BackgroundAfrican locust bean tree (Parkia biglobosa) is a multipurpose species used widely in arid Africa by local communities. The present study focused on ethnic differences in use values and use patterns of P. biglobosa in Northern Benin, where the species widely grows. The use values according to the various ethnic groups in the study area have been evaluated in detail for P. biglobosa.MethodsFrom 13 ethnic groups, 1587 people were interviewed in the study area using semi-structured questionnaires. Principal Component Analysis was applied to analyze the use value and the use patterns of P. biglobosa for the different ethnic groups.ResultsAll interviewees in the study area knew at least one use of P. biglobosa. The various uses identified were medicinal (47%), handicraft and domestic (3%), medico-magic (1%), veterinary (1%), cultural (1%), food (25%) and commercial (22%). The various parts involved in these types of uses were: fruits [shell (2%), pulp (22%) and seeds (36%)], bark (17%), leaves (9%), roots (3%), flowers (1%) and branches (10%). The ethnic group consensus values for P. biglobosa parts showed that the seeds are used the most. The interviewees diversity value (ID) and equitability value (IE) indicated that knowledge concerning P. biglobosa use was distributed homogeneously among the ethnic groups.ConclusionsP. biglobosa is well-known and used in different ways by the local populations in the study area. Local knowledge on the species is diversified and influenced by ethnic group. Ethnic differences in use values and use patterns of the species were evident in this study.

Structural changes in secondary forests are less known in West Africa, and this precludes their management. This study aims at providing quantitative information on floristic composition and structure of the Lama secondary forests (Benin), so as to contribute to their restoration, and fill part of knowledge gaps on West African secondary forests. Data of 77 permanent plots each of 0.5 ha were used to analyze the floristic composition, the trajectory of the recovery and the recovery of stocking in these forests, compared to nearby old-growth forests. The results showed that the forests were less diversified with few species very common in the forest stands; the most dominant were Lonchocarpus sericeus and Anogeissus leiocarpa in the secondary forests, and Dialium guineense, Diospyros mespiliformis and Afzelia africana in the old-growth forests. The secondary forests hold more species than the mature ones. Their compositions will recover that of the original forest because species of the original forest were actively regenerating in the secondary forests. About 28 years after recovery, large trees were insufficient and basal area was about 60% of those of the mature forests. Further studies are needed to elucidate barriers to tree regeneration and dynamics of tree population.

Dialium guineense is a multipurpose species useful in many respects. It is used in agroforestry and the trade of most of its organs is source of income for rural populations. Despite the high interests of this species to populations, we do not know much about how its spatial distribution could be impacted by climate change and which strategies to implement for its sustainable use and conservation. In order to overcome these challenges, MaxEnt was used to model the ecological niche of D. guineense and different decision thresholds w ere used to interpret and classify the outputs. Climate will impact the distribution of D. guineense. Indeed under Africlim rcp 4.5 horizon 2055, the predicted stable areas of species distribution will be about 73% of West Africa when the threshold of the minimum training presence is considered and will decrease to 12% when the threshold of the maximum training sensitivity plus specificity is considered. Under Africlim 8.5 horizon 2055, the corresponding values for the stable areas of the species are, respectively 70 and 8% of the study area. In comparison with the global results of West Africa, in Benin, D. guineense will be less threatened by climate change. As strategies for sustainable use and conservation of the species, growing and introducing it in its favorable areas to account for its absence or low densities, is recommended. Also, building capacities to the users of the species so that they can grow it on their farms is recommended.

Khaya senegalensisDesr & Juss is an urban tree species with high quality wood, unfortunately disturbed by Hypsipyla robusta Moore. However, how vulnerable this species is with regard to climate change and to Hypsipyla robusta over time and space is unknown. This study aimed at assessing as well the climate change impacts on both species as the overlapping extent of their suitable areas over time and space. To this end, the MaxEnt approach for Ecological Niche Modelling was used to compute suitable areas for both species under current and future climates (Africlim RCP 4.5 and RCP 8.5). Spatio-temporal Analysis was performed using Geographic Information System. Upon 2055, climate change will impact negatively 15-16% of Benin while the positive impacts will account only for 2-3%, and the stable areas will represent 74-75%. As for Hypsipyla robusta, climate change will provide only habitat loss of about 66% of the country. So, many plantation sites are exposed to biological attack from the pest, but wouldn"t be more in future, giving hope for Khaya senegalensis' high quality wood production. Meanwhile, there will be an ecological imbalance due to the drastic potential habitat loss for the insect.

African teak (Milicia excelsa (Welw.) C.C. Berg) is an endangered multi-use species. Understanding the impact of climate change on the distribution of this species may improve the ability to anticipate or recognize its decline or expansion and to take appropriate conservation measures if necessary. Ecological niche modeling was projected in geographical space to study the current and future distribution of M. excelsa in Bénin. MaxEnt was used to estimate the potential geographic distribution of the species under two Representative Concentration Pathways (RCP). Miroc 5 summaries and two RCP 4.5 and RCP 8.5 scenarios were used as predictor variables for projections of the geographic potential of this species. The performance of the model was assessed by the area under the curve (AUC), true skill statistics (TSS) and partial receiver operating characteristics (Partial ROC). From the results, M. excelsa was more a secondary species in the Guinean climatic zone and part of the Sudanian-Guinean and Sudanian climatic zone. The projections show a significant decrease in suitable habitats for the species from the two RCP scenarios. Only a part of the Guinean climatic zone remained suitable and few protected areas will conserve in situ M. excelsa. For the sustainable conservation of M. excelsa, it is essential to strengthen the protection of sacred forests located in the Guinean climatic zone.