Investigation of tropical coastal forest regeneration after farming and livestock grazing exclusion

It is critical to understand how forests regenerate after the exclusion of human induced disturbances because the regenerating species drive the renewal of resources and ecosystems,which in turn support human beings locally and globally.This study of forest regeneration was conducted in the tropical coastal forest ecosystems of Tanzania at Uzigua Forest Reserve(24,730 ha)in the Pwani Region.We collected data from adult trees in 47 sampling plots(25×25 m)randomly established in closed forest sites(control)and in sites disturbed by farming and livestock grazing.Sapling and seedling data were collected and analyzed in 2×2 m nested subplots.Plots in the closed forest had higher mean basal area and volume for adult trees than those in sites disturbed by farming and livestock grazing.Plots in sites disturbed by farming had the highest Shannon–Wiener index for seedlings and saplings,followed by closed forest and livestock grazed sites.Closed plots and farmed plots had higher Simpson’s index for seedlings and saplings than in grazed sites.Plots in farmed and livestock-grazed sites had a higher Simpson index for adult trees than in closed sites.Equitability of seedlings and saplings was highest in closed forest sites,followed by farmed and livestock grazed sites.Plots disturbed by farming had higher equitability for adult trees than in livestock-grazed and closed sites.Moreover,plots disturbed by farming and grazing had a higher importance value index for seedlings than in closed sites.Plots in closed forests had higher sapling importance values than in farmed and grazed sites.Again,plots in closed forest had a higher importance value for adult trees than in farmed and grazed sites.The differences in tree species subcategories of regeneration across land-use indicates that farming and livestock grazing disturbances create heterogeneous microhabitats,which positively or negatively affects regeneration capacity of species after exclusion.

Evaluation of tropical coastal land cover and land use changes and their impacts on ecosystem service values

Understanding about land cover and land use(LCLU)changes,as well as the associated impacts on ecosystem service values(ESV)is extremely important in the management of coastal ecosystems globally.Thus,this study assessed temporal LCLU changes,the underlying socio-economic drivers and dynamics of ESV in the coastal zone of Tanzania.The LCLU data for 2000 and 2010 were from the Globe Land 30 mapping products at 30-meter spatial resolution developed by National Geomatics Center of China,while 2016 images were produced from Landsat 8.Classification of images was done from Landsat TM/ETM+for 2000,2010,and 2016 years complemented with MODIS and Normalized Difference Vegetation Index time series,and Chinese HJ imagery.LCLU categories and ecosystem service coefficients were used to compute ESV on each LCLU categories.Between 2000 and 2016,farmland,shrub land,waterbody,and artificial surface expanded while forest,grazing land,and wetlands declined.The ESV increased on farmland,shrub land,and waterbody,while the decline was found on forest,grazing land,and wetlands.The ESV and the total population ratios declined from$80.4,63.8,and$46.0 million in 2000,2010,and 2016,respectively.Perfect positive correlation was on LCLU change and ESV,population and households in crop farming,livestock keeping,and bioenergy use.Population pressure and socioeconomic activities have amplified the degradation of the coastal ecosystems.If not abetted,there is a danger of further impairments on these ecosystems.We advise to regulate population and socioeconomic activities to avoid more negative impacts of coastal LCLU change.