Koba sandstone bowal

GUITIPA008
Koba sandstone bowal

Country: Guinea

Administrative region: Dalaba (Prefecture)

Central co-ordinates: 10.63306 N, 12.27861 W

Area: 1km²

Qualifying IPA Criteria

A(i)Site contains one or more globally threatened species, A(iii)Site contains one or more highly restricted endemic species that are potentially threatened, C(iii)Site contains nationally threatened or restricted habitat or vegetation types, AND/OR habitats that have severely declined in extent nationally

IPA assessment rationale

The site at Koba represents the largest populations of Mesanthemum tuberosum and Raphionacme caerulea in the Fouta Djallon and is a good example of high altitude sandstone bowal. This is a pure sandstone outcrop and is unlike some other bowal areas in the Fouta which are iron-based bowal. Mesanthemum tuberosum is endemic to the Fouta Djallon, and although present in many areas in small numbers, there is no other site at present with such a concentration.

Site description

Sandstone outcrop and bowal, known locally as ‘kapété’, with shallow and medium depth soils, close to the village of Koba, c. 7km south west of the town of Dalaba. Grassland with trees in the deeper soils or growing through cracks in the rocky outcrop. The outcrop is part of the high altitude plateau of the Fouta Djallon and is between 1050m and 1350m altitude and c. 1km2 in area.

Botanical significance

The flat, plain area has the largest population of Mesanthemum tuberosum (rediscovered in 2017) found in the Fouta Djallon area. It also has a population of Raphionacme caerulea. This is a good example of high altitude sandstone bowal in the Moyenne Guinee region. It is considered likely that revisiting the site at different seasons (e.g. Oct), will result in additional threatened species being identified.

Habitat and geology

High altitude sandstone bowal grassland, dominated by Elymandra subulata with many herbs present including Mesanthemum tuberosum, Buchnera bowalensis, Cyanotis arachnoidea, Cyanotis lanata, Tephrosia platycarpa, Crotalaria lathyroides, Fimbristylis schweinfurthiana, Nemum spadiceum, Raphionacme caerulea and Platycornye paludosa. In the deeper soil pockets, trees and shrubs of Dichaetanthera echinulata, Vismia guineensis and Psorospermum febrifugum and Ficus sp. can be found. There is a river to the south west of the site with riverine species present. This area is part of the Oundou series of interbedded quarzitic sandstone and dolomitic clays with Mesozoic intrusions of dolerite or gabbro-dolerites. (Source: Carte des Mineraux Utiles de la Republique de Guinee, 2006).

Conservation issues

The area is used for grazing cattle and goats and this could cause problems for some species from grazing and trampling. Also, increased nitrification of the soil may lead to enrichment and a decrease in species diversity. It has been observed that the Raphionacme caerulea plants do not seem to make it to seed dispersal stages – plants viewed in flower and GPS marked, could not be refound in the fruiting season (Couch, pers. Obs. 2017).

Site assessor(s)

Charlotte Couch, Royal Botanic Gardens Kew

Martin Cheek, Royal Botanic Gardens Kew

IPA criterion A qualifying 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
Raphionacme caerulea E.A.Bruce A(i) True True True False False Scarce
Mesanthemum tuberosum Lecomte A(i) True True True False False Frequent
Cyanotis ganganensis Schnell A(i) True True True False False Scarce
Dichaetanthera echinulata Hook.f. A(i) True True True False False Scarce

Raphionacme caerulea E.A.Bruce

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:
Scarce

Mesanthemum tuberosum Lecomte

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:
Frequent

Cyanotis ganganensis Schnell

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:
Scarce

Dichaetanthera echinulata Hook.f.

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:
Scarce

IPA criterion C qualifying habitats

Habitat Qualifying sub-criterion ≥ 5% of national resource ≥ 10% of national resource 1 of 5 best sites nationally Areal coverage at site
High Altitude Sandstone Bowal Grasslands C(iii) False True True 1

High Altitude Sandstone Bowal Grasslands

Qualifying sub-criterion:
C(iii)
≥ 5% of national resource:
False
≥ 10% of national resource:
True
Areal coverage at site:
1

General site habitats

General site habitat Percent coverage Importance
Grassland - Subtropical/Tropical Seasonally Wet/Flooded Lowland Grassland No value

Grassland - Subtropical/Tropical Seasonally Wet/Flooded Lowland Grassland

Percent coverage:
No value
Importance:

Land use types

Land use type Percent coverage Importance
Agriculture (pastoral) No value Minor

Agriculture (pastoral)

Percent coverage:
No value
Importance:
Minor

Threats

Threat Severity Timing
Agriculture & aquaculture - Livestock farming & ranching - Small-holder grazing, ranching or farming Medium Ongoing - stable
Natural system modifications - Fire & fire suppression - Increase in fire frequency/intensity Medium Ongoing - stable

Agriculture & aquaculture - Livestock farming & ranching - Small-holder grazing, ranching or farming

Severity:
Medium
Timing:
Ongoing - stable

Natural system modifications - Fire & fire suppression - Increase in fire frequency/intensity

Severity:
Medium
Timing:
Ongoing - stable

Bibliography

Lisowski, S., 2009

Flore (Angiospermes) de la République de Guinée.

Couch, C; Magassouba, S; Rokni, S; Cheek, M., 2018

Threatened plants species of Guinea-Conakry: A preliminary checklist

Peerj Preprints

IUCN, 2019

IUCN Red List

Available online

Phillips, S.M., Fofana, F. & Cheek, M., 2018

Mesanthemum tuberosum Lecomte resurrected from M. prescottianum (Bong.) Körn. (Eriocaulaceae), variation and lectotypification

Kew Bulletin, Vol 73:13 (pub. Springer London) Available online

Couch, C., 2016

TIPAs Guinea Darwin Project report: Field expedition to Fouta Djalon

Available online

Couch, C., 2017

TIPAs Guinea Darwin Project report: Field expedition to Fouta Djallon

Available online

Recommended citation

Charlotte Couch, Martin Cheek (2021) Tropical Important Plant Areas Explorer: Koba sandstone bowal (Guinea). https://tipas.kew.org/site/koba-sandstone-bowal/ (Accessed on 04/03/2021)