This species is known from the Krokosua Hills Forest Reserve and the neighbouring Sui Forest Reserve, both in southwestern Ghana (Ernst et al. 2008, R. Ernst pers. comm. April 2010, Adum et al. 2011). There is an unpublished record from Mount Nimba in Guinea (M.-O. Rödel pers. comm. June 2012), where only one specimen was recorded. The Mount Nimba area is well surveyed and this species seems to be very rare there. The highest point within the Krokosua Hills Forest Reserve is 594 m asl (Ernst et al. 2008), but it does occur up to 1,070 m asl within its range. Its extent of occurrence (EOO) is estimated at 29,535 km² and its area of occupancy (AOO) at 3,563 km². This species is known from a total of three sites (two in Ghana and one in Guinea), which are considered to be two threat-defined locations. The area between the two known locations requires more surveys as the new site at Mt. Nimba makes an occurrence into Ivory Coast (or at least a former occurrence) very likely (M.-O. Rödel pers. comm. August 2013).
Habitat and Ecology
The larger Krokosua Hills area is part of the northwest subtype of moist semi-deciduous forest, but the slopes where this species is found are moist uphill evergreen forest, with a thick leaf litter on a granitic outcrop (R. Ernst pers. comm. July 2010). Trees in this type of forest are taller than in other Ghanaian forest types. No open bodies of water were recorded in direct vicinity of the type locality (Ernst et al. 2008). It is presumed to breed by direct development.
At Mount Nimba, it was found in primary rainforest, not near water (L. Sandberger pers. comm. June 2012).
It is believed that it could be a rare species (R. Ernst pers. comm. April 2010) and due to ongoing habitat loss, its population is suspected to be decreasing.
Both Ghanaian reserves' (Krokosua Hills Forest Reserve and the Sui Forest Reserve) vegetation has been severely disturbed by both past and current logging activities, fragmentation, farming and mining (Adum et al. 2011). Sui Forest Reserve is affected by illegal farming and small-scale mining (R. Ernst pers. comm April 2010). While alluvial gold mining was a past threat, the current major threat to this species is illegal logging, which causes habitat degradation. In addition, a botanical survey in 1991 confirmed extreme patchiness with very damaged, logged areas on flatter land and unlogged areas with less damage on steep slopes. Between Sui and Krokosua there are large unforested areas and the entire region is extremely patchy, with fragments of forest interspersed with deforested agricultural land (R. Ernst pers. comm July 2010). This species occurs in a very small area which is now under human encroachment pressure (Ernst et al. 2008), consisting mostly of habitat loss due to illegal plantations, which is occurring at an alarming rate (R. Ernst pers. comm. April 2010). It might be affected by mining in the Mount Nimba area even though it is a World Heritage site (L. Sandberger and M.-O. Rödel pers. comm. June 2012).
Although this species occurs in two forest reserves, and Mount Nimba in Guinea is a World Heritage Site, these are still subject to habitat degradation and loss because of human encroachment, so much so that Mount Nimba is currently listed in UNESCO's World Heritage in Danger list (UNESCO 2013). Urgent reserve management and enforcement is therefore required to protect the species' habitat. Additional habitat protection is also needed outside the forest reserves. Further survey work is needed to determine the extent of this species' distribution and its population status, as well as its ecology.
Red List Status
Near Threatened (NT)
This species is listed as Near Threatened. Although its area of occupancy is estimated to be 3,563 km² (which is well above the threshold for criterion B2), its extent of occurrence (EOO) is estimated to be 29,535 km², which is relatively close to the criterion B1 threshold. It is considered to occur in two threat-defined locations (one in Guinea and one in Ghana), and is undergoing a continuing decline in the extent and quality of its habitat. The species is therefore close to qualifying for Vulnerable under criterion B1.
IUCN SSC Amphibian Specialist Group 2015. Arthroleptis krokosua. The IUCN Red List of Threatened Species 2015: e.T174591A16862286. http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T174591A16862286.en .Downloaded on 19 November 2018