Volume 7, Issue 9, September – 2022 International Journal of Innovative Science and Research Technology ISSN No:-2456-2165 IJISRT22SEP012 www.ijisrt.com 359 Importance Value Index and Species Relative Contribution to Carbon Stocks in Savanna Ecosystems : Implications for Climate Change Mitigation and Forest Management in Patako Forest (Senegal) Simon Sambou 1* , Laurice Codou Faye 1 , Fatimata Niang Diop 1 , Sara Danièle Dieng 1 , Cheikh Mbow 1 1 University Cheikh Anta Diop of Dakar, Faculty of Sciences and Technologies, Institute of Environmental Sciences, Research Unit on Natural Ecosystems and Environment, Dakar-Fann, Senegal Abstract:- Understanding species Importance Value Index (IVI) and contribution to carbon storage is key to improving knowledge on climate change mitigation and forest management models. The present study conducted in Patako Forest aims to investigate how species harvested for fuelwood and timber contributed to carbon sequestration. Data was collected using a stratified random sampling in 251 plots from different vegetation types. The results showed a good species richness of 102 species with significant variation of IVIs among vegetation types. Indeed, more than 90% of the IVIs was dominated by 21 species. It was dominated by fuelwood species in the savanna types and woodland, whereas timber species dominated in the gallery forest. This relative importance influenced species carbon storage contribution. In the shrub savanna 88.57% of carbon was stored by four species among which Combretum glutinosum (56.95%), with an IVI of 160.62 recorded an average of 7.67±1.30 t.C/ha. An inequitable carbon distribution was also recorded in tree savanna where five species counted about 80% of the carbon stock. Combretum glutinosum, Terminalia macroptera and Cordyla pinnata were the most frequent species and contributed about 72% of carbon stock in the woodland. In gallery forest, Khaya senegalensis stored the largest carbon stock (40.36±2.31 t.C/ha) with an IVI estimated at 38.52. The relations between IVI and species contribution to carbon storage should be taken into consideration for sustainable forest management in the context of climate change. Keywords:- Importance Value Index, Carbon stocks, Forest management, Patako Forest, Savanna ecosystems. I. INTRODUCTION Carbon is globally held in a variety of carbon sinks forming a biogeochemical cycle with permanent carbon fluxes exchanges between sinks that play an important role in the global climate. As part of the biosphere, forests store about 862 Gt carbon in live and dead vegetation and soil, with 42% of it stored in live above and belowground biomass (Pan et al., 2011). Carbon sequestration involves the capture, transformation or energy conversion and storage of the carbon from the atmosphere which would otherwise increase global warming through cumulative effect. Among approaches being proposed to mitigate climate change, the need to enhance forest ecosystems through carbon sequestration has gained momentum these last decades (Anthony et al., 2011). Forests play a significant role in climate change mitigation as they emit as well as sequester CO2. Tree cover loss due to deforestation and forest degradation contribute to about 10-20% of global CO2 annual emissions (van der Werf et al., 2009). The importance of forest carbon storage is more and more amplified by a warming climate that needs to be urgently addressed with reduction in greenhouse gases (GHG) and natural-based solutions initiatives (Ripple et al., 2020). Hence, estimating the carbon content in the woody vegetation becomes relevant to improve the knowledge of carbon sequestration potential of the most important and preferred species for communities. Restoring degraded forest ecosystems or planning and implementing a sustainable forest management strategy can support long term carbon sequestration and has a combined co-benefit of controlling wood collection and conserving of biodiversity while reducing GHG emissions from uncontrolled deforestation rates. Savannas are known as dynamic ecosystems with many direct and indirect drivers that influence biomass (Sambou et al. 2015) but have a huge potential of carbon sequestration (Mbow et al., 2014). Sudanian savannas are spatially large and sensitive due to various human activities they cover but are key option to mitigate global warming and global climate change. Human activities on forests ecosystems can affect CO2 source/sink dynamics through factors such as fuelwood collection and timber harvesting. These activities often imply an exportation of biomass outside the ecosystem. This result in a loss of carbon as biomass combustion (fuelwood and