individually to evaluate their knowledge about the species and their opinion about its possible return in the Koutous. The results emphasized that the ostriches were mainly sources of food (meat or eggs) and traditional medicines (topical pain killers), and to a lesser extent, of ornament objects. Additionally, wildlife products trade still occurs in three of the four weekly markets monitored and one stallholder still had an ostrich bone to sell. Entailing either animal hunting or disturbance, these uses could represent limiting factors to the re-establishment of wild populations. No mention was made of cultural, natural or religious heritage or source of incomes, suggesting the value was limited to subsistence. However, with eight usable products listed, the value of a single animal is relatively high since it can fulfil various demands. Most of the interviewees had limited knowledge about the species’ ecology but they anticipated a lack of suitable habitat. No other cause than lack of water (low rainfall, climate change, desertification...), habitat encroachment by human activities (urbanisation and agriculture) and hunting was thought to have caused the extinction. Habitat restoration was indeed the most-cited prerequisite for successful restoration of wild populations; however the need to ensure the animals’ security (fences, patrols, regulations, anti-poaching campaigns...) was also put forward. The confidence rate in the reintroduction initiatives was mitigated: none of the people interviewed was confident it would be a success in the current context but 56.66% of them were optimistic if preliminary requirements are met. The interpretation of the answers to the open-ended questions suggests underlying risks of illegal hunting and human-wildlife conflict but the request for public awareness campaigns and regulations gives hope for the return of free-ranging North-African ostriches in the future. This study provides key baseline data about the local communities’ perception of ostrich conservation and key elements in a Participatory Rural Appraisals (PRA) approach (also known as “Méthode Active de Recherche et Planification Participative” - MARP) in any conservation project. In particular, this work will contribute to the development of feasibility plan for future North African ostrich reintroduction in the Koutous.

This study aims to investigate the composition and Important Value Index (IVI) of the woody stands of Tchillala, a 130-ha area selected for future North-African ostriches (Struthiocameluscamelus) prerelease in the Koutous region in Niger. The forest inventory method was implemented in 42 plots of 50 m x 20 m (1000 m²) for tree-level observation, using stratified random sampling. For each woody specimen, the trunk diameter, total height and crown diameter have been recorded; thespecimens with a trunk diameter smaller than 5 cm are considered as regenerations. A total of 17 woody species distributed across 10 families have been identified and most of them belongs either to the Mimosaceae (4 species) or the Tiliaceae (3 species). The plants density, domination and frequency were used to determine the IVI: Acacia tortilis and Balanitesaegyptiaca are the species with the highest IVI(118.43 and 88.28 respectively). The woody plants condition assessment has emphasized that trees have been facing natural (uprooting) and anthropogenic (cutting, pruning) threats. Consequently, the diameter class structures within the whole woody species community of Tchilala, as well as of the Acacia tortilis and Balanitesaegyptiaca, are mainly small size trees. The results of this study inform silvicultural management actions that would benefit to the North-African ostrich’establishment in Tchilala and the data collected are considered as possible indicators for long-term monitoring of habitat.