ArticlePDF Available

Abstract and Figures

This paper is a contribution to the understanding of the West African phytogeography, and particularly the vegetation of Benin. We describe the major vegetation types in Benin using numerical analysis, analyse the chorological differentiation of the flora within them using a phytogeographical index and examine the relations between vegetation types, chorological categories and underlying ecological factors using cluster, correspondence and linear regression analyses. Twenty vegetation types grouped into four geographically separated groups are described and patterned along a south-north climatic gradient. We demonstrate the predictive value of vegetation type with regard to chorological categories and underlying ecological factors. Furthermore, we propose a phytochorological map that represents a synthesis reflecting the vegetation, chorological and climatic patterns in Benin.
Content may be subject to copyright.
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=tabg20
Download by: [191.103.17.81] Date: 30 January 2016, At: 21:39
Acta Botanica Gallica
ISSN: 1253-8078 (Print) 2166-3408 (Online) Journal homepage: http://www.tandfonline.com/loi/tabg20
Notulae Florae Beninensis, 13—Biogeographical
analysis of the vegetation in Benin
Aristide C. Adomou , Akpovi Akoègninou , Brice Sinsin , Bruno de Foucault &
Laurentius J.G. van der Maesen
To cite this article: Aristide C. Adomou , Akpovi Akoègninou , Brice Sinsin , Bruno
de Foucault & Laurentius J.G. van der Maesen (2007) Notulae Florae Beninensis,
13—Biogeographical analysis of the vegetation in Benin, Acta Botanica Gallica, 154:2, 221-233,
DOI: 10.1080/12538078.2007.10516053
To link to this article: http://dx.doi.org/10.1080/12538078.2007.10516053
Published online: 26 Apr 2013.
Submit your article to this journal
Article views: 140
View related articles
Citing articles: 1 View citing articles
Acta Bot. Gallica, 2007, 154 (2), 221-233.
Notulae Florae Beninensis, 13 - Biogeographical analysis of the vegeta-
tion in Benin
by Aristide C. Adomou(1), Akpovi Akoègninou(1), Brice Sinsin(2), Bruno de Foucault(3)
and Laurentius J.G. van der Maesen(4)
(1) Laboratoire de botanique, Faculté des sciences et techniques, Université d’Abomey-Calavi, 01
B.P. 4521, Cotonou, Bénin ; adomouaristide@yahoo.fr
(2) Laboratoire d’écologie appliquée, Faculté des sciences agronomiques, Université d’Abomey-
Calavi, B.P. 526, Cotonou, Bénin ; bsinsin@syfed.bj.refer.org
(3) Département de botanique, Faculté de pharmacie, BP 83, F-59006 Lille Cedex
(4) Biosystematics Group, Wageningen University, Gen. Foulkesweg 37, NL-6703 BL Wageningen;
jos.vandermaesen@wur.nl
Abstract.- This paper is a contribution to the understanding of the West African
phytogeography, and particularly the vegetation of Benin. We describe the major
vegetation types in Benin using numerical analysis, analyse the chorological dif-
ferentiation of the flora within them using a phytogeographical index and exami-
ne the relations between vegetation types, chorological categories and
underlying ecological factors using cluster, correspondence and linear regres-
sion analyses. Twenty vegetation types grouped into four geographically sepa-
rated groups are described and patterned along a south-north climatic gradient.
We demonstrate the predictive value of vegetation type with regard to chorolo-
gical categories and underlying ecological factors. Furthermore, we propose a
phytochorological map that represents a synthesis reflecting the vegetation, cho-
rological and climatic patterns in Benin.
Key words : chorology - biogeography - vegetation type - Benin.
Résumé.- Ce travail est une contribution à la compréhension de la phytogéo-
graphie ouest-africaine en général et de la végétation du Bénin en particulier.
Les principales communautés végétales sont identifiées sur la base d’analyses
multivariées. Un indice phytogéographique a permis de synthétiser les données
chorologiques. Les analyses de régressions linéaires ont permis d’examiner les
relations entre les types de végétation, les catégories chorologiques et les fac-
teurs écologiques déterminants. Il est décrit vingt types de végétation regroupés
en quatre groupes chorologiques géographiquement séparés le long d’un gra-
dient climatique. La valeur prédictive de la végétation au regard des catégories
chorologiques est mise en évidence. Nous proposons une carte phytochorolo-
gique représentant la synthèse des relations entre végétation, catégories choro-
logiques et facteurs écologiques.
Mots clés : chorologie - biogéographie - type de végétation - Bénin.
received September 5, 2006, accepted September 27, 2006
Downloaded by [191.103.17.81] at 21:39 30 January 2016
I. INTRODUCTION
The distribution of plant species and communities generally provides the best assessment
of environment. Overlap between different species distribution patterns means that species
composition at a site may indicate particular environmental conditions, a basic premise of
using vegetation to predict the environment (Hall & Swaine, 1976). In Africa south of the
Sahara, the amount of Guineo-Congolian plant species decreases with increasing latitude
from south (closed forest zone) to north (savannah zone), where the amount of rainfall
becomes low and the drought stress is high. On the contrary, the proportion of Sudanian
elements increases along this south-north latitudinal gradient. In the Sudanian region, the
Guineo-Congolian elements tend to take refuge in riparian forest, where soil moisture is
higher (Meave & Kellman, 1994; Natta, 2003). Therefore, we expect a strong correlation
between vegetation patterns and proportions of various chorological categories.
Understanding plant distribution patterns and the underlying ecological factors is a cru-
cial step for the conservation and management of plant communities and ecosystems.
There is a general agreement that climate is the primary factor explaining the distribution
of forest and savannah, at least at a continental scale (Adejuwon, 1971; Swaine, 1992). In
West Africa, there is a strong south-north climatic gradient from the coastal zone to the
Sahelian and the vegetation species composition changes accordingly (van Rompaey,
1993; Bongers et al., 1999; Wieringa & Poorter, 2004). If studies on the relation between
ecological factors and vegetation are common, the relations between chorological catego-
ries and vegetation types have never been statistically examined in West Africa.
In the present paper, we describe the major vegetation types in Benin, analyse the cho-
rological differentiation of the flora within them and examine the relations between vege-
tation types and chorological categories; these relations are analysed in the light of
ecological factors and historical evidence.
II. STUDY AREA
The study was conducted in the Republic of Benin,
situated in West Africa between latitudes 6° 10’ N
and 12° 25’ N and longitudes 45’ E and 55’ E
(Fig. 1). Geologically, the southern part refers to the
West African continental terminal made of sedimen-
tary rock, while the central and northern sections
refer to the Precambrian shield made of granito-
gneissic rock. Four major groups of soils can be dis-
tinguished (Willaine & Volkoff, 1967): ferrallitic
soils covered by semi-deciduous forest, ferruginous
soils covered by dry forest, woodland and savannah,
vertisols soils in the depression of Lama covered by
a dry type of semi-deciduous forest and hydromor-
phic soils covered by swamp and riparian forests.
The mean annual rainfall varies from 900 to 1,300
mm. Its lowest values are recorded in the southwest
and in the far north (900-950 mm). The highest pre-
cipitation (1,200-1,300 mm) is confined to South-
222
Fig. 1.- Map of Benin showing the
study sites.
Fig. 1.- Carte du Bénin montrant
les sites d’étude.
Downloaded by [191.103.17.81] at 21:39 30 January 2016
eastern and Centre-western parts of the country. Three climate zones can broadly be dis-
tinguished (Adjanohoun et al., 1989; Akoègninou, 2004; Adomou, 2005):
- the Guinean zone: from the coast up to the latitude 7° N, the climate is Guinean with a
bimodal rainfall regime;
- the transition zone: between the latitudes 7° and 9° N, the climate is subsudanian with
a tendency to a unimodal rainfall regime;
- the Sudanian zone: characterised by a truly Sudanian climate with a unimodal rainfall
regime.
Southern Benin falls in the so-called Dahomey gap, which is the dry wedge that inter-
rupts the zonal West African rain forest belt and divides it into the upper Guinea and lower
Guinea/Congolian forest blocks (White, 1983; Ern, 1988; Jenik, 1994; Tossou, 2002). The
vegetation consists of savannahs, grasslands, farmlands and fallows intermingled with
small islands of closed forest.
III. MATERIALS AND METHOD
A. Data collection
The vegetation map of Benin (FAO/PNUD, 1980) was used as the basis for site selec-
tion. Aided by field experience of local botanists, we made a checklist of protected areas,
sacred forests and all unprotected areas hosting a tract of relatively undisturbed vegetation.
At each locality, we avoided vegetation plots with strong human interference in the choi-
ce of sites and placement of sample plots. Phytosociological relevés according to Braun-
Blanquet’s (1932) approach were carried out at sites hosting the major plant formations
(Fig. 1) such as mangrove, swamp forest, semi-deciduous forest, dry forest, riparian forest,
woodland and savannah (Aubréville, 1957). The geographical coordinates and altitude
were noted using a GPS (global positioning system). General information related to soil
conditions (texture, flooding, outcrops etc.) and topography (plateau, slope, and valley)
was noted. We visually estimated the cover of each species using the Braun Blanquet’s
cover/abundance scale (Westhoff & van der Maarel, 1978). In total 598 floristic relevés
were, in most cases, performed within quadrates of 30 x 30 m2, except in riparian forest
where rectangular plots of 50 x 10 m2were laid out. The number of relevés per plant for-
mation is as follows: mangrove: 2, swamp forest: 29, semi-deciduous forest: 176, dry
forest: 72, riparian forest: 133, and woodland & savannah: 186. Botanical nomenclature
was according to Keay & Hepper (1954-1972), updated by Lebrun & Stork (1991-1997).
B. Data analysis
Classification and ordination of vegetation samples
An abundance matrix consisting of 598 phytosociological relevés and 1021 plant spe-
cies was submitted to two-way indicator species analysis (Twinspan; Hill, 1979a) available
in the program package « Community analysis package (CAP) » (Pisces Conservation,
2002). This allowed the whole data set to be stratified into major vegetation types, each of
which was named after the two most differential species as singled out by Twinspan. We
elucidated the floristic relationships among vegetation types using the average linkage
clustering based on the Jaccard’s (1901) similarity index, defined as follows:
Pj= 100xc/(a+ b- c)
where Pjis the Jaccard’s community coefficient, cis the number of shared species between
communities to be compared, aand bare the number of species in each community. The
223
Downloaded by [191.103.17.81] at 21:39 30 January 2016
224
maximum value of Pj(100) indicates that the two compared vegetation types have the
same floristic composition; the minimum value (0) indicates that the two vegetation types
have no species in common.
We used detrended correspondence analysis (DCA) to explore the distribution patterns
of the described vegetation types based on species composition (Hill, 1979b). We used the
resulting vegetation type scores to elucidate the relationships between chorological cate-
gories, vegetation types and underlying environmental factors.
Chorological characterisation of plant communities
We used the publications of Keay & Hepper (1954-1972), White (1983) and Aké Assi
(2001, 2002) to determine the chorotype (i.e. range of distribution type) of each species.
The five main chorotypes used are as follows: GC Guineo-Congolian species, S Sudanian
species, SZ Sudano-Zambesian species, GC-S Guineo-Congolian/Sudanian transition spe-
cies, i.e. linking elements between the Guineo-Congolian and Sudanian regions, and Wd
species with wide distribution such as Cosmopolitan, Pantropical and Paleotropical. The
proportions of the various chorotypes were calculated using the species checklist compi-
led for each vegetation type. To characterise each vegetation type chorologically, we esta-
blished the phytogeographical index IP following Akpagana (1989), defined as follows:
IP = (S+ SZ)/GC
where Sis the proportion of Sudanian species within a vegetation type, SZ the proportion
of Sudano-Zambezian species and GC the proportion of Guineo-Congolian species. When
IP < 1, the vegetation type shows an affinity to the Guineo-Congolian region; when IP >
1, the vegetation type shows an affinity to the Sudanian region.
We examined the correlation among chorotypes (GC, S and SZ) using linear regression
analysis. The nature and strength of the relationship were assessed using Spearman’s rank
correlation (rS). The critical values for rSin our case (n= 20 vegetation types or degree of
freedom n-2 = 18) are 0.377 at p< 0.05 and 0.534 at p< 0.01.
IV. RESULTS
A. Vegetation types and their floristic relationships
The hierarchical clustering of the 598 vegetation samples and 1,021 plant species using
Twinspan and average linkage clustering (classification) resulted in five major clusters
subdivided into 20 vegetation types. Fig. 2 synthesises their floristic relationships and
Table I summarised their ecological and floristic characteristics.
B. Chorological spectrum of the vegetation types
Chorological affinities among vegetation types
Based on the values of the phytogeographical index IP, we distinguished two major
groups of vegetation types (Table II):
- vegetation types with IP < 1, include those showing an affinity to the Guineo-
Congolian region; these can be subdivided into two groups:
* vegetation types with IP < 0.2, expressing a strong affinity to the Guineo-Congolian
region,
* vegetation types with IP > 0.2, expressing affinity to the « Guineo-Sudanian » tran-
sition zone, i.e. the transition zone between the Guineo-Congolian and Sudanian
regions where the Guineo-Congolian elements prevail;
Downloaded by [191.103.17.81] at 21:39 30 January 2016
225
- vegetation types with IP > 1, includes those showing affinity to the Sudanian region;
these can be subdivided into two groups:
* vegetation types with IP < 4, showing affinity to the « Sudano-Guinean » transition
zone, i.e. the transition zone between the Guineo-Congolian and Sudanian regions
where the Sudanian elements prevail,
* vgetation types with IP > 4, showing a strong affinity to the Sudanian region.
The four chorological groups of vegetation types are geographically separated and cor-
respond to four different phytochorological zones (Fig. 3): the Guineo-Congolian region
(GCr), the « Guineo-Sudanian » transition zone (GStz), the « Sudano-Guinean » transition
zone (SGtz) and the Sudanian region (Sr). The GStz is chorologically close to the GCr,
while the SGtz is chorologically close to the Sr. There is a west-northern extension of the
GStz edging the SGtz. Riparian forest types such as Garcinia livingstonei-Vitex chryso-
carpa community and Synsepalum passargei-Broenadia salicina community are actually
situated in the Sudanian region, but express a chorological affinity to the « Sudano-
Guinean » transition zone. This can be explained by the presence of water, which allows
some Guineo-Congolian species to extend their ecological amplitude far inland.
Fig. 2.- Dendrogram summarising the floristic relationships among the 20 vegetation types.
Major clusters: I - Semi-deciduous forest (and mangrove), II - Dry semi-deciduous forest,
dry forest and associated riparian forest; III - Swamp forest, IV - Woodland, savannah
woodland, tree & shrub savannahs and associated riparian forest, V - Riparian forest in
dry savannah zone. See Table I for details on the clusters.
Fig. 2.- Dendrograme résumant les relations floristiques entre les types de végétation.
Principaux groupements : I - Forêt dense humide semi-décidue (et mangrove), II - Forêt
dense humide semi-décidue de type sec, forêt dense sèche et forêt galerie associée, III
- Forêt marécageuse, IV - Forêt claire, savanes boisée, arborée et arbustive, et forêt
galerie associée, V - Forêt galerie en zone de savane sèche. Voir Tableau I pour details
sur les groupements.
Downloaded by [191.103.17.81] at 21:39 30 January 2016
226
Table I.- Floristic and ecological characteristics of the 20 vegetation types described.
Tableau I.- Caractéristiques floristiques et écologiques des 20 communautés végétales
décrites.
Cluster Vegetation Plant formation & Rainfall (mm/year) Soil types
(Fig. 2) types the 2 most abundant species and rainfall regime
Te-Pi: Terminalia superba- Semi-deciduous forest: Piptadeniastrum - 1200-1300 Deep, ferrallitic
Piptadeniastrum africanum africanum, Parkia bicolor - bimodal (temporarily flooded)
Rh-Av: Rhizophora racemosa- Mangrove: Rhizophora racemosa, - 1200 Halomorphic (saline)
Avicennia germinans Avicennia germinans - bimodal on sedimentary rock
Tr-Ce: Triplochiton scleroxylon- Semi-deciduous forest: Triplochiton - 1100-1200 Deep, ferrallitic
ICeltis zenkeri scleroxylon, Celtis spp. - bimodal
Dr-Ne: Drypetes aframensis- Semi-deciduous forest: Nesogordonia - 1100 Shallow, ferrallitic
Nesogordonia papaverifera papaverifera, Mansonia altissima - bimodal on sedimentary rock
Chr-Bar: Chrysobalanus icaco- Semi-deciduous forest: Dialium - 1100-1200 Sandy (coastal)
Barteria nigritana guineense, Chrysobalanus icaco - bimodal
Mi-Cy: Mimusops andongensis- Semi-deciduous forest: Dialium - 1100 Vertisols
Cynometra megalophylla guineense, Diopyros mespiliformis - bimodal
Cy-Pa: Cynometra megalophylla- Riparian forest: Cynometra - 1200 Hydromorphic on
Parinari congensis megalophylla, Pterocarpus santalinoides - trend to unimodal crystalline rock
(riparian)
Kh-Au: Khaya grandifoliola- Semi-deciduous forest: Cola - 1250 Shallow, ferrallitic
Aubrevillea kerstingii gigantea, Celtis zenkeri - trend to unimodal on crystalline rock
Co-Kh: Cola gigantea- Khaya Riparian forest: Pterocarpus - 1250 Shallow, ferrallitic
grandifoliola santalinoides, Cola gigantea - trend to unimodal on crystalline rock
(hydromorphic)
II An-Lec : Anogeissus leiocarpa- Dry forest: Anogeissus - 1100-1200 Ferruginous on
Lecaniodiscus cupanioides leiocarpa, Diospyros mespiliformis - trend to unimodal crystalline rock
Hi-Ap: Hildegardia barteri- Dry forest: Hildegardia - 1100 Ferruginous (boulder
Aphania senegalensis barteri, Ceiba pentandra - trend to unimodal meanders in
rocky place)
An-Anch: Anogeissus leiocarpa- Dry forest: Anogeissus - 1050 Ferruginous on
Anchomanes welwitschii leiocarpa, Diospyros mespiliformis - unimodal crystalline rock
III Mi-La: Mitragyna ledermannii- Swamp forest: Syzygium - 1100-1200 Hydromorphic on
Lasiomorpha senegalensis owariense, Xylopia rubescens - bimodal sedimentary rock
Sy-Br: Synsepalum passargei- Riparian forest: Synsepalum passargei - 1100 Poorly evolved soil
Broenadia salicina -Broenadia salicina - unimodal with raw minerals
(hydromorphic)
Iso-Ch: Isoberlinia doka- Woodland & savannah - 1100 Ferruginous on
Chromolaena odorata woodland: Isoberlinia doka - unimodal crystalline rock
IV Iso-Br: Isoberlinia spp.- Woodland & savannah woodland: - 1100-1200 Ferruginous on
Bridelia ferruginea Isoberlinia doka, I. tomentosa - unimodal crystalline rock
Iso-Hae: Isoberlinia spp.- Woodland & savannah woodland: -1000-1100 Poorly evolved soil
Haematostaphis barteri Isoberlinia doka, I. tomentosa - unimodal with raw minerals
Iso-Co: Isoberlinia spp.- Woodland & savannah woodland: - 1050 Ferruginous on
Combretum glutinosum Isoberlinia spp, Combretum glutinosum - unimodal crystalline rock
Al-Bal: Albizia chevalieri- Shrub savannah: Combretum spp, - 975 Ferruginous on
Balanites aegyptiaca Albizia chevalieri - unimodal sedimentary rock
Ga-Vi : Garcinia livingstonei- Riparian forest: Garcinia - 975 Ferruginous on
VVitex chrysocarpa livingstonei, Vitex chrysocarpa - unimodal sedimentary rock
(hydromorphic)
Downloaded by [191.103.17.81] at 21:39 30 January 2016
227
Fig. 3.- Phytogeographical map of
Benin showing the main chorologi-
cal zones. GCr: Guineo-Congolian
region, GStz: « Guineo-
Sudanian » transition zone, SGtz:
« Sudano-Guinean » transition
zone, and Sr: Sudanian region.
Fig. 3.- Carte phytogéographique du
Bénin montrant les principales
zones chorologiques. GCRr :
région guinéo-congolaise, GStz :
zone de transition « guinéo-sou-
danienne », SGtz : zone de transi-
tion « soudano-guinéenne » et Sr:
région soudanienne.
Fig. 4.- Relationships among chorotypes. A and B:
highly significant negative relationships bet-
ween GC and S or SZ; C: highly significant posi-
tive relationship between S and SZ. The best-fit
regression line, equation, coefficient of determi-
nation (R2), Spearman’s rank correlation coeffi-
cient (rS), and significance level are given.
Fig. 4.- Relations entre types chorologiques. A et
B : relations négatives très significatives entre
GC et S ou SZ ; C : relation positive très signifi-
cative entre S et SZ. Le meilleur ajustement,
l’équation, le coefficient de détermination (R2),
le coefficient de correlation de Spearman (rS) et
le seuil de probabilité sont précisés.
Downloaded by [191.103.17.81] at 21:39 30 January 2016
228
Correlation between chorotypes
Fig. 4 pictures highly significant linear relations between the proportions of Guineo-
Congolian species (GC), Sudanian (S), and Sudano-Zambezian (SZ) elements. This indi-
cates that the regression equations are good predictors of the variations observed.
C. Phytogeographical gradient and underlying factors
The DCA of the 20 described vegetation types and 1,021 plant species shows a major
indirect floristic factor (axis 1), which seems to be correlated to climate (Fig. 5). The axis
scores (0.61 for axis 1 and 0.29 for axis 2) indicate that the axis 1 explains the major varia-
tion in species composition. Along this axis, we distinguish four clusters of vegetation
types, which correspond to the four phytochorological groups described in Table II using
the phytogeographical index IP. Thus, the DCA strengthens the chorological analysis
using IP and highlights the correlation between vegetation types and chorological catego-
ries. The floristic change along the axis 1 is better elucidated by the highly significant cor-
relation between this axis and the proportion of Guineo-Congolian (GC) species or
Sudanian species (S and SZ) (Fig. 6 a, b). More explicitly, from the left hand side to the
Fig. 5.- DCA ordination of 20 vegetation types and 1,021 plant species in Benin, showing
four clusters of vegetation types. The axis 1 and 2 explain 61% and 29% of the total varia-
tion, respectively. GCr: vegetation types showing affinity to the Guineo-Congolian region,
GStz: vegetation types showing affinity to the « Guineo-Sudanian » transition zone, SGtz:
vegetation types showing affinity to the « Sudano-Guinean » transition zone and Sr:
vegetation types showing affinity to the Sudanian region; *: Riparian forest types. The
average value of IP for each cluster is indicated between brackets.
Fig. 5.- Ordination (DCA) de 20 communautés végétales et 1 021 espèces végétales au
Bénin, montrant quatre groupes. Les axes 1 et 2 expliquent respectivement 61% et 29%
de la variation totale. GCr : communautés végétales ayant une affinité avec la région gui-
néo-congolaise, GStz : communautés végétales ayant une affinité avec la zone de tran-
sition « guinéo-soudanienne », SGtz : communautés végétales ayant une affinité avec la
zone de transition « soudano-guinéenne » et Sr : communautés végétales ayant une affi-
nité avec la région roudanienne; * : communautés végétales de forêt galerie. La valeur
moyenne de IP pour chaque groupe est précisée entre parenthèses.
Downloaded by [191.103.17.81] at 21:39 30 January 2016
229
Fig. 6.- Relationship between the first DCA axis scores (indicating the largest variability in
species composition) and chorotype proportions. a: proportion of Guineo-Congolian spe-
cies, b: proportion of Sudanian and Sudano-Zambezian species (S and SZ). The best-fit
regression line, coefficient of determination (R2), Spearman’s rank correlation coefficient
(rS) and significance level are given.
Fig. 6.- Relations entre l’axe 1 de la DCA (indiquant la plus grande variabilité en composi-
tion spécifique) et les chorotypes. a : proportion des espèces guinéo-congolaises, b : pro-
portion des espèces soudaniennes et soudano-zambéziennes (S et SZ). Le meilleur
ajustement, l’équation, le coefficient de détermination (R2), le coefficient de correlation de
Spearman (rS) et le seuil de probabilité sont précisés.
Table II.- Chorological spectrum of the 20 described vegetation types. N: species richness,
GC: Guineo-Congolian species, GC-S: Guineo-Sudanian transition species, S: Sudanian
species, SZ: Sudano-Zambezian species, Wd: widespread species, IP: phytogeographi-
cal index, Ph-Zone: phytochorological zone (GCr: Guineo-Congolian region, GStz:
« Guineo-Sudanian » transition zone, SGtz: « Sudano-Guinean » transition zone et Sr:
Sudanian region); *: riparian forest types.
Table II.- Spectre chorologique des 20 communautés végétales décrites. N : richesse spé-
cifique, GC : espèces guinéo-congolaises, GC-S : espèces de la zone de transition gui-
néo-soudanienne, S : espèces soudaniennes, SZ : espèces soudano-zambéziennes,
Wd : espèces à large distribution, IP : index phytogéographique, Ph-Zone: zone phyto-
chorologique (GCr : région guinéo-congolaise, GStz : zone de transition « guinéo-sou-
danienne », SGtz : zone de transition « soudano-guinéenne » et Sr : région soudaniene) ;
*: communautés végétales de forêt galerie.
%
Vegetation types N GC GC-S S SZ S+ SZ Wd IP Ph-zone
Mitragyna ledermannii-Lasiomorpha senegalensis 121 79 11 01110 0.01 GCr
Rhizophora racemosa-Avicennia germinans 85 72 12 11214 0.03 GCr
Terminalia superba-Piptadeniastrum africanum 368 80 10 13460.05 GCr
Chrysobalanus icaco-Barteria nigritana 178 71 14 13411 0.06 GCr
Drypetes aframensis-Nesogordonia papaverifera 179 72 13 14511 0.07 GCr
Triplochiton scleroxylon-Celtis zenkeri 329 72 14 246 80.08 GCr
Mimusops andongensis-Cynometra megalophylla 151 70 10 5510 10 0.14 GCr
Cynometra megalophylla-Parinari congensis* 207 56 16 6 11 16 12 0.29 GStz
Khaya grandifoliola-Aubrevillea kerstingii 241 55 17 7 11 18 10 0.33 GStz
Cola gigantea- Khaya grandifoliola* 264 47 20 7 11 17 16 0.36 GStz
Hildegardia barteri-Aphania senegalensis 135 41 19 10 12 22 18 0.54 GStz
Anogeissus leiocarpa-Lecaniodiscus cupanioides 203 43 17 9 16 26 14 0.6 GStz
Anogeissus leiocarpa-Anchomanes welwitschii 197 28 25 16 15 31 16 1.11 SGtz
Synsepalum passargei-Broenadia salicina* 341 26 21 16 26 42 11 1.62 SGtz
Garcinia livingstonei-Vitex chrysocarpa* 93 22 23 18 22 40 16 1.82 SGtz
Isoberlinia doka-Chromolaena odorata 213 15 24 17 29 46 15 3.07 SGtz
Isoberlinia spp.-Bridelia ferruginea 231 14 23 20 30 50 13 3.57 SGtz
Isoberlinia spp.-Combretum glutinosum 232 6 22 25 31 56 16 9.33 Sr
Isoberlinia spp.-Haematostaphis barteri 157 7 18 29 38 66 9 9.43 Sr
Albizia chevalieri-Balanites aegyptiaca 238 5 24 22 31 53 18 10.60 Sr
Downloaded by [191.103.17.81] at 21:39 30 January 2016
230
right hand side of this axis (Fig. 5), the importance of the Guineo-Congolian species
decreases (negative correlation), while the proportion of « Sudanian and Sudano-
Zambezian » elements increases (positive correlation). This fact corroborates the hypothe-
sis that this axis reflects a climatic gradient with decreasing humidity from the left to the
right. Thus, the axis 1 can be regarded as carrying a chorological gradient associated with
a vegetation gradient determined by a climatic gradient. The riparian forest types turn out
to be well separated along this floristic gradient suggesting the influence of climate on their
species composition and spatial distribution. Two groups can be distinguished (Fig. 5):
- the Cola gigantea-Khaya grandifoliola (Co-Kh) and Cynometra megalophylla-
Parinari congensis (Cy-Pa) communities showing chorological affinity to the « Guineo-
Sudanian » transition zone;
- the Synsepalum passargei-Broenadia salicina (Sy-Br) and Garcinia livingstonei-Vitex
chrysocarpa (Ga-Vi) communities expressing chorological affinity to the « Sudano-
Guinean » transition zone.
The position (outlier) of the Rhizophora racemosa-Avicennia germinans (Rh-Av, mangro-
ve) and Mitragyna ledermannii-Lasiomorpha senegalensis (Mi-La, swamp forest) com-
munities in the ordination space reflects their strong azonal behaviour (Fig. 5).
V. DISCUSSION
Our chorological zonation established using statistical tools largely overlaps with that pre-
viously made in Benin (Adjanohoun et al., 1989; Akoègninou, 2004) and in neighboring
countries such as Togo (Ern, 1979) and Nigeria (Keay, 1953). However, a number of points
need to be emphasised on.
Southern Benin is phytogeographically referred to as part of the Dahomey gap, which
is the savannah corridor that separates the West African rain forest belt into the upper
Guinea and lower Guinea/Congolian forest blocks (White, 1983; Ern, 1988; Jenik, 1994).
However, many studies showed that the climax vegetation of southern Benin (from the
coast up to latitude 30’ N) is a semi-deciduous forest of « Triplochiton-Celtis type »
(Paradis, 1983; Sokpon, 1995; Akoègninou, 2004), which corresponds to the dry periphe-
ral semi-evergreen rain forest of the regional Guineo-Congolian phytochorion (Guillaumet
& Adjanohoun, 1971; White, 1983). The dominance of the Guineo-Congolian species as
revealed by the chorological analysis corroborates this fact, which is supported by earlier
local studies (Adjanohoun et al., 1989; Sokpon, 1995; Akoègninou, 2004) and numerical
analyses of African plant distribution patterns (Linder, 1998). Lake sediment records from
southern Benin showed that during early-mid Holocene (8,500-4,000 years BP), the low-
land rain forest was represented by a continuous semi-evergreen forest dominated by
Triplochiton scleroxylon Schum. and Celtis spp. (Tossou, 2002; Salzmann & Hoelzmann,
2005). The current semi-deciduous forest islands can be considered as relics from the sub-
sequent dry period of late Holocene (4,000-3,000 years BP), during which the semi-ever-
green forest would have contracted to just a few suitable areas such as river banks.
The transition zone between the Guineo-Conglian and Sudanian regions as established
in this paper is in agreement with what has been observed at regional scale, where the
forest-savannah transition zone occurs at latitudes 8-9° N (Gautier & Spichiger, 2004). It
also fulfils the basic criterion of the forest-savannah boundary in West Africa, which is
interpreted as a transitional belt of varying width, where Guineo-Congolian and Sudanian
floras coexist and compete (Spichiger, 1975). The distinction between the « Guineo-
Downloaded by [191.103.17.81] at 21:39 30 January 2016
231
Sudanian » transition zone and the « Sudano-Guinean » transition zone has already been
made in the phytogeographical subdivision of Cameroon (Letouzey, 1985; van der Zon,
1992). The southern part of the « Guineo-Sudanian » transition zone (GStz) falls within the
Guinea-Congolia/Sudania regional transition zone, which is characterised by the dry semi-
deciduous forest dominated by Hildegardia barteri (Mast.) Kosterm., Diospyros mespili-
formis Hochst. ex DC. and Pouteria alnifolia (Bak.) Rob. (White, 1983; Adjanohoun et al.,
1989). The climax vegetation of the west-northern part of the GStz (Fig. 3) was assumed
to be a dry semi-deciduous forest floristically similar to the Khaya grandifoliola-
Aubrevillea kerstingii community as described in Ivory Coast and Ghana (Guillaumet &
Adjanohoun, 1971; Hall & Swaine, 1981). At first sight, it is difficult to say that this nor-
thern extension is either a consequence of the present climatic (annual rainfall of 1,200-
1,300 mm) and pedological (fairly deep ferrallitic soil) conditions or an indication of
quaternary climatic changes. But, a thorough analysis of the flora reveals that populations
of many Guineo-Congolian species such as Khaya grandifoliola DC., Aubrevillea kerstin-
gii (Harms) Pellegr., Erythrophleum suaveolens (Guill. & Pierr.) Brenan and Pentadesma
butyracea Sab. are confined to this part of the country. This fact substantiates the hypo-
thesis that the flora of this area have originated from the upper Guinea forest block using
the Togo mountains as route of dispersion during the humid periods of quaternary clima-
tic changes (Aubréville, 1937; Guillaumet, 1967; Adjanohoun et al., 1989; Akpagana,
1989; Akoègninou et al., 2002; Akoègninou, 2004; Adomou, 2005). The high proportion
of Guineo-Congolian species (> 40%) observed in riparian forest types of the GStz can be
an indication of a former floristic connection with the Guineo-Congolian zone (Wild,
1968).
Our results highlight the highly predictive value of vegetation types with regard to cho-
rological categories and ecological factors (Lausi & Nimis, 1985). This is corroborated by
the strongly significant relation between the first DCA-axis scores interpreted as carrying
a climatic or humidity gradient and the chorological categories. Furthermore, the results
underline the strength of the criteria set in the use of the phytogeographical index IP,
which is simply coined on purpose to have a single value expressing the variation in the
proportions of Guineo-Congolian, Sudanian and Sudano-Zambesian elements (Akpagana,
1989). The four chorological groups of vegetation types distinguished on the basis of IP
turn out to be similar to the four clusters of vegetation types derived from the DCA ordi-
nation. Thus, the proposed phytochorological map (Fig. 3) can be regarded as a synthesis
reflecting the vegetation, chorological and climatic patterns in Benin. This phytochorolo-
gical map largely overlaps the climatic map established by Akoègninou (2004). Therefore,
it should be taken into account along with the associated vegetation types in biodiversity
conservation and management plans. When responses of plant species and community to
environment are understood, their occurrence can be predicted based on environmental
data only (Hall & Swaine, 1976).
VI. CONCLUSION
The highly significant relations between the proportions of the various chorotypes indica-
te that their non-random distribution and the regression equations are good predictors. The
strong correlation between the first DCA-axis and chorological categories highlights the
highly predictive value of vegetation type with regard to chorological categories and eco-
logical factors. The proposed phytochorological map should be regarded as a synthesis
Downloaded by [191.103.17.81] at 21:39 30 January 2016
232
reflecting the vegetation, chorological and climatic patterns in Benin. It should be taken
into account along with the associated vegetation types in biodiversity conservation plan-
ning.
Acknowledgements - This research, in the framework of the Project Flora of Benin, was supported by the
Netherlands government grant under the project contract number Bj 003407. We are grateful to O. Joseph and E.
Ewèdgè for the GIS mapping. The manuscript was critically read and commented on by Dr. P. Ketner.
REFERENCES
Adejuwon J.O., 1971.- Savannah patches within forest
areas in Western Nigeria: a study of the dynamics of
forest-savannah boundary. Bull. Inst. Fond. Afr. Noire,
série A, 33, 327-344.
Adjanohoun E.J., V. Adjakidjè, M.R.A. Ahyi, L. Aké Assi,
A. Akoègninou, J. d’Almeida, F. Apovo, K. Boukef, M.
Chadare, G. Cusset, K. Dramane, J. Eyme, J.-N.
Gassita, N. Gbaguidi, E. Goudote, S. Guinko, P.
Houngnon, L.O. Issa, A. Keita, H.V. Kiniffo, D. Kone-
Bamba, A. Musampa Nseyya, M. Saadou, Th.
Sodogandji, S. de Souza, A. Tchabi, C. Zinsou Dossa
& Th. Zohoun, 1989.- Contribution aux études ethno-
botaniques et floristiques en République populaire du
Bénin. Agence de coopération culturelle et technique,
Paris, 895 p.
Adomou A.C., 2005.- Vegetation patterns and environ-
mental gradient in Benin: implications for biogeogra-
phy and conservation. PhD thesis, Wageningen
University, the Netherlands, 136 p.
Aké Assi L., 2001.- Flore de la Côte-d’Ivoire: catalogue
systématique, biogéographie et écologie, I. Boissiera,
57, 1-396.
Aké Assi L., 2002.- Flore de la Côte-d’Ivoire: catalogue
systématique, biogéographie et écologie, II.
Boissiera, 58, 1-401.
Akoègninou A., 2004.- Recherches botaniques et écolo-
giques sur les forêts actuelles du Bénin. Thèse d’État,
Université de Cocody-Abidjan, 326 p.
Akoègninou A., G.C. Houndagba, M.G. Tossou, J.P.
Essou & K. Akpagana, 2002.- La végétation d’une
zone de transition entre la forêt dense humide semi-
décidue et les savanes : la région de Bantè (Bénin,
Afrique de l’Ouest). J. Bot. Soc. Bot. Fr., 15, 99-108.
Akpagana K., 1989.- Recherche sur les forêts denses
humides du Togo. Thèse Doctorat d’État, Université
de Bordeaux 3, 181 p.
Aubréville A., 1937.- Les forêts du Dahomey et du Togo.
Bull. Com. Et. Hist. Sc. A.O.F., 20, 1-112.
Aubréville A., 1957.- Accord à Yangambi pour la nomen-
clature des types africains de végétation. Bois et
Forêts Trop., 51, 22-27.
Bongers F., R.S.A.R. van Rompaey & M.P.E. Parren,
1999.- Distribution of twelve moist forest canopy tree
species in Liberia and Côte d’Ivoire: response curves
to a climatic gradient. J. Veg. Sci., 10, 371-382.
Braun-Blanquet J., 1932.- Plant sociology: the study of
plant communities. McGraw Hill, New York and
London, 439 p.
Ern H., 1979.- Die Vegetation Togos. Gliederung,
Gefährdung, Erhaltung. Willdenowia, 9, 295-312.
Ern H., 1988.- Flora and vegetation of the Dahomey
Gap. A contribution to the plant geography of West
tropical Africa. Ann. Missouri Bot. Gard., 25, 520-571.
FAO/PNUD, 1980.- Projet pilote sur la surveillance conti-
nue de la couverture forestière tropicale. Bénin, carto-
graphie du couvert végétal et étude de ses
modifications. FAO, Rome, 75 p.
Gautier L. & R. Spichiger, 2004.- The forest-savanna
transition in West-Africa. In: Biodiversity of West
African forests: an ecological atlas of woody plants
species. L. Poorter, F. Bongers, F.N’. Kouamé & W.D.
Hawthorne (eds), CABI Publishing, Oxon, UK and
Cambridge, USA, 33-40.
Guillaumet J.L., 1967.- Recherches sur la végétation et
la flore de la région du Bas-Cavally (Côte-d’Ivoire).
Mém. ORSTOM, 20, 247 pp.
Guillaumet J.L. & E. Adjanohoun, 1971.- La végétation
de la Côte-d’Ivoire. In: Le milieu naturel de la Côte-
d’Ivoire. J.M. Avenard, E. Eldin, G. Girard, J.
Sircoulon, P. Touchebeuf, J.L. Guillaumet, E.
Adjanohoun & A. Perraud (eds), Mém. ORSTOM, 50,
156-263.
Hall J.B. & M.D. Swaine, 1976.- Classification and eco-
logy of closed canopy forest in Ghana. J. Ecol., 64,
913-951.
Hall J.B. & M.D. Swaine, 1981.- Distribution and ecology
of vascular plants in a tropical rain forest: forest vege-
tation in Ghana. Geobotany, 1, 1-383.
Hill M.O., 1979a.- Twinspan, a Fortran program for
arranging multivariate data in an ordered two way
table by classification of individual and attributes.
Cornell University, Ithaca, N. Y., 90 p.
Hill M.O., 1979b.- Decorana, a Fortran program for
detrended correspondence analysis and reciprocal
averaging. Cornell University, Ithaca, N.Y., 52 p.
Jaccard P., 1901.- Distribution de la flore alpine dans le
bsasin des Dranes et dans quelques régions voisines.
Bull. Soc. Vaudoise Sci. Nat., 37, 241-272.
Jenik J., 1994.- The Dahomey Gap: an important issue
in African phytogeography. Mém. Soc. Biogéogr., 3e
série, IV, 125-133.
Keay R.W.J., 1953.- Isoberlinia woodlands in Nigeria
and their flora. Lejeunia, 16, 17-26.
Keay R.W.J. & F.N. Hepper (eds.), 1954-1972.- Flora of
West Tropical Africa, 2nd edition, I (828 p.), II (544 p.),
III (574 p.). Millbank, London, UK.
Lausi D. & P.L. Nimis, 1985.- Quantitative phytogeogra-
phy of the Yukon Territory (NW Canada) on a choro-
logical-phytosociological basis. Vegetatio, 59, 9-20.
Lebrun J.P. & A.L. Stork, 1991-1997.- Énumération des
plantes à fleurs d’Afrique tropicale, 4 volumes.
Conservatoire et jardin botaniques de la ville de
Downloaded by [191.103.17.81] at 21:39 30 January 2016
233
Genève.
Letouzey R., 1985.- Notice de la carte phytogéogra-
phique du Cameroun au 1:500 000. 5 documents et 6
cartes. Inst. Carte Intern. Vég., Toulouse, France.
Linder H.P., 1998.- Numerical analyses of African plant
distribution patterns. In: Chorology, taxonomy and
ecology of the floras of Africa and Madagascar. C.R.
Huxley, J.M. Lock & D.F. Cutler (eds), Royal Botanical
Gardens, Kew, 67-86.
Meave J. & M. Kellman, 1994.- Maintenance of rain
forest diversity in riparian forests of tropical savannas:
implications for species conservation during
Pleistocene drought. J. Biogeogr., 21, 121-135.
Natta A.K., 2003.- Ecological assessment of riparian
forests in Benin. Phytodiversity, phytosociology and
spatial distribution of tree species. PhD thesis,
Wageningen University, 215 p.
Paradis G., 1983.- Phytogeographic survey of southern
Benin. Bothalia, 14 (3-4), 579-585.
Pisces Conservation Ltd, 2002. Community analysis
package (CAP), a program to search for structure in
ecological community data, version 2.0. Pennington,
UK.
Salzmann U. & P. Hoelzmann, 2005.- The Dahomey
Gap: an abrupt climatically induced rain forest frag-
mentation in West Africa during the late Holocene.
The Holocene, 15 (2), 190-199.
Sokpon N., 1995.- Recherches écologiques sur la forêt
dense semi-décidue de Pobè au sud-est du Bénin:
Groupements végétaux, structure, régénération natu-
relle et chute de litière. Thèse Doctorat, Université
libre de Bruxelles, 350 p.
Spichiger R., 1975.- Contribution à l’étude du contact
entre flores sèche et humide sur les lisières des for-
mations forestières humides semi-décidues du V-
Baoulé et de son extension nord-ouest (Côte-d’Ivoire
centrale). Thèse d’État, Université de Genève, 261 p.
Swaine M.D., 1992.- The influence of fire on savannah
vegetation at Kpong, Ghana. Biotropica, 24, 166-172.
Tossou M.G., 2002.- Recherche palynologique sur la
végétation H olocèn e du Sud-Béni n (Afrique de
l’Ouest). Thèse, Université de Lomé, Togo, 136 p.
van der Zon A.P.M., 1992.- Graminées du Cameroun, I -
Phytogéographie et pâturages. Wageningen
Agricultural University Papers, 92 (1), 1-86.
van Rompaey R.S.A.R., 1993.- Forest gradients in West
Africa: a spati al gradient analysis. PhD Thesis,
Wageningen Agricultural University, the Netherlands,
142 p.
Westhoff V. & E. van der Maarel, 1978.- The Braun-
Blanquet approach. In: Classification of plant commu-
nities. R.H. Whittaker (ed.), Junk, The Hague,
287-399.
White F., 1983.- The vegetation of Africa, a descriptive
memoir to accompany the UNESCO/AETFAT/UNSO.
Natural Resources Research, 20, 1-356.
Wieringa J.J. & L. Poorter, 2004.- Biodiversity hotspots in
West Africa: patterns and causes. In: Biodiversity of
West African Forests: an ecological atlas of woody
plants species. L. Poorter, F. Bongers, F.N’. Kouamé
& W.D. Hawthorne (eds), CABI Publishing, Oxon, UK
and Cambridge, USA, 61-72.
Wild H., 1968.- Phytogeography of South Central Africa.
Kirkia, 6, 197-222.
Willaine P. & B. Volkoff, 1967.- Carte pédologique du
Dahomey à l’échelle de 1/1000 000. ORSTOM, Paris,
France.
Downloaded by [191.103.17.81] at 21:39 30 January 2016
... Several types of soil were found in southern Benin whose vertisols at the experimental site. The vegetation consists of savannahs composed of several strata dominated by Daniella laxiflora and Parkia biglobosa (Adomou et al., 2007). ...
Article
Full-text available
The scarlet eggplant (Solanum aethiopicum L.) is an African traditional vegetable grown for its edibles leaves and fruits, which can contribute to food security in Republic of Benin. However, very little information is available on the genetic variability of this vegetable for varietal improvement purposes. Sixty accessions of scarlet eggplants collected throughout 52 villages in Benin republic were characterized using 34 (10 qualitative and 24 quantitative) variables. The experiment was laid out using complete randomized block design with three replications on the experimental site of Massi. The Principal Component Analysis (PCA) analysis revealed 18 discriminating quantitative variables. A strong correlation was observed between plant height, number of fruits per plant, fruit diameter, fruit weight and number of seeds per fruit. A cluster phenogram divided the 60 accessions into three groups corresponding to Kumba (Cluster 1), Gilo (Cluster 2), and Shum groups (Cluster 3). These groups differed by the number of seeds per fruit, weight of fruits, diameter of fruits, number of fruits per plant, plants height at flowering stage, plants length, and plant width. Accessions Samibi, Ikangougou, Kannan and Yètchanmiyé with the highest fruit weight per plant can be used as parents in the framework of a scarlet eggplant breeding program in Republic of Benin.
... However, goats are known to be more likely to valorize a large range of tree and shrub leaves (Camacho et al. 2010). In addition, there should be differences in woody plants found in different vegetation zones (Adomou et al. (2007), which surely affect the diversity of forage trees used by goats. ...
Article
Full-text available
In order to identify the most promising browse species for sustaining goat production, the nutritional characteristics of leaves of trees and shrubs and their use in farmers’ feeding strategies were assessed in sub-humid areas of Benin. Two hundred and forty (240) goat farmers were surveyed and their uses of different leaves of trees and shrubs for supplementing their goats documented in two vegetation zones, namely the Sudano-Guinean and Guineo-Congolese zones. Then, samples of 32 leaves were collected at the end of rainy season in October–November, just before the long dry season and analyzed for their chemical composition, in vitro digestibility, and tannin content. Principal component and cluster analyses were performed to identify homogenous groups of leaves on the basis of their nutritional characteristics. Free grazing on natural perennial grasses with supplementation with leaves of trees and shrubs was the main goat feeding practice during the dry season in both zones. Agro-processing by-products were used as feed supplements mainly in the Guineo-Congolese zone. Most of the leaves of trees and shrubs elicited by the surveyed goat farmers had a crude protein content higher than 15%, sufficient for their use as feed supplements. However, this potential could be limited by their high tannin content. One non-native (Gliricidia sepium) and five native shrub species (Ficus thonningii, Antiaris africana, Phyllanthus discoideus, Morinda lucida, Mallotus oppositifolius) were identified as the most promising for supplementing goats during dry season in both zones. Our study was useful in identifying some underutilized and neglected leaves of trees and shrubs that could be recommended to smallholder goat farmers in agroforestry systems for enhancing animal productivities in small-scale farms.
... Southern Benin has a subequatorial climate with two rainy seasons and two dry seasons of unequal length. The region is characterized by a rain fall gradient from 900 mm in the West to 1300 mm in the East (Adomou et al., 2007). The mean annual rainfall is 1200 mm. ...
... L'étude a été réalisée dans les départements de l'Ouémé et du Plateau au Sud-Est du Bénin. Dans ces deux départements qui ont une frontière commune avec le Nigéria (Figure 1), le climat est subéquatorial à quatre saisons : 2 saisons pluvieuses et 2 saisons sèches (Akoègninou et al., 2004), la pluviométrie varie entre 900 mm et 1300 mm par an et le sol est majoritairement ferralitique (Adomou et al., 2007). Dans le département de l'Ouémé, 3 communes à savoir Adjohoun, Bonou et Dangbo ont été choisies sur les neuf que compte le département tandis que dans le département du plateau où il y a cinq communes, ce sont les communes d'Adja-Ouèrè, Pobè et Kétou qui ont été retenues ( Figure 1). ...
Article
Full-text available
Procreation has been and continues to be today the fundamental reason for marriage in Africa since immemorial time. Infertility of the couple is seen as a fatality that it seeks to fight at all costs for a good part of his life. To know the recipes used in Benin to treat female infertility, a survey was undertaken towards the traditional healers and resource persons in the departments of Ouémé and Plateau in South of Benin Republic. On the whole, 93 traditional healers and resource persons were surveyed. This is an ethnobotanical sample survey which has permitted to identify the causes of female infertility and 123 recipes in which involved 90 plant species belonging to 86 genera and 47 families, the most represented being Leguminosae (10%), Euphorbiaceae (6.67%), Annonaceae (5.55%). The organs of species such as Afromomum melegueta, Allium cepa, Baphia nitida, Carissa spinarum, Elaeis guineensis, Garcinia kola, Kigelia africana, Monodora myristica, Mrinda lucida, Musa sapientum, Olax subscorpioidea, Pupalia lappacea, Tetrapleura tetraptera, Pterocarpus erinaceus, Xylopia aethiopica are the most cited in the recipes. These plants contribute to relieve several infertile couples and deserve to be protected for posterity. Keywords: Infertility, recipes, traditional healers, resource persons, South of Benin.
... The vegetation is dominated by savanna with gallery forests along waterways in the Sudanian (9˚30'-12˚N) and Sudano-Guinean (7˚30'-9˚30 N) regions and by agricultural lands, remnant Guinean savanna with small patches of semi-deciduous forests and sacred groves in the Guineo-Congolian region (6˚-7˚30 N). There is an ecological gradient from the southern Guineo-Congolian region to the northern Sudanian region [24]. The Sudano-Guinean region with annual rainfall of 1100-1300 mm and the annual temperature of 25-29˚C and less mean annual insolation (2420 h) is wetter than the Sudanian region with mean annual rainfall, temperature and insolation of 900-1100 mm, 24˚C-31˚C and 2660 h respectively [25]. ...
Article
Full-text available
Non-timber forest products (NTFPs) are widely harvested by local people for their livelihood. Harvest often takes place in human disturbed ecosystems. However, our understanding of NTFPs harvesting impacts in fragmented habitats is limited. We assessed the impacts of fruit harvest, and reduction in habitat size on the population structures of Pentadesma butyracea Sabine (Clusiaceae) across two contrasting ecological regions (dry vs. moist) in Benin. In each region, we selected three populations for each of the three fruit harvesting intensities (low, medium and high). Harvesting intensities were estimated as the proportion of fruits harvested per population. Pentadesma butyracea is found in gallery forests along rivers and streams. We used the width of gallery forests as a measure of habitat size. We found negative effects of fruit harvest on seedling and adult density but no significant effect on population size class distribution in both ecological regions. The lack of significant effect of fruit harvest on population structure may be explained by the ability of P. butyracea to compensate for the negative effect of fruit harvesting by increasing clonal reproduction. Our results suggest that using tree density and population structure to assess the ecological impacts of harvesting clonal plants should be done with caution.
... The vegetation is dominated by savanna with gallery forests along waterways in the Sudanian (9˚30'-12˚N) and Sudano-Guinean (7˚30'-9˚30 N) regions and by agricultural lands, remnant Guinean savanna with small patches of semi-deciduous forests and sacred groves in the Guineo-Congolian region (6˚-7˚30 N). There is an ecological gradient from the southern Guineo-Congolian region to the northern Sudanian region [24]. The Sudano-Guinean region with annual rainfall of 1100-1300 mm and the annual temperature of 25-29˚C and less mean annual insolation (2420 h) is wetter than the Sudanian region with mean annual rainfall, temperature and insolation of 900-1100 mm, 24˚C-31˚C and 2660 h respectively [25]. ...
Article
Full-text available
Studies on the ecological impacts of non-timber forest products (NTFP) harvest reveal that plants are often more resilient to fruit and seed harvest than to bark and root harvest. Several studies indicate that sustainable fruit harvesting limits can be set very high (>80% fruit harvesting intensity). For species with clonal and sexual reproduction, understanding how fruit harvest affects clonal reproduction can shed light on the genetic risks and sustainability of NTFP harvest. We studied 18 populations of a gallery forest tree, Pentadesma butyracea (Clusiaceae), to test the impact of fruits harvest, climate and habitat size (gallery forest width) on the frequency of sexual or clonal recruitment in Benin, West Africa. We sampled populations in two ecological regions (Sudanian and Sudano-Guinean) and in each region, we selected sites with low, moderate and high fruit harvesting intensities. These populations were selected in gallery forests with varying width to sample the natural variation of P. butyracea habitat size. Heavily harvested populations produced significantly less seedlings but had the highest density and proportion of clonal offspring. Our study suggests that for plant species with dual reproductive strategy (via seeds and clonal), fruit harvesting and associated disturbances that come with it can lead to an increase in the proportion of clonal offspring. This raises the issue that excessive fruit harvest by increasing the proportion of clonal offspring to the detriment of seed originated offspring, may lead to a reduction in genetic diversity with consequence on harvested species capability to withstand environmental stochasticity.
... Les différentes communautés végétales ont été caractérisées sur la base de leur indice phytogéographique (Ip) (Adomou et al., 2007) : Ip = (S + SZ)/GC, avec S : le nombre d'espèces soudaniennes, SZ : le nombre d'espèces soudano-zambéziennes et GC : le nombre d'espèces guinéocongolaises. Lorsque Ip < 1, la flore humide est dominante, par contre la flore sèche est dominante si Ip > 1. ...
Article
Full-text available
Objective: The objective of this study is to identify the plant species and to characterize the vegetation of the Ouoghi forest reserve in the commune of Savè (Center-Benin). Method and results: Floristic and forest inventories were carried out through 144 relevés in according to the Braun-Blanquet method. A total of 246 plant species were identified. They belong to 178 genera and 63 families. Multivariate analyzes with the Community Analysis Package (CAP) software made it possible to individualize 3 vegetation formations comprising 8 plant groups. This is the shrub savannah with Prosopis africana and Pennisetum polystachion, the tree savannah with Hymenocardia acida and Pennisetum polystachion, the tree savannah to Vitellaria paradoxa and Pennisetum polystachion, the tree savannah to Pterocarpus erinaceus and Hyptis suaveolens, the woodland savannah with Daniellia Oliveri and Chromolaena odorata, the woodland savannah at Isoberlinia doka and Pennisetum polystachion, the woodland savannah at Daniellia oliveri and Andropogon tectorum and the tree flood savannah to Daniellia oliveri and Leersia hexandra. The floristic and structural parameters change from one group to another. Thus, the specific richness varies from 49 to 153 species and the diversity of families is between 22 and 49 with a predominance of Leguminosae. The density varies from 95 to 275 stems / ha, basal area from 2.35 to 8.44 m² / ha. Conclusion and application of results: The study evaluated the floristic diversity of the Ouoghi reserve. In addition, it indicated the need for its integral protection for its dynamics towards dry dense forest vegetation. Sustainable management of this site needs implication of local population.
... La végétation au Bénin est à peu près divisée en 10 districts phytogéographiques (régions homogènes floristiques) basés sur des facteurs écologiques (climat, sol, géologie utilisation des terres) et des événements historiques (ie dernières fluctuations climatiques au cours de l'Holocène) (Adomou et al., 2006 Boko, 1983). Les précipitations moyennes annuelles est d'environ 1000-1300 mm (dans le sud), 900-1100 mm (dans la zone de transition) et 750-900 mm (dans la plus au nord). ...
Article
Full-text available
This study examined the diversity and ecological distribution of riparian bird species across a climatic gradient in Benin. Riparian bird communities were compared among three climatic zones in Benin Republic from December 2012 to November 2015. The diversity and ecological distribution of riparian bird was examined from a census (inventory) of birds in forests galleries across the three climatic zones in Benin by means of a technique of sampling of limited (punctual) type centred on no listening of 20 minutes in a circular plot of 18 m of beam. A total of 140 species richness belonging to 18 orders and 44 families were recorded across climatic zones. The highest (73) species richness were recorded in Guinean zone, followed by Soudanean zone (70) and Soudano – guinean zones, the lowest (68). Similarly, species diversity was highest in Soudanean zone (H’=5.77 bits) and lowest in Soudano – guinean zone (4,28 bits). But we have a significant difference in species diversity between the study climatic zones, but relative abundance of bird are not differed between zones. Further, diverse bird guilds were recorded varying across the climatic gradients indicating the riparian forest conservation importance. Increasing farmland severs more suitable habitats with dire consequences on the survival of disturbance – sensitive bird species. These researches underpin the need for considering integrated bird conservation strategies and are important for planning local ecotourism activities and to protect riparian forest in Benin.
Article
Full-text available
In this work, we conducted a 1200 km belt transect for field survey in typical and meadow steppes across Inner Mongolia Plateau in 2018. The field investigation, laboratory soil analysis, and quantitative ecology methods were utilized to explore the differentiation characteristics of the plant community, and their relationships with ecological factors. The results showed that a total of 140 vascular plants within 108 quadrats mainly comprised of Asteraceae, Poaceae, Rosaceae, and Fabaceae. Two-way Indicator Species Analysis (TWINSPAN) revealed eight vegetation typologies: I: Stipa sareptana var. krylovii + Dysphania aristata, II: Stipa grandis + Leymus chinensis, III: Stipa sareptana var. krylovii + Leymus chinensis, IV: Stipa grandis + Cleistogenes squarrosa, V: Stipa grandis + Carex duriuscula, VI: Stipa baicalensis + Leymus chinensis, VII: Carex pediformis + Stipa baicalensis, VIII: Leymus chinensis + Elymus dahuricus. Detrend Correspondence Analysis (DCA) confirmed the above eight vegetation typologies and indicated a relatively small variation. Redundancy analysis (RDA) revealed that the spatial differentiation characteristics in the typical steppe were chiefly driven by precipitation, while the influencing factor in the meadow steppe was soil nutrients, followed by temperature and precipitation. The contrast between typical and meadow steppes revealed that the spatial distribution of typical steppe was influenced by precipitation, while the contribution of heat and water in the meadow steppe was equal. The conclusion revealed that the temperature and precipitation conditions coupled with soil nutrients shaped the spatial differentiation characteristics of temperate steppe vegetation in the Inner Mongolia grassland. Therefore, this study advanced our knowledge of the spatial patterns of temperate steppe along longitude and latitude gradients, providing scientific and theoretical guidance for the biodiversity conservation and sustainable ecosystem management of the Inner Mongolia grassland.
Article
Full-text available
Southern Benin has a dry subequatoriai climate with a rainfall gradient from 850 mm in the west to 1 500 mm in the east, the geomorphology is varied and the vegetation has been subjected to strong human influence. There are numerous plant formations, namely: 1, forest islands which are probably relics of the primitive vegetation and include (a) dense semi-deciduous forests of several types, (b) swamp forests of two types, (c) periodically flooded forest of two types, (d) Lophira lanceolata (Hutchinson & Dalziel, 1954-72) woodlands and (e) mangrove swamps; 2, formations which are probably derived and include (a) thickets of several types, (b) tree savannas and shrub savannas, (c) grassy savannas and prairies varying according to soil characteristics and (d) halophytic grasslands; and 3, floating vegetation on fresh-water lakes.