1 Introduction

In the current era, the degradation of an environment is linked with the developmental activities and unconsciousness of people about maintaining the ecological balance of the Earth. Humans since pre-historic times utilized natural resources for their comfort despite of their limited availability. Naturalization of humans has turned into the humanization of nature eventually changing the very existence of repletion of both biotic and abiotic resources. Mining of important elements from Earth’s crust is an old phenomenon which eventually turns it into barren nutrient less land. The restoration of such drastically disturbed mined lands had always achieved a great significance throughout the world. The process of restoration has become an integral part of the developmental processes around the globe (Maiti and Ahirwal 2019).

Human activities in the name of development have changed Earth’s surface and ecosystems the most in recent decades (Hu et al. 2020), and mining, like most human livelihoods, has had the greatest impact on ecosystem structure and function (Gabarron et al. 2018; Luna et al. 2018). Mining regions often experience severe environmental deterioration, including vegetation loss, soil erosion, and quality reduction (Karaca et al. 2018). Certain measures like tree planting, agricultural reclamation, and other vegetation restoration programs can speed up soil repair and increase the biological richness of land degraded by mining (Hou et al. 2019). The damage which is caused by mining is tabulated in Table 1.

Table 1 Environmental damage due to mining
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2 Significance of Soil Restoration

Soil restoration is the most important and foremost step in ecological restoration. Soil being one of the limited resources available to mankind, it needs proper attention during ecological restoration as it takes thousands of years for soil to restore its fertility. Some environmental, natural, and anthropogenic factors directly or indirectly affect the soil. Climate change and global warming affect the decomposition pattern and nutrient cycling. Besides these, natural disturbances like floods, drought, and landslides also add to soil degradation (Williams et al. 2020). Some anthropogenic factors which drastically affect the soil are mentioned in Fig. 1.

Fig. 1
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Anthropogenic causes of soil degradation

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Soil health indicators include soil organic matter, total nutrient elemental concentration, available nutrient elemental concentration, pH, and electrical conductivity. Plant recolonization and establishment depend upon the physical, chemical, and biological (nutrient) support from the soil health (Shrestha et al. 2019). Vegetation restoration improves soil conditions making it conducive for species colonization and ecosystem development by increasing soil organic matter and nutrients (Kumar et al. 2015). To forecast vegetation restoration status and soil conditions, humans must understand the likely changes in soil organic matter content and nutrient proportion throughout the restoration period.

Revegetation in arid environments is one of the best approaches to improve the soil quality and address ecological restoration (Li and Liber 2018). However, very few plant species can thrive in degraded mined lands due to the scarce availability of soil nutrients and the high degree of metal toxicity (Wang et al. 2018). Furthermore, choosing promising plants is challenging when biological invasion concerns are considered because invasive species suppresses the growth of native plant species which leads to low biodiversity and an unstable environment (Bauman et al. 2015). For speedy restoration of degraded mined lands, the use of native plant species may be the optimal tool to wade off the threat of invasive and alien species.

The mining sector is an important sector and is related to the development of a country. But mining brings deterioration of environmental entities along with it. The degradation of soil is an unavoidable issue which accompanies mining activities. Deforestation, soil erosion, and overburdened dumps are the consequences of mining. Post the mining process, the lands get degraded which if left as such will take many decades to reach the climax stage of ecological succession. The challenging task in ecological restoration is the soil restoration which can be carried out through the plantation of species preferably native plant species for faster growth and reclamation of land.

Ecosystem reconstruction—restoring the land’s ability to capture and retain resources—is the main objective of mined land restoration. Ecosystem restoration can stop degradation, increase ecosystem utility, and restore biodiversity. Ecosystems and species loss harm people and the environment. Ecosystem service decrease might cost $10 trillion in global GDP by 2050. Thirty-three percent of commercial fish stocks are overfished, threatening over 60 million fishermen worldwide (FAO 2020). Fresh water supports 1.4 billion livelihoods, including food, energy, and water (United Nations 2018). A healthy and productive ecosystem is required to reap environmental, economic, and social advantages to its optimum. Ecosystem restoration can stop degradation, increase ecosystem utility, and restore biodiversity (Strassburg 2020). Figure 2 shows the need for ecological restoration of degraded mined lands.

Fig. 2
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Need for ecological restoration

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Though mineral extraction and utilization in any country are pertinent to boost up its economy, yet in the same context, maintenance of the ecosystem is equally important for the subsistence of life on this planet earth. After mining the overburdened dumps do not support any vegetation, here arises the necessity for human intervention to restore such degraded mined lands. Knowledge on the adaptability of different plant species and their role in nutrient dynamics is vital to indulge in restoration measures through biological means (Gairola 2014).

Margenau et al. (2019) suggested plantation of native plant species accelerates the forest succession on degraded mined lands. The restoration of the degraded mine sites includes the control of all types of disturbances of soil, i.e., physical, chemical, and biological. Various factors like the pH of soil, fertility of soil, and soil microbial community which makes the degraded soil productive need to be monitored for better results. Revegetation with native species has been the oldest yet an effective process for restoration of the degraded lands (Gairola 2014).

2.1 Importance of Plantation in Degraded Mined Lands

The mining methods, height, slope of the overburdened piles, the nature of the mine soil, and the geo-climatic conditions are not only the factors on which the success of the mined soil recovery depends but in addition to these factors like the choice of plant species selected for reclamation/restoration of the mined land plays a key role (Pinto et al. 2020). Ahirwal and Pandey (2020), in their study, focused on the selective plantation of the species which can withhold the stress conditions, climate resilience, and moreover be native to the study area. The restoration success depends on the selection of plant species and various soil amendments made so that the topsoil productivity can be enhanced and degraded mined areas can be recovered and restored quickly. Gordana et al. 2019 studied the importance of vegetation on the fly ash deposits generated from coal combustion by using native plant species. The reason for the selection of native plant species is its best adaptation to the local environment and boosting up the ecorestoration management. Native species can tolerate the harsh weather condition thereby increasing the chances of thriving on degraded areas as stable plant communities. Table 2 describes the important studies taken worldwide on the importance of plantation in degraded lands and their major outcomes.

Table 2 Importance of selecting native plant species for ecological restoration
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Pietrzykowski (2019) emphasized that for ensuring landscape and environmental profits of degraded mined lands, restoration and establishment of a sustainable ecosystem are necessary. The plantation of tree species on the reclaimed mined soil is significant, because the success of restoration depends on the selection and adaptation of tree species on the degraded mined lands. Figure 3 shows the impact of ecological restoration on the environment.

Fig. 3
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Impacts of ecological restoration on the environment

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Buta et al. (2019) aimed at developing the strategy on the eco-restoration of degraded mined land in the northwestern part of Transylvania (Romania). The soil quality was improved overall with the increasing years of restoration. The results showed the revegetation in the abandoned and degraded mined land had brought out considerable changes in soil quality. The ecological integrity and self-sustainability of the degraded mined land were restored with the help of revegetation.

Swab et al. (2017) studied many species in combination with prairie species making a standard reclamation mix. The prairie species were used as they were native species of North America and were most helpful in creating higher diversity plantation in the three mined sites in South Eastern part of Ohio. Mishra and Patra (2017) found that the native plant species were helpful for faster restoration of the degraded mined land with initially few human facilitation and then naturally.

Pioneer species mainly the hardy plants, algae, or moss occupies the degraded area as they are able to survive in a hostile environment. They are the first species which returns to the degraded lands. During the restoration of degraded mined lands, emphasis shall be on planting the native species as it fulfills the restoration and reforestation objectives. Native species suits best for the restoration process. The use of native plant species in the ecorestoration process restores the socio-economic gains, and it enhances the environmental gains also, in the form of soil and water retention. It also helps in carbon sequestration and enhances the ecological succession in a degraded area. Figure 4 represents the steps which leads to ecological succession in degraded lands. Some of the major studies which have been undertaken by various researchers are tabulated in Table 3 with the outcome of their studies.

Fig. 4
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Steps leading to ecological succession

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Table 3 Key findings from degraded mined land studies
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3 Restoration of Degraded Land Sustainably

The goal of the “Decade on Ecosystem Restoration,” which the United Nations has designated to run from 2021 to 2030, is to restore damaged landscapes so they may once again support human livelihoods, mitigate the effects of climate change, and increase biodiversity. Restoring healthy ecosystems may benefit land and people, promoting biodiversity and stimulating economic growth—both now and after the pandemic, in a sustainable fashion when both environment and economic resiliency are urgently needed. Mansuy (2020) concluded that a chance to restore degraded landscapes and provide co-benefits, such as livelihoods and commercial prospects, is by investing in restoration. In India, 29% (96.4 million hectares) of land is degraded. India became the part of “Bonn Challenge” which is a global effort to restore the world’s degraded lands (approximately 150 million hectares) till 2020 and approximately 350 million hectares by the year 2030. While the challenge is a tougher one, therefore, a systematic planning is required for restoring vast amounts of degraded lands (The Hindu 2020).

In the current scenario, the plantation of the native species seems the best possible way not only to restore the degraded land but also to the onset of ecosystem functions and ecosystem services sooner. Singh et al. (2019) in their study discussed about the success of bioenergy plantation in degraded lands. Biofuels are the genetically engineered bioenergy crops which have the capability of growing in stressful conditions and can increase the soil fertility. On the other hand, the consumption of crude oil is increasing at a faster pace. Therefore, the biofuel plantation on the degraded lands can be a solution for solving the problem of energy crises and accelerate the restoration of degraded lands in a sustainable way.

4 Role of Degraded Mined Land Restoration in Mitigating Climate Change

The importance of physical features of restoration, the choice of plant species for biological restoration, and their combined impact on creating socioeconomic and environmental advantages are highlighted through practical approaches that are feasible for ecosystem restoration. Ahirwal and Maiti (2021) advise including a site-specific restoration strategy, using native plants for replanting, and including the neighborhood in restoration initiatives. In addition, they are crucial for achieving the UN-Sustainable Development Goals (UN-SDGs), which include eradicating poverty and hunger, supplying affordable and clean energy, reducing global warming, and restoring life to damaged lands. Some of the impacts are shown in Fig. 5.

Fig. 5
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Effects of climate change on the environment

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Mining and related activities severely disrupt the terrestrial ecology, causing significant land degradation and a crisis in the global climate. The formation of ecosystems and improved SOC sequestration are possible as a result of soil restoration techniques in mine wastes. Reclaiming mine waste increases soil horizon development rather quickly, which increases carbon sequestration capacity. As a result, reclaimed soil serves as a significant sink for atmospheric CO2. Though initially quite low when compared to undisturbed soils, the SOC content of restored mine soil steadily rises with the age of the revegetation.

The productivity of land uses developed on reclaimed areas and the properties of technosols determine the rate of carbon sequestration. Mine soils therefore have a great potential to increase their C capital. The accumulation and the current level of carbon in the soil determine a soil ‘s capacity to sequester carbon (Bandyopadhyay and Maiti 2022). Figure 6 depicts the customary practice of ecological restoration.

Fig. 6
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The ecorestoration of degraded land

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Ecological restoration can serve as a genuine climate change adaptation strategy because the plant it produces has a long lifespan and does not require ongoing maintenance (Lim et al. 2022). Degraded lands not only negatively affect the ecosystem services but also adversely affect the livelihood of the people. According to a published study, the restoration efforts in 15% of the total degraded lands in the world can prevent approximately 60% of extinction, and approximately 299 gigatonnes of carbon dioxide can be soaked up which has increased since the onset of industrial revolution. The study further reveals that 70% of the birds, amphibians, and mammals can be saved from the risk of extinction, provided 30% of the world’s degraded lands are restored to their original condition, and additional 465 billion tons of carbon dioxide will be sequestered (Strassburg 2020). The degraded mined lands if restored efficiently can act as a carbon sink for greenhouse gases. The process of reclamation is a significant part of mining operation which aims to stabilize degraded mine sites and also results in carbon sequestration. The restored land can act as a carbon sink and can also contribute potentially to the future carbon credit commodity.

5 Future Prospects of Ecorestoration

Active interventions are the need of the hour to stop or reverse ecological function and loss in degraded ecosystems worldwide. Under future climates, restoration may not be enough to reverse habitat loss and restore functions. Restoration could also include primitive steps to strengthen extant populations’ resilience and adaptability to expected future conditions. Adapting lost habitats to future conditions may improve restoration success. In general, restoration in the classic sense of returning a system to a prior state is unlikely to be sufficient or effective under future climates; instead, restoration should strengthen and may redefine populations and species to endure future environmental shocks. According to an online UNEP report, ecosystem services, or the advantages individuals get from ecosystems, are worth more than 10% of global economic production and influence 3.2 billion people or 40% of the world’s population (UNEP 2021).

The world needs to fulfil its current obligations to rehabilitate 1 billion hectares of damaged land. One of the most crucial and viable methods for providing biologically based solutions to issues like food insecurity, climate change, global warming mitigation and adaptation, and biological diversity loss is ecosystem restoration. It would not be quick or simple, and it will require significant adjustments to everything from how we gauge economic growth to how and what we consume. The wonder of ecosystem restoration, however, is that it can take place at any scale, and everyone can play a part.

6 Conclusion

The degraded lands are one of the important contributors to climate change as they lose soil carbon and also emit the GHG’s (Greenhouse Gases). In the current scenario, when the world is combating the problem of climate change, degraded lands can prove to be an asset if restored efficiently. Degraded lands which are lying unutilized, through proper restoration strategy, can become the bigger source of carbon sink. According to an estimate, ecosystem services loss due to the degradation of land is between 6.6 and 10.6 trillion USD annually. (IUCN 2015). Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem (IPBES) reported the reduction of crop yield by 10% globally, and in certain regions, the reduction will be approximately 50% by the year 2050 (SEI 2018).

Thus, the above-mentioned scenario poses to be the biggest threat for us and our future generation, which can worsen if not controlled. The restoration of degraded lands at an extensive scale has become the need of an hour. Turning the degraded land into agricultural land can be a difficult choice, but when a country like India with the second highest population in the world is developing at a faster pace and wants to end up its food insecurity, then turning the reclaimed land into agricultural land seems to be a good option Lei et al. (2016). Many climate-resilient crops which can undertake the abiotic stress like soil infertility and less availability of water can be planted according to the topography of the area. Apart from the plantation of native species, millets can become a suitable option for restoring the fertility of restored sites. Research and development regarding the plantation of millets in the restoration lands is highly required.