Variability in the Carbon Management Index and Enzymatic Activity Under Distinct Altitudes in the Alpine Wetlands of Lesotho

Knight Nthebere (), Dominic Mazvimavi, Makoala Marake, Mosiuoa Mochala, Tebesi Raliengoane, Behrooz Mohseni, Krasposy Kujinga and Jean Marie Kileshye Onema
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Knight Nthebere: Department of Soil Science and Resource Conservation, National University of Lesotho, Maseru 180, Lesotho
Dominic Mazvimavi: Department of Earth Science, University of the Western Cape, Bellville 7535, South Africa
Makoala Marake: Department of Soil Science and Resource Conservation, National University of Lesotho, Maseru 180, Lesotho
Mosiuoa Mochala: Department of Soil Science and Resource Conservation, National University of Lesotho, Maseru 180, Lesotho
Tebesi Raliengoane: Department of Soil Science and Resource Conservation, National University of Lesotho, Maseru 180, Lesotho
Behrooz Mohseni: Research Department of Natural Resources, Golestan Agricultural and Natural Resources Research and Education Center, AREEO, Gorgan 4915677555, Iran
Krasposy Kujinga: Unit of Environmental Sciences and Management, North West University, Mahikeng Campus, Mmabatho 2790, South Africa
Jean Marie Kileshye Onema: Unit of Environmental Sciences and Management, North West University, Mahikeng Campus, Mmabatho 2790, South Africa

Sustainability, 2025, vol. 17, issue 19, 1-23

Abstract: Alpine wetlands, key carbon sinks and biodiversity hubs, remain understudied, especially under climate change pressures. Hence, the present study was conducted to assess the variability in soil enzyme activity (SEA) and the carbon management index (CMI) and to utilize principal component analysis (PCA) to explore the variation and correlation between SEA and CMI as influenced by altitudinal gradients in alpine wetlands. This information is essential for exploring the impacts of soil degradation and guiding restoration efforts. The study was designed in blocks (catchments) with six altitudinal variations (from 2500 to 3155 m a.s.l), equivalent to alpine wetlands from three catchments (Senqunyane, Khubelu and Sani) as follows: Khorong and Tenesolo in Senqunyane; Khamoqana and Khalong-la-Lichelete in Sani; and Lets’eng-la-Likhama and Koting-Sa-ha Ramosetsana in Khubelu. The soil samples were collected in February 2025 (autumn season, i.e., wet season) at depths of 0–15 and 15–30 cm and analyzed for bulk density, texture, pH, electrical conductivity (EC), soil organic carbon (SOC), SEA, and carbon pools, and the CMI was computed following standard procedures. The results demonstrated that the soil was loam to sandy loam and was slightly acidic and non-saline in nature in the 0–15 cm layer across the wetlands. The significant decreases in SEA were 45.33%, 32.20% and 15.11% ( p < 0.05) for dehydrogenase, fluorescein di-acetate and β-Galactosidase activities, respectively, in KSHM compared with those in Khorong (lower elevated site). The passive carbon pool (C PSV ) was dominant over the active carbon pool (C ACT ) and contributed 76–79% of the SOC to the total organic carbon, with a higher C PSV (79%) observed at KSHM. The CMI was also greater (91.05 and 75.88) under KSHM at the 0–15 cm and 15–30 cm soil depths, respectively, than in all the other alpine wetlands, suggesting better carbon management at higher altitudinal gradients and less enzymatic activity. These trends shape climate change outcomes by affecting soil carbon storage, with high-altitude regions serving as significant, though relatively less active, carbon reservoirs. The PCA-Biplot graph revealed a negative correlation between the CMI and SEA, and these variables drove more variation across sites, highlighting a complex interaction influenced by higher altitude with its multiple ecological drivers, such as temperature variation, nutrient dynamics, and shifts in microbial communities. Further studies on metagenomics in alpine soils are needed to uncover altitude-driven microbial adaptations and their role in carbon dynamics.

Keywords: soil degradation; climate adaptation; soil biological activity; carbon sink; ecosystem-based adaptability; high altitudinal gradient (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2025
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