Can Restoring Ecosystems Reverse Land Degradation? Lessons from China's Loess Plateau
"A half-century study reveals how ecological restoration reshapes ecosystem services and offers crucial insights for sustainable land management."
Ecosystem services (ESs) are the diverse benefits humans derive from the natural environment, encompassing everything from clean water and fertile soil to climate regulation and pollination. However, these essential services are increasingly threatened by land degradation, driven by factors like deforestation, unsustainable agriculture, and climate change.
Ecological restoration emerges as a vital strategy to combat land degradation and revitalize these crucial ecosystem services. It involves active interventions to rehabilitate degraded landscapes, aiming to recover their natural functions and enhance their capacity to provide essential resources and benefits.
To understand the long-term impacts of ecological restoration, researchers have turned to the Loess Plateau in China, a region with a long history of land degradation and ambitious restoration efforts. A recent study published in Science of the Total Environment delves into the intricate changes in ecosystem services over half a century, offering valuable lessons for sustainable land management worldwide.
The Scale of Global Land Degradation
Globally, one-fifth of the Earth's land area is degraded — an area nearly the size of India and Russia combined — driving species loss and undermining ecosystems. Approximately 3.2 billion people, or 40 percent of the global population, are adversely affected by nature loss and degradation. Land degradation affects roughly two billion hectares worldwide, primarily driven by deforestation, and restoration efforts have delivered only about 10 percent of national pledges, according to the IUCN.
The Restoration Continuum and Its Methods
The UN Decade on Ecosystem Restoration defines restoration as encompassing the full continuum of responses — from prevention and halting degradation to reversing ecosystem damage entirely. Stepwise ecological restoration offers a framework that addresses immediate degradation with targeted interventions while planning for long-term ecosystem recovery. However, estimates of global land degradation range widely from 25% to 75% of Earth's land surface, and the ambitious target of restoring 350 million hectares by 2030 faces significant methodological and practical hurdles.
The Promise of Restoration History
Ecological restoration has emerged as a critical discipline for reversing biodiversity loss, combating climate change, and supporting local economies. The UN Decade on Ecosystem Restoration (2021–2030) was established to mobilize global action on restoration, with the target of restoring 350 million hectares of degraded terrestrial and aquatic ecosystems. Ecological restoration projects can generate US$9 trillion in ecosystem services by 2030, though outcomes have historically been variable and unpredictable, limiting their overall impact on biodiversity.
How Ecological Restoration Transformed the Loess Plateau
The Loess Plateau, characterized by its easily erodible soil and semi-arid climate, faced severe land degradation due to unsustainable agricultural practices and deforestation. In response, the Chinese government implemented a series of ecological restoration programs starting in the mid-20th century.
- Food Provisioning: measured by crop yield
- Soil Retention: the amount of soil preserved annually
- Hydrological Regulation: water yield
- Carbon Sequestration: carbon stored in soil
- Water Purification: the level of nutrient retention
- Habitat Provisioning for Biodiversity: the quality of habitats for local species
Contemporary Research Frontiers
Recent reviews emphasize that ecosystem restoration is critical for achieving land degradation neutrality (LDN) by fostering synergistic relationships between land use patterns, ecological processes, and ecosystem services. The concept of LDN has been critically examined as a strategic approach to halt, prevent, and reverse land degradation, aligning restoration with broader sustainability goals. Restoration of degraded ecosystems is considered essential for maintaining a stable climate, reducing weather extremes and disease burden, and producing sufficient food and raw materials.
Challenges and Risks of Restoration
Many restoration efforts fail because they do not consider the needs and motivations of local stakeholders who interact most directly with the land. Restoration projects in terrestrial ecosystems generally rely on actions within minimal (97%) and maximal (86%) intervention categories, suggesting limited methodological diversity. Relying on restoration as a primary strategy is considered risky at best, since the processes it depends on are threatened by widespread loss across many regions, and the IUCN's UN Decade on Ecosystem Restoration acknowledges that massive scale-up remains an enormous challenge.
Restoration vs. Rewilding
Rewilding and ecosystem restoration are distinct approaches that are often conflated because both rely on similar management techniques and ecological principles. The key difference lies in their goals: restoration aims to return an ecosystem to a historically known state, whereas rewilding seeks to allow natural processes to shape the ecosystem without predetermined outcomes. Both approaches offer valuable strategies but require different considerations depending on the landscape context, stakeholder expectations, and ecological baseline.
Balancing Ecosystem Services for a Sustainable Future
The study underscores the importance of long-term monitoring and adaptive management in ecological restoration projects. Understanding the complex interactions between ecosystem services and tailoring restoration strategies to local conditions are crucial for achieving sustainable outcomes and ensuring a healthy planet for future generations. Further research is needed to address the limitations of data availability and model uncertainties, refine restoration approaches, and foster a more holistic and integrated approach to land management.
Evaluating Restoration Effectiveness
The IPBES assessment report on land degradation and restoration recognizes that combating land degradation is an urgent priority occurring in all parts of the world. Expert frameworks have been developed to evaluate land degradation and restoration effectiveness through multi-criteria assessment, aimed at enhanced land use planning. The report concludes that avoiding land degradation and restoring degraded lands makes sound economic sense, resulting in increased ecosystem services and improved livelihoods.
The Decade Ahead for Restoration
Restoring 350 million hectares of degraded land between now and 2030 could generate USD 9 trillion in ecosystem services and remove an additional 13 to 26 gigatons of greenhouse gases from the atmosphere. Because environmental degradation problems do not remain local, ecosystem restoration will require international collaboration to be effective at scale. The UN Decade on Ecosystem Restoration offers an unparalleled opportunity for job creation, food security, and addressing climate change simultaneously.
Systemic Barriers to Scale
According to the Joint Research Centre, 75% of lands on Earth were degraded as of 2021, posing dangers for biodiversity, food security, and climate resilience. Restoring and rehabilitating 12 million hectares of degraded land per year could help close the emissions gap by up to 25 percent by 2030, but without intervention, prolonged land abandonment can trigger further degradation and reduce ecosystem service capacity. These systemic challenges require coordinated global responses to prevent compounding environmental risks.
From Pledges to Action
Countries have committed to restoring at least 1 billion hectares of degraded land and coastal ecosystems by 2030, representing a significant global mobilization from ambition to action. Natural regeneration is an understudied field within restoration, with real-world cases providing insights into the potential and limits of passive recovery approaches. Organizations worldwide are changing communities through ecosystem restoration projects that demonstrate scalable, replicable models for engaging local populations in land stewardship.