Water Retention Potential in Novel Terrestrial Ecosystems Restored on Post-Mine Sites: A Review

Many activities are conducted with the view of reducing CO2 emission from fossil fuels, but mining extraction will continue to be important for energy sources, mineral and metal ores, and the general economy. This activity has negative environmental consequences such as habitat loss, water scarcity, and soil degradation in novel ecosystems. Additionally, climate change, drought, and desertification accelerate important problems with water retention. From one point of view, identifying and conserving critical regions for ecological sustainability are issues of fundamental importance, but on the other hand, post-mine sites could provide additional carbon sinks and improve regional water retention (WR). This review paper analyses different studies focusing on the impact of the reclamation of mining sites on the water retention properties of soil. Water retention in reclaimed mining soil (RMS) increased considerably after various restoration efforts were implemented. The amount of water holding capacity in RMS was mostly affected by reclamation methods, soil properties, soil biota, restoration duration, and vegetation type. The major conclusions from the analysis were that (i) the bulk density of reclaimed mining soil ranges from 1.35 to 1.50 g/cm3 and decreases with restoration duration; (ii) Soil fauna increases soil water storage capacity and plant litter and earthworms convert litter to fecal pellets, which increases water field capacity; and (iii) water holding capacity increases with duration of reclaimed sites and type of plants, i.e., afforestation and tree communities have higher WR than younger grasslands. Therefore, identification of the suitable reclamation method, restoration duration, vegetation type, and soil fauna are important factors for increasing water retention capacity at a regional scale.