Assessing Changes In Ecosystem Services Value In Response To Land Use And Land Cover Changes In Africa

Globally,the ecosystems,ecosystem services(ESs),and ecosystem functions upon which humanity,directly and indirectly,depends for food,water,energy,etc.,are constantly altered by human pressure(indirect cause)and natural pressure(direct cause).Anthropogenic pressure includes the conversion of natural vegetation covers(e.g.,forests,savannahs,water bodies,and wetlands,through deforestation,urbanization,and population growth,to artificial land covers e.g.,built-up land,and cultivated land),and by natural pressure including impacts of climate change(e.g.,desertification,rising sea level,climate variability),thereby threatening sustainability and sustainable development.The spatial determination of these changes in LULC at a substantial scale(e.g.,national,regional,and continental scale)provides valuable insights to environmental managers.Also,the quantitative evaluation of the impacts(of LULC)on ecosystem services value(ESV)and functions and the estimation of the spatial trade-offs and synergies among the ecosystem services are informative.Appropriate management of multiple ecosystem services(ESs)in a balanced manner is a crucial and demanding duty.However,due to infrastructural limitations,we need more understanding of the spatial interactions among ESs in most African countries.So,these assessments provide insights that are crucial for tracking the progress in the African Union’s ’Agenda 2063’ initiative,the United Nations Global Goals,and enriching available scientific literature.Yet such broad research has not received the needed attention.Such a gap exists mainly in the African continent due to insufficient technical know-how,little or no international collaborative research,and lack of access to relevant infrastructure(such as the internet,electricity,fund,etc.)that aid such research.Therefore,we took 48 countries,5 African geopolitical regions,and the African continent as case studies,using MODIS imagery 500 m × 500 m spatial resolution to assess changes in 8 LULC types and determine their(LULC)continental hotspots.Our studies also used Benefit Transfer Method(BTM)to estimate changes in the total value of 17 ecosystem services(ESV).Also,we used it(BTM)to determine the changes in the value of the individual ecosystem services function in response to changes in land use and land cover(CLULC)from 2000 to 2019.Then,we conducted a sensitivity analysis to determine how sensitive the estimates of the value of ecosystem services were to the applied valuation coefficients.We further examined the trade-offs and synergies among 17 ESs and 8 LULC types based on our case studies.It was done by mapping the continental-level distributions for each of the 17 ESs,using classified land cover data of MODIS remotely sensed data,with a spectral band between 0.405 and 14.385μm and a spatial resolution of 500 m.Finally,we used Spearman’s rank correlation coefficient to determine the interactions among these 17 ESs.In addition,these studies utilized CA-Markov to simulate 2030 and 2040 ESs projections.Our findings show(1)LULC have changed from 2000 to 2019 at the continental scale due to climate change(direct cause)and anthropogenic activities(indirect cause),including desertification,climate variability,and rising sea level,also conversion of natural vegetation covers,particularly,forests(FS),and grassland(GL),to artificial land covers(e.g.,urban&built-up land-UB).These human activities are increasingly encouraged by rapid economic development,short-term economic gains,growing population,and expansion of UB(urbanization).(2)Between 2000 and 2019,the Central African region contributed the highest percentage gain in FS(294.23%)to the continent,followed by East Africa,with an increase of 112.54%.In contrast,West Africa contributed loss in FS(139.70%).This study discovered that the percentage of natural vegetation cover(FS,GL,and Shrubland-SL)increased the highest(403.10%)in Central Africa.It is followed by East Africa.However,West Africa contributes the most to the loss of natural vegetation.Forests are mainly distributed among a few countries in the Central African region from 2000 to 2019,including Gabon(68.87%),the Republic of Congo(67.48%),and the Democratic Republic of Congo(64.32%).Between 2000 and 2019,cultivated land(CL)was mainly distributed in the western and Eastern African nations.(3)At the continental level,cultivated land declined from 12.01%(402.06 billion hectares)in 2000 to 7.65%(256.20 billion hectares)in 2019.This amounts to a negative 4.36%(-145.86 billion hectares)change from 2000 to 2019.(4)We also found that African ESV of natural ecosystems increased from approximately 9.13 trillion US$ yr-1 to 11.63 trillion US$ yr-1.(5)However,continentally,on an individual(LULC type)basis,forests(FS)and grassland(GL)saw respective losses of 76.86 billion US$ yr-1(-4.46%),and 433.53 billion US$ yr-1(-25.13%).(6)Man-made ecosystems decreased(by 77.79 billion US$ yr-1)from 2.24 trillion US$ yr-1 to 1.47 trillion US$ yr-1.CL accounted for 97.27%of the decrease,while UB contributed 2.73%.(7)Generally,at the African(continental)scale,the total ESV increased between 2000 and 2019,from US$11.37 trillion to US$13.10 trillion,gaining 1.73 trillion US$ yr-1,with an annual rate of 3%.(8)The overall change from 2000 to 2019 indicated a decrease in food production from 23.28%in 2000 to 18.09%in 2019 at the continental level.(9)Regionally,the increase in ESV is highest in East Africa and lowest in Southern Africa.(10)On the other hand,the highest decrease in ESV occurred in West Africa.Our assessment of the synergies and trade-offs among ESs demonstrated that moderate levels of interactions among most ESs across the 48 countries,and most regulating services and supporting services revealed trade-offs with ESs of the other categories,etc.(11)At the continental level,17 ESs indicated that regulation services were positive values in Gas Regulation(0.66),Climate Regulation(0.71),Pollination(0.68),Biological Control(0.65),and Erosion Control(0.58),Disturbances Regulation(0.14),Water Regulation(0.53),and Waste Treatment(0.06).Provisioning services,including Food Production(0.72),Raw Materials(0.73),Genetic Resources(0.69),and Water Supply(0.71),increased in value,showing that there has been a synergy among these ecosystem services for years.Also,Cultural Services,consisting of Culture(0.62)and Recreation(0.60),show that there is synergy while Supporting Services,Nutrient Cycling(0.01),Soil Formation(0.88),and Habitat(0.58)represent a synergy among the ecosystem services.Nationally,Algeria showed trade-offs in CL(-0.27),WL(-1),WB(-0.25),and UB(-0.72),whereas the others indicated synergic relationships.Angola demonstrated trade-offs in WL(-0.9),WB(-0.21),and UB(-0.61),while the remaining LULC types indicated synergies,etc.The synergic outcome in Algeria indicates good economic growth and strong cultural and tourism development.This studt shows that unprecedented changes in land use and land cover(CLULC),which impacted ESV,have occurred across 48 African countries,5 African geopolitical regions,and the continent at large,from 2000 to 2019,due to climate change and anthropogenic activities.The situation is currently difficult,as it impacts food security on the continent.However,as the Africa Union’s ’Agenda 2063’progresses and the United Nation’s SDG initiatives continue to pursue Global Goals,our future projection offers a glimpse of hope for Africa.The Creation and implementation of environmental protection policies,appropriate land use management laws,and advanced agricultural practices will encourage the use of green energy(solar and wind energy).By so doing,authorities ensure sustainable LULC change,increasing ESV and sustainable ecosystems to benefit our generation and future generations.We recommend that the conversion of the natural ecosystem is a priority in future land use management across African countries and in Africa-a continent vulnerable to climate change and continually affected by extreme climate events,including drought,flooding,and desertification.Policymakers should focus on managing land for construction,and protecting forests,grasslands,and surface water bodies with high environmental benefit values.