Genet Resour Crop Evol (2013) 60:1337–1352 DOI 10.1007/s10722-012-9923-6 RESEARCH ARTICLE National inventory and prioritization of crop wild relatives: case study for Benin Rodrigue Idohou • Achille Ephrem Assogbadjo • Belarmain Fandohan • Gerard Nounagnon Gouwakinnou • Romain Lucas Glele Kakai • Brice Sinsin • Nigel Maxted Received: 11 June 2012 / Accepted: 10 October 2012 / Published online: 2 November 2012 Ó Springer Science+Business Media Dordrecht 2012 Abstract Species prioritization is a crucial step in Convolvulaceae (11.25 %), Poaceae (10.31 %), As- any development of conservation strategy, especially teraceae (7.81 %), Solanaceae (6.87 %) and Dioscore- for crop wild relatives (CWR), since financial aceae (5.31 %). Among the 20 species of highest resources are generally limited. This study aimed at: priority for conservation, Manihot glaziovii Mu¨ll. Arg. assessing the biodiversity of crop wild relatives in and Piper guineense Schumach. et Thonn., appeared Benin and identifying priority species for active as the most represented species on top of the list. conservation. Data were collected through literature review to establish an exhaustive list of CWR in Keywords Biodiversity Á Conservation Á Benin. Eight prioritization criteria and different Crop wild relatives Á Threat Á West Africa 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 Introduction plant species belonging to 65 genera and 36 families were identified. The most represented are: Cyperaceae Millions of the world’s poor rely for a large part of (12.50 %), Leguminosae-Papilionoideae (11.87 %), their income/food intake on a wide variety of indig- enous edible plants to sustain their livelihood. This is R. Idohou Á A. E. Assogbadjo Á B. Fandohan (&) Á particularly the case in Sub-Saharan Africa, where G. N. Gouwakinnou Á R. L. Glele Kakai Á B. Sinsin over 70 % of the people reside in rural areas and use Laboratory of Applied Ecology, plant resources to meet their routine needs (Cavendish University of Abomey-Calavi, 01 BP 526 Cotonou, Benin 2000; Mahapatra et al. 2005). Crop wild relatives e-mail: [email protected]; [email protected] (CWR) are wild plant taxa more or less closely related to species of direct socio-economic importance B. Fandohan including food, fodder and forage crops, medicinal International Ecosystem Management Partnership, plants, condiments, ornamental and forestry species, United Nations Environment Programme, c/o Institute of Geography and Natural Resources as well as those related to crops used for industrial Research, Chinese Academy of Sciences, purposes such as oils and fibres (Maxted et al. 2007). No. 11A Datun Rd., Beijing 100101, China CWR include the progenitors of crops as well as other species more or less closely related to them, and N. Maxted School of Biosciences, University of Birmingham, have been undeniably beneficial to modern agricul- Edgbaston, Birmingham B15 2TT, UK ture, providing plant breeders with a broad pool of 123 1338 Genet Resour Crop Evol (2013) 60:1337–1352 potentially useful genetic resources (Hajjar and Hodg- in Portugal (Brehm et al. 2010). This new scheme kin 2007). Hence, CWR represent a tangible resource was applied in the current study. The objective of of actual or potential economic benefit for humankind the present study was to create a national inventory as they have contributed significantly to improvement of wild relatives of priority crops in Benin and of food production. Prescott-Allen and Prescott-Allen highlight priority species as a useful case study for (1986) calculated that the yield and quality contribu- the establishment of Phytogenetic Genetic Resource tion by CWR to the US-grown or imported crops was (PGR) conservation strategies. over US$350 million a year. Phillips and Meilleur (1998) noted that losses of rare wild plants represent a substantial economic loss to agriculture, estimating Materials and methods that the endangered food crop relatives have a worth of about US$10 billion annually in wholesale farm Study area values. Pimentel et al. (1997), for their part, estimate a global value of CWR at US$115 billion per annum. The study was carried out in the Republic of Benin, Like for the rest of biodiversity, CWR are threatened located between 6° and 12°500N and 1° and 3°400Ein by mismanagement of landscape. Furthermore, habitat West Africa (Adomou 2005). Three large chorological fragmentation, climate change and agricultural inten- climatic zones (Sudanian, Sudano-Guinean and Gui- sification put at risk the CWR and traditional cultivars. neo-Congolian zones; Fig. 4) embody ten phytogeo- Accordingly, it is urgent to take actions to reduce graphic zones, which are Atacora chain, Bassila, genetic erosion or species extinction. coastal, Mekrou-Pendjari, North-Borgou, Plateau, FAO (2009) reported a significant increase in the Pobe`, South-Borgou, Valley of Oueme and Zou number of CWR inventories. However, in Sub-Saha- (Adomou 2005). Vegetation in Benin comprises ran Africa, there is a recurrent lack of knowledge semi-deciduous rain forest, swamp forest, gallery regarding the breadth and/or potential use of CWR forest, dense dry forest, open forest, woodland diversity. Presently, inventories are lacking for most savanna and tree and shrub savanna (Adomou et al. countries and CWR diversity is largely uncharacter- 2010). The flora is estimated at 2,807 species of plants ized or un-evaluated and not systematically conserved. divided into 1,129 genera and 185 families (Akoe`gni- With so much CWR diversity, it’s necessary to nou et al. 2006). The most diversified families in terms inventory the diversity of these species and establish of number of species are: Leguminosae (14.8 %), priorities for conservation (Kell et al. 2008). Prioriti- Poaceae (9.3 %), Rubiaceae and Cyperaceae (5 % zation for conservation can be undertaken at different each), Asteraceae (4.6 %) and Euphorbiaceae (4.3 %). levels: species, ecosystem, etc. (Brehm et al. 2010). A In the south of the country, mean monthly temper- method of prioritizing at species level is preferable atures oscillate between 26 and 28 °C while in the because it allows conservationists to know which taxa north they are generally above 35 °C, and in some should be primarily targeted for conservation, which places they average out at 40 °C (Adomou 2005). are not priorities, and which have insufficient infor- Rainfall varies from 900 to 1,400 mm per year mation to know whether they are priorities for according to West-East and South-North gradient. conservation or not (Brehm et al. 2010). Rainfall distribution shows two types of climates. In Numerous methods for setting species’ priorities the south, the climate is tropical humid (Subequatorial have been developed over time (Rabinowitz et al. or Guinean) with two rainfall maxima in April–July 1986; Coates and Atkins 2001). There has been and September–October. In the North, the climate is considerable debate over which criteria should be tropical sub-humid dry to arid from 8°N northwards, considered when prioritizing species for conservation with one maximum in June (Adomou 2005). (see Maxted et al. 1997). Recently, Brehm et al. In 2009, agriculture contributed 33.2 % to the Gross (2010) proposed various criteria and different prior- National Product (GNP) of Benin. The main crops are itization schemes. This study aimed at developing an cereals (maize, rice, sorghum, etc.), legumes (cowpea, innovative prioritization scheme making use of the peanuts, etc.), tubers (manioc, yam, etc.), market garden readily available data and to identify priority CWR products (lettuce, cabbage, etc.) and industrial crops and Wild Harvested Plants (WHP) for conservation (cotton, cashew nuts, pineapple, etc.) (MAEP 2010). 123 Genet Resour Crop Evol (2013) 60:1337–1352 1339 Inventory of crop wild relatives in Benin 3. Ethnobotanical value. This was assessed through local knowledge on the species uses. Priority was The starting point for preparing a national CWR given to the species having a high importance for conservation strategy is the generation of a national local communities. CWR inventory. Here, we recorded Taxa selected on 4. Global distribution. Priority increases with the the basis of their closeness to priority crops of Benin, more a restricted distribution, therefore, nation- using the ‘‘taxonomic group’’ concept of Maxted et al. ally- or regionally-restricted species (or endem- (2006). Since the flora of Benin is not yet accessible in ics) were given higher priority than species a database that can be matched digitally with the occurring world-wide. existing crop databases, the process to produce the 5. National distribution. National distribution was national CWR inventory was carried out manually. considered here as an indicator of rarity. A species This approach was recently successfully implemented occurring in a few provinces was considered rarer for Bhutan (Tamang 2004), the Seychelles (Antoine than a species occurring throughout the country. 2004), and Venezuela (Chiara and Crespo 2012). It 6. In-situ and ex-situ conservation status. Before a consisted, first, of making an exhaustive census of all taxon can be given high priority for conservation, the cultivated crops in Benin. Data were collected current conservation activities relating to it should from libraries (public and private), agricultural exten- be reviewed. If sufficient genetic diversity is sion services, research institutes, laboratories, and already being conserved in situ and/or ex-situ, botanical garden of the University of Abomey Calavi. additional conservation efforts may not be justi- Then a list of the cultivated crops was matched with fied, and resources should focus on those species the existing floras (Flora of West Tropical Africa, that are not being conserved. Analytic flora of Benin and Biodiversity atlas for West 7. Legislation. A species under any kind of legisla- Africa) to select the species in the same genus as the tion requires conservation attention because crops.