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Corresponding author: Alfred Houngnon ( quenh77@gmail.com ) Academic editor: Thomas L.P. Couvreur
© 2021 Alfred Houngnon, Aristide C. Adomou, William D. Gosling, Peter A. Adeonipekun.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Houngnon A, Adomou AC, Gosling WD, Adeonipekun PA (2021) A checklist of vascular plants of Ewe-Adakplame Relic Forest in Benin, West Africa. PhytoKeys 175: 151-174. https://doi.org/10.3897/phytokeys.175.61467
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Covering 560.14 hectares in the south-east of Benin, the Ewe-Adakplame Relic Forest (EARF) is a micro-refugium that shows insular characteristics within the Dahomey Gap. It is probably one of the last remnants of tropical rain forest that would have survived the late Holocene dry period. Based on intensive field investigations through 25 plots (10 × 50 m size) and matching of herbarium specimens, a checklist of 185 species of vascular plant belonging to 54 families and 142 genera is presented for this forest. In addition to the name for each taxon, we described the life form following Raunkiaer’s definitions, chorology as well as threats to habitat. The Rubiaceae family was the richest (20 species) followed by the Fabaceae (15 species). Life forms showed the preponderance of phanerophytes (88%). The Chorological spectrum was dominated by Guineo-Congolean species (66%). Species richness estimated were 200.52 ± 9.2808 for Bootstrap; 217.62 ± 14.5972; 224.16 ± 15.3725 and 242.67 respectively for Chao, Jacknife1 and Jacknife2. Bootstrap appears to be the estimation closer to the field records. In Benin, EARF is home for Rinorea species described as West African forest bio-indicators and single location for Nesogordonia papaverifera, Mansonia altissima, Englerophytum oblanceolatum, Octolobus spectabilis, Vitex micrantha and most of Drypeteae tribe species (Drypetes aframensis, Drypetes afzelii, Drypetes gilgiana and Drypetes leonensis) recorded in Benin. Our results provides baseline information for further in-depth analysis of vegetation history in Benin by raising the question on the past floristic connection of the Dahomey gap and community engagement in conservation.
Dahomey Gap, Flora, Kétou, Range-restricted species, Refugial
At the continental level, African rain forests, primarily those of the Guineo-Congolean block, are the main centres of species diversity (
However in Benin, most of these remaining forest patches, although playing the role of a high conservation priority area for heritage plants, are still experiencing severe threats due to the lack of adequate conservation strategies (
In this context, floristic details on EARF may be very useful for conservation purposes through restoration and rehabilitation of degraded land with native trees. Such information is necessary for further studies in biogeography and phylogeny on the one hand, to address the main speciation models and mechanisms that may apply across tropical Africa (
This paper aims to provide a comprehensive checklist of vascular plants occurring in EARF that will serve as baseline for understanding the history of this vegetation over millennia. By exploring the floristic composition of EARF, we can better appreciate the biogeographic status of some species previously reported by
The EARF covers 560.14 hectares in the Kétou District in the south-east of Benin Republic at 07°27'59.195"N, 002°34'29.395"E (Fig.
The mean annual rainfall in the EARF is between 900–1300 mm (
Location | 6°25–7°30N |
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Annual rainfall | 900–1100 mm |
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Rainfall trend | Bimodal |
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Rainy season(s) | March–July & September–October |
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Dry season | August and November–February |
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Temperature | 24–37 °C |
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Insolation | 2135 h |
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Relative humidity | 78–95% |
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Climate type | Sub-equatorial |
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Length of plant growing season | 240 days |
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Vegetation | Mosaic of Savanna |
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Soil types | Ferralitic soils without concretion |
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Altitude | 200–286 m above sea level |
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The inventory of EARF plant species was conducted from February 2014 to December 2017. The forest investigation was based on a vegetation map divided into 250,000 m2 (500 × 500 m) grids following 6 transects, each of 500 m width and 3000 m length. Transects were oriented south-north. The floristic sampling covered different components of the EARF (Fig.
The Angiosperm Phylogeny Group (
Life forms assessment followed
The Chorology types were established after
The data underpinning the analysis reported in this paper are deposited in the Dryad Data Repository at https://doi.org/10.5061/dryad.z8w9ghxbg (
Fig.
Vascular plants of Ewe-Adapklame relict forest in Benin with their binomial, family life-forms and Chorotypes [Life-forms are meg: megaphanerophyte (> 30 m tall), mes: mesophanerophyte (8–30 m), mph: microphanerophyte (2–8 m), nph: nanophanerophyte (0.5–2 m); Ch: chamaephyte, Hc: hemicryptophyte; Th: therophyte; G: geophyte (Gb: with bulb, Gr: with rhizome and Gt: with tuber); Ep: epiphyte and their climbing forms L: liana (Lmph, Lnph and Lmes, LGr, LHc) and chorotypes are GC: Guineo-Congolean, SG: Sudano/Guinean transition, GE: Lower Guinean, GO: Upper Guinean, TA: Tropical Africa, AM: Afro-Malagasy and Pan: Pantropical].
Scientific name | Life forms | Chorology types | Voucher specimens |
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Acanthaceae | |||
Rhinacanthus virens var. virens | Ch | GC | Houngnon 3860 |
Amaranthaceae | |||
Cyathula prostrata (L.) Blume | Th | Pan | Houngnon 3383 |
Amaryllidaceae | |||
Scadoxus multiflorus subsp multiflorus | Gb | TA | Houngnon 6724 |
Anacardiaceae | |||
Lannea nigritana var. nigritana | mes | GO | De Souza 1971 a |
Spondias mombin L. | mes | Pan | Maesen 7705 |
Annonaceae | |||
Artabotrys dahomensis Engl. & Diels. | Lnph | GE | Houngnon 97e |
Artabotrys velutinus Sc. Elliot | Lnph | GC | Maesen 6612 |
Monanthotaxis parvifolia (Oliv.) Verdc. | Lnph | GE | Houngnon s.n. |
Monodora tenuifolia Benth. | mph | GC | Éq. Bot. 105d |
Uvariodendron angustifolium (Engl. & Diels) R.E.Fr | mph | GC | Houngnon 5571 |
Uvariopsis tripetala (Baker f.) G.E.Schatz Syn. Dennettia tripetala Baker f. | mph | GE | Akoègninou 2201 |
Xylopia longipetala De Wild. & T. Durand | mph | GC | Houngnon 4524 |
Apocynaceae | |||
Alafia barteri Oliv. | Lmph | GC | Chevalier 22841 |
Ancylobotrys scandens (Schumach. & Thonn.) Pifchon | Lmph | GC | Chevalier 23456 |
Baissea zygodioides (K. Schum.) Stapf | Lmph | GC | Houngnon 118c |
Cryptolepis nigrescens (Wennberg) L. Joubert & Bruyns Syn. Parquetina nigrescens (Afzel.) Bullock | Lmph | GC | Le Testu 297 |
Holarrhena floribunda (G. Don) Dur. & Schinz | mph | TA | Houngnon 6574 |
Hunteria umbellata (K. Schum.) Hall. f. Syn. H. eburnea Pichon | mph | GC | Aké Assi 20284 |
Landolphia hirsuta (Hua) Pichon | Lmes | GC | Chevalier 23922 |
Marsdenia latifolia (Benth.) K. Schum., | Lmph | TA | Akoègninou 5438 |
Mondia whitei (Hook. f.) Skeels | Lmph | TA | Adjakidjè 3007 |
Motandra guineensis (Thonn.) A. DC. | Lmph | TA | Adjanohoun 102 |
Saba thompsonii (A. Chev.) Pichon | Lmes | GC | Chevalier 22967 |
Secamone afzelii (Schultes) K. Schum. | Lmph | GC | Essou 3208 |
Araceae | |||
Anchomanes difformis (Blume) Engl. (Syn. A. welwitschii Rendle) | Gt | GC | Essou 1554 |
Cercestis mirabilis (N. E. Br.) Bogner Syn. Rhektophyllum mirabile N.E.Br. | Ep | GE | Akoègninou 3299. |
Aristolochiaceae | |||
Pararistolochia goldieana (Hook. f.) Hutch. & Dalz. | LGr | GC | Houngnon 4605 |
Asparagaceae | |||
Dracaena arborea Bak | mph | GC | Maesen 6340 |
Asteraceae | |||
Chromolaena odorata (L.) R. King & H. Robinson | nph | AM | Sokpon B14 |
Gymnanthemum coloratum (Willd.) H. Rob. & B.Kahn | mph | SZ | Ayichédéhou 395 |
Laggera crispata (Vahl) Hepper & J. R. I. Wood. | Th | TA | Maesen 6746 |
Bignoniaceae | |||
Newbouldia laevis (P. Beauv.) Seem. ex Bureau | mph | GC | Houngnon 3087 |
Boraginaceae | |||
Ehretia cymosa Thonn. | mph | GC | Houngnon 5081 |
Cannabaceae | |||
Celtis mildbraedii Engl. | mes | GC | Essou 1648 |
Celtis philippensis Blanco Syn. C. brownii Rendle | mph | GC | Houngnon 2783 |
Celtis zenkeri Engl. | meg | GC | Sokpon 852 |
Trema orientalis Syn. T. guineensis | mph | GC | Houngnon 1714d |
Capparaceae | |||
Capparis brassii DC. Syn. C. thonningii Schum. | Lnph | GC | Maesen 6701 |
Capparis erythrocarpos var. erythrocarpos | nph | GC | Esson 1087 |
Maerua duchesnei (De Wild.) F. White Syn: Ritcheia duchesnei (De Wild.) Keay | mph | GC | Houngnon 229a |
Ritchiea capparioides var. capparoides | Lnph | GC | Houngnon 4200 |
Ritchiea erecta Hook. f. Syn. R. pentaphylla Gilg & Bened. | nph | GE | Aké Assi 20288 |
Celastraceae | |||
Loeseneriella africana var. africana Syn. Hippocratea Africana (Willd.) Loes. | Lmph | Pan | Houngnon 6573 |
Reissantia indica (Willd.) N. Hallé | Lnph | Pan | Akoègninou 4026 |
Salacia longipes (Oliv.) N. Hallé | nph | TA | Akoègninou 3291 |
Salacia pallescens Oliv. | nph | GC | Sokpon 2221 |
Simicratea welwitschii (Oliv.) Syn. S. welwitschii (Oliv.) N. Hallé | Lmph | GC | Essou 1467 |
Combretaceae | |||
Combretum racemosum P. Beauv. | Lmph | GC | Le Testu 191 |
Commelinaceae | |||
Cyanotis lanata Benth. | Ch | SG | Morton A4570 |
Connaraceae | |||
Cnestis ferruginea Vahl ex DC. | nph | GC | Houngnon 3051 |
Cnestis corniculata Lam. Syn. Cnestis longiflora Schellenb. | Lmph | GO | Chevalier 22828 |
Rourea coccinea (Bak.) Jongkind syn. Byrsocarpus coccineus Thonn. & Schumach. | nph | TA | Chevalier 22798b |
Convolvulaceae | |||
Calycobolus africanus (G. Don) heine | Lnph | GC | Adjakidjè 4111 |
Ipomoea mauritiana Hall. f. | Lmph | Pan | Oumorou 740 |
Cucurbitaceae | |||
Coccinia grandis (L.) Voigt | Lnph | GC | De Souza & Paradis 444a |
Lagenaria breviflora (Benth.) Roberty Syn. Adenopus breviflorus Benth. | Lmes | TA | Houngnon 443a, 1518a |
Luffa cylindrica (L.) M. J. Roem syn. Luffa aegyptiaca Mill | Lnph | Pan | Houngnon 453a |
Momordica charantia L. | Lnph | GC | Houngnon 1676 |
Dichapetalaceae | |||
Dichapetalum madagascariense Poir. Syn. D guineense (DC.) Keay | Lmph | GC | Adomou 95 |
Tapura fischeri Engl. | mph | GC | Houngnon 1878a |
Dioscoreaceae | |||
Dioscorea bulbifera L. var. bulbifera | Gt | Pan | Essoun 3316 |
Dioscorea lecardii De Wild. | Gt | SZ | Pauwels 8139 |
Dioscorea odoratissima Pax Syn. D. praehensilis sensu F.T.A, F.W.T.A | Gt | SG | Chevalier 24154 |
Dioscorea quartiniana A. Rich. | Gt | SZ | Sokpon 2329 |
Dioscorea sagittifolia Pax syn. D. abyssinica Hochst. ex Kunth | Gt | SZ | Paradis et Houngnon: 619d |
Ebenaceae | |||
Diospyros abyssinica (Hiern) White | mes | GC | Houngnon 627b |
Diospyros monbuttensis Gürke | mph | GC | Houngnon 629c |
Diospyros soubreana F. White | nph | GC | Houngnon 2824 |
Euphorbiaceae | |||
Erythrococca anomala (Juss. ex Poir.) Prain | nph | GC | Houngnon 3345 |
Mallotus oppositifolius var. oppositifolius | nph | AM | Adjakidjè & Akoègninou 590c |
Tragia senegalensis Müll. Arg. | Lnph | SG | Adjakidjè 2803 |
Fabaceae | |||
Caesalpinoideae (Mimosoid clade) | |||
Acacia pennata (L.) Willd. | Lmph | TA | Essou 1672 |
Acacia polyacantha subsp. Campylacantha (Hochst. ex A. Rich.) Brenan | mes | SZ | Maesen 6703 |
Albizia adianthifolia var. adianthifolia | mes | GC | Adjakidjè 4163 |
Albizia glaberrima (Schum. & Thonn.) Benth. | mph | GC | Houngnon 6532 |
Albizia ferruginea (Guill. & Perr.) Benth. | mes | GC | Paradis & Houngnon 933a |
Albizia zygia (DC.) J. F. Macbr. | mes | GC | Houngnon 936d |
Mezoneuron benthamianum (Baill.) Herend. & Zarucchi | Lmph | GC | Paradis & Houngnon 277c |
Detarioideae | |||
Detarium senegalense J.F. Gmel. | mes | GC | Houngnon 268e |
Dialioideae | |||
Dialium guineense Willd. | mes | GC | Spire 118 |
Faboideae / Papilionoideae | |||
Abrus precatorius L. | Lnph | Pan | Houngnon 1423g |
Dalbergia lactea Vatke | Lmph | GE | De Souza & Paradis 1239e |
Dalbergia melanoxylon Guill. Perr. | mph | SG | Adomou 167 |
Desmodium salicifolium var. salicifolium | nph | GC | Frahm-Leliveld 57139 |
Dolichos trilobus | Lnph | SZ | Adomou 80 |
Millettia thonningii (Schum. & Thonn.) Bak. | mph | GC | Essou 1164 |
Icacinaceae | |||
Stachyanthus occidentalis (Keay & Miège) Boutique syn. Neostachyanthus occidentalis Keay & Miège | Lnph | GO | Essou 1102 |
Lamiaceae | |||
Clerodendrum capitatum (Willd.) Schum. & Thonn. | Lmph | GC | Lisowski 0-929 |
Hoslundia opposita Vahl | nph | AM | Pauwels 8286 |
Premna quadrifolia Schum. & Thonn. | nph | GO | Sokpon 1068 |
Vitex micrantha Gürke* | mes | GC | Adomou s.n. |
Linaceae | |||
Hugonia platysepala Welw. ex Oliv. | Lmph | GC | Paradis & Houngnon 831a |
Loganiaceae | |||
Strychnos barteri Soler. | Lmes | GC | Paradis & Houngnon 838a |
Strychnos floribunda Gilg | Lmes | GC | Maesen 6821 |
Strychnos nigritana Bak. | Lmes | GC | Akoègninou 3289 |
Strychnos splendens Gilg | Lmes | GC | Houngnon 835b |
Malvaceae | |||
Abutilon mauritianum (Jacq.) Medic. | Ch | TA | De Souza & Paradis 851a |
Ceiba pentandra (L.) Gaertn. | meg | Pan | Houngnon 188a |
Hibiscus lunariifolius Willd. | Lmph | Pan | Adomou s.n. |
Hibiscus owariensis P. Beauv. | nph | GC | Paradis et Houngnon 856a |
Cola milfenii K. Schum. | mph | GC | Houngnon 4399 |
Glyphaea brevis (Spreng.) Monachino | mph | GC | Houngnon 2036e |
Grewia carpinifolia Juss. | mph | GC | Houngnon 1446f |
Mansonia altissima var. altissima* | mes | GC | Houngnon 1309a ; 4322 |
Nesogordonia papaverifera (A. Chev.) syn N. kabengaensis (K.Schum.)* | mph | GC | Houngnon 13l0a |
Octolobus spectabilis Welw. Syn. O. angustatus Hutch.* | nph | GC | Adomou s.n. |
Pterygota macrocarpa K. Schum *. | mph | GC | Houngnon 4321 |
Sterculia tragacantha Lindl. | mes | GC | De Souza & Houngnon 188d |
Triplochiton scleroxylon K. Schum. | meg | GC | Chevalier 22819 |
Melastomataceae | |||
Memecylon afzelii G. Don var. afzelii | Lnph | GC | Houngnon 897c |
Warneckea memecyloides (Benth.) Jac. Fél Syn. Memecylon memecyloides (Benth) | Lmph | GC | De Souza & Paradis 900a |
Meliaceae | |||
Trichilia prieureana subsp. prieureana | mph | GC | Adomou 90 |
Menispermaceae | |||
Dioscoreophyllum cumminsii (Stapf) Diels | Lnph | GC | Houngnon 919a |
Rhigiocarya racemifera Miers | Lnph | GC | Maesen 6820 |
Tiliacora funifera (Miers) Oliv. | Lmph | GC | De Souza 92li |
Triclisia subcordata Oliv. | Lnph | GC | Sokpon 31 |
Moraceae | |||
Antiaris toxicaria Lesch. | meg | GC | Essou 1547 |
Ficus recurvata De Wild. Syn. Ficus goliath A. Chev. | mes | GC | Adomou s.n. |
Ficus ovata Vahl, | Ep | GC | Adomou s.n. |
Milicia exelsa (Welw.) Berg Syn. Chlorophora excelsa (Welw.) benth. | meg | GC | Chevalier 23169 |
Olacaceae | |||
Olax subscorpioidea var. subscorpioidea | mph | GC | Houngnon 7652 |
Oleaceae | |||
Schrebera arborea A. Chev. | mes | GC | Akoègninou 2187 |
Opiliaceae | |||
Opilia amentacea Roxb. Syn. O. celtidifolia (Guill. & Perr) Endl., | Lmph | SZ | Adjakidjè 1477 |
Pandaceae | |||
Microdesmis keayana J. Léonard, syn. M. puberula Hook. f. | mph | GC | Pauwels 8298 |
Passifloraceae | |||
Adenia cynanchifolia (Benth.) Harms | Lmph | GE | Adomou s.n. |
Adenia lobata (Jacq.) Engl. | Lmph | GC | Essou 1637 |
Phytolaccaceae | |||
Hilleria latifolia (Lam.) H. Walt. | Ch | AM | Adomou 129 |
Poaceae | |||
Acroceras gabunense (Hack.) Clayton* | Th | GC | Mission ACCT/Bénin 2165 |
Olyra latifolia L. | nph | GC | Houngnon 720c |
Oplismenus hirtellus subsp. Hirtellus | Ch | SG | De Souza & Paradis 722a |
Streptogyna crinita P. Beauv. | Gr | GC | Houngnon 765b |
Polygalaceae | |||
Carpolobia lutea G. Don | mph | GC | Maesen 6617 |
Putranjivaceae | |||
Drypetes aframensis Hutch.* | mph | GO | Adomou s.n. |
Drypetes afzelii (Pax) Hutch.,* | mes | GO | Houngnon 177 la |
Drypetes floribunda (Müll. Arg.) Hutch. | mph | GC | Houngnon 4266 |
Drypetes gilgiana (Pax) Pax & Hoffm.* | nph | GC | Akoègninou 2196 |
Drypetes leonensis Pax,* | mes | GC | Houngnon 1771b |
Rhamnaceae | |||
Lasiodiscus mannii Hook. f. | mph | GC | Houngnon 1329b |
Rubiaceae | |||
Aidia genipiflora (DC.) Dandy | mph | GC | Maesen 6611 |
Chassalia kolly (Schumach.) Hepper | nph | GC | Maesen 6358 |
Coffea ebracteolata (Hiern) Brenan | Lnph | GC | Lejoly&Ganglo 2 |
Cremaspora triflora (Thonn.) K. Schum. | Lmph | GC | Maesen 6284 |
Leptactina involucrata Hook. f. | Lnph | GC | Adomou s.n. |
Gardenia nitida Hook. | mph | GC | Adomou 73 |
Hymenodictyon floribundum (Steud. & Hochst.) B.L.Rob. | mes | GC | Sinsin 2863 |
Keetia hispida (Benth.) Bridson | Lmph | GC | Adomou s.n. |
Morinda lucida Benth. | mph | Pan | Maesen 6651 |
Oxyanthus pallidus Hiern | nph | GC | Adomou s.n. |
Oxyanthus speciosus subsp. speciosus | nph | GC | Essou 2496 |
Pavetta corymbosa (DC.) F. N. Williams | mph | SG | Sokpon 1884 |
Pouchetia africana DC. | nph | GC | Houngnon 6659 |
Psydrax horizontalis (K. Schum. & Thonn.) Bridson | Lmph | SG | Maesen 6710 |
Psydrax parviflora (Afzel.) Bridson | nph | GO | Maesen 6287 |
Rothmannia longijlora Salisb | mph | GC | Le Teslu 101 |
Rothmannia urcelliformis (Hiern) Bullock ex Robyns | mph | GC | Dansi TW 50799 |
Rytigynia canthioides (Benth.) Robyns | mph | GC | Adomou s.n. |
Vangueriella nigerica (Robyns) Verdc. Syn. Vangueriopsis nigerica Robyns | mph | SZ | Maesen 6315 |
Vangueriella spinosa (Schumach.&Thonn.)Verdc. Syn. Vangueriopsis spinosa Hepper | mph | SZ | Adomou 32 |
Rutaceae | |||
Zanthoxylum leprieurii Guill. & Perr. Syn. Fagara angolensis Engl. | mph | GC | Houngnon 535a |
Zanthoxylum zanthoxyloides (Lam.) Zepernick & Timber | mph | SG | Essou 2396 |
Salicaceae | |||
Dovyalis zenkeri Gilg (+) Syn. D. afzelii Gilg. (+) | nph | GO | Houngnon 1364a |
Flacourtia indica (Burm. f.) Merr. Syn. Flacourtia flavescens Willd. | mph | GC | Houngnon 6606 |
Sapindaceae | |||
Allophylus africanus P. Beauv. | mph | GC | Houngnon 4037 |
Allophylus spicatus (Poir.) Radlk. | mph | GC | Houngnon 4037 |
Blighia sapida Koenig | mPh | Pan | Houngnon 5472 |
Blighia unijugata Bak. | mph | GC | Paradis & Houngnon 1693d |
Deinbollia pinnata (Poir.) Schumach. & Thonn. | nph | GC | Maesen 6397 |
Lecaniodiscus cupanioides Planch. | mph | GC | Maesen 6310 |
Majidea forsteri (Sprague) Radlk. | meg | GC | Houngnon 1254a |
Pancovia bijuga Willd. | mph | GC | Houngnon 4978 |
Sapotaceae | |||
Chrysophyllum welwitschii Engl.* (+) | Lnph | GC | Adomou s.n. |
Englerophytum oblanceolatum (S.Moore) T.D.Penn. syn. Bequaertiodendron oblanceolatum* (S.Moore) Heine & J. H. Hemsl. | nph | TA | Maesen 6154 |
Pouteria alnifolia (Baker) Roberty Syn. Malacantha alnifolia (Baker) | mph | GC | Sokpon 1915 |
Smilacaceae | |||
Smilax anceps Willd.Syn. S. kraussiana Meissner | LGr | TA | Chevalier 24225 |
Solanaceae | |||
Solanum terminale Forssk. Subsp inconstans (C.H. Wright) Heine | Lmph | GC | Yédomonhan 173 |
Ulmaceae | |||
Chaetachme aristata Planch. | mph | GC | Houngnon 1784c |
Violaceae | |||
Rinorea batesii Chipp, Kew Bull. 293 (1923). | nph | GC | Adomou 83 |
Rinorea brachypetala (Turcz.) Kuntze | nph | GC | Adomou s.n. |
Rinorea dentata (P.Beauv.) Kuntze | mph | GC | Houngnon |
Rinorea ilicifolia (Welw. ex Oliv.) Kuntze * | nph | GC | Adomou 109 |
Rinorea kibbiensis Chipp. | nph | GC | Paradis & Houngnon 1347a |
Vitaceae | |||
Cissus glaucophylla Hook. f. | Lnph | GC | Adomou s.n. |
Cissus petiolata Hook. f. | Lnph | GC | Adjakidjè 2976 |
Cissus populnea var. populnea | LHc | SZ | Houngnon 68d |
Cissus quadrangularis L. | Lmph | SZ | Houngnon 5105 |
Common species of Ewe-Adakplame Relict Forest A Drypetes gilgiana (Photo of Alfred Houngnon 2017) B Triplochiton scleroxylon (Samsung photo A. Houngnon 2017) C Englerophytum oblanceolatum (Olympus photo A.
The most common life forms were phanerophytes (88%), containing, 3% of mega phanerophytes (meg) which are very large forest trees, 14% of mesophanerophytes (mes) or medium-sized forest trees, 43% of microphanerophytes (mph) or small forest trees and 28% of shrubs gathered into nanophanerophytes (nph). We recorded 33% of lianas, 6% of geophytes and 6% for chamaephyte, therophyte, epiphyte, hemicryptophyte (Fig.
Life form spectrum of the Ewe-Adakplame relict forest. Erects are represented by Ph: Phanerophytes including megaphanerophytes (meg), mesophanerophytes (mes), microphanerophytes (mph), nanophanerophytes (nph), G: Geophytes are: Gb: with bulb, Gr: with rhizome and Gt: with tuber Ch: Chamaephytes, Th: Therophytes, Ep: Epiphytes, Hc: Hemicryptophytes. Climbing forms are L: Lianas (mph, nph and mes, Gr, Hc).
The most representative chorotypes (Fig.
The counted number of plant species for the EARF was 185. This corresponds to the species richness (S) or the number of species that has been recorded from plot sampling and listed in Table
The Ewe-Adakplame Relict Forest corresponds to the semi-deciduous forest type, which was described in Benin as the only Drypetes aframensis-Nesogordonia papaverifera community (
Unlike
The connection of EARF with the West African forests blocks located on both side of the Dahomey Gap is emphasized here by the high proportion of Guineo-Congolean species recorded (66%). The high rate of phanerophytes and their phytochories testifies to the floristic originality of EARF in a crop and savanna dominated landscape. This justifies the physiognomic and floristic links of EARF with the two Guinean and Congolia forest blocks and substantiates the hypothesis that EARF is a remnant of the dense forests which were once a continuous block from west to central Africa as demonstrated by numerous palynological studies (
In contrast, the surrounding vegetation at the immediate edge of EARF is composed of savanna species (Fig.
Species collected in the surrounding zone of Ewe-Adakplame Relict Forest A Adansonia digitata (Samsung photo A.
In total, we counted thirteen species restricted to one site in EARF. This is higher than the nine species previously reported by
Some of these species found in the single location of EARF within Benin (e.g., Acroceras gabunense, Chrysophyllum welwitschii, Dovyalis afzelii, Drypetes aframensis, Drypetes gilgiana, Englerophytum oblanceolatum, Mansonia altissima, Nesogordonia papaverifera, Octolobus spectabilis, Pterygota macrocarpa, Rinorea ilicifolia, Rinorea kibbiensis and Vitex micrantha) may gain more attention in the National Red List (
The importance of the flora of EARF testifies to its role in conserving forest biodiversity in the Dahomey gap corridor. This justifies its peculiarity and the relevance of this baseline vegetation information that could be used as complete range taxa that may allow us to test the forest refuge hypothesis against alternative speciation models across ecological gradients. As it happens, the management of the forest of this type, also raises the question of deepening interactions linking human environment in order to better understand the actual role that humans would have played in shaping ecosystems in the Dahomey gap since millennia. So, it would be interesting to understand the interplay between locals and EARF in order to explain its persistence in this savanna dominated landscape. Therefore, the actions to be considered following this checklist of EARF must take into account the community’s engagement in rehabilitating the degraded lands inside and around EARF.
We are grateful to the Rufford Foundation for financial field assistance and the University of Amsterdam for the publication fees. We thank especially François Romazzotti and Professeur Angel Argiles for their assistance and the local communities of Ewe and Adakplame villages for their collaboration. The authors thank David Goyder, Kolawolé V. Salako and Thomas Couvreur for their contribution and their constructive comments that improved substantially the quality of this paper.