N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 
DOI 10.1186/s13002-015-0017-3 JOURNAL OF ETHNOBIOLOGY 
AND ETHNOMEDICINERESEARCH Open AccessModelling socioeconomic determinants for
cultivation and in-situ conservation of Vitex
doniana Sweet (Black plum), a wild harvested
economic plant in Benin
Sognigbe N’Danikou1,2*, Enoch G Achigan-Dako1, Dedeou A Tchokponhoue1, Chaldia OA Agossou1†,
Carlos A Houdegbe1†, Raymond S Vodouhe2 and Adam Ahanchede1Abstract
Background: Cultivation is the most appropriate management option when both demand and harvesting of wild
plant species increase beyond natural production levels. In the current study we made the assumption that, besides
the intrinsic biological and ecological characteristics of the species, the decision to cultivate and/or to conserve an
overharvested wild plant species is triggered by the socioeconomic factors such as land tenure and size, origin of
respondents, gender, and users’ knowledge of the plant phenology.
Methods: We carried out semi-structured interviews with 178 informants involved in V. doniana exploitation. The
data collected were related to socio-demographic characteristics of informants’ household situation, knowledge of
the biology and propagation of the species, willingness to cultivate the species, in-situ maintenance of populations,
and costs associated with management of the species. According to data types we used Student’s t, Spearman
correlation, Kruskal-Wallis, Fisher’s exact and χ2 tests to test the effects of land tenure, origin of respondents, gender
and users’ knowledge of plant phenology on the decision making process. Conditional inference tree models and
generalized additive models were also used to identify variables which were significantly determinant in the decision
to cultivate and/or to conserve the species in-situ.
Results: We found that men were more willing to cultivate the species than women and this is conditioned by land
area available. The willingness to conserve the species in-situ depends mainly on the total land area available, the number
of trees within the landscape, accessibility of the trees, land tenure, gender, location, seedling cost, and trade-off cost for
conservation. People who offered more than one US dollar to acquire a seedling of V. doniana, landowners, and those
who own a total land area in excess of 6.5 ha were most willing to conserve the species in-situ.
Conclusions: From our findings we conclude that future management and conservation initiatives for V. doniana should
first target specific user groups for sustainable exploitation of the species. Also, the Cultivation Opportunity Ratio is an
important indicator for quick determination of the likelihood of farmers to engage into cultivation and conservation of
the species.
Keywords: Active management, Sustainable utilization, Local knowledge, Domestication, Tree models, Benin* Correspondence: ndanikou@gmail.com
†Equal contributors
1Horticulture and Genetics Unit, Faculty of Agronomic Sciences, University of
Abomey-Calavi, BP: 2549 Abomey-Calavi, Republic of Benin
2Bioversity International, West and Central Africa office, 08 BP 0932 Cotonou,
Republic of Benin
© 2015 N'Danikou et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain
Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article,
unless otherwise stated.
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 2 of 16Background
The decision to conserve wild-harvested species is based
on factors that are presumed to be community and re-
source specific. When the value of a non-wood forest
product (NWFP) and quantities harvested are both high,
it will be under high risk of local extinction, and cultiva-
tion is the most effective management option to sustain
both the species and livelihoods of the different user
groups [1]. The continuous selection and cultivation of
variants of useful species to humans, most often, result
in domesticated crops [2,3]. Gepts et al. [4] indicated
that the increase in human demand represents new push
for domestication. The main advantages of domesti-
cating intensively wild-harvested edible plant species
include: (a) enhanced local livelihoods and food se-
curity, (b) increased supply of market commodities
and maintenance of food diversity, and (c) increased
ecosystem services and resilience. Overall, the eco-
nomic, social and environmental rewards of domesti-
cation are obvious, and domesticated plants should
repay better human investments than collection of re-
sources from the wild [5]. For Clement [6] plant do-
mestication is a co-evolutionary process whereby
humans select phenotypes of most utility to them and
bring them into cultivation. Domestication implies a
process in which wild plants are taken from their nat-
ural habitats and grown in cultivation systems where
growth conditions can be manipulated to enhance
production of the desired product (e.g. fruits, leaves,
roots, seeds). In simple terms it is the human-
mediated adaptation of the wild plant to cultivation
in plantation or farmlands [5]. This involves socioeco-
nomic and biophysical processes [7], which lead to
both changes to human culture and plant phenology,
and begins when species become objects of owner-
ship, inheritance, purchase and exchange [8]. These
processes put local communities at the centre of the
domestication process, and Clement [6] noted that “for
plant domestication to take place, there must be selection
and management”. Selection of candidates at species and
variety levels begins with local communities and is often
continued with support of formal breeding and genetic
improvement by science. It is important to indicate that
domestication is a gradual transition which starts from
wild-harvesting through to pre-agriculture (selective har-
vesting, sparing, etc.), proto-agriculture or incipient do-
mestication (sowing, transplanting, irrigation, etc.), and
full domestication characterized by small-scale and/or
large-scale agriculture [4]. Success of domestication relies
on management of domesticates, which is carried out by
farmers. In this context, the recruitment of potential
growers and users and their engagement in large scale
production of the domesticated species is an important
question which needs to be figured out [4].From the biological point of view, domestication is a
continuous endeavour, the result of intensive selection
and cultivation of variants with useful traits to humans,
with no clear demarcated end points, whereby new phe-
notypes are created and continuously improved based
on new social and economic needs [2,3,6,9]. It then ap-
pears that cultivation is the ground for domestication of
useful plants to humans. Therefore, in this paper we
evaluated the motives for cultivation of wild-harvested
economic plants.
Although the scope of ethnobotanical studies has ex-
panded and now covers a wide range of topics related to
human - plant interactions and ably demonstrated the
importance of wild harvesting to livelihoods of the poor,
there is now need to move further to provide insights
and guidance for conservation professionals to enhance
the sustainable use of highly valued species. For the suc-
cess of conservation programmes designed by natural
resource managers, there is need to understand and in-
tegrate drivers of active engagement of local communi-
ties, individually and collectively. From the literature,
there is very limited knowledge of factors affecting people’s
decisions related to plant selection for cultivation [10-12].
Thus, several variables remained unknown for predicting
the success or failure of conservation initiatives aimed at
bringing wild plants into cultivation. Here, we used Vitex
doniana Sweet (Verbenaceae) as a case study to investigate
and pinpoint local drivers that favour both active cultiva-
tion and conservation of wild populations of the species by
local communities.
Vitex doniana (black plum) is one of the most import-
ant wild-harvested multipurpose trees and leafy vegeta-
bles of tropical Africa [13-15] particularly in Benin
(where it is sold in almost all markets [12,16]), Burkina
Faso [17] and Nigeria [18,19] to provide income and
support livelihoods of many households. It is one of the
most widespread of the 150 species of the Vitex genus,
with several uses [14,20]. Vitex doniana is found in sa-
vanna woodlands and gallery forests, and is also indicated
to be present in about 50% of traditional agroforestry sys-
tems in southern Benin [21], where it is just spared during
land clearance [12,22,23]. The species is deciduous and its
leaves renewed annually, during the dry season. Intensive
harvesting occurs after bush burning associated with farm
clearance, with the development of new shoots that are
used as vegetable. Leaves, bark and roots also have many
applications in indigenous medicine [20]. The fruit is eaten
raw or used for making candies, jams and syrups [18,19].
However, the species is currently perceived as the most
threatened of edible wild-harvested plants by local com-
munities in Benin [12,24]. Field inventories indicated that
the natural populations are continuously eroded and dens-
ities of trees and regeneration are becoming low in natural
habitats [16,22-24]. Agossou [22], N’Danikou [23] and
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 3 of 16N’Danikou et al. [12] reported that harvesting practices
represent the most important threat to the species, con-
trasting with Oumorou et al. [24]’s findings. In fact, har-
vesting of V. doniana vegetable by local communities
mainly consists in removing all the new shoots, most often
with twigs. Furthermore, some harvesters just cut the
whole tree down to make harvesting easier [22,23]. These
forms of harvesting reduce fruit production, and subse-
quently sexual propagation. Meanwhile, the suckers that
regenerate from root stock are subject to bush fire in the
natural habitat, jeopardizing the natural regeneration of
the species. Thus, threat is mainly attributed to overhar-
vesting of wild populations and habitat loss. Therefore,
understanding and considering the complex interplay of
local valuation and perception of threats would give an
important ground for policy and decision making that will
sustain the use of the species and also the livelihoods of
various user groups.
This situation triggers our study knowing that V. doni-
ana is under high harvesting pressure and belongs to a
complex market chain [12,13,16], with increased price
(authors’ personal observation) whereas natural stands
are subjected to private ownership [22]. In this condition
which socioeconomic and cultural factors would favour
cultivation of V. doniana? Is gender an important issue
for the success of cultivation? How the access to re-
sources and local knowledge shape the decision-making
to cultivate and/or conserve V. doniana in-situ?
To answer these questions, we based this investigation
on the assumption that, besides the intrinsic biological
and ecological characteristics of the species, the decision
to cultivate and/or to conserve an overharvested wild
plant species is determined by the socioeconomic factors
such as land tenure and size, origin of respondents, gen-
der and users’ knowledge of the plant phenology. In fact,
in Africa and particularly in Benin, there are societal
rules and other factors that affect farmers’ decision to
manage useful plants. These factors include gender, age,
occupation, wealth status, importance of wild-harvesting
in household food security, scarcity of resources, and
land holding status [10,11,25,26]. For instance, male
farmers and young people were more likely to accept
production of non-wood forest products in their farms
in Nigeria, because men are more likely to invest in the
future than women [10], and this may be because
women are uncertain about the security of their tenure
due to possible change in their marital status [26]. Also,
generally the local customary laws do put restrictions on
plantation of perennial crops, particularly tree species
which a migrant cannot grow on a rented or borrowed
land, unless the land is purchased. This is simply be-
cause trees are used to mark human presence and dating
land occupation. It is also shown that farmers’ know-
ledge of the reproductive biology, including phenology,of species is taken into account for selecting candidate
species for conservation [3,12].Materials and methods
Study area
This study was carried out in Djidja municipality (Figure 1),
one of the most important areas where V. doniana is har-
vested and sold. The species is a highly valued one which is
under high human pressure in this area [12,22]. Djidja is
the biggest municipality in size (out of nine) in the Zou re-
gion (41.66%) in southern Benin. According to the popula-
tion census by DED-INSAE [27], Djidja holds the second
highest population (84,590 inhabitants), representing
14.50% in the entire population of the Zou region. About
78.00% of the district population live in rural areas. The
study area is located on flat land at around 250 m altitude
in the Sudano-Guinean transition zone. This is a transi-
tional zone between the Guinean forests and the Sudanian
woodlands and savannas, and is characterized by a vegeta-
tion mosaic of forest islands, gallery forests, and savannas.
The annual rainfall varies from 900 to 1200 mm with two
rainy seasons (March to July and September to October).
Soils are predominantly hydromorphic and sandy-clay. The
natural vegetation is made up of savanna woodlands, fal-
lows, and a mosaic of secondary and gallery forests. This
landscape provides a range of forest resources from which
many edible wild plants are collected, including black plum.
However, the natural vegetation is being depleted by land
clearance for agriculture, logging for charcoal production,
and grazing [12]. As presented below, a total of 12 villages
were investigated in this municipality.Selection of study sites
Prior to selecting survey villages a market investigation
was conducted in local markets in Bohicon and Djidja
municipalities which are the major townships where V.
doniana vegetable is sold. In Bohicon where the regional
market is located, twelve vegetable sellers were randomly
selected and interviewed. This market survey helped es-
tablish the origin of products, the abundance periods
and villages supplying the regional market in Bohicon.
The interviewees ranked the supplier villages according
to the importance of their contributions to the supply.
The ranking exercise revealed that the highest share of
supply comes from Djidja municipality. In Djidja, a sec-
ond market investigation was undertaken in five local
markets. A total of 42 vendors of black plum products
(fruits and/or vegetable) at the local markets were ran-
domly interviewed on the most important supplier villages.
Interviewees ranked villages according to the importance of
primary collection and sale of the target products. The top
12 villages with higher contribution to the supply were tar-
geted for final survey.
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 4 of 16
Figure 1 Study area showing surveyed villages in Djidja Ditrict, southern Benin.Informants sampling and data collection
A total of 178 key informants (persons having know-
ledge of uses and users of V. doniana in their commu-
nity) were identified for interviews using a snowball
sampling approach. The number of key informants was
deemed representative when a saturation limit was
attained. This saturation limit was defined as the point
at which there are no new names of key informants be-
ing mentioned by the last interviewee. At this point, the
plot of the number of key informants becomes asymp-
totic with the addition of any new interviewee. The data
collected include three categories of information: a) the
socio-demographic characteristics of informants (gender,
age, ethnic background, marital status, size of household,
land ownership, origin, education of the head of house-
hold, occupation and revenue sources, social group mem-
bership, social responsibilities, and experience with
management of wild species), b) ranking of the five most
important and valued tree species to the respondent, and c)
informant’s knowledge of black plum (ownership status,
uses and use frequency, knowledge of the phenology,threats and drivers, individual conservation initiatives,
trade-off and cultivation opportunity costs and ratio, and
willingness to cultivate and to maintain the species in-situ).
We obtained the permission from the chief of each
village involved in the study before interviews were
conducted, following the ethical guidelines of the
International Society of Ethnobiology [28]. Partici-
pants were selected and included in the study after
obtaining their verbal prior informed consent.
No ethical approval was needed for this study.
Data analysis
Determination of the importance and use value of Vitex
doniana in the surveyed communities
Before testing the research hypotheses, we first deter-
mined the relative importance of V. doniana within the
diversity of useful local trees, against a number of socio-
economic characteristics. Based on value scores attrib-
uted by each respondent for the five most important
tree species to them (55 species mentioned in all), we
calculated the Species Use Value (SUV) for each species
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 5 of 16as the sum of the species value for all 178 respondents
as:
Xn
SUV i ¼ Sij
j¼1
with Sij being the score given to the species i by the in-
formant j.
Ranks were converted into scores and SUV calculated
using the method by Lawrence et al. [29]. The species
that was ranked first by a respondent received the score
5 whereas the fifth received the score 1. A species which
was not mentioned by a given informant was given the
score zero. The SUV of each species was disaggregated
by gender, origin and schooling of respondents.
We also determined the Relative Use Value (RUV) of
V. doniana for each category of informant (for e.g.
farmers versus vegetable sellers). This helped identify
user groups with specific knowledge on the use of the
species and the relative importance to them.
X
RUVk ¼ 1 n
S
n kj;
j¼1
adapted from Phillips et al. [30].
Skj is the informant j of user group k’s use value for
the species; n is the total number of informants in the
user group k.
To reveal a minimum consensus on the use of the spe-
cies in the community only species cited by at least two
respondents were included in further analyses. We used
Student’s t-test to examine the influence of gender and
origin and Kruskall-Wallis’ statistic to test the influence
of schooling on the perceived value attributed to V.
doniana. We also determined the Informant Agreement
Ratio (IAR) following Bakwaye et al. [31] as follow:
IARi ¼ nri−nai
nri−1
where nri is the total number of citations recorded for a
given use category i; and nai the total number of differ-
ent plant parts that are employed in this specific use cat-
egory i. This index measures if there are specific plant
parts employed for particular uses. Five different use cat-
egories were identified, viz. food, income, medicine, con-
struction, and others (handicraft, ink, stools).
Test of research hypothesis using classical non-parametric
tests
We used Fisher’s exact test to test if resource manage-
ment depends on socioeconomic variables such as tree
ownership, origin of respondent, and accessibility to re-
sources. The relationships respectively between gender,
land tenure and land holding, schooling and literacy,origin, participation in social organizations, level of in-
come earned from V. doniana sales, technical training
and management of V. doniana were evaluated using
Spearman’s correlation tests.
As cultivation of the species was not yet evident in Djidja,
we assessed the economic value and respondent’s willing-
ness to cultivate and also to conserve the species based on
five parameters, namely the Cultivation Opportunity Ratio
(COR), the Land Allocation Ratio (LAR), the Trade-off
Value (TOV) which represents the minimum amount the
informant is ready to accept for the maintenance of one
“Cantin” (equivalent 400 m2) of the species, the willingness
to conserve the species in the wild, and the willingness to
experiment with cultivation of the species. These are new
parameters that we introduced to determine socioeconomic
drivers for plant cultivation by local communities. COR
and LAR are calculated as follow:
COR ¼ Sp−Ac  100 ; and LAR ¼ Smax  100
Sp St
Sp is the estimated price at which the respondent would
sell a seedling of black plum, Ac is the estimated cost
that the respondent would be willing to pay to acquire a
seedling of black plum, Smax is the maximum size of
land an informant is ready to allocate to black plum
within his/her farm and St the total land size s/he holds.
We tested differences in COR, LAR, and TOV using
Mann–Whitney and Kruskal-Wallis’ tests. Relationships
between household socioeconomic characteristics and
willingness to maintain the species in its natural habitat
(in-situ conservation) and/or to invest in black plum cul-
tivation were tested using Chi-square or Fisher exact
tests as appropriate.
Test of research hypotheses using statistical models
Due to the large number of explanatory variables (69 in
total), we used the conditional inference tree model to
select variables with most significant effects on the deci-
sion to cultivate and/or to conserve the species in-situ.
The tree model is appropriate in cases where there is
large number of explanatory variables and these can be a
mix of continuous and categorical variables [32]. The
tree-based models have a number of advantages in esti-
mating a non-parametric regression relationship by bin-
ary recursive partitioning using conditional distributions.
Such models are not based on any kind of distribution
assumptions, and most importantly complex interactions
with a large number of explanatory variables and non-
linear relationships that are difficult to examine with
traditional statistical methods can be modelled. Further
details on tree models and conditional inference tree-
based classification can be found in Hothorn et al. [33]
and Crawley [32]. Further analyses of the relationships
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 6 of 16between the selected variables with the response vari-
ables (willingness to cultivate and willingness to con-
serve wild populations in-situ) were tested with
generalized additive models (GAMs) which are appropri-
ate for binary responses with at least one continuous ex-
planatory variable.
Definition of terms
In-situ conservation
In Article 2 of the Convention on Biological Diversity
(CBD) in-situ conservation is defined as “the conserva-
tion of ecosystems and natural habitats and the main-
tenance and recovery of viable populations of species in
their natural surroundings and, in the case of domesti-
cated or cultivated species, in the surroundings where
they have developed their distinctive properties” [34].
On-farm conservation of useful species by farmers has
been recognized as an in-situ or circa-situ conservation
strategy [4,35].
Ex-situ conservation
In the same Article 2 of the CBD, ex-situ conservation
means “the conservation of components of biological di-
versity outside their natural habitats”. The conservation
of germplasms in genebanks is recognized as an ex-situ
measure as is conservation in botanical gardens [4].
Results
Household characteristics of informants
Women represented 60.00% of informants, and the Fon
ethnic group dominated the sample (89.00%). Other eth-
nic groups include, by importance, Agouna, Mahi, Nagot
and Adja. Vitex doniana resource users were between 12
to 66 years old, and 42.73 ± 16.12 years in average. The
sample was characterized by a low proportion (17.98%)
who has attended primary school and the main activities
were farming, and trade of agricultural products. About
83.00% of respondents are owners of their land (with an
average of 12.05 ha per household) whereas those who
rent their land represented 16.29% with an average of
4.91 ha/household. Those who were landowners but also
rented additional land for farming represented a very
small proportion (0.71%). About 38.40% of respondents
participated in social groups; the most common of these
included self-help groups who provide agricultural prod-
uct storage, groups formed to undertake sales and pro-
cessing of agricultural products. Women participated
more than men in such groups. Autochthons repre-
sented 68.00% of the sample against 32.00% migrants.
The size of households greatly varied. Households with
less than five members represented 28.65% of the sam-
ple; a high proportion of households had between 5–10
members (52.81%). Those with 11–15 members repre-
sented 16.85%, and households with more than 15members represented 1.69%. All the households were in-
volved with black plum.
Diversity of most valued tree species in the communities
From the individual respondents’ lists of their five most
important tree species, we recorded a total of 55 species
belonging to 24 families. The determinants of the value
given by respondents included the nutritional value, the
market value, the medicinal value, the cultural functions
and use in construction. The families most often mentioned
were Leguminosae-Caesalpinioideae and Anacardiaceae.
The species mentioned in the Leguminosae-Caesalpinioideae
family included Daniellia oliveri (Rolfe) Hutch. & Dalziel,
Afzelia africana Pers., Detarium microcarpum Guill. &
Perr., Bauhinia thonningii Schum., and Tamarindus
indica L.; those in the Anacardiaceae included
Anacardium occidentale L., Mangifera indica L., Lannea
schimperi (Hochst. ex A.Rich.) Engl., and Spondias
mombin L. The results also indicated that wild species
were dominant (60.00%), especially V. doniana and Parkia
biglobosa (Jacq.) G.Don which were respectively ranked
the second and the third species, behind A. occidentale
which was a cash crop in the survey area. The seven most
frequently mentioned species have high nutritional and
market values, whereas the next eight species are mainly
used in folk medicine and construction (Table 1).
We also found that among the wild species V. doniana
was the most valued. This perception was not affected by
whether the informant was indigenous or migrant (t =
0.47; p = 0.64). However, gender (t = 6.48; p < 0.001) and
schooling (H = 8.62; p = 0.013) significantly affected the
perceived value ascribed to the species. Women valued
the species significantly higher (mean SUV = 2.61) than
men (mean SUV= 1.52). Vitex doniana seemed to be the
most valued species by people who have not attended
school (SUV = 2.38) and this value decreased with
schooling (SUV = 1.67 for primary and SUV = 0.25 for
secondary and higher education). Gender, origin and
schooling also showed strong and positive correlations
with each other (r ≈ 0.99; p < 0.001).
Variations in Vitex doniana use patterns
A total of 34 different uses were recorded for six parts
of V. doniana, namely fruits, leaves, bark, trunk,
branches and roots (Table 2). Those uses were classified
into five use categories such as household food con-
sumption, folk medicine, sales, construction material
and fuel, and others (stools, handcrafts, ink making).
The values of Informant Agreement Ratio (IAR) calcu-
lated for each use category revealed a consensus on the
use of the different plant parts (Table 3). All plant parts
are used but roots are only used in folk medicine. Leaves
and fruits are used for human food and also sold in mar-
kets to generate income. All plant parts had applications
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 7 of 16
Table 1 Top 15 priority tree species based on species use values (SUV); wild species are in bold
Species Instruction level Rankinst Origin RankOrig Gender Rankgend
No schooling Primary Secondary Indigenous Migrants Men Women
Anacardium occidentale L. 2.16 1.92 1.50 1 2.40 1.98 1 2.33 2.17 1
Vitex doniana Sweet 2.38 1.67 0.25 3 2.15 2.53 2 1.52 2.61 2
Parkia biglobosa (Jacq.) G.Don 2.15 1.68 1.25 2 1.94 2.09 3 1.75 2.26 3
Mangifera indica L. 1.26 1.27 0.88 4 1.09 1.49 4 0.82 1.44 5
Elaeis guineensis Jacq. 1.15 1.00 1.88 5 1.49 0.82 5 1.94 0.69 4
Tectona grandis L.f. 1.36 1.03 1.38 6 1.02 0.94 7 1.42 0.84 6
Citrus sinensis (L.) Osbeck 1.53 0.48 0.50 7 1.14 1.12 6 1.28 0.97 6
Pterocarpus erinaceus Poir. 0.51 1.19 0.00 8 0.70 0.48 8 1.00 0.34 8
Vitellaria paradoxa C.F.Gaertn. 0.56 0.58 1.00 9 0.47 0.50 9 0.43 0.53 9
Pseudocedrela kotschyi 0.24 0.35 0.00 10 0.19 0.25 11 0.09 0.30 11
(Schweinf.) Harms
Ficus sur Forssk. 0.28 0.20 0.25 12 0.20 0.24 10 0.03 0.31 12
Prosopis africana 0.17 0.38 0.00 11 0.24 0.02 15 0.27 0.16 10
(Guill. & Perr.) Taub.
Azadirachta indica A.Juss. 0.12 0.33 0.00 13 0.08 0.25 12 0.22 0.12 12
Daniellia oliveri (Rolfe) 0.11 0.32 0.00 14 0.16 0.18 14 0.18 0.12 14
Hutch. & Dalziel
Lannea schimperi 0.15 0.18 0.00 15 0.15 0.13 13 0.16 0.15 14
(Hochst. ex A.Rich.) Engl.
Table 2 Vitex doniana plant parts and their uses in Djidja
district
Plant parts Use Uses
used categories
Roots Folk Against snake and scorpion bites,
medicine haemorrhoids, malaria, ulcers, diabetes,
sexual impotence, stomach-ache, wounds,
constipation, eye pains, intestine worms,
sprain
Bark Folk Sterility, haemorrhoids, snake and scorpion
medicine bites, intestine worms, ulcers, stomach-ache,
diabetes, constipation, malaria, wounds,
sexual impotence, eye pain, cough,
amenorrhea, dysmenorrhea, strokes
Trunk and Construction Fuel wood, charcoal, planks, beam
branches and fuel
Other uses Drums, stool of the king
Leaves Food Household use for consumption as
cooked vegetable
Sales Sale as cooked vegetable
Folk Haemorrhoids, snake bites, mouth
medicine candidiasis, whitlow, annulet, malaria, ulcers,
sexual impotence, stomach-ache
Other uses Ink
Fruits Food Direct consumption of fruits, juice making
Sales Sale of fruits for direct consumption
Folk Haemorrhoids
medicinein traditional medicine, except trunk and branches; the
most commonly treated ailment being haemorrhoids.
The relative use value (RUV) calculated for each user
group indicated that traders of black plum products as-
cribed higher use value (RUV = 3.26) to the species than
other stakeholders (Table 4). The average profit from sales
of V. doniana vegetable during the last season was esti-
mated at XOF 38,100 (US $79.16) per user. The results
also indicated that women realized more profit from sales
than men (p < 0.001). Although youths realized more
profit than teenagers and elderly people the differences
were not statistically significant between age groups
(Table 5). The values of the coefficient of variation were
greater than 1 for all age categories and for women. ThisTable 3 Vitex doniana major use types and Informant
Agreement Ratio (IAR)
Use Number of Plant parts Number of IAR
categories use citations involved parts involved
(nr) (na)
Construction 3 Trunk and 2 0.500
and fuel branches
Food 298 Fruits and 2 0.996
leaves
Sales 120 Fruits and 2 0.992
leaves
Folk 58 Fruits, leaves, 4 0.947
medicine bark, roots
others 11 Trunk, branches, 3 0.800
and leaves
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 8 of 16
Table 4 The relative use values (RUV) of Vitex doniana
per user group
Occupations Total scores n RUV
Traders of V. doniana products and 137 42 3.26
other small businesses
Farming only 182 79 2.30
Artisans, forest product businesses 33 16 2.06
Transport, part time farming, singing, 20 10 2.00
traditional healer
Other traders of household goods, 46 31 1.48
plus other activities
Figure 2 Perception of constraints to V. doniana exploitation in
different land use types.indicates a big variability in the profit earned by these
groups out of the sale of V. doniana products. It is note-
worthy to mention that the profit did not follow a normal
distribution. Overall, there is an uneven distribution of the
profit along the value chain of V. doniana (this was exam-
ined further in another study and not discussed here).
Management of Vitex doniana
Vitex doniana is under both individual and collective
management in the study area, with collective manage-
ment being dominant. About 92.00% of informants
maintained trees of the species within their farmlands.
The species is harvested from different habitats. By de-
creased order of importance, V. doniana is harvested
from farms and fallows (100% of informants), savannas
(87.00%), and woodlands and gallery forests (83.00%).
An important proportion of informants (55.60%) re-
ported that the species was either very scarce or scarce.
According to informants three main constraints were
encountered during harvesting, namely: difficulties
accessing some sites due to thickets, the personal risks
of climbing trees for harvesting, and privatization of
some trees (Figure 2). Trees occurring in savannas and
woodlands were more difficult to climb while
privatization was more prominent for trees occurring on
farms and fallows. Felling of taller trees to harvest new
shoots has become a common practice.
The people’s knowledge of species’ phenology was highly
variable. For instance, knowledge of the fruiting period
was dependent on gender and origin of respondents (p <
0.001). Men (average score = 5.19) had better knowledgeTable 5 Profits from Vitex doniana products sale by
different age categories and gender in Djidja district
Variable Groups Profit Standard Coefficient Significance
earned deviation of variation
<20 years 22,787.5 38,399.7 1.7 Age
(p = 0.206)
Age 20 – 55 years 41,067.2 41,704.7 1.0
>55 years 29,576.9 34,720.8 1.2
Men 12,916.7 9,769.4 0.8 Gender
(p = 0.000)
Gender Women 40,290.6 41,268.2 1.0of fruiting period than women (average score = 3.51); and
autochthones (average score = 5.23) had better knowledge
of the fruiting period than migrants (average score = 2). In
addition, men had a significantly better knowledge of the
period of appearance of new shoots than women (p =
0.02). Land tenure also significantly affected this know-
ledge (p < 0.001), with the best knowledge of shooting
period registered among autochthon landlords. Moreover,
schooling seemed to be negatively correlated with know-
ledge and we reason that attendance at school deprives
children of the chance to be in contact with the species,
hence elite people in the surveyed communities had less
knowledge on the biology compared to those who have
not gone to school (p = 0.01). Results also indicated that
there was a minimum growth required before a specific
plant part can be harvested and the timing of this varies
with the plant parts harvested (Figure 3). Except for leaves,
harvesting of all other plant parts (e.g. bark, branches,
stems, and roots) starts at the earliest at the shrub-like
stage. Harvesting of leaves can occur on juvenile subjects,
while fruits harvesting occurs only on mature trees.Figure 3 Perception of the minimum growth required before
harvesting the different parts of Vitex doniana.
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 9 of 16
Table 6 Willingness to cultivate and mean seedling price
and acquisition cost (in XOF) for positive and negative
cultivation opportunity ratio (COR) value groups,
N = 101
Negative Positive COR Significance
COR
Mean ± sd −1.1 ± 2.1 21.7 ± 82.5 p < 0.05
cultivation cultivation
Yes No Yes No
n = 23 n n = 61 n = 17
= 0
Selling price 115.2 ± - 10,300.0 ± 42,297.1 ± p < 0.05
424.6 29,655.6 122,605.6
Acquisition 958.7 ± - 753.8 ± 370.6 ± p < 0.05
cost 1,677.8 1,928.0 1,197.6Local perception on status and conservation strategies
Most informants (55.00%) considered V. doniana
populations as declining in the local environment and
this perception was equally shared among men and
women farmers (p > 0.05). According to our infor-
mants, the decline in V. doniana’s populations is trig-
gered by human pressure that is characterized by
intense harvesting of new shoots, sometimes involving
cutting of whole tree that are difficult to climb. The
species is also used in charcoal for which mature
trees are cut down. About 50.00% of informants re-
ported that cutting of V. doniana tree to harvest
leaves was the main threat to the species. Informants
also reported low regeneration rates which they at-
tributed to low production of fruits and low germin-
ation rates (7.92% of informants), natural death of
stands, and other drivers such as bushfires (2.97%),
agricultural expansion and urbanization (2.97%).
Respondents recognized propagation through seeds
(81.47%) as the major route to regenerate the species.
Only 6.17% mentioned the possibility of using stem
cuttings. However, attempts to propagate the species
were very rare and only 5.61% of informants (five
men and five women in a sample of 178) have tried
to regenerate it. Among respondents, only owners of
land (acquired either through inheritance or gift) re-
generated the species. Among those who have tried,
30.00% of them experimented regeneration with stem
cuttings; the other 70.00% used seeds. The success
rate is 33.33% (only one success over three cases re-
ported) for stem cuttings and 57.14% (four successes
over seven cases reported) for the regeneration by
seeds. When disaggregated by gender, this success
rate was 60.00% for women and 40.00% for men. In
the cases reported no additional care was provided to
the transplanted seedlings or the regenerated plants.
Successful results were obtained for seedlings trans-
planted in the wet season; seedlings were rain-fed.
Trees produced by these means were found on-farm
and were intensively harvested by their owners. No
consideration of selective sowing of seeds or planting
of stem cuttings was reported.
Readiness of communities to engage in cultivation of
Vitex doniana
Exploration of relationships between socioeconomic
variables and willingness to actively conserve the species as
wild and cultivated resource, using Fisher’s test
In order to better promote cultivation of V. doniana in
the surveyed communities, we evaluated informants’ will-
ingness to engage in its active conservation (i.e. both
planting and caring of the trees on-farm but also mainten-
ance of wild trees in-situ). Overall, 76.50% of informants
were ready to invest in agroforestry of the species, whereas74.40% said they are willing to maintain woodlots of the
species. The Fisher test on individual variables indicated
that the willingness to plant the species seemed independ-
ent of gender, origin, land ownership, literacy level, school-
ing, and household consumption or sale of black plum
products (p > 0.05). Plant resources management was also
independent of social group membership and participation
in technical training (p > 0.05). However, the willingness to
maintain wild trees in-situ was significantly affected by
land tenure (p < 0.05). Landowners were the most willing
to conserve stands of the species. However, this does not
significantly affect the trade-off value (TOV). The TOV
was only significantly affected by schooling (p < 0.05). We
observed that people reaching secondary and higher for-
mal education reported TOVs more than three times
higher (XOF 270,000; equivalent USD 600) to maintain a
400 m2 stands of black plum, compared to those who
stopped at primary level (XOF 78,000; equivalent USD
173). The average land size that respondents were ready to
allocate for V. doniana agroforestry is 0.98 ha, represent-
ing an average land allocation ratio (LAR) of 8.33%. The
LAR was significantly affected by gender (p < 0.05).
Women were ready to allocate an average of 23.66% of
their land to black plum while men were only willing to al-
locate an average of 14.04% of their agricultural land to V.
doniana. However, this did not imply that women allo-
cated more land than men. In absolute terms men’s land
holding (18.9 ha in average) is far larger than that of
women (5.6 ha in average). These ratios imply that men al-
located 2.7 ha while women allocated 1.3 ha.
The in-situ conservation cost was not evaluated for
8.42% of the respondents, as they were not able to evalu-
ate the costs related to this. For the other 91.58%, there
was no significant difference in the Cultivation Oppor-
tunity Ratio (COR) with respect to gender, origin, access,
and schooling. However, the COR had significant effect
on the willingness to cultivate (Table 6) or to conserve
the species in-situ (Table 7). Negative COR values
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 10 of 16
Table 7 Willingness to conserve species in-situ and mean seedling price and acquisition cost (in XOF) for positive and
negative cultivation opportunity ratio (COR) value groups, N = 101
Negative COR Positive COR Significance
Mean ± sd −1.1 ± 2.1 21.7 ± 82.5 p < 0.05
Conservation Conservation
Yes No Yes No
n = 22 n = 1 n = 56 n = 22
Selling price 139.5 ± 465.6 0.0 ± 0 10,879.2 ± 31,640.4 36,702.4 ± 11,0351.1 p < 0.05
Acquisition cost 1,001.1 ± 1704.6 25.0 ± 0 970.0 ± 2140.2 83.6 ± 116.3 p < 0.05indicated the informants were ready to be actively en-
gaged (p < 0.05). The average acquisition cost an inform-
ant was ready to pay for a V. doniana seedling was
disaggregated by negative and positive COR values.
These values indicated a great variation among the
amounts proposed by users. The negative COR was as-
sociated with a high value ascribed to the seedling by
the informant in a way that s/he was ready to offer
higher price to acquire than s/he would sell his/her own
seedlings. Interestingly, informants who were most will-
ing to cultivate or to conserve wild plants of V. doniana
(negative COR values) offered the highest prices to ac-
quire seedlings. Therefore, the sign of the COR is a good
indicator of the willingness to cultivate, but also the will-
ingness to conserve the species in-situ. Among those
with negative COR, all are willing to cultivate and also
willing to conserve, excepted one informant. This was
more prominent with other respondents who indicated
they “will never sell seedling of black plum” due to its
importance for them. Those informants were not in-
cluded in the calculations, as they did not suggest any
price. In the case of positive values of COR, there
seemed to be additional variables that are taken into ac-
count in the decision making.
Determinants of the willingness to cultivate Vitex doniana,
using the conditional inference tree approach
The conditional inference tree classification using all so-
cioeconomic and biological variables (Figure 4) indicated
that the maximum land size that people are ready to al-
locate for the agroforestry of V. doniana was the main
indicator of readiness to cultivate. Among people whose
maximum allocated land was less than 0.0002 ha, gender
was key in the decision making process, and men were
more (or the most) willing to cultivate. For the women
informants in this category, educational level determined
the decision. Non-schooled women and school drop-
outs were not willing to cultivate V. doniana, but those
women who have attended secondary or higher educa-
tion were more willing to cultivate the species.
Among those farmers ready to allocate more than
0.0002 ha, people from Agbohoutogon, Dan, Djessi,
Djidja centre, Lakpo, and Sekpongon villages were themost engaged to cultivate. In the other locations such as
Kakatehou, Kome, and Oungbega, the type of access to
resources (e.g. wild harvesting or purchase) was key in
the decision making process. Among people who collect
V. doniana in the wild, those from Kakatehou and Kome
were ready to cultivate, without condition. Among this
category, literacy level plays a role in the decision-
making process in Oungbega and illiterate people (who
cannot read and write their mother tongue) were most
likely to cultivate the species; the literate were not.
Among those who can only access the resource through
purchasing, either for trading or for household con-
sumption, in Kakatehou, Kome, and Oungbega; literacy
level was also a determinant, and literate people were
most willing to cultivate. Among the illiterate, percep-
tion of the hardship endured to climb trees to collect
the leaves was crucial in the decision making process,
and surprisingly those who find it difficult to climb trees
in woodlands were not willing to cultivate the species.
Among those who did not perceive it difficult to climb
trees in woodlands, the existence or not of protection
mechanisms of trees in private lands (farmlands) plays a
role in the decision to cultivate. In fact, in farmlands
where there is no ban on trees, people were more likely
to cultivate. In communities where trees occurring on
farmlands were private resources, the maximum amount
the informant is ready to pay to acquire a seedling of the
species was the best indicator of the willingness to culti-
vate with highest levels among those proposing over
XOF 650 (USD 1.44) per seedling. This is well in line
with the results presented in Table 6.
Determinants for the conservation of wild trees of Vitex
doniana in-situ, using the conditional inference tree
approach
The conditional inference tree (Figure 5) indicated that
the maximum area people were ready to allocate was a
main factor in respondents’ willingness to conserve the
species in-situ. For people allocating less than 0.18 ha of
land to V. doniana, the total land available was key to the
decision, and people with less than 1.1 ha of total available
land were the most likely to conserve the species. Among
those with more than 1.1 ha of land, availability of V.
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 11 of 16
Figure 4 Conditional inference tree showing factors determining the decision of local people to cultivate Vitex doniana. The response Yes = the
informant is willing to cultivate; and No = informant not likely to cultivate. Sex (a = Female, b = Male); Instruction level, with reference to western
education (a = No schooling, b = Primary, c = Secondary and higher education); Literacy level (a = Cannot read nor write in mother tongue
“illiterate”, b = Can write and read in mother tongue “literate”); Location (a = Agbohoutogon, b = Dan, c = Djessi, d = Djidja centre, e = Kakatehou,
f = Kome, g = Lakpo, h = Oungbega, i = Sekpongon); Veg_bought, i.e. Vegetable bought or purchase of Vitex doniana vegetable (a = No, b = Yes);
Woodl_diff_climb, i.e. Difficult to climb Vitex doniana trees in the woodland (a = No, b = Yes); Famland_forbid, i.e. Harvesting is forbidden in
farmland (a = No, b = Yes).doniana trees (measured through abundance of mature
trees for harvest) was determinant to the decision making
process, and people who have easy access to trees were
not likely to conserve wild populations. Among those with
limited access to the resource (assessed as high pressure
on immature trees), tenure has a bearing on the decision
and only landowners were likely to conserve, land tenants
were not.
For people who were ready to allocate more than
0.18 ha to the species, the decision to conserve
depended mainly on location, with people from Dan,
Djessi, Djidja centre, Lakpo, and Sekpongon villagesFigure 5 Conditional inference tree showing factors determining the decisio
informant is willing to conserve the species in-situ; and No= informant not lik
minimal plant developmental stage required for exploitation of fruits (a = Juve
stage); Tenure (a = Land owner, b = Tenant of land); Location (a = Agbohouto
g = Lakpo, h = Oungbega, i = Sekpongon); Farmland_diff_climb, i.e. Difficult to
(a = Female, b =Male).more engaged into for its conservation. For other re-
spondents from Agbohoutogon, Kakatehou, Kome, and
Oungbega, the perceived cost of one seedling was key to
the decision. People who were ready to pay more than
XOF 450 (1 USD) were most engaged to conserve the
species in-situ, supporting the results in Table 7. Among
informants who proposed less than 1 USD, tenure sys-
tem has to be taken into account, with tenants not likely
to conserve. Among landowners of this category, main
variables used in the decision making process included
knowledge of plant phenology (fruiting period), the total
land available, the trade-off value (TOV) or conservationn to conserve wild trees of Vitex doniana in-situ. The response Yes = the
ely to conserve the species in-situ. Minimal_dev_fruit_exploit, e.i. The
nile stage, b = Fruits not used, c = Shrub-like stage, d =Mature tree
gon, b = Dan, c = Djessi, d = Djidja centre, e = Kakatehou, f = Kome,
climb Vitex doniana trees in the farmland (a = No, b = Yes); Sex
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 12 of 16cost, the perceived difficulties in climbing trees to har-
vest products and gender. In fact, among those farmers
with less than 6.5 ha of total available land, people who
requested a TOV below XOF 80,000 (USD 177) were
likely to conserve, while those who requested more than
USD 177 were not. Among the farmers with more than
6.5 ha of total land, people who perceived it less difficult
to harvest the trees occurring within farmlands were
more likely to conserve. Among those who find it diffi-
cult to harvest trees on their farm, only women were
ready to conserve the species in-situ, men were not.
Discussion
Valuation of tree resources in the surveyed area
Findings indicated that wild species represented the
major part of the edible tree resources diversity in the
twelve surveyed communities, meaning that local people
still rely to a great extent on nature for their livelihoods.
Out of the top 15 most valued woody plants, eleven have
a high market value and species such as A. occidentale,
V. doniana, and P. biglobosa combined high market and
nutritional values. Vitex doniana stood out as the most
important wild tree species followed by P. biglobosa,
with both falling just behind A. occidentale which is an
important cash crop in the surveyed communities. This
result is consistent with findings by several authors who
investigated the use of plant diversity in rural livelihoods
in the West African sub-region [16,36-38]. Parkia biglo-
bosa and V. doniana were already reported among the
most valued NWFP resources in southern Benin [12], in
Burkina Faso and Cameroon [39]. The two species are
almost always used together in local cuisine where the
local mustard “afintin” processed from seeds of P. biglo-
bosa is used as seasoning for cooking leaves of V. doni-
ana into a much appreciated popular vegetable dish in
the region, known as “fonman”. Therefore, the current
results call for a close attention for safeguarding and
valuing these species.
Cultivation appears to be the best management option
to sustain both species and livelihoods when the value of
a non-wood forest product (NWFP) and quantities har-
vested are high [1]. This opinion was also backed by
Kupzow [5] who supported that plant cultivation is most
stimulated by economic demand and highlighted that
many cultivation experiments resulted in nothing be-
cause they failed to take economic aspects into consider-
ation. Studies have revealed that black plum has an
important market [13], that keeps expanding and this
represents an incentive for its cultivation and conserva-
tion [40]. The species was also mentioned as present in
at least 20% of traditional agroforests, from a country-
wide survey in Benin [21]. In these conditions, cultiva-
tion of black plum is likely to be successful. In fact, V.
doniana has the highest use value among the wild treeresources of importance to local livelihoods, especially
for women and illiterate people, who tend to value it
more than any other tree species. We also found that
people with higher educational level seemed to value
cash tree crops more highly than others, namely E.
guineensis, A. occidentale, and T. grandis by decreasing
order of importance. This could be an indication of the
erosion of local value among the more “westernized”
households. The educational elite classify resources al-
most solely based on market value of species, completely
ignoring the social and cultural values associated with
them. Another consideration is that they have less con-
tact with wild resources in nature. Migrants also seemed
to value V. doniana and P. biglobosa more highly than
autochthons to whom the cash tree crop A. occidentale
is the top most important. In fact, in the local land ten-
ure systems migrants who are not owners of land have
no right to plant perennial species. However, they have
free access to wild resources in the nature, a fact which
could explain this high value they attributed to the wild
species. Overall, these variables are significantly import-
ant and should be carefully taken into account when
selecting stakeholders in wild resource conservation
programmes.
Uses, management and conservation strategies
Results clearly indicated that black plum is a multipurpose
species, a characteristic of most NWFPs [41]. The inven-
toried uses confirmed the current state of knowledge on
the species as reported by previous studies [12,16,40,42].
The high IAR values confirmed that knowledge of these
uses is well distributed among user communities and the
species is important in rural livelihoods. Exploitation of
the species is profitable for all age groups, but more so for
women than men. This is explained by the fact that men
are most involved at the primary stage of exploitation, as
primary collectors; while women are more involved in the
wholesale and retail of processed leaves and fruits. By the
law of profit distribution along the market chains of
NWFPs, wholesalers and retailers (involving mainly
women) obtain the bigger profit [43]. Species of this type
are classified under the “women goods” categories of
NWFPs [44].
Overall, juvenile trees are more vulnerable to disrup-
tion caused by destructive harvesting practices and wild
fires. Therefore, much of any regeneration dies out at
the end of the dry season. Overharvesting of leaves re-
duces fruiting ability of the overharvested trees, and this
coupled with fruit harvesting obviously reduces the pos-
sibility of regeneration from seed. All these represent
important threats to survival of wild populations. None-
theless, the current level of roots and bark harvesting for
medicinal purposes is low and does not add significantly
to existing threats.
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 13 of 16The analysis of access to resources of different land-
scapes indicated an incipient privatization of V. doniana
trees occurring in farmlands and fallows. In fact, trees
that are spared during land clearance for agriculture be-
come the property of the farm owner. This tenurial sys-
tem enhances conservation, as harvesting is better
scheduled and competition with other harvesters is lim-
ited. On common lands (woodlands and savannas) trees
are often cut down to harvest the leaves when they are
too difficult to climb. The trunk and branches left out
are then used to make charcoal or fuel wood. In farms,
when the owner grants a usufruct right to a person to
harvest trees on his or her fields, that person is not
allowed to cut V. doniana trees. These kinds of mea-
sures protect the species.
From our data, local communities did not report any
variants of V. doniana that can be subject to artificial se-
lection in the sense of Blancas et al. [3]. However, refer-
ring to Blancas et al. [3]’s classification of the different
management types, we distinguished the following cat-
egories which are considered as in-situ actions:
i) “Gathering without recognition of variants”.
Respondents did not report any selective harvesting
of V. doniana resources. No variants were reported
within the species.
ii) The species is also “tolerated without recognition of
variants”, whereby stands were spared in farms but
without any special tendering. This tolerance did not
consider variants.
iii)For the very few cases of regeneration reported by
local communities (5.61%), the species is “enhanced
without recognition of variants”. People tried to
regenerate the species in order to increase its
abundance and subsequent availability, and this was
not based on variants.
iv) The species is “protected without recognition of
variants”. This protection mainly happens in farms
where people spare V. doniana trees during land
clearance and weeding, without any distinction of
variants. No additional care is provided.
Other categories such as “seed sowing” and “propaga-
tion of vegetative parts” described by Blancas et al. [3]
were observed at a very low proportion (3.93% used
seeds and 1.68% used stem cuttings). These two categor-
ies were classified as ex-situ management by Blancas
et al. [3]. However, based on the definitions of in-situ
and ex-situ conservation by the CBD [34], we rather
identified them as in-situ management, as these activities
entirely happened in farms in the case of V. doniana.
Furthermore, future horticultural investigations should
tackle the issue of keeping trees at a size and height that
facilitate harvesting. This was further emphasized in theconditional inference model where it clearly appeared
that some farmers put this as a condition before they en-
gage into the cultivation of the species. Those farmers
would prefer a shorter V. doniana tree which can be
easily harvested.
Men have better knowledge of tree phenology (especially
the fruiting period) than women, although women were
the most involved in V. doniana exploitation. This is ex-
plained by the fact that men are the most involved in the
primary collection of the resources and thus are more in
contact with the species in its natural habitat. In addition,
the autochthons have better knowledge of the biology of
the species than migrants. Explanation to this might be
that the autochthons have been in contact with the species
for long time and knowledge is transmitted through gen-
erations. This indicates the importance of indigenous peo-
ple’s ecological knowledge on NWFPs. It was also found
that local knowledge of people is eroded with schooling.
This negative effect was also reported by Chukwuone [10]
where schooling had negative effect on involvement of
local people in NWFPs cultivation in Nigeria. At the
current state, conservation initiatives are very poor in the
study area, with very limited on-farm sparing of trees dur-
ing land clearance for agriculture. This has been reported
by N’Danikou et al. [12] and Dadjo et al. [40]. With regard
to this and taking into account the pace with which the re-
source is harvested, wild populations of V. doniana are
undoubtedly under threat. Based on the current level of
local conservation initiatives, V. doniana falls under steps
1 and 2 of the domestication process [6,35]. Step 1 is char-
acterized by wild plants maintained on farms during land
preparation (e.g. clearance, burning and weeding) due to
their proven utility and regular need, and their scarcity
within household’s compound limits. These spared plants
are regularly observed to learn about their reproductive
biology. In Step 2, farmers start giving more care to the
protected plants (e.g. weeding, protection against animal
damage) for their survival and their normal growth; a sort
of ownership on the plants starts [35]. It is important to
note that up to Step 2, no modification of plants has
occurred due to selection; but plants just incidentally co-
evolved to adapt to the disturbance imposed by human
activities in the environment [6].
Motivations for cultivation and conservation of wild
populations of V. doniana by user communities
Based on the current demand for V. doniana products
and the intensity of the harvest, cultivation would be the
best option to sustain the species and also the livelihoods
of the different user groups. However,V. doniana is still at
the earlier stage of the domestication process as indicated
above and is still intensively collected from the wild. Thus,
it is vital to understand what could motivate resource
users to engage in cultivation of the species. From our
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 14 of 16study and based on the conditional inference tree statis-
tical approach, four main variables have important effects
on the decision-making process to cultivate V. doniana in
the surveyed communities. This is partly consistent with
previous studies in this domain [12,21]. First, an important
proportion of users have expressed their willingness to
cultivate the species for its importance in household food
consumption and income. The second important param-
eter to be considered is schooling and literacy. Findings in-
dicated that the use value of V. doniana to people declines
with schooling. In this respect, awareness needs to be
raised to sensitize elite classes. A third variable weighting
in the cultivation of the species is the land tenure. Tenants
were less likely to accept cultivation. In fact, the land ten-
ure system in southern Benin and in any other parts of the
country does not grant the tenants the right to plant trees
[25]. Perennial species and most often trees are used to
mark ownership of land. Thus, individuals with no prop-
erty right on land may be willing but not ready to invest
into cultivation of the species. At fourth and the most im-
portant, tenure size is key to the decision to cultivate and
to maintain the species in-situ. People with larger parcels
of land were eager to allocate bigger plots for the agrofor-
estry of the species and were more likely to consider culti-
vation. Where land is available gender is an important
factor in the likelihood for V. doniana cultivation. Al-
though women’s use value of the species was higher than
men’s, the men were more likely to plant the species. This
could in fact be explained by the tenure system in which
women have less access to land. There are also other vari-
ables such as the importance of wild-harvesting, the loca-
tion and the cost of seedlings that were considered by
people in their decision making. The threshold of XOF
650 (USD 1.44) found is well reflected in the positive rela-
tionship between the cultivation opportunity ratio (COR)
and the likelihood to cultivate. All those who proposed a
seedling acquisition cost below this threshold were not
willing to cultivate.
Implications for management of overharvested wild
resources
Several wild resource conservation programmes have
failed around the world due to the lack of clear under-
standing of local drivers for success [10]. Gepts et al. [4]
indicated that the success of conservation through use
and restoration of biodiversity requires continued and
increased research, and policies. Our findings pinpoint
the main socioeconomic factors that trigger the success
of conservation and management of threatened wild har-
vested plant resources with high economic value. Moti-
vated local communities should be at the heart of
conservation management, and we demonstrate that
there is considerable willingness to engage in conserva-
tion of a locally threatened economically significant wildspecies. The availability of land was the most import-
ant element in our study with gender and lack of
awareness of the importance of local foods among
the elite class. The determined affordable cost of
seedlings for farmers is a good entry point for nur-
sery development. The negative values found for the
cultivation opportunity ratio is also a good indication
of the willingness of people to grow V. doniana in
their farmlands and conserve wild populations. This
means that less effort would be needed to get this
category of participants involved.
The present study also encompasses the principle of
complementarity between biological diversity conserva-
tion strategies. In fact, each of the elements treated in
this paper (i.e. cultivation and in-situ conservation) have
both positive and negative outcomes for biodiversity
conservation, which need to be discussed. Plant cultiva-
tion can result in important setbacks if not well man-
aged, despite its important advantages [45]. A plant
cultivation programme that is not sustainably managed
could lead to genetic drift and important biodiversity
loss caused by high selection and breeding of superior
lines. In the case of wild-harvested species such as V.
doniana which have not been evaluated genetically, it is
necessary to conserve wild populations in their natural
habitats and in ex-situ genebanks (if possible) while they
are undergoing domestication; in order to safeguard the
gene pools in the species for future breeding purposes.
Besides, there are examples of successful domestication
of plant species whereby this undertaking has increased
diversity. For instance in the case of maize which, des-
pite the long history of selection and genetic improve-
ment it has undergone, developed a huge diversity of
cultivars. This was possible thanks to the ecological di-
versity of agricultural landscapes, which promoted the
spread of cultivars and their adaptation to a diversity of
agroecological niches [46], but also due to conservation
of ancestors in the wild and ex-situ in genebanks. In
the other hand, despite its positive effect in safeguard-
ing diversity, in-situ conservation can also have adverse
effects. In fact, populations that are conserved in-situ
undergo natural selection. Although this favours coevo-
lution and adaption to the changing environment, a
fact which is sought in breeding for adaptive traits, a
great diversity of genes is lost during the process. The
weakest individuals which cannot survive changes that
occur in the natural environment, though they may
possess other useful traits for future breeding purposes,
disappear and new genetic material of surviving indi-
viduals is established. Taking all the above into consid-
eration, Article 9 of the Convention on Biological
Diversity (CBD) advocates that in-situ conservation, as
far as possible and as appropriate, be complemented by
ex-situ measures [34].
N’Danikou et al. Journal of Ethnobiology and Ethnomedicine  (2015) 11:28 Page 15 of 16Implications for research and development
From our findings, there is an avenue for domestication of
V. doniana and conservation managers and horticulturalists
should consider means to alleviate agronomic con-
straints such as keeping the plants at a shape and height
to facilitate harvesting. Based on intrinsic characteristics
and behavior of plants in the agricultural environment,
domestication of V. doniana would just require adapta-
tion to the agricultural environment [5]. Early results of
horticultural trials indicated that the species responds
very well in agroforestry systems (authors’ unpublished
data). In the debate on where and when domestication
of wild species takes place it is often argued that the key
determinant is the ecological but also the intrinsic char-
acteristics of the wild plant or animal species which ren-
dered them suitable for domestication which downplays
the cultural, social and technological prowess of the
hunter-gatherers themselves [4]. The authors, however,
argue that in addition to biological and ecological traits,
there are socio-cultural and economic factors influen-
cing the genetic make-up of farmer bred varieties. In
this regard, our findings make an important contribu-
tion to practical NWFP conservation. They are particu-
larly relevant for the future of ethnobotanical studies
aimed at providing advice to conservation management.
The decision making process in the co-management or
participatory natural resource management frameworks
should use holistic approaches that integrate the social,
cultural and economic dimensions of the local people in
relation to wild plants use. Selection of participants in
conservation and domestication programmes should be
based on criteria that help to recruit members that are
most likely to take actions to good ends. The approach
used in the current research is simple and can be ap-
plied to any wild harvested resource similar to black
plum. Nonetheless, future investigations of this type
should dig further into the characteristics of locations
that might make their inhabitants more active in wild
resource cultivation. Chukwuone [10] identified the dis-
tance to reach harvesting sites and level of resource deple-
tion. The effect of market access should also be further
investigated. In our study access to market was not investi-
gated as a variable, as all villages have relatively easy access
to a market. Another important area of investigation is the
analysis of the value chain of the species and the role of the
stakeholders in a scenario of an organized commercial pro-
duction of the species. Final, it is worthwhile noting the
limitation of testing the relationship between presumed sin-
gle explanatory variables and a response variable which is
under the control of several factors. In our study the condi-
tional inference tree model seemed most robust to unveil
the rationale behind the decision making process about cul-
tivation and in-situ conservation of species. This calls for
caution when drawing general conclusions from inferentialstatistics on a phenomenon which is under the control of
complex social, biological and environmental factors [47].
Conclusion
This study highlighted factors that trigger cultivation
and in-situ conservation of wild harvested resources,
with V. doniana as a case study. The species is thought
to be declining at a high rate and all informants agreed
that there is a need for action. Overall, we demonstrated
that cultivation of the species is possible and eight main
drivers were identified. These included land tenure, size
of land holding, gender, cultivation opportunity ratio,
schooling and literacy, resource availability measured
through the importance of wild-harvesting, affordability
of seedlings, and location. We also demonstrated that the
Cultivation Opportunity Ratio is an important indicator
for quick assessment of the likelihood of farmers to engage
into cultivation and conservation of the species. The find-
ings come in support to the agronomic investigations that
are being developed for cultivation of the species. Only
the combination of on-farm management and in-situ con-
servation would help take pressure off wild populations to
safeguard genetic diversity in the species and enhance live-
lihoods of the various user groups.
Competing interests
The authors declare that they have no competing interests.
Author’s contributions
SN designed the study, analyzed data and finalized the manuscript. EGAD
designed the study, gave conceptual advice, read and improved the
manuscript. DAT supervised the field work, contributed to data analysis and
manuscript preparation. COAA and CAH contributed to field data gathering,
read and improved the manuscript. RSV and AA supervised the work and
improved the manuscript. All authors read and approved the final
manuscript.
Acknowledgement
Authors are very grateful to New Alliance Trust for the financial support. We
thank local communities of Djidja municipality for their kind participation in
the study and for sharing their knowledge. We thank Jenny Wong for
language editing. We also thank Christelle Komlan for her contribution to
field data collection and Hounnankpon Yedomonhan of the National
Herbarium of Benin, University of Abomey Calavi for the identification and
maintenance of plant voucher specimens. The first author is also grateful to
Hermane Avohou for his advices during manuscript preparation.
Received: 24 September 2014 Accepted: 17 March 2015
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