Connaissances traditionnelles et pratiques locales sur une espèce endémique Ipomoea beninensis Akoègninou, Lisowski & Sinsin (Convolvulaceae): une évaluation préliminaire pour sa conservation au Bénin

Ipomoea beninensis Akoègn., Lisowski & Sinsin (Convolvulaceae) is the only endemic plant known for Benin. To date, no data exist on its usages, distribution, abundance, and threats. An improved understanding of indigenous knowledge and of local practices can provide insight into how the species could be sustainably conserved. We interviewed 114 local residents for collecting ethnobotanical and ethnoecological data in six sites known to host the species. Data were processed by calculation of descriptive statistics and variance and multivariate analyses. A total of twelve uses were reported. Among them, treatment of varicella (19%), malaria (18%) and fodder (17%) were the most recurrent. These mainly involve use of the species rootstock. Almost all respondents mentioned decline of the species in natural habitats. None of them was aware about the endemic status of the species. Consequently, negative practices toward the protection of I. beninensis were prevalent among local residents. Several conservation measures are proposed to ensure the longterm survival of I. beninensis.Ipomoea beninensis Akoègn., Lisowski & Sinsin (Convolvulaceae) est la seule plante endémique connue pour le Bénin. À ce jour, aucune donnée n'existe sur ses usages, sa distribution, son abondance et ses menaces. Une meilleure compréhension des connaissances autochtones et des pratiques locales peut donner un aperçu de la manière dont l'espèce pourrait être conservée de manière durable. Des interviews ont été réalisées auprès de 114 résidents locaux pour la collecte de données ethnobotaniques et ethnoécologiques dans six localités. Les données ont été traitées par le calcul de statistiques descriptives et d'analyses de variance et multivariées. Au total, douze utilisations ont été signalées parmi lesquelles le traitement de la varicelle (19%), du paludisme (18%) et le fourrage (17%) étaient les plus rapportées. Ces derniers impliquent principalement l'utilisation des racines de l'espèce. Presque tous les enquêtés ont mentionné le déclin de l'espèce dans les habitats naturels. Aucun d'entre eux n'est au courant du statut endémique de l'espèce. Par conséquent, les pratiques négatives à l’encontre de la protection de I. beninensis étaient répandues. Plusieurs mesures de conservation sont proposées pour assurer la survie à long terme de I. beninensis

Identification of socio-economic characteristics and farmers’ practices affecting rice (Oryza spp.) yields in Benin (West Africa)

Rice (Oryza spp.) is one of the major staple foods in Benin. Benin has increased rice production through the expansion of cultivation area rather than increasing rice yields. To better understand the factors affecting rice yields, a thorough understanding of the current rice production system characteristics and constraints is required. The present study identifies socio-economic characteristics and farmers’ practices affecting rice yields and suggests improved cultivation practices in the sector. Data were collected through semi-structured interviews, including socio-economic characteristics and rice cultivation practices from 230 randomly selected rice producers in North and Central Benin. Descriptive statistics and cluster analysis were used to group rice producers into different groups. Findings revealed that the proportion of rice producers having access to credit was low (33.5 %). Out of seventeen variables, only three (lowland rice cultivation, irrigated rice cultivation and total land cultivated area) discriminated best the rice producers in three (03) clusters with distinct characteristics in terms of socio-economics factors and cropping practices affecting rice yields. Most respondents (more than 70 %) did not practice crop rotation or fallow. This, together with low levels of chemical fertiliser applications and type of rice cultivation, explains poor rice production in particular in clusters 1 and 2. Yield enhancement is possible through the combination of lowland and irrigated cultivation performed by farmers in cluster 3 with the highest mean rice yield (3.8 t.ha-1). We suggest tackling the specific characteristics and needs of rice producers would more adequately help to improve rice yields. Interventions to enhance rice yields include training on best rice production practices, provision of input subsidies and access to irrigation tailored to the specific constraints and needs of each rice grower type. Finally, enabling access to credit will improve productivity of rice farmers in Benin

Physico-chemical properties of crude oil of Khaya senegalensis (Desr.) A. Juss according to bioclimatic zones in Chad

The mature seeds of Khaya senegalensis are from 2 to 2.5 cm long and weigh 289 g per 1000 seeds. These seeds contain about 67% oil by weight. This oil, which is fairly rich in oleic acid (66%), is used in West Africa for cooking, for cosmetics, as an insecticide and in traditional medicine. Prospecting to enhance the development of this oil in Chad, the present study aims to determine the physico-chemical properties of this oil according to bioclimatic zones. The density, acidity, peroxide value, moisture content and percentage of impurities were the parameters studied. The results showed that the crude oil of the seeds of K. senegalensis has the qualities close to those of other edible oils. The study also revealed that climate has influenced the physico-chemical parameters of this oil. Further and more research investigations are necessary to guide decisions on the valorisation and large-scale production of this oil. Keywords: Khaya senegalensis, seed crude oil, physico-chemical parameters, valorisation, bioclimatic zone, Cha

Impact of Climate Change on Priority Plant Species Conservation in The Forests Under ONAB (the National Wood Office of Benin) Management

The sustainable conservation of forest resources in a context of climate change and population growth would be compromised in their current form of exploitation by rural communities. The objective of this study is to assess the impact of climate change on the dynamics of habitats favorable to species of conservation priority in the forests under ONAB management as these species are heavily used by the populations living along the shores of these forests. The study will consist of: Khaya senegalensis, Afzelia africana, Khaya grandifoliola, Pterocarpus erinaceus, Anogeissus leiocarpa, Milicia excelsa, Albizia zygia, Vitex doniana, Antidesma laciniatum and Bombax costatum. Techniques based on the principle of maximum entropy (Maxent) combined with GIS were used to project the favorable habitats of these ten species under current and future climatic conditions (Horizon 2050). Species occurrence data were collected and combined with bioclimatic data derived from the Worldclim database and the edaphic (soil) variable. Two climate models were used for future projections (CNRM-CM5, HadGEM-ES models) under the IPCC A2 scenario, and the partial ROC approach was used for the evaluation of the predictions of ecological niche models. Variables such as cec2 (cation exchange capacity, horizon 5-15cm), bio17 (precipitation of the driest quarter), bio12 (annual precipitation), bio3 (isothermality), bio6 (minimum temperature of the coldest month) and bio7 (annual thermal amplitude) were found to be the most relevant respectively for the distribution of Khaya grandifoliola, Albizia zygia, Anogeissus leiocarpa, Antidesma laciniatum, Afzelia africana and Khaya senegalensis. Under current conditions, only 7% of the Beninese territory would be very favorable to the conservation of Khaya senegalensis and the CNRM-CM5 model predicts an increase of 27.5% and 13.2% respectively of these very favorable and moderately favorable areas by 2050 through conversion of unfavorable areas (7.4%). On the other hand, this model predicts an opposite trend at the level of Afzelia africana where it predicts a decrease of 8.1% and 1.8% respectively of the very favorable and moderately favorable areas and an increase of 5.1% of the unfavorable areas. Ecological niche modeling has basically revealed the conversion of some currently unfavorable habitats into very favorable habitats for conservation (this is the case of Khaya grandifoliola, Khaya senegalensis and Vitex doniana) and the extension of some habitats unfavorable to conservation (Anogeissus leiocarpa, Bombax costatum, and Pterocarpus erinaceus) by 2050. This study provides scientific support for planning and is a decision support tool for the conservation of these species at the socio-economic level

How Far the Mono Transboundary Biosphere Reserve Protects Biodiversity in the Dahomey-Gap Corridor, West Africa?

Mono Transboundary Biosphere Reserve (MTBR) is rich in biodiversity associated with different multi-functional ecosystems in the Dahomey-Gap corridor in the southern border between Benin and Togo. The reserve has been facing many anthropogenic pressures since few years including the uncontrolled exploitation of forest resources, and fragmentation of habitats and permanent search for arable land. Thus, it becomes important to develop prospective analysis approaches in order to provide specific insights for a balanced biodiversity. This study aims to provide scientific evidence to better understand and project future changes in LULC in the MTBR at different spatial and temporal scales. Changes in LULC were used to map the MTBR in 1986, 2000, and 2015 and to predict the LULC in the future up to 2070 using Markovian chain analysis. During 1986–2000, urban agglomeration/bare soil (8.79 ha/year) increased, whereas the natural vegetation cover increased during the period 2000–2015, particularly mangroves (9.81 ha/year). Assuming the dynamic observed, the mangroves will increase by 2070 (6% of its cover). However, an important increase is also expected for farmland (13% of its cover). It is, therefore, important to strengthen the actions and strategies around and within the MTBR for sustainable management of biological resources

Developing policy-relevant biodiversity indicators : lessons learnt from case studies in Africa

There is an increasing need for monitoring schemes that help understand the evolution of the global biodiversity crisis and propose solutions for the future. Indicators, including temporal baselines, are crucial to measure the change in biodiversity over time, to evaluate progress towards its conservation and sustainable use and to set conservation priorities. They help design and monitor national and regional policies on biodiversity; they also feed into national reporting on international agreements such as the Convention on Biological Diversity and the Sustainable Development Goals. We analyse the methodological approach of five small African projects resulting from a call to promote indicator development, improve monitoring capacity and strengthen the science-policy interface in the field of biodiversity. We compared their approach to existing guidance provided by the international community, specifically the Biodiversity Indicators Partnership. To this end, we assess whether internationally recommended steps are effectively applied to national/local biodiversity monitoring in selected developing countries. We also present lessons learnt from workshop interactions between partners involved in these projects. Through our pilot projects we identified data availability and data accessibility, together with the involvement of stakeholders, as critical steps in indicator development. Moreover, there is a need for a better awareness and a wider application of the indicator concept itself. Hence, training of key actors both in the policy and science spheres is needed to operationalize indicators and ensure their continuity and sustainability. We hope that these case studies and lessons learnt can stimulate and support countries in the Global South to formulate policy-relevant biodiversity indicators.Peer reviewe

Modélisation de la distribution des espèces en Afrique : état de l'art et perspectives

Modeling the distribution of species has become a very popular tool to aid in anticipation and decision-making in the conservation of biological resources. The current review aimed to summarize the existing work in this area in Africa, identify the shortcomes and suggest research perspectives. To this end, online databases were used to identify and download the publications considered here. Of the 229 studies carried out in Africa, 167 published between 2003 and 2019 in 100 journals were deemed relevant for this review. Almost 27 % of the publications were made in Benin and South Africa. Twenty-three methodological modeling approaches have been identified and divided into two main groups: empirical or correlative methods and mechanistic ones. Correlative methods and more specifically the principle of maximum entropy Maxent (113 studies out of 167) were the most used (about 68% of the studies). This could be explained by the fact that the correlative methods are open access, less restrictive, less demanding on data and more easily implementable. Among the weaknesses noted in those studies were the level of data quality, not always sufficient to ensure the validity of the drawn conclusions. Likewise, sampling biases are generally ignored in the specification of models while the observed distribution of occurrences is rather the result of sampling biases or the inaccessibility of certain areas rather than the environmental preferendum of the modeled species. Finally, most studies on the continent did not include species demography or biotic interactions. Exploring such aspects could help to improve the quality of the models

Potential Geography and Conservation of Ipomoea beninensis, an Endangered Plant Species for Benin (West Africa)

The endemic plant of Benin, Ipomoea beninensis Akoègn, Lisowski and Sinsin, is threatened in its natural habitats. This study assesses the suitability of the current and future habitat for its conservation countrywide. Maxent models were run using records added to environmental variables under present and two climates. The results showed that the most suitable areas for I. beninensis will be mainly in the phytodistrict of southern and northern Borgou. The species could lose 9% and 13.6% of its suitable habitats under RCP4.5 and RCP8.5, respectively. Urgent and timely strategies are needed to save the remaining population of the species

DIVERSITY OF WILD PALMS (ARECACEAE) IN THE REPUBLIC OF BENIN: FINDING THE GAPS IN THE NATIONAL INVENTORY COMBINING FIELD AND DIGITAL ACCESSIBLE KNOWLEDGE

Despite many efforts by researchers worldwide to assess the biodiversity of plant groups, many locations on Earth remain not well surveyed and data-deprivation biases often occur. Robust estimates of inventory completeness could help alleviate the problem. This study aimed at identifying areas representing gaps in current knowledge of African palms, with a focus on Benin (West Africa). We assessed the completeness of knowledge of African palms targeting geographical distance and climatic difference from well-known sites. Data derived from intensive fieldwork were combined with independent data available online. Completeness inventory indices were calculated and coupled with other criteria to decide on the extent of knowledge. Results showed a high overall value for inventory completeness, as well as an even distribution of well-known areas across the country. However, poorly-known areas were distinctly identified and correlated to remote locations with low accessibility. This study illustrates how biodiversity survey and inventory efforts can be guided by existing knowledge. We strongly recommend the combination of digital accessible knowledge and fieldwork, coupled with expert knowledge, to obtain a better picture of the completeness of the inventory in tropical ecosystems