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Idohou R, Assogbadjo A, Kakaï R, Peterson A (2016)
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., Eremospatha macrocarpa (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.
Keywords: Biodiversity, Ecological niche, GIS, Representative concentration pathways, Zonation
Fandohan A, Koko I, Avocevou-Ayisso C, Gouwakinnou G, Savi M, Assogbadjo A et al. (2015)
Lantana camara (verbenaceae) : a potential threat to the effectiveness of protected areas to conserve flora and fauna in Benin
Agronomie Africaine 27(2) 115-126.
Invasive plant species are today among the biggest threats to integrity of many ecosystems including that of the protected areas. Climate change may exacerbate the negative effects of invasive plant species. Here, we used the Maximum Entropy model to project habitat suitability for Lantana camara L. , an invasive plant species under current and future climates in the national protected areas network of Benin. The models were run using bioclimatic data and data on soil type. Nineteen percent of the total land in the protected areas network was highly suitable for L. camara under current climate. Highly suitable areas under current and future climates cover about 65 % of the Pendjari Biosphere Reserve, the major wildlife sanctuary in Benin. Other bio-reserves such as W National Park, Lama, Agoua, Dogo-Kétou, Atchérigbé, Mékrou and Kouandé Forest Reserves were also suitable for the species. Presence of L. camara in the protected areas represents a great potential threat to the global food webs being conserved. Based on these results, areas with highly suitable habitats are at high risk of invasion by L. camara , and should be accorded high priority when formulating appropriate management strategies. Keywords: Invasive species ; Climate change ; Habitat suitability ; Protected areas ; West Africa Lantana camara et les aires protegees au Benin Les espèces invasives font de nos jours partie des plus importantes menaces aux quelles font face les écosystèmes y compris les aires protégées. Les changements climatiques peuvent amplifier leurs effets négatifs. Dans la présente étude, nous avons utilisé un algorithme de modélisation de niche écologique, le Maximum Entropy pour analyser la susceptibilité des habitats à être colonisés par Lantana camara L ., une plante invasive, sous les conditions climatiques actuelles et futures dans les aires protégées du Bénin. Les modèles ont été établis en utilisant des données bioclimatiques et des données relatives aux types de sol. Dans les conditions climatiques actuelles, 19 % de la superficie totale du réseau des aires protégées est significativement favorable à L. camara. Sous les conditions climatiques actuelles et futures, 65 % de la réserve de biosphère de Pendjari, le plus important sanctuaire de faune sauvage du Bénin, est hautement favorable à l’espèce. D’autres bio-réserves telles que le Parc National W et les reserves forestières de Lama, Agoua, Dogo-Kétou, Atchérigbé, Mékrou et Kouandé ont aussi des habitats favorable à l’espèce. En nous fondant sur ces résultats, les zones favorables sont à haut risque d’invasion par L. camara et devraient être priorisées lors de la formulation de stratégies préventives appropriées. Mots clés: Espèces envahissantes ; Changements Climatiques ; Habitats favorables ; Aires protégées, Afrique de l’Ouest.
Keywords: Climate change, Habitat suitability, Invasive species, Protected areas, West Africa
Idohou R, Ariño A, Assogbadjo A, Glele Kakai R, Sinsin B (2015)
DIVERSITY OF WILD PALMS (ARECACEAE) IN THE REPUBLIC OF BENIN: FINDING THE GAPS IN THE NATIONAL INVENTORY COMBINING FIELD AND DIGITAL ACCESSIBLE KNOWLEDGE
Biodiversity Informatics 10(2).
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.
Keywords: Biological databases, GIS, inventory, sampling efficiency, spatial resolution
Padonou E, Teka O, Bachmann Y, Schmidt M, Lykke A, Sinsin B (2015)
Using species distribution models to select species resistant to climate change for ecological restoration of bowé in West Africa
African Journal of Ecology 53 83–92.
Bowalization is a particular form of land degradation and leads to lateral expansion of ferricrete horizons. The process occurs only in tropical regions. In this study, the most adapted and resistant species towards climate change were identified on bowé. The 15 most common bowé species of the subhumid and semi-arid climate zones of Benin were submitted together with significant environmental variables (elevation, current bioclimatic variables, soil types) to three ecological niche modelling programmes (Maxent, Domain and GARP). For future prediction (2050), IPCC4/CIAT and IPCC5/CMIP5 climate data were applied. Asparagus africanus, Andropogon pseudapricus and Combretum nigricans were identified as the most resistant species for ecological restoration of bowé in the semi-arid climate zone and Asparagus africanus, Detarium microcarpum and Lannea microcarpa in the subhumid climate zone. The ‘Pull’ strategies were identified as appropriate for ecological restoration of bowé in Benin.
Keywords: Benin, Bowé, climate change, ecological restoration, resistant species, subhumid and semi-arid climate zones
Adite A, Sonon S, Gbedjissi G (2013)
Feeding ecology of the mangrove oyster, Crassostrea gasar (Dautzenberg, 1891) in traditional farming at the coastal zone of Benin, West Africa
Natural Science 05(12) 1238-1248.
Wild collection management and farming of the mangrove oyster (Crassostrea gasar) occurring widely at the Benin (West Africa) coastal zone require knowledge on the feeding ecology to explore energy sources and nutritional needs. Six hundred thirty (630) individuals of C. gasar have been sampled in the rearing site at the Benin coastal lagoon to investigate on the trophic ecology of this cultivated bivalve. The diet analysis revealed that C. gasar is a filter-feeder foraging mainly on phytoplankton (72.70%) and substrate particles (22.95%). This trophic specialization results from anatomical structure, mainly the presence of gills which facilitate the filtering of number of plankton taxa.
Keywords: Conservation, Crassostrea, Diet Overlaps, Farming, Filter-Feeder, Food Web, Foraging Strategy, Phytoplankton
Idohou R, Assogbadjo A, Fandohan B, Gouwakinnou G, Glele Kakai R, Sinsin B et al. (2012)
Genetic Resources and Crop Evolution.
Species prioritization is a crucial step in any development of conservation strategy, especially for crop wild relatives (CWR), since financial resources are generally limited. This study aimed at: assessing the biodiversity of crop wild relatives in Benin and identifying priority species for active conservation. Data were collected through literature review to establish an exhaustive list of CWR in Benin. Eight prioritization criteria and different prioritization systems were used. The top 50 species obtained by each of these methods were identified and twenty final top CWR were shortlisted as those occurring as priority across methods. A total of 266 plant species belonging to 65 genera and 36 families were identified. The most represented are: Cyperaceae (12.50 %), Leguminosae-Papilionoideae (11.87 %), Convolvulaceae (11.25 %), Poaceae (10.31 %), Asteraceae (7.81 %), Solanaceae (6.87 %) and Dioscoreaceae (5.31 %). Among the 20 species of highest priority for conservation, Manihot glaziovii Müll. Arg. and Piper guineense Schumach. et Thonn., appeared as the most represented species on top of the list.
Keywords: biodiversity, conservation, crop wild relatives, threat, west africa
Rodenburg J, Zossou-Kouderin N, Gbèhounou G, Ahanchede A, Touré A, Kyalo G et al. (2011)
Rhamphicarpa fistulosa, a parasitic weed threatening rain-fed lowland rice production in sub-Saharan Africa – A case study from Benin
Crop Protection 30(10) 1306-1314.
Expansion of the facultative parasitic plant Rhamphicarpa fistulosa as a weed of rain-fed lowland ricewas studied in 2007 on a national level (Benin) by repeating a survey from 1998. Wider species’ distribution was investigated in 2008. Current and potential impact and management strategies were investigated through farmer surveys and pot experiments. Out of 36 cultivated inland valleys visited across Benin, eight were found to be infested with Rhamphicarpa. Out of nine inland valleys inspected in 1998, Rhamphicarpa was found in five in 2007, compared with only three in 1998. Farmers estimated Rham- phicarpa-inflicted yield losses could exceed 60% and indicated that heavily infested fields are abandoned. In a pot experiment with a wide infestation range, the popular cultivar Gambiaka, combining resistance with sensitivity, showed a mean relative yield loss (RYL) of 63%. Parasitic Rhamphicarpa biomass (PRB), the difference between the above-ground biomass produced with and without a host, was suggested as indicator for infection level of this facultative parasite and hence as a practical measure for host resis- tance. Genetic variation in resistance and tolerance levels was observed among rice cultivars, but fertilizer applications significantly reduced parasite numbers, biomass and effects, cancelling out such genotypic differences. Depending on the tolerance level of the cultivars, the PRB only accounted for 3.7 e38.8% of the average parasite-inflicted host biomass reductions, indicating phytotoxic effects of Rhamphicarpa infection. R. fistulosa is an apparently increasing constraint to rain-fed lowland rice in Benin, threatening rice production in the wider region. The use of resistant and tolerant cultivars, combined with fertilizer applications could reduce Rhamphicarpa infections and mitigate negative effects on rice yields.
Keywords: inland valleys, integrated weed management, parasitic plants, subsistence farming