LDN as an integral indicator for sustainable land management (SLM)
The achievement of LDN is sufficiently linked with SLM applications to ensure ecological balance, food security and economic efficiency. However, the methods of assessment sustainability and related criteria remains important. It is obvious (and this is emphasized in a large number of works) that SLM approaches and technologies can be considered as a direct tool for achieving LDN, but in many cases the opposite is also true: LDN concept and indicators can be used to assess the sustainability of land use and land management (Andreeva et al. 2021; Kust et al. 2017; Orr et al. 2017). Despite the seeming simplicity of this nexus, which was first expressed in (Andreeva and Kust 2014), it appears to be an effective tool for decision makers at national and subnational level. For example, considering the multidirectional variety of degradation and restoration trends in different climatic and economic conditions of Russia’s territory, the “LDN Index” serves as a simple and effective tool for indicating SLM, effective land policy and reducing the risk of LD for any region. Negative values of the Index indicate a high proportion of degraded and vulnerable land and the need for sharing SLM good practices (Andreeva and Kust 2020, Kust et al. 2021a). The same principle is useful for individual farms: joint LDN and SLM assessment and mapping conducted in pilot sites of agricultural areas in the Kursk, Samara and Rostov regions demonstrated that territories with a positive LDN Index are characterized by effective SLM practices. For example, reducing soil erosion, decompaction of topsoil and SOC growth in the soils of the Samara region resulted from no-till technology (IGRAS, 2021).
The consistent development of the idea of using LDN for SLM assessment and the analysis of good SLM practices sets in Russia and in the world, have made it possible to classify land management models, and to determine the criteria for the sustainability of land management practices based on the analysis of land natural potential, risks of degradation processes and human impact. A hierarchy of land management practices was described with the determination of categories “practice”, “model”, “type”, and “class” (Andreeva et al. 2021). Fifteen types of land management were combined into four classes, including three classes of models (9 types in total) characterized by SLM practices, and one class (6 types) included practices, which are not sustainable. A detailed analysis of land management types showed that not all practices contribute to LDN achievement, and vice versa, not every LDN case is associated with any SLM model. This seemingly paradoxical and unexpected conclusion allowed us to rethink the SLM-LDN nexus.
Land management practices demonstrate growing human impact on the environment. However, they cannot considerably change dominating natural background processes but may act as triggers for shifting these processes to positive or negative direction and determining the intensity of soil erosion, salinization-desalinization, compaction-decompaction of soils, accumulation or loss of organic matter, etc. It was further proposed (Andreeva et al. 2022) to assess the “risks of not reaching” LDN due to the weakness of SLM practices against the background of dominating degradation processes. The latter is forming the basis for including the previously mentioned salinity, density, alkalinity, soil erosion as additional LDN indicators. This proposal is fully in line with the LDN response hierarchy and emphasizes that preventing and reducing degradation risks are more effective and less costly compared to land rehabilitation/restoration.
Further analysis puts forward a hypothesis that the achievement of LDN in a certain territory is determined not so much by the coverage of this territory with effective SLM practices, as by keeping an ecological frame of certain SLM type (core SLM areas and networks). Such frames maintain the sustainability of specific SLM models at minimal cost due to high natural potential or efficient land management technologies (Andreeva et al. 2022). These include, for example, agricultural areas using adaptive landscape and soil conservation technologies, networks of forest shelterbelts, hydrological networks of river basins, including their floodplains and valleys, etc. Such frames and core areas contribute not only to reducing LD risks, but also conserving biodiversity and mitigating climate change effects. The development of this hypothesis is the subject of further research.
Application of ecological standards and principles in achieving LDN becomes essential as the UN announced 2021-2030 as a Decade for Ecosystem Restoration. As the world is embracing a new paradigm of ecological restoration, rewilderness and nature-based solutions, some practical tools such as landscape restoration approaches or integrated land use planning (ILUP) could serve as useful decision-making tools which allow for optimization of SLM measures and planning for sustainable multifunctional landscapes. However, the spatial planning tools are not yet sufficiently discussed in the reviewed publications. This is reinforced by the analysis of the LDN targets in twelve countries of Europe and Central Asia (UNCCD 2021) which revealed that ILUP has not been considered as an entry point for LDN implementation. Current LDN targets in these countries largely represent the collection of isolated SLM interventions across various ecosystems.