Plant Ecology and Evolution 152(1): 8-29, doi: 10.5091/plecevo.2019.1547
Mine versus Wild: a plant conservation checklist of the rich Iron-Ore Ngovayang Massif Area (South Cameroon)
expand article infoVincent Droissart, Olivier Lachenaud§, Gilles Dauby|, Steven Dessein, Gyslène Kamdem#, Charlemagne Nguembou K.#, Murielle Simo-Droissart#, Tariq Stévart¤, Hermann Taedoumg#, Bonaventure Sonké¤
‡ Institut de Recherche pour le Développement, Montpellier, France§ Botanic Garden Meise, Nieuwelaan 38, 1860 Meise, Belgium| AMAP Lab, IRD, CIRAD, CNRS, INRA, Université de Montpellier, Montpellier, France¶ Meise Botanic Garden, Domein van Bouchout, Nieuwelaan 38, BE-1860 Meise, Belgium# Plant Systematics and Ecology Laboratory, Higher Teachers’ Training College, University of Yaoundé I, P.O. Box 047, Yaoundé, Cameroon¤ Missouri Botanical Garden, Africa and Madagascar Department, P.O. Box 299, St. Louis, Missouri 63166-0299, United States of America
Open Access
Abstract

Background and aims – The rapid expansion of human activities in South Cameroon, particularly mining in mountainous areas, threatens this region’s exceptional biodiversity. To comprehend the effects of land-use change on plant diversity and identify conservation priorities, we aim at providing a first comprehensive plant checklist of the Ngovayang Massif, focusing on the two richest plant families, Orchidaceae and Rubiaceae.

Location – The Ngovayang Massif Area (NMA) is located in the South Region of Cameroon. It is covered by lowland and submontane rainforest (100 to 1110 m elevation).

Methods – We compiled a dataset of 6116 georeferenced herbarium specimens, of which 2787 belong to Rubiaceae and Orchidaceae. We used rarefaction methods to explore sampling and diversity patterns, and investigated the altitudinal distribution of rare and/or threatened taxa.

Key results – The NMA, which houses about 1500 vascular plant taxa, is the richest documented area for Rubiaceae in Atlantic Central Africa (ACA) and the fifth for Orchidaceae, with respectively 281 and 111 taxa. Among these taxa, 178 (45%) are endemic to ACA and 67 (17%) are considered globally threatened according to IUCN categories and criteria. We show that higher elevation areas (> 750 m), which are also the main areas targeted for mining, are the richest in endangered and/or rare species. Three new records for Cameroon are reported here.

Conclusion – The NMA represents an Important Plant Area of Cameroon as confirmed by its exceptional plant diversity (> 20% of the total Flora of Cameroon), by the concentration of many threatened and/or restricted range species (10 taxa are strict endemics of the massif) as well as by the threat on rare habitats (i.e. the submontane vegetation above ~750 m elevation). A management plan involving in situ and ex situ conservation actions is urgently needed to reduce the potential threats of future mining activities.

Keywords
biodiversity, endangered species, Important Plant Area, iron and gold exploitation, new records, orchids, Rubiaceae, submontane forest

References

  • Azandi L., Stévart T., Sonké B., Simo-Droissart M., Avana M.-L., Droissart V. (2016) Synoptic revision of the genus Cyrtorchis Schltr. (Angraecinae, Orchidaceae) in Central Africa, with the description of a new species restricted to submontane vegetation. Phytotaxa 267: 165–186. https://doi.org/10.11646/phytotaxa.267.3.1
  • Cable S., Cheek M. (1998) The plants of Mount Cameroon. A conservation checklist. Kew, Royal Botanic Gardens.
  • Cheek M., Harvey Y., Onana J.-M. (2010) The plants of Dom, Bamenda Highlands, Cameroon. A conservation checklist. Kew, Royal Botanic Gardens.
  • Cheek M., Harvey Y., Onana J.-M. (2011) The plants of Mefou proposed National Park, Central Province, Cameroon. A conservation checklist. Kew, Royal Botanic Gardens.
  • Cheek M., Onana J.-M., Pollard B.J. (2000) The plants of Mount Oku and the Ijim Ridge. A conservation checklist. Kew, Royal Botanic Gardens.
  • Cheek M., Pollard B.J., Darbyshire I., Onana J.-M., Wild C. (2004) The plants of Kupe, Mwanenguba and the Bakossi Mountains, Cameroon. A conservation checklist. Kew, Royal Botanic Gardens.
  • Darbyshire I., Anderson S., Asatryan A., Byfield A., Cheek M., Clubbe C., Ghrabi Z., Harris T., Heatubun C.D., Kalema J., Magassouba S., McCarthy B., Milliken W., de Montmollin B., Lughadha E.N., Onana J.-M., Saïdou D., Sârbu A., Shrestha K., Radford E.A. (2017) Important Plant Areas: revised selection criteria for a global approach to plant conservation. Biodiversity and Conservation 26: 1767–1800. https://doi.org/10.1007/s10531-017-1336-6
  • Dauby G., Zaiss R., Blach-Overgaard A., Catarino L., Damen T., Deblauwe V., Dessein S., Dransfield J., Droissart V., Duarte M.C., Engledow H., Fadeur G., Figueira R., Gereau R.E., Hardy O.J., Harris D.J., de Heij J., Janssens S., Klomberg Y., Ley A.C., MacKinder B.a., Meerts P., van de Poel J.L., Sonké B., Sosef M.S.M., Stévart T., Stoffelen P., Svenning J.-C., Sepulchre P., van der Burgt X., Wieringa J.J., Couvreur T.L.P. (2016) RAINBIO: a mega database on the distribution of tropical African vascular plants. PhytoKeys 74: 1–18. https://doi.org/10.3897/phytokeys.74.9723
  • Descourvières P., Dubuisson J.-Y., Droissart V., Cribb P.J., Cawoy V., Simo-Droissart M., Sonké B., Stévart T. (2013) Rhipidoglossum montealenense (Orchidaceae), a new species from Equatorial Guinea and Cameroon. Plant Ecology and Evolution 146: 389–394. https://doi.org/10.5091/plecevo.2013.841
  • Droissart V. (2009) Etude taxonomique et biogéographique des plantes endémiques d’Afrique centrale atlantique: le cas des Orchidaceae. Ph.D. thesis, Université Libre de Bruxelles, Brussels, Belgium.
  • Droissart V., Dauby G., Hardy O.J., Deblauwe V., Harris D.J., Janssens S., Mackinder B.A., Blach-Overgaard A., Sonké B., Sosef M.S.M., Stévart T., Svenning J.-C., Wieringa J.J., Couvreur T.L.P. (2018) Beyond trees: Biogeographical regionalization of tropical Africa. Journal of Biogeography 45: 1153–1167. https://doi.org/10.1111/jbi.13190
  • Droissart V., Hardy O.J., Sonké B., Dahdouh-Guebas F., Stévart T. (2012) Subsampling herbarium collections to assess geographic diversity gradients: a case study with endemic Orchidaceae and Rubiaceae in Cameroon. Biotropica 44: 44–52. https://doi.org/10.1111/j.1744-7429.2011.00777.x
  • Droissart V., Sonké B., Hardy O.J., Simo M., Taedoumg H., Nguembou K.C., Stévart T. (2011) Do plant families with contrasting functional traits show similar patterns of endemism? A case study with Central African Orchidaceae and Rubiaceae. Biodiversity and Conservation 20: 1507–1531. https://doi.org/10.1007/s10531-011-0042-z
  • Edwards A.C. (2001) Monograph 23 – Mineral Resource and Ore Reserve Estimation – The AusIMM Guide to Good Practice – Second Edition. Carlton South, Vic 3053, Australia, Australasian Institute of Mining and Metallurgy.
  • Edwards D.P., Sloan S., Weng L., Dirks P., Sayer J., Laurance W.F. (2014) Mining and the African Environment. Conservation Letters 7: 302–311. https://doi.org/10.1111/conl.12076
  • ESRI (2017) ArcGIS 10.5.1. for desktop. Redlands, CA, Esri. Available from https://desktop.arcgis.com/en/ [accessed 11 Dec. 2018].
  • Figueiredo E., Paiva J., Stévart T., Oliveira F., Smith G.F. (2011) Annotated catalogue of the flowering plants of São Tomé and Príncipe. Bothalia 41: 41–82. https://doi.org/10.4102/abc.v41i1.34
  • Gonmadje C., Picard N., Gourlet-Fleury S., Réjou-Méchain M., Freycon V., Sunderland T., McKey D., Doumenge C. (2017) Altitudinal filtering of large-tree species explains above-ground biomass variation in an Atlantic Central African rain forest. Journal of Tropical Ecology 33: 143–154. https://doi.org/10.1017/S0266467416000602
  • Gonmadje C.F., Doumenge C., McKey D., Tchouto G.P.M., Sunderland T.C.H., Balinga M.P.B., Sonké B. (2011) Tree diversity and conservation value of Ngovayang’s lowland forests, Cameroon. Biodiversity and Conservation 20: 2627–2648. https://doi.org/10.1007/s10531-011-0095-z
  • Gonmadje C.F., Doumenge C., Sunderland T.C.H., Balinga M.P.B., Sonké B. (2012) Analyse phytogéographique des forêts d’Afrique Centrale: le cas du massif de Ngovayang (Cameroun). Plant Ecology and Evolution 145: 152–164. https://doi.org/10.5091/plecevo.2012.573
  • Harvey Y., Pollard B.J., Darbyshire I., Onana J.-M., Cheek M. (2004) The plants of Bali Ngemba Forest Reserve, Cameroon. A conservation checklist. Kew, Royal Botanic Gardens.
  • Harvey Y., Tchiengué B., Cheek M. (2010) The plants of Lebialem Highlands, Cameroon. A conservation checklist. Kew, Royal Botanic Gardens.
  • Hsieh T.C., Ma K.H., Chao A. (2016) iNEXT: an R package for rarefaction and extrapolation of species diversity (Hill numbers). Methods in Ecology and Evolution 7: 1451–1456. https://doi.org/10.1111/2041-210X.12613
  • IUCN (2012) IUCN Red List Categories and Criteria. Version 3.1. Second Edition. [online]. Available from https://www.iucnredlist.org/resources/categories-and-criteria [accessed 21 Jan. 2019].
  • IUCN (2017) Guidelines for using the IUCN Red List Categories and Criteria. Version 13 [online]. Available from https://www.iucnredlist.org/resources/redlistguidelines [accessed 21 Jan. 2019].
  • IUCN (2018) The IUCN Red List of Threatened Species. Version 2018-1 [online]. Available from http://www.iucnredlist.org [accessed 1 Aug. 2018].
  • Lachenaud O., Droissart V., Dessein S., Stévart T., Simo M., Lemaire B., Taedoumg H., Sonké B. (2013) New records for the flora of Cameroon, including a new species of Psychotria (Rubiaceae) and range extensions for some rare species. Plant Ecology and Evolution 146: 121–133. https://doi.org/10.5091/plecevo.2013.632
  • Maley J. (1987) Fragmentation de la forêt dense humide africaine et extension des biotopes montagnards au Quaternaire récent: nouvelles données polliniques et chronologiques. Implications paléoclimatiques et biogéographiques. Palaeoecology of Africa 18: 307–334.
  • Maley J., Doumenge C., Giresse P., Mahé G., Philippon N., Hubau W., Lokonda M.O., Tshibamba J.M., Chepstow-Lusty A. (2018) Late Holocene forest contraction and fragmentation in central Africa. Quaternary Research 89: 43–59. https://doi.org/10.1017/qua.2017.97
  • Mimba M.E., Tamnta N.M., Suh C.E. (2014) Geochemical dispersion of gold in stream sediments in the Paleoproterozoic Nyong Series, southern Cameroon. Science Research 2: 155–165. https://doi.org/10.11648/j.sr.20140206.12
  • Onana J.-M. (2011) The vascular plants of Cameroon: a taxonomic checklist with IUCN assessments. Yaoundé, Cameroon, IRAD-National Herbarium of Cameroon.
  • Onana J.-M (2013) Synopsis des espèces végétales vasculaires endémiques et rares du Cameroun. Check-liste pour la conservation de la biodiversité. Flore du Cameroun 40. Yaoundé, Ministère de la Recherche Scientifique et de l’Innovation.
  • Onana J.-M., Cheek M. (2011) Red data book of the flowering plants of Cameroon. Kew, Royal Botanic Gardens.
  • Saenz S., Walschburger T., González J.C., León J., McKenney B., Kiesecker J. (2013) Development by design in Colombia: making mitigation decisions consistent with conservation outcomes. PloS one 8: e81831. https://doi.org/10.1371/journal.pone.0081831
  • Saura S., Bastin L., Battistella L., Mandrici A., Dubois G. (2017) Protected areas in the world’s ecoregions: How well connected are they? Ecological Indicators 76: 144–158. https://doi.org/10.1016/j.ecolind.2016.12.047
  • Sonké B., Bidault E., Droissart V. (2015) Taxonomic revision of the genus Massularia (Rubiaceae, Gardenieae), with a new species from Central Africa. Phytotaxa 203: 263–270. https://doi.org/10.11646/phytotaxa.203.3.5
  • Sonké B., Taedoumg H., Robbrecht E. (2012) A reconsideration of the Lower Guinean species of Sericanthe (Rubiaceae, Coffeeae), with four new species from Cameroon and Gabon. Botanical Journal of the Linnean Society 169: 530–554. https://doi.org/10.1111/j.1095-8339.2012.01254.x
  • Sosef M.S., Dauby G., Blach-Overgaard A., van der Burgt X., Catarino L., Damen T., Deblauwe V., Dessein S., Dransfield J., Droissart V., Duarte M.C., Engledow H., Fadeur G., Figueira R., Gereau R.E., Hardy O.J., Harris D.J., de Heij J., Janssens S., Klomberg Y., Ley A.C., Mackinder B.A., Meerts P., van de Poel J.L., Sonké B., Stévart T., Stoffelen P., Svenning J.-C., Sepulchre P., Zaiss R., Wieringa J.J., Couvreur T.L.P. (2017) Exploring the floristic diversity of tropical Africa. BMC Biology 15: 15. https://doi.org/10.1186/s12915-017-0356-8
  • Sosef M.S.M., Wieringa J.J., Jongkind C.C.H., Achoundong G., Azizet Issembé Y., Bedigian D., van den Berg R.G., Breteler F.J., Cheek M., Degreef J., Faden R., Gereau R.E., Goldblatt P., van der Maesen L.J.G., Ngok Banak L., Niangadouma R., Nzabi T., Nziengui B., Rogers Z.S., Stévart T., Taylor C.M., van Valkenburg J.L.C.H., Walters G., de Wilde J.J.F.E. (2006) Check-list des plantes vasculaires du Gabon / Checklist of Gabonese vascular plants. Scripta Botanica Belgica 35: 1–438. Meise, National Botanic Garden of Belgium.
  • Taedoumg H., De Block P., Hamon P., Sonké B. (2011) Craterispermum parvifolium and C. robbrechtianum spp. nov. (Rubiaceae) from west central Africa. Nordic Journal of Botany 29: 700–707. https://doi.org/10.1111/j.1756-1051.2011.01297.x
  • UNEP-WCMC (2018) Protected Area Profile for Cameroon from the World Database of Protected Areas [online]. Available from https://www.protectedplanet.net/country/CMR [accessed 1 Nov. 2018].
  • Vande weghe J.P., Bidault E., Stévart T. (2016) Les plantes à fleurs du Gabon. Une introduction à la flore des angiospermes. Libreville, Agence Nationale des Parcs Nationaux (ANPN).
  • Velayos M., Barbera P., Cabezas F.J., De La Estrella M., Fero M., Aedo C. (2014) Checklist of the Vascular Plants of Annobón (Equatorial Guinea). Phytotaxa 171: 1–78. https://doi.org/10.11646/phytotaxa.171.1.1
  • Velayos M., Cabezas F.J., Barberá P., de la Estrella M., Aedo C., Morales R., Quintanar A., Velayos G., Fero M. (2013) Preliminary checklist of vascular plants of Bioko Island (Equatorial Guinea). Botanica Complutensis 37: 109–133. https://doi.org/10.5209/rev_BOCM.2013.v37.42275
  • Verstraete B., Lachenaud O., Smets E., Dessein S., Sonké B. (2013) Taxonomy and phylogenetics of Cuviera (Rubiaceae–Vanguerieae) and reinstatement of Globulostylis with the description of three new species. Botanical Journal of the Linnean Society 173: 407–441. https://doi.org/10.1111/boj.12062
  • Wendt G. (2012) Weekly Ressource Report - Legend Mining (LEG). Minelife 65: 2–7. Available from http://legendmining.com.au/wp/wp-content/uploads/2012/02/MineLife_Article_March_2012.pdf [accessed 13 Dec. 2018].
  • White F. (1979) The Guineo-Congolian Region and its relationships to other phytochoria. Bulletin du Jardin botanique national de Belgique 49: 11–55. https://doi.org/10.2307/3667815
  • WRI (2012) Interactive forest atlas of Cameroon, version 3.0 [online]. Available from http://www.wri.org [accessed 1 Mar. 2017].
  • Zemagho L.A., Liede-Schumann S., Lachenaud O., Dessein S., Sonké B. (2017) Taxonomic revision of Sabicea subgenus Anisophyllae (Ixoroideae, Rubiaceae) from Tropical Africa, with four new species. Phytotaxa 293: 1–68. https://doi.org/10.11646/phytotaxa.293.1.1