Landscape patterns and modelling of soil-vegetation relationship and related ecosystem services to support landscape conservation in the Mo River Basin (Togo)

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MAY 2016
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In order to support integrated land scapes and restoration efforts, this research focused on the a ssessment and monitoring of the spatio - temporal land use/cover change (LUCC) and degradation in the Mo River Basin (a subunit of the Volta basin of about 1,490 km 2 in Central Togo). Field measurements, legacy and ancillary data were subjected to s equential multivariate methods , correlation analyses , geostatistics and modelling to analyse landscape conditions. First, a long a gradient of land protection regime, data from extensive soi l sampling and forest inventory were used to analyse soil organic carbon ( SO C ) and total nitrogen ( TN ) storage up to 30 cm depth, and the interactions between vegetation - soil conditions. Next, Landsat images o f 1972, 1987, 2000 and 2014 combined with most updated global topographic and soil databases were used to analyse the land s cape cha nges a nd its impacts on SOC , TN , soil loss potential and landscape patterns. Finally, the Landscape Management and Planning Tool adapted for the Mo basin (LAMPT_Mo), a spatially explicit model based on the Revised Universal Soil Loss Equation (RUSL E) , was used to model the historical soil loss, and evaluate the efficiency of some land management scenarios. Different databases and field characterisation were used for model calibration and validation. The results showed that SOC and TN varied signific antly according to land use/ cover types, soil depths, topographical positions and land protection regime. With forests and woodlands exhibiting highest amounts of nutrients, mean TN varied from 0.06 to 0.16 % in the topsoil (0 – 10 cm) and 0.04 to 0.09 % i n the subsoil (10 – 30 cm). Similarly, SOC ranged from 1.81 % in farmlands to 3.58 % in forests in the topsoil while woodlands had highest SOC in the subsoil (2.23 %). The river basin is made up of four and three vegetation types in unprotected and protect ed areas, respectively. The synergized effects of land protection status, soil conditions, landform, and human disturbances drive these vegetation patterns.
A thesis submitted to the Department of Civil Engineering in partial fulfillment of the requirements for the award of a Doctorate Degree in Climate Change and Land Use.