Millennia of climate and human influence on Gashaka-Gumti montane landscape, West Africa: Implications for biodiversity conservation and management

Abstract

The palaeoecology and palaeoclimate of montane ecosystems in Africa are poorly understood due to limited available studies. This is particularly true for Gashaka-Gumti National Park (GGNP) montane landscape in the largest forest reserve in Nigeria, western Africa. To fill this knowledge gap, we analysed pollen and non-pollen palynomorphs from Chappal Hendu shallow sedimentary deposits dating back at least ∼12,000 years, to understand millennial vegetation changes and identify drivers of change in the GGNP. During the Holocene humid period, wet forests gradually replaced montane communities over millennia, whereas in modern times, this shift has occurred abruptly within decades. Forest expansion was greatest in the area in recent decades, whereas a mosaic of forest and non-forest communities characterized the landscape throughout the Holocene partly due to human landscape management with fire. The establishment of GGNP as a forest reserve has resulted in forest area doubling Holocene levels and the reduction of open vegetation types. Our results demonstrate the sensitivity of montane ecosystems to climatic pressure and susceptibility to future warming. They further underscore the importance of park management strategies that balance forest expansion with the preservation of ancient cultural mosaic landscape to prevent the total loss of open vegetation communities and associated fauna diversity in the long term. These findings provide a framework for developing conservation goals for sustainable outcomes.