Massif des Mamelles

CMNTIPA026
Massif des Mamelles

Country: Cameroon

Administrative region: South (Region)

Central co-ordinates: 2.56760 N, 9.94870 E

Area: 93km²

Qualifying IPA Criteria

A(i)Site contains one or more globally threatened species

IPA assessment rationale

The site qualifies as a potential IPA under Criterion A(i) due to the presence of globally threatened species such as Afrotrewia kamerunica, Rhapiostylis ovatifolia, Deinbollia mezilii and Culcasia bosii (all EN), which are known from very few other sites. Considering the small size of the site, quite a large number of threatened, endemic or nationally rare species are known. However, there are caveats against some of these species due to the paucity of data available. Tchouto (2004) mentions several taxa as associated with the site but for several of these, such as Monanthotaxis elegans, Gilbertiodendron pachyanthum and Monodora zenkeri, specimen numbers are not available. Other taxa, such as Cassipourea alternifolia, Pauridiantha multiflora, Cola hypochrysea and Culcasia bosii have been included here although they occur a little distance from the main hills, while other rare or threatened taxa that are recorded imprecisely from nearby (such as Ochthocosmus calothyrsus) have not been included but should be searched for at the site. In summary, further surveying of this small site should be performed to verify the state of the habitat and what taxa still occur. This should be an urgent priority given the imminent threats faced from mining, palm-oil clearance and coastal development.

Site description

Massif des Mamelles is a low ridge of forested hills, approximately 15 km long and 2 km wide, running NNE-SSW parallel to the coast, which is 12 km away. The nearest town is Ebodje, on the N7 coastal road between Campo and Kribi. Three peaks are named on the map, from north to south, Mont Puku, Mont Mbimba and Mont Die Buster (Openstreetmap 2022; results from Geonames). The hills interrupt the low plain between the sea and Campo Ma'an National Park 25 km to the east. Mt Elephant (475 m) lies around 20 km to the north, while to the south the low plain stretches across the border and well into Equatorial Guinea.

Botanical significance

The site is relatively little known but was noted in the work of Tchouto (2004) on the Campo Ma'an area as a botanical hotspot and key site for rare and range-restricted taxa. While some of the taxa are also recorded from within the Campo Ma'an National Park, others are not, such as Afrotrewia kamerunica (Cheek & Lovell, 2020). Some taxa are also shared with Mont Elephant. Both sites represent a vegetation type categorised by Tchouto (2004), following Letouzey (1986), as "Caesalpsa" vegetation type 3 ("Lowland evergreen forest rich in Caesalpinioideae, with Sacoglottis gabonensis and other coastal indicators"). The site was actually explored for several days in September 1862 by Richard Francis Burton but no observations or specimens were recorded (Letouzey, 1968b).

Habitat and geology

South Cameroon lies on the northern edge of the Congo craton, in a zone where Archean rocks became reactivated in the Proterozoic eon to form the metasedimentary and meta-igneous Ntem complex, which is in turn subdivided by age into the Ntem, Nyong and Ayna units (Teutsong et al., 2020). Within the Nyong unit, which consists of paleoproterozoic (c. 2089–2050 Ma) gneisses and amphibolites, the Massif des Mamelles is a greenstone belt containing banded iron formations (Moudioh et al., 2020). To the west it is bordered by an eastward thrusting coastal band which extends down from the neo-proterozoic Yaoundé group zone bordering the Congo craton to the north. The iron ores at the site predominantly consist of martite, goethite and quartz with lesser amounts of magnetite, hematite, kaolinite, and halloysite (Teutsong et al., 2020). Tchouto (2004) reports xanthic ferrasols, ferralic cambisols and ferric acrisols around the Massif. Teutsong (2020) describes the "loose horizon" as dark brown, lumpy sandy-clay and also reports low phosphorous content in the geological profile, although it is unclear if this influences soil phosphate levels.
The vegetation of the site is little reported. Tchouto's (2004) multivariate analysis categorises the local forest as the Caesalpsa vegetation type ("Lowland evergreen forest rich in Caesalpinioideae, with Sacoglottis gabonensis and other coastal indicators"), which is more or less absent from the National Park area and differs from the dominant Caesalp evergreen forest in much of the park by the abundance of Sacoglottis gabonensis and other coastal indicators. However, it is unclear if the hills themselves are continuous with this type and to what extent their height, exposure and soil characteristics are responsible for a locally unique flora.

Conservation issues

The site was one of the first iron ore reserves to be identified in the southern Cameroon iron ore corridor but has yet to be exploited (Ngoran et al., 2016; Teutsong et al., 2020). However, recent increased demand for steel has led to greater iron prospecting in Cameroon (Ngoran et al., 2016). Teutsong et al., (2020) suggest that the Mamelles reserves are of mainly medium grade ore with acceptable contaminant levels, and that further investigation is justified. Approximately 350 Mt of ore at a mean composition of 30% Fe are reported for the site by (Nkoumbou et al., 2017). Proximity to the deep sea Kribi port is a major factor contributing to the potential exploitation of these reserves compared to richer reserves further east that require major new transport infrastructure (Teutsong et al., 2020). The Cameroon company SteelCam was reported recently to have hired a French consultancy in relation to the site (Africa Intelligence, 2019). At nearby Lobé, SinoSteel have been widely reported as investing US$660 million in the 35% ores. Although no extraction had taken place by 2017 (Nguepjouo, 2017), the Chinese funded deep sea port at Kribi is now operational, providing a nearby export route (Yingwu, 2019).
In addition to the direct threat of mining at the site, the area is under threat from development and population growth associated with the port development. The forests outside of Campo Ma'an National Park, towards the coast, were already more disturbed (Tchouto, 2004) and huge rubber and palm oil (Hevecam and SocaPalm) plantations have cleared most of the area north of the site up to the Kribi-Ebolowa road. To the south the forest, although considerably altered from its natural state, was relatively well-managed as a logging concession (FMU 09-025) by the Dutch firm Wijma between 2005 and 2016 (Nforngwa, 2019). This is now to be developed as a major palm oil plantation by a little known company Camvert, with almost the whole area of 60,000 hectares between the national park and the coast scheduled for clearance (Nforngwa, 2019). Because the Mamelles site lies in a notch in the north edge of this block, this development will isolate it on three sites from other natural habitat while exposing it to clearance for small scale logging and agriculture.

Ecosystem services

The forest between the coast and Campo Ma'an is of great value as a buffer zone for the National Park, enlarging overall habitat for many species and providing corridors enabling gene flow between populations, as well as unique habitat not found in the National Park. If most of this zone is lost to agro-industrial plantations and coastal development as planned (Nforngwa, 2019) then remaining sites such as the Massif des Mamelles would become especially important.
Landslides are a common danger associated with steep topography in Cameroon (Zogning et al., 2007). Maintenance of forest cover on hills such as these is generally advisable to limit this danger and associated flooding (Forbes & Broadhead, 2013), although it is not known if this is a significant concern at the site.

Site assessor(s)

Bruce Murphy, Royal Botanic Gardens, Kew

Jean Michel Onana, University of Yaounde I, Faculty of Science, Department of Plant Biology; IRAD-Herbier National Camerounais

IPA criterion A species

Species Qualifying sub-criterion ≥ 1% of global population ≥ 5% of national population 1 of 5 best sites nationally Entire global population Socio-economically important Abundance at site
Cassipourea alternifolia Breteler A(i) True True True False False
Cola hypochrysea K.Schum. A(i), A(iii) True True False False False
Culcasia bosii Ntépé Nyamè A(i) True True True False False
Deinbollia mezilii D.W.Thomas & D.J.Harris A(i) True True True False False
Uvariopsis vanderystii Robyns & Ghesq. A(i) False False True False False
Begonia zenkeriana L.B.Sm. & Wassh. A(i) True False True False False
Afrotrewia kamerunica Pax & K.Hoffm. A(i) True True True False False
Rhaphiostylis ovatifolia Engl. ex Sleumer A(i) False False False False False
Gilbertiodendron pachyanthum (Harms) J.Léonard A(i) True True True False False
Psychotria lanceifolia K.Schum. A(i) True False False False False
Isomacrolobium leptorrhachis (Harms) Aubrév. & Pellegr. A(i) True False False False False
Hymenocoleus glaber Robbr. A(i) True False False False False
Dichapetalum oliganthum Breteler A(i) False False False False False
Gilbertiodendron klainei (Pierre ex Pellegr.) J.Léonard A(i) False False True False False
Psychotria arborea Hiern A(i) True True True False False
Globulostylis rammelooana Sonké A(i) True False True False False

Cassipourea alternifolia Breteler

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Cola hypochrysea K.Schum.

Qualifying sub-criterion:
A(i), A(iii)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
False
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Culcasia bosii Ntépé Nyamè

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Deinbollia mezilii D.W.Thomas & D.J.Harris

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Uvariopsis vanderystii Robyns & Ghesq.

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
False
≥ 5% of national population:
False
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Begonia zenkeriana L.B.Sm. & Wassh.

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
False
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Afrotrewia kamerunica Pax & K.Hoffm.

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Rhaphiostylis ovatifolia Engl. ex Sleumer

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
False
≥ 5% of national population:
False
1 of 5 best sites nationally:
False
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Gilbertiodendron pachyanthum (Harms) J.Léonard

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Psychotria lanceifolia K.Schum.

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
False
1 of 5 best sites nationally:
False
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Isomacrolobium leptorrhachis (Harms) Aubrév. & Pellegr.

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
False
1 of 5 best sites nationally:
False
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Hymenocoleus glaber Robbr.

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
False
1 of 5 best sites nationally:
False
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Dichapetalum oliganthum Breteler

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
False
≥ 5% of national population:
False
1 of 5 best sites nationally:
False
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Gilbertiodendron klainei (Pierre ex Pellegr.) J.Léonard

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
False
≥ 5% of national population:
False
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Psychotria arborea Hiern

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
True
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:

Globulostylis rammelooana Sonké

Qualifying sub-criterion:
A(i)
≥ 1% of global population:
True
≥ 5% of national population:
False
1 of 5 best sites nationally:
True
Entire global population:
False
Socio-economically important:
False
Abundance at site:

General site habitats

General site habitat Percent coverage Importance
Forest - Subtropical/Tropical Moist Lowland Forest 90 Major

Forest - Subtropical/Tropical Moist Lowland Forest

Percent coverage:
90
Importance:
Major

Land use types

Land use type Percent coverage Importance
Extractive industry No value Major
Agriculture (arable) No value

Extractive industry

Percent coverage:
No value
Importance:
Major

Agriculture (arable)

Percent coverage:
No value
Importance:

Threats

Threat Severity Timing
Agriculture & aquaculture - Annual & perennial non-timber crops - Agro-industry farming High Ongoing - increasing
Transportation & service corridors - Roads & railroads Medium Ongoing - increasing
Energy production & mining - Mining & quarrying High Future - planned activity
Agriculture & aquaculture - Annual & perennial non-timber crops - Shifting agriculture Unknown Ongoing - trend unknown

Agriculture & aquaculture - Annual & perennial non-timber crops - Agro-industry farming

Severity:
High
Timing:
Ongoing - increasing

Transportation & service corridors - Roads & railroads

Severity:
Medium
Timing:
Ongoing - increasing

Energy production & mining - Mining & quarrying

Severity:
High
Timing:
Future - planned activity

Agriculture & aquaculture - Annual & perennial non-timber crops - Shifting agriculture

Severity:
Unknown
Timing:
Ongoing - trend unknown

Management type

Management type Description Year started Year finished
No management plan in place No value No value

No management plan in place

Year started:
No value
Year finished:
No value

Bibliography

Letouzey, R., 1985

Notice de la carte phytogéographique du Cameroun au 1: 500,000.

Zogning, A., Ngouanet, C. & Tiafack, O., 2007

The catastrophic geomorphological processes in humid tropical Africa: A case study of the recent landslide disasters in Cameroon

Sedimentary Geology, Vol 199, page(s) 13 – 27 Available online

Forbes, K. & Broadhead, J., 2013

Forests and Landslides: The Role of Trees and Forests in the Prevention of Landslides and Rehabilitation of Landslide-Affected Areas in Asia. Second Edition

Tchoutou, M.G.P., 2004

Plant Diversity in a Central African Rain Forest. Implications for biodiversity conservation in Cameroon. PhD thesis, Wageningen University

Available online

Nforngwa, E.N., 2019

NGOs reject new oil palm plantation in southern Cameroon

Available online

Yingwu, W., 2019

Port portal for Sino-African pragmatic cooperation. China Daily.com.cn Updated 2019-09-20 08:38

Available online

Moudioh C., Tamehe, L., Ganno, S., Tankwa, Soares, M.B., Ghosh, R., Kankeu, B. & Nzenti, J.P., 2020

Tectonic setting of the Bipindi greenstone belt, northwest Congo craton, Cameroon: Implications on BIF deposition

Journal of African Earth Sciences, Vol 171(103971)

Nkoumbou, C., Gentry, F.C., Numbem, J.T., Lobé, Y.V. & Keyamfé, C.S., 2017

Petrology and geochemistry of REE-rich Mafé banded iron formations (Bafia group, Cameroon)

Comptes Rendus Geoscience, Vol 349(4), page(s) 165-174

Africa Intelligence, 2019

AFM Conseil seeks funds for Mamelles de Kribi iron ore.

Africa Intelligence, Vol Issue dated 22/01/2019 Available online

Nguepjouo, D., 2017

The spatialisation of China’s presence in Cameroon: The case of the mining sector

The Extractive Industries and Society, Vol 4, page(s) 513-524

Ngoran, G.N.,Suh, C.E., Bowker, D., Verla, R.B. & Bafon, G.T., 2016

Petrochemistry of Two Magnetite Bearing Systems in the Precambrian Belt of Southern Cameroon

International Journal of Geosciences, Vol 7, page(s) 501-517

Teutsong, T.,Temga, J.P., Enyegue, A.A., Feuwo, N.N. & Bitom, D., 2020

Petrographic and geochemical characterization of weathered materials developed on BIF from the Mamelles iron ore deposit in the Nyong unit, South-West Cameroon

Acta Geochimica

Cheek, M. & Lovell, R., 2020

Afrotrewia kamerunica. The IUCN Red List of Threatened Species 2020: e.T110081019A110081021

Available online

Letouzey, R., 1968b

Flore du Cameroun, Volume 7, Les Botanistes au Cameroun.

Recommended citation

Bruce Murphy, Jean Michel Onana (2024) Tropical Important Plant Areas Explorer: Massif des Mamelles (Cameroon). https://tipas.kew.org/site/massif-des-mamelles/ (Accessed on 27/05/2024)