Country: Guinea
Administrative region: Forecariah (Prefecture)
Central co-ordinates: 9.41833 N, 13.23778 W
Area: 6.12km²
Qualifying IPA Criteria
A(i)Site contains one or more globally threatened species, 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
This inselberg complex is the one of the best examples of coastal inselbergs in Guinea and West Africa in general. The inselbergs have significant populations of at four endangered species, including the largest known population of Raphionacme caerulea (EN). They are under threat from quarrying, nomadic cattle grazing and invasive species.
Site description
The Tonkoyah inselberg complex is located in the coastal zone of Forécariah. It is a series of low lying granite shield inselbergs varying in size from c. 1km to 100m. Many of the inselbergs are bordered by mangrove and some have small patches of forest associated with them. In the dry season, the only vegetation is the dehydrated plants of Afrotrilepis pilosa, often forming candelabra structures, and most of the inselbergs are covered with an algal crust. In the wet season these inselbergs are covered with a variety of species and habitats which can be classified into microhabitats (Porembski, 1999) such as temporary pools and wet depressions, the latter dominated by the grass Dilophotiche occidentalis. Some of the inselbergs in this complex also have endangered species present such as Raphionacme caerulea (EN) and Plectranthus linearifolius (EN). In the forest patches associated with some of these inselbergs Stylochaeton pilosus (EN) can be found. Inselbergs in this area are under threat from quarrying for building material. One quarry was started in the area in 2013.
Botanical significance
The microhabitats found on these inselbergs have several threatened species present. The largest inselberg has one of the most significant populations of Raphionacme caerulea and Plectranthus linearifolius; the forest adjacent also has a small population of Stylochaeton pilosus. Other inselbergs in the complex have small populations of Raphionacme and the forest patches adjoining them have populations of Stylochaeton pilosus. One also has a small population of Marsdenia exellii, a rare Apocynaceae liana associated with the vegetation at the interface of inselbergs and forest.
Habitat and geology
Granite shield inselbergs with several different microhabitats present. Areas of seepage and depressions with thin soils, Afrotrilepis pilosus forming clumps, temporary ponds, cracks and crevices, and associated forest patches.
Conservation issues
The main threat to inselbergs in Guinea is from quarrying. There has already been one quarry opened up in the area, this may increase the likelihood of more. The invasive species Breynia disticha was also recorded here in 2012, in small numbers. We have been working with the villagers at Tonkoyah for a number of years and they are aware of the importance of the rare species of plants. They also have issues with nomadic herders coming through and burning the inselberg vegetation and nearby areas for new pasture. This can influence the amount of seed produced and distributed by Raphionacme as the fires are often set in January when the fruits are ripening.
Site assessor(s)
Assessed by:
Charlotte Couch, Royal Botanic Gardens Kew
Denise Molmou, Herbier National de Guinee/ Simfer
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 |
|---|---|---|---|---|---|---|---|
| Raphionacme caerulea E.A.Bruce | A(i) |  |
|
|
 |
|
Common |
| Plectranthus linearifolius (J.K.Morton) B.J.Pollard & A.J.Paton | A(i) | |
|
|
|
|
Frequent |
| Marsdenia exellii C.E.Norman | A(i) | |
|
|
|
|
Scarce |
| Stylochaeton pilosus Bogner | A(i) | |
|
|
|
|
Frequent |
Raphionacme caerulea E.A.Bruce
Qualifying sub-criterion:
A(i)
≥ 1% of global population:
≥ 5% of national population:
1 of 5 best sites nationally:
Entire global population:
Socio-economically important:
Abundance at site:
Common
Plectranthus linearifolius (J.K.Morton) B.J.Pollard & A.J.Paton
Qualifying sub-criterion:
A(i)
≥ 1% of global population:
≥ 5% of national population:
1 of 5 best sites nationally:
Entire global population:
Socio-economically important:
Abundance at site:
Frequent
Marsdenia exellii C.E.Norman
Qualifying sub-criterion:
A(i)
≥ 1% of global population:
≥ 5% of national population:
1 of 5 best sites nationally:
Entire global population:
Socio-economically important:
Abundance at site:
Scarce
Stylochaeton pilosus Bogner
Qualifying sub-criterion:
A(i)
≥ 1% of global population:
≥ 5% of national population:
1 of 5 best sites nationally:
Entire global population:
Socio-economically important:
Abundance at site:
Frequent
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 |
|---|---|---|---|---|---|
| Granite Inselbergs | C(iii) | |
|
|
6 |
Granite Inselbergs
Qualifying sub-criterion:
C(iii)
≥ 5% of national resource:
≥ 10% of national resource:
Areal coverage at site:
6
General site habitats
| General site habitat | Percent coverage | Importance |
|---|---|---|
| Rocky Areas - Rocky Areas [e.g. inland cliffs, mountain peaks] | |
Minor |
Rocky Areas - Rocky Areas [e.g. inland cliffs, mountain peaks]
Percent coverage:
Importance:
Minor
Land use types
| Land use type | Percent coverage | Importance |
|---|---|---|
| No use | |
No use
Percent coverage:
Importance:
Threats
| Threat | Severity | Timing |
|---|---|---|
| Transportation & service corridors - Roads & railroads | Medium | Ongoing - stable |
| Invasive & other problematic species, genes & diseases - Invasive non-native/alien species/diseases - Named species | Low | Ongoing - increasing |
| Agriculture & aquaculture - Livestock farming & ranching - Nomadic grazing | High | Ongoing - increasing |
| Energy production & mining - Mining & quarrying | High | Future - inferred threat |
Transportation & service corridors - Roads & railroads
Severity:
Medium
Timing:
Ongoing - stable
Invasive & other problematic species, genes & diseases - Invasive non-native/alien species/diseases - Named species
Severity:
Low
Timing:
Ongoing - increasing
Agriculture & aquaculture - Livestock farming & ranching - Nomadic grazing
Severity:
High
Timing:
Ongoing - increasing
Energy production & mining - Mining & quarrying
Severity:
High
Timing:
Future - inferred threat
Management type
| Management type | Description | Year started | Year finished |
|---|---|---|---|
| No management plan in place | |
|
No management plan in place
Year started:
Year finished:
Bibliography
Flore (Angiospermes) de la République de Guinée.
Threatened plants species of Guinea-Conakry: A preliminary checklist
Peerj Preprints
IUCN Red List
Recommended citation
Charlotte Couch, Denise Molmou (2025) Tropical Important Plant Areas Explorer: Tonkoyah Inselberg Complex (Guinea). https://tipas.kew.org/site/tonkoyah-inselberg-complex/ (Accessed on 05/02/2025)