Assessing wetland functionality using soil surface indicators in Letšeng- la-Letsie wetland in Quthing District, Lesotho

Abstract

Wetlands are globally valuable ecosystems as they provide many important services to the human society, yet the ecology of some of them is yet to be understood. This study assessed the functionality of Letšeng-la-Letsie wetland in Lesotho, using the Landscape Function Analysis (LFA) technique and soil quality indicators. LFA threshold values for stability, infiltration and nutrient cycling were found to be >50%, >30% and >20%, respectively, whereas the mean surface stability, infiltration and nutrient cycling were 55.4 ± 1.9%, 28 ± 1.9%, and 15.5 ± 2% respectively. Although soil cover was high, the soil was unstable with low litter and low cryptogam cover. These rendered the soil less fertile, resulting in lower primary plant productivity and nutrient cycling potential. The three LFA indices were correlated with soil quality indicators, including pH, carbon, nitrogen, soil texture, calcium, magnesium, sodium, potassium, cation exchange capacity and phosphorus. Clay content and CEC had a significant (p < 0.05) negative correlation with the LFA indices and soil organic carbon. Redundancy analysis showed that stability was positively correlated to soil carbon and potassium. Monitoring of this wetland ecosystem is deemed necessary for the early warning of possible landscape degradation, as a result of induced pressures on the ecosystem.