Journal of Earth Science & Climatic Change
Open Access

Abstract

Assessments were carried-out for six years on wetlands located in the Orange-Senqu River Basin (OSRB), the Foot-Hills Agro-Ecological Zone (AEZ) of Lesotho - (Ha-Matela- (HM)) and compared with an un-disturbed wetlands (Khalongla- lithunya (KHL)), in Mountains AEZ. Data were collected on climate, profile soil samples (1.50 m), hydrochemistry (subsurface) and socio-economics of the inhabitants. Soil and water samples were analyzed for Ca, Mg, K, Na, N and P and micronutrients and vegetation isotopic N15. Results showed that higher base cations were observed in the groundwater of ORRB and HM, compared to KHL. The hydrochemistry of groundwater in OSRB and HM had elevated levels of phosphorus beyond the limits of the USEPA/NOAA (1988) compared to that in the KHL which was in the normal range. The results of the N15 isotopes varied between -2.52 to -2.93â?° (KHL) compared to 2.00 to 6.18 â?° (HM). Results of the d13Cshowed that has significant negative values at KHL (i.e. -28.13 to -28â?°) compared to HM (-11.77 to -12.72â?°). Results of the socio-economic study showed that the livelihoods of most inhabitants were crop production (51.3%) and crop-livestock production (47.5%). Between 67-83% of the population living close to the wetlands believed that degradation of wetlands in the past 25 years was due to increase in human population (70%), house construction (72.5%), farming (67.5%), sand mining (73.8%) and aquaculture (80%). The study concludes that even after six years wetlands (OSRB and HM) have not returned to the status of an undisturbed wetlands (i.e. KHL) status indicated by high SOM and more negative N15 and d13C values.

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