Costus kupensis

Two collections of this species were from Mt. Kupe in the Tombel municipality (Southwest region) where agricultural encroachment is a major threat (Fotso et al. 2001, Ngea 2006, PNDP 2011). Almost 90% of the population of Tombel are involved in agriculture, growing food crops such as cassava, banana, maize and cocoyam (PNDP 2011). Additionally, cocoa, coffee, and rubber are important cash crops in the region, with cocoa accounting for about 50% of the cultivated land, and palm oil cultivation is increasing (PNDP 2011). All sides of Mount Kupe have faced encroachment from agriculture and in 2001 this encroachment was reported to have reached varying elevations of up to 1,500 m asl around the mountain (Fotso et al. 2001). Therefore, this species, which is known to occur at altitudes between 800 and 1,000 m asl, is very likely to have been impacted by the clearance of forests for agriculture. Additionally, a collection of this species (Cheek K #7111) reports that towards Kupe village, forest was largely coffee farms with shade trees. The majority of this forest clearance is for small-holder agriculture, mainly for food crops, and a slash and burn approach is reported to be used in the area (Ngea 2006). However, agro-industrial plantations may also threaten this species and it has been collected near to oil palm concessions (Global Forest Watch 2020). An additional threat in Tombel is the uncontrolled, unsustainable exploitation of forest resources (PNDP 2011). Timber is exported by logging companies in the region and trees are also cut to be used locally (PNDP 2011, Ejedepang-Koge 2016). Such logging activities have been reported in the Mount Kupe area (Ngea 2006). Additionally, one of the collections is situated near to the town of Tombel and the species is threatened by its expansion (Google Earth 2020). The species has also been collected from the western slope of Mont Nlonako in the Littoral region of Cameroon. The collection is situated 5 km from the town of Nkongsamba, and therefore, the western and northern sides of Mt. Nlonako, where this species was collected, have faced repeated human encroachment, particularly for agriculture (Fotso et al. 2001, Herrmann et al. 2005). Much of the remaining forest in this area is secondary forest (Fotso et al. 2001). These slopes are heavily cultivated, and in 2005 the forest as reported to be destroyed up to 1,100 m asl (Herrmann et al. 2005). As this species’ elevation range is between 800 and 1,000 m asl., it is highly likely to have been impacted by agriculture in the area. Additionally, the collection site is situated within a mining concession and so mining may also pose a threat in this area (Global Forest Watch 2020). The other collection in the Littoral region was in Ebo proposed National Park. The major threats to Ebo forest are from logging, forest clearance for oil palm plantations, and opencast iron ore mining. Ebo forest is highly threatened by logging (Onana and Cheek 2011, Abwe et al. 2019, Cheek et al. 2018). The park is currently bordered by logging concessions, the proximity of which means they may threaten the forest's biodiversity (Global Forest Watch 2020, Mahmoud et al. 2019), and illegal logging activities occur within the forest (Casey and Elias 2015). Additionally, in March 2020, the Cameroon government moved to convert the entire Ebo forest area into logging concessions (Global Wildlife Conservation 2020). Secondly, an oil palm company has begun to develop a plantation on the western boundary of the proposed Ebo National Park, in what is the biggest source of oil palm-driven deforestation in the region (Mowbray 2017, Orozco and Salber 2019, IDM 2018). This has caused the clearing of land close to the border of the proposed Ebo national park, representing a significant threat to the forest (IDM 2018, Orozco and Salber 2019, Mowbray 2017). It was reported that 1,749 hectares had been cleared by March 2017, and by 2018, the clearance of land had already reached within 5 km of the proposed reserve boundary (Orozco and Salber 2019, IDM 2018). Loggers are continuing to fell trees for the plantation and it is estimated that six football pitches worth of forest are now being cleared every day (Mowbray 2017, Orozco and Salber 2019). However, the specific plans for the plantation are shrouded by secrecy, with the total area controlled by the company unknown and no map of the planned plantation publicly available (IDM 2018, Orozco and Salber 2019). Current reports suggest that the plantation could cover anywhere between 30,000 and 123,000 hectares (Mowbray 2017, IDM 2018). A buffer zone of 182 m was recommended for the plantation, however, this has not been respected and boundary pillars have been found both within the buffer zone and within the proposed national park (Orozco and Salber 2019). As roads have been developed, human dwellings have been expanding around Ebo and they are now present within 10 km of the forest (Mahmoud et al. 2019). Additionally, many sites within Ebo were formerly inhabited by humans and while some regeneration is slowly occurring, there are extensive amounts of secondary forest, including in areas previously heavily modified by small stakeholder agriculture (Abwe et al. 2019, Morgan et al. 2011). Slash and burn agriculture remains prevalent in the area and represents a threat to this species, with the income of the villages surrounding Ebo heavily dependent on subsistence agriculture (Onana and Cheek 2011, Abwe 2013). Open-cast mining also poses a threat to this species, and the species has been collected within an iron mining concession (Global Forest Watch 2020). Although proposed as a National Park prior to 2010, the park's gazetting has been stalled and Ebo is currently unprotected, leaving it vulnerable to anthropogenic pressures (Nana 2010, Mowbray 2017, Mahmoud et al. 2019). Mahmoud et al. (2019) report that the current rate of land conversion in close proximity to Ebo forest, alongside its lack of protection, render it highly threatened. Even if the national park is officially designated, the forest is likely to face continued threats, such as from illegal logging (Mowbray 2017). Additionally, there are fears that even if the proposed National Park is gazetted, the oil palm plantation will have attracted labourers who may exploit the forests for further income, thereby increasing the challenges of protecting the area (Orozco and Salber 2019, Mowbray 2017).

There are no targeted conservation actions for this species and there are currently no known ex-situ conservation sites (BGCI 2020). The species does occur within the proposed Mount Kupe Integral Ecological Reserve and the proposed Ebo National Park. To secure conservation efforts at Ebo, and to protect the forest from planned logging concessions, official designation of National Park status for Ebo is urgently needed. Further research is needed into this species' distribution, population status and trends, and life history and ecology.