When survey teams entered Mbam Djerem for the first time in March 2000, they carried maps printed in 1976 from aerial photographs taken in the 1950s and 1960s. The maps showed bush savannah in the park's interior. What the team found instead was shady woodland -- dense stands of Xylopia aethiopica trees, all roughly the same age, with dying savannah bushes mixed in among them and almost no grass on the forest floor. The forest had been quietly advancing into the grassland for decades, and the maps had not kept up. It was the first sign that Mbam Djerem was not just another protected area but a place where the boundary between two of Africa's great biomes was actively shifting underfoot.
Established in January 2000, Mbam Djerem National Park covers 4,200 square kilometers in the center of Cameroon. Roughly half is lowland tropical forest. The other half is Sudano-Guinean tree and woodland savannah. Between them runs a broad ecotone belt -- part of the Northern Congolian forest-savanna mosaic that stretches across Central Africa. This straddling of two major vegetation zones gives Mbam Djerem what is likely the highest habitat diversity of any protected area in Cameroon. Gallery forests line the river valleys. Transitional woodland grades into rainforest. Open, seasonally flooded grasslands spread beside the major rivers, one of which drops over a spectacular waterfall. Stand on any hilltop and the view is ridge after ridge fading into haze, some forested, some open, every valley threaded with a strip of green along the water's edge.
The park's main artery is the Djerem River, which is navigable throughout its length within the park and eventually becomes the Sanaga -- Cameroon's longest river -- further south. The Djerem connects the open savannahs of the north to the dense forest of the interior, and it is this waterway that structures life in the park. During the dry season, bushfires reduce the grasslands to ash and rivers shrink to trickles. Animals that need regular water are forced toward the Djerem and its larger tributaries, concentrated along the banks for months at a time. Hunters know this pattern intimately. Commercial bushmeat hunters travel in from the CamRail railway line that runs along the park's eastern border, using the dry season bottleneck to target buffalo, waterbuck, and kob -- meat destined for the markets of Yaounde and Bertoua, hundreds of kilometers to the south.
The ecotone creates biological collisions found almost nowhere else. Olive baboons, a savannah species, forage literally within meters of crested mona monkeys, creatures of the deep forest. All three African pig species -- red river hog, common warthog, and giant forest hog -- share the park. Hippopotamuses occupy several stretches of the Djerem. At least ten primate species have been confirmed, including chimpanzees. The bird list reached 360 species after the first comprehensive surveys, spanning savannah specialists like the brown-rumped bunting and forest dwellers like the black-casqued hornbill. Most remarkable was the discovery that the Bamenda Apalis -- a bird previously thought to exist only in a small area of the Bamenda Highlands, 200 kilometers to the west -- was relatively common throughout the park. Elephants survive in the south-central forest but have vanished entirely from the north.
Older residents of villages west of the park remember the interior as grassland and bush forty years ago. The closed-canopy forest that survey teams found in its place tells a story of long-term ecological change -- the forests of Central Africa expand and contract on cycles linked to climate, advancing during wetter periods and retreating during drier ones. Mbam Djerem sits at the frontier of this process, a living laboratory for watching one biome become another. Scientists have flagged the ecotone as a zone where genetic differences within species may be precursors to speciation -- where the long separation of forest and savannah populations produces, over millennia, entirely new kinds of life. The park has no villages inside its boundaries, though a colonial-era dirt road along its western edge still carries traffic from communities that were relocated there generations ago. Young people from these villages are drifting to the cities, leaving the park increasingly alone with its shifting borders.
Located at 5.833N, 12.75E in central Cameroon. The park covers 4,200 square kilometers and is visible from altitude as a dramatic patchwork of dark forest and lighter savannah, bisected by the Djerem River. The CamRail railway line from Garoua to Yaounde runs along the eastern boundary. From the air, the ecotone -- the transition zone between forest and savannah -- is clearly visible as a gradient rather than a sharp line. Nearest airports are N'Gaoundere Airport (FKKN) to the north and Yaounde Nsimalen International Airport (FKYS) to the south. The park's western edge follows an old dirt road that was once the main route from Cameroon to Chad.