Rodrigue Idohou

Biodiversity conservation in home gardens: traditional knowledge, use patterns and implications for management

There is increasing interest in home gardens (HGs) as biodiversity hot spots. However, knowledge on how sociocultural characteristics and environment influence knowledge and management of HG species is still limited. Eliciting these links helps illustrate how HG could conserve biodiversity. This study addressed the following hypotheses: (i) age and gender shape the knowledge of HG species; (ii) knowledge on HG species varies across phytochorological zones; (iii) use values (UVs) of HG species are correlated to their ecological importance and (iv) HG species is mostly used for food and medicinal purposes. Data were collected from 285 HGs, across three phytochorological zones of Benin, using semi-structured interviews. Quantitative analyses were performed using ethnobotanical indexes and statistical tests. Our results confirmed our assumptions except for hypothesis (i). Gender and age did not determine knowledge on HG species. Nevertheless, noticeable differences were encountered among the zones regarding species, knowledge and use types. UV and ecological importance were highly correlated. Our results support the point that HGs sustain food and medicine supply while contributing to conservation of local biodiversity. However, with modern mutations, HGs are unlikely to be preserved if they are not actively mainstreamed in production and conservation policies.

Spatio-temporal dynamic of suitable areas for species conservation in West Africa: eight economically important wild palms under present and future climates

Sustainable conservation of tropical resources required understanding of their distribution for effective assessment and definition of conservation priorities. In tropical areas, wild palms are highly valued keystone resources with growing demand for both subsistence uses and commercial trade. Here we focused on eight such species (Borassus aethiopum Mart., Eremospathamacrocarpa (G.Mann & H.Wendl.) H.Wendl., Hyphaene thebaica Mart., Laccosperma opacum (G.Mann & H.Wendl.) Drude, Phoenix reclinata Jacq., Raphia hookeri G.Mann & H.Wendl., Raphia sudanica A. Chev., and Raphia vinifera P.Beauv.). This study tested (i) how those palms distributions may be affected under future climate scenarios, and (ii) if species are effectively conserved currently and under future forecasts for their native distributional areas. Finally, we defined spatial priorities for the species’ conservation. Available bioclimatic and soil data layers were used for the modelling with maximum entropy approaches, and resulting maps were overlaid on the existing protected areas network. Results showed that much of the distribution of the species will remain largely stable, albeit with some expansion and retraction in some species; relationships with protected areas networks suggest that protected portions of species distributions will also remain stable. The areas identified as highest conservation priority differ between models even though the highest-priority areas holding most palm species are located along the coast (from Guinea to Nigeria). Further development of these analyses could aid in forming a more complete picture of the distributions and populations of the species, which in turn could aid in developing effective conservation strategies for this botanically important family.

Estimation of cultivable areas for Irvingia gabonensis and I. wombolu (Irvingiaceae) in Dahomey-Gap (West Africa)

Cultivation of priority plant species ensures their sustainable management. African bush mango trees (Irvingia gabonensis and I. wombolu) are the most exploited Irvingiaceae species. Experts disagree on the status of these very similar taxa, as taste remains the only character by which they can be distinguished in the field. We combined occurrences and environment data in ecological niche models to assess suitable areas for the two species. Irvingia gabonensis presented a wider occurrence area due to cultivation across contrasting ecological areas. Irvingia wombolu does not appear to be cultivated and only occurred in southwestern Togo. These differences in range is likely determined by phenological limitations of I. wombolu, reinforced by differences in local management systems, thus confirming the failure of market development to impact useful plant species’ conservation significantly. Highly suitable areas for I. wombolu were in the Volta Forest, where I. gabonensis saw low suitability, while out of this inverse situation was observed, as regard environmental suitability. These differences are significant, implying different ecological adaptation. However, anthropogenic influences, related to domestication history, are also important. Therefore, updated genetic investigations and field trials in contrasting ecological areas are required for understanding the origin of differences between these two forms.

Modelling the current and future distribution of Kigelia africana under climate change in Benin, West Africa

Kigelia africana (Bignoniaceae), is an indigenous species widely recognised for its medicinal, magic uses and therapeutic virtue used throughout Africa and especially in Benin Republic. Distribution of the species coincides with that of the intermediate hosts as determined by environmental factors. This study aimed to model the present-day and future distribution of Kigelia africana in Benin. Maximum Entropy (MaxEnt) modelling technique was used to predict the distribution of suitable habitats of Kigelia africana using presence data combined with two future forescats: CNRM-CM5and HadGEM2-ES. Results showed that Annual Temperature range, precipitation seasonality, soil, temperature seasonality, maximum temperature of the warmest month were most significant variables. Which mean that the excellent of the model. Likewise, must of the distribution of the species will be find mostly stable. The different model used identified different areas as highest conservation priority although the highest priority areas keeping most of Kigelia africana species are located in the Guineo-Congolian and Sudano-Guinean region. Additional analyses could help to have more information about the distribution and population and cultivation of Kigelia africana species, which in future will help us to improve operative conservation strategies for this medicinal species. MaxEnt model is robust in Kigelia africana species habitat modelling.

Variation in Hyphaene thebaica Mart. fruit: physical characteristics and factors affecting seed germination and seedling growth in Benin (West Africa)

Summary Hyphaene thebaica (dum palm) is an important tree species that grows wild in the semi-arid regions of tropical Africa. Increased knowledge on the effect of stress on the propagation and establishment of these plants is needed to optimise its domestication. This study assessed the physical characteristics of H. thebaica fruit harvested from three phytodistricts in Benin. The germinability of the seeds, before and after water-soaking and removal of the seed coat, was tested, and the number and size of the leaves produced in the resulting seedlings were measured. Hierarchical classification of the characteristics of fruit revealed the existence of three morphotypes. A Factorial Discriminant Analysis performed on these morphotypes revealed highly significant differences (P 0.001). Morphotype 3 (48 seeds) had the highest rate of seed germination (49.99%) and the widest leaves (28 mm) over the 154 d of the experiment. Seedlings of morphotype 2 and morphotype 3 (48 seeds each) had the highest number of leaves (two per seedling), whereas only morphotype 2 seedlings had the longest leaves (35 mm). Results from Analysis of Variance revealed that the time of germination and water-soaking had significant effects (P 0.05) on seed germination. The study also showed that the growth of seedlings differed with the time of germination, and that these differences varied with morphotype.These results may be used to improve current propagation and conservation strategies in this species in its areas of origin.