Impact of Land Use and Climate Change on Vegetation Dynamics of Doma Forest Reserve in Nasarawa State, Nigeria

Abstract

Nigeria’ forests reserve are reducing due to human activities. Forest reserves in Nigeria are depleted as a result of cropland expansion, pastureland and logging activities. A lot of studies have showed that deforestation is serious environmental problem in Nigeria with forest loss occurring at a highest world ‘rate of 3.3% per year. The aim of this study is investigate the impact of land use and climate change on Doma forest reserve dynamics by combining Remote Sensing, GIS techniques and field data measurement. Land satellite images for 1984, 1999 and 2015 were downloaded from GlOVIS. The field data were obtained from Doma forest inventory and questionnaire was used. The three years of satellites images were processed using ArcGIS 10, ENVI4.7 and IDRISI 17, for computerizing the maps of Normalized Vegetation Index (NDVI).Excel was used for statistical calculations. NDVI map comparison, NDVI differencing and descriptive statistic were used for the data analysis for Doma forest change detection. Floristic analysis was used to describe the woody flora of Doma forest reserve. Descriptive statistic was used to find out climate change perception of Doma forest reserve communities and their perception about the impact of climate change and land use affecting Doma forest dynamics. Doma forest reserve NDVI analysis revealed that high positive NDVI values of + 0.57 was recorded in 1999 while the lowest of -0.035 occurred in 1984 and followed by + 0.05 of 2015.But there was much reduction in Doma forest reserve greenness in 2015. As for Doma forest reserve woody flora description, the analysis showed that 36 woody species were recorded belonging to 16 botanical families and 36 genera within 10 plots but Fabaceae had the highest number of woody species (seven species) distributed in seven genera. All the recorded genera were monospecific. Questionnaire data analysis revealed that that 69 among 100 of the respondents were aware of climate change but only 31 respondents were not aware of climate change. Further, the analysis showed that 30% of the people perceived that climate change has impact on Doma forest reserve dynamics. Their feeling was that the impacts of climate change on Doma forest reserve dynamics were dryness of the forest and the long presence of Fulani men within the reserve due to the long delayed onset of rainfall. Nevertheless, 41% of Doma forest communities perceived that farming activities impacted more Doma forest dynamics followed by illegal logging and grazing. The study concluded there was substantial decrease in Doma forest reserve greenness form 1999 to 2015.Further, the study concluded that unsuitable land use practices such as the use of fire, cutting down the trees for land clearance, the collection for timber, the huts of Fulani men within the reserve were the land use of the depletion of Doma forest reserve.