Land-Cover Change Threatens Tropical Forests and Biodiversity in the Littoral Region, Cameroon M AHMOUD I

Land-cover change threatens tropical forests and biodiversity in the Littoral Region, Cameroon M AHMOUD I. MAHMOUD,MASON J. CAMPBELL,SEAN S LOAN M OHAMMED A LAMGIR and W ILLIAM F. LAURANCE Abstract Tropical forest regions in equatorial Africa are et al., ; WWF, ). They also provide numerous and threatened with degradation, deforestation and biodiversity valuable environmental services, including carbon storage, loss as a result of land-cover change. We investigated his- protection of threatened ecosystems, hydrological func- torical land-cover dynamics in unprotected forested areas tioning (Abernethy et al., ), and medicinal products of the Littoral Region in south-western Cameroon during (Colfer, ). African forests also provide significant socio- –, to detect changes that may influence this impor- economic resources, including plant and animal products, tant biodiversity and wildlife area. Processed Landsat im- food, medicine, products of cultural value, and building agery was used to map and monitor changes in land use and construction materials. and land cover. From to the area of high-value forest Tropical African forests are threatened by a wide array landscapes decreased by c. , ha, and increasing forest of anthropogenic activities that imperil natural ecosystems fragmentation caused a decline of c. %inthelargestpatch and biodiversity. For instance, the few previous studies index. Conversely, disturbed vegetation, cleared areas and conducted in the threatened forests of the Cross–Sanaga urban areas all expanded in extent, by %(c., ha), River region (Fa et al., ), the Gulf of Guinea biodiver- .% (c. , ha) and .% (c. , ha), respectively. sity hotspot (Oates et al., ), and the greater Congo The greatest increase was in the area converted to oil palm Basin (Laurance et al., ) identified deforestation as a plantations (c. , ha), followed by logging and land major factor driving both forest loss and degradation clearing (c. , ha), all of which were the major factors (Hosonuma et al., ; Ordway et al., ; Aleman et al., driving deforestation in the study area. Our findings ). Deforestation, along with other smallholder activities highlight the increasing threats facing the wider Littoral in African tropical forests, is also known to damage impor- Region, which includes Mount Nlonako and Ebo Forest, tant wildlife habitats, leading to biodiversity loss and the both of which are critical areas for regional conservation destruction of forest-based livelihoods. However, the extent and the latter a proposed National Park and the only siz- to which small vs large landholder activities influence land- able area of intact forest in the region. Intact forest in the cover change and conservation in these forests remains Littoral Region, and in particular at Ebo, merits urgent unclear. Known drivers of forested land-cover conversion protection. include industrial logging (Laporte et al., ), agricultural expansion (van Soesbergen et al., ), settlement expan- Keywords Biodiversity loss, Cameroon, deforestation, Ebo sion (Mahmoud et al., ) and road infrastructure expan- Forest, equatorial Africa, logging, oil palm, roads, wildlife sion (Alamgir et al., ; Laurance et al., ; Mahmoud Supplementary material for this article is available at et al., ). These processes can also lead to forest fragmen- https://doi.org/./S tation and degradation, resulting in depauperate forests with significantly reduced biodiversity compared to intact forests (Fahrig, ; Haddad et al., ; Laurance et al., ). Introduction The rate and scale of land-cover change currently occur- ring in equatorial Africa is unprecedented and unsustain- ’ frica s tropical forests are the most extensive after those able (Tchuenté et al., ). However, there is a paucity of Aof the Amazon (Cincotta et al., ; Sosef et al., ), studies examining human-driven land-cover change and covering . million km , with the majority concentrated in threats to conservation at fine spatial scales in unprotect- the greater Congo Basin. These forests harbour c. , ed yet still highly biodiverse regions of equatorial Africa. species of vertebrates and , plant species (Orme Regional studies examining land-cover change have often been at a coarse scale, and many of the findings are based on inferences (Singh et al., ; Thompson et al., ). MAHMOUD I. MAHMOUD (Corresponding author, orcid.org/0000-0002-0432- 0429), MASON J. CAMPBELL,SEAN SLOAN,MOHAMMED ALAMGIR and WILLIAM Consequently, many of these regional studies overlook F. LAURANCE Center for Tropical Environmental and Sustainability Science, challenges associated with localized land-use and land-cover College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia. E-mail [email protected] change processes such as selective logging, small-scale log- Received May . Revision requested June . ging, land clearing and the establishment of smallholder Accepted June . First published online August . oil palm plantations, particularly in areas of high biodiversity Oryx, 2020, 54(6), 882–891 © 2019 Fauna & Flora International doi:10.1017/S0030605318000881 Downloaded from https://www.cambridge.org/core. IP address: 170.106.35.234, on 25 Sep 2021 at 05:06:24, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605318000881 Threat of land-cover change in Cameroon 883 containing disturbance-sensitive wildlife. Understanding tropical forest conservation in the Littoral Region or in equa- underlying land-use and land-cover change processes and torial Africa as a whole. patterns retrospectively at a detailed scale is important for The history of extensive forest loss in the Littoral Region conservation managers, as it can facilitate the development is poorly documented, and its drivers are poorly under- of sustainable socio-ecological management solutions for stood. Here, we provide spatially explicit land-cover change addressing current and imminent environmental challenges analysis and information about forest fragmentation. We in these forests. also discuss the potential influence of these human actions Southern Cameroon is experiencing rapid forest loss on the long-term sustainability of natural forest conserva- (Cheek et al., ; Ingram et al., ). The Littoral tion. To achieve these aims, we addressed the following Region, in south-western Cameroon, has the largest area questions: () How have land surface dynamics changed in of continuous tropical forest, within the Nkam and Sanga- the Littoral Region from to ?() What are the Maritime areas, bordering the Ebo and Dibamba rivers drivers of land-cover change? () How may land-cover north of Cameroon’s industrial capital Douala. This area in- change imperil future conservation of critical biodiversity cludes the proposed Ebo National Park, which is among the and wildlife habitats? few remaining intact forest landscapes in Africa north of the Sanga River (Potapov et al., ). However, Ebo Forest remains legislatively unprotected despite efforts to designate Study area the area as a National Park. Ebo Forest provides important We examined a , km study area encompassing Ebo habitat for the Critically Endangered Preuss’s red colobus Forest (c. , km ) in the Littoral Region of Cameroon Piliocolobus preussi and gorilla subspecies Gorilla gorilla (Fig. ). Mean annual precipitation in the area is ,– diehli and Gorilla gorilla gorilla, the Endangered Nigeria– , mm in the northern and interior regions, and Cameroon chimpanzee Pan troglodytes ellioti and drill ,–, mm in the southern and coastal zones. Mean Mandrillus leucophaeus, and the Vulnerable African forest annual temperature is – °C (Molua, ). The land- elephant Loxodonta cyclotis (Morgan et al., , who also scape is relatively flat, although there are some areas of provide further details of the ecology and geography of undulating terrain, and a few mountains rising to , m the region). Given the unprotected status of Ebo Forest, it inside the boundaries of the proposed Ebo National Park remains particularly vulnerable to anthropogenic pressures (the proposed boundaries are currently under review). such as deforestation and hunting, especially considering Human activities in the Littoral Region, such as unsus- the unprecedented scale and pace of deforestation in the tainable levels of logging, selective logging, land clearing, surrounding areas. These threats remain unchallenged be- farming and hunting, place the regions’ biodiversity (in- cause of delays in securing legal protection, thus threatening cluding that in Ebo Forest) under severe threat (Morgan the long-term integrity of Ebo Forest. et al., ; Whytock et al., ). Large-scale bushmeat The Littoral Region of Cameroon also encompasses wholesalers travel to local villages near Ebo Forest by Mount Nlonako, along the north-western axis of the region. timber trucks, motorcycles and taxis to buy bushmeat Mount Nlonako has a rich diversity of amphibians, birds from hunters to supply the region’s rapidly increasing and reptiles but is subject to human incursions. Both population (from . million in to nearly . million Mount Nlonako and Ebo Forest are located in relatively in ). In addition, the humid equatorial climate of the close proximity to Douala (Mount Nlonako c. km to Littoral Region makes it a suitable location for oil palm the north-west of the city, and Ebo Forest c. km to the plantations. Palm oil production is expanding rapidly, north-east). With its proximity to wildlife habitat, Douala

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