The phenomenon of woody plant encroachment (WPE), which is characterized by the proliferation of woody vegetation in non-forested biomes such as grasslands, is a less well-known but equally important global trend. Grasslands cover more than 31% of the Earth's surface and are a significant part of global livestock production. To better understand and manage this phenomenon, it is essential to identify key drivers, feedbacks, and thresholds within a social-ecological system change framework. This study reviews recent and authoritative scientific articles related to woody plant expansion and dominance to explore the perspective of system change in social-ecological systems. The social-ecological system dynamics of both grass and woody plant communities are governed by competitive feedback loops (ecological and social processes) that work simultaneously to determine the vegetation cover. Identifying pivotal points in the form of feedback loops and direct and indirect local and global drivers is a key strength of the comprehensive social-ecological system change framework for effective management of grassland systems. Efficient management requires finding points in the system where changes will have the greatest benefit, which necessitates a better understanding of interactions between ecological and social systems. Future studies can address this.


Introduction

The process of deforestation, which is dominated by clearing of woody plants caused by natural and unnatural factors, has intensified. The phenomenon of woody plant encroachment (WPE), which is characterized by the proliferation of woody vegetation in non-forested biomes such as grasslands, is a less well-known but equally important global trend. Grasslands cover more than 31% of the Earth's surface and are a significant part of global livestock production. However, evidence suggests that these regions have been experiencing WPE over the past two centuries. Grasslands alternate between plant communities of grasses and woody plants. This shift in plant community structure, known as the phenomenon of WPE, has impacted ecosystem services globally. This phenomenon often occurs unexpectedly and is difficult to reverse. It requires a new framework to understand this phenomenon, one that recognizes WPE as a social-ecological system. Ecological components interact with social components through the provision of ecosystem services. Human decisions influence the receipt or non-receipt of key and valuable ecosystem services. To better understand and manage this phenomenon, it is essential to identify key drivers, feedbacks, and thresholds within a social-ecological system change framework.

Materials and methods
This study reviews recent and authoritative scientific articles related to woody plant expansion and dominance to explore the perspective of system change in social-ecological systems.

Results and discussion
The social-ecological system dynamics of both grass and woody plant communities are governed by competitive feedback loops (ecological and social processes) that work simultaneously to determine the vegetation cover. The feedback loops include balancing and reinforcing loops. The set of feedback loops that dominate the system at a given time determines the current system state. In grassland systems, the fire feedback loop is dominant. In contrast, woody plant systems are influenced by two reinforcing feedback loops: the climate-establishment feedback loop, which is prevalent in dry grasslands, and the fire-suppression feedback loop, which is likely to occur in wet grasslands. Fire suppression feedback is directly influenced by fire policies, which are related to regional population growth and urbanization. The drivers of woody plant expansion and dominance can be categorized into internal (plant density, grasshoppers, leaf-eaters, and soil moisture) and external (population growth and urbanization, land use changes, organizational arrangements, and global CO2 concentration) factors. These drivers play different roles in initiating, starting, and sustaining WPE, which is crucial for understanding and managing this phenomenon. The WPE is considered a structural change in social-ecological systems, focusing on the interactions between fundamental feedback processes, particularly the interactions between social and ecological processes. The analysis of existing studies indicates that humans have a local and global impact on grasslands and that this increasing shift from grass to woody plant communities may be largely related to population growth. Given the current preferences and consumption technologies, population growth is associated with increased demand for livestock production as a food source and increased CO2 emissions through various human activities. Additionally, there is a direct correlation between human population growth and fire suppression. All these factors have a greater impact on grassland systems, increasing the likelihood of WPE.

Conclusion
Identifying pivotal points in the form of feedback loops and direct and indirect local and global drivers is a key strength of the comprehensive social-ecological system change framework for effective management of grassland systems. Efficient management requires finding points in the system where changes will have the greatest benefit, which necessitates a better understanding of interactions between ecological and social systems. Future studies can address this.
Introduction

The process of deforestation, which is dominated by clearing of woody plants caused by natural and unnatural factors, has intensified. The phenomenon of woody plant encroachment (WPE), which is characterized by the proliferation of woody vegetation in non-forested biomes such as grasslands, is a less well-known but equally important global trend. Grasslands cover more than 31% of the Earth's surface and are a significant part of global livestock production. However, evidence suggests that these regions have been experiencing WPE over the past two centuries. Grasslands alternate between plant communities of grasses and woody plants. This shift in plant community structure, known as the phenomenon of WPE, has impacted ecosystem services globally. This phenomenon often occurs unexpectedly and is difficult to reverse. It requires a new framework to understand this phenomenon, one that recognizes WPE as a social-ecological system. Ecological components interact with social components through the provision of ecosystem services. Human decisions influence the receipt or non-receipt of key and valuable ecosystem services. To better understand and manage this phenomenon, it is essential to identify key drivers, feedbacks, and thresholds within a social-ecological system change framework.

Materials and methods
This study reviews recent and authoritative scientific articles related to woody plant expansion and dominance to explore the perspective of system change in social-ecological systems.

Results and discussion
The social-ecological system dynamics of both grass and woody plant communities are governed by competitive feedback loops (ecological and social processes) that work simultaneously to determine the vegetation cover. The feedback loops include balancing and reinforcing loops. The set of feedback loops that dominate the system at a given time determines the current system state. In grassland systems, the fire feedback loop is dominant. In contrast, woody plant systems are influenced by two reinforcing feedback loops: the climate-establishment feedback loop, which is prevalent in dry grasslands, and the fire-suppression feedback loop, which is likely to occur in wet grasslands. Fire suppression feedback is directly influenced by fire policies, which are related to regional population growth and urbanization. The drivers of woody plant expansion and dominance can be categorized into internal (plant density, grasshoppers, leaf-eaters, and soil moisture) and external (population growth and urbanization, land use changes, organizational arrangements, and global CO2 concentration) factors. These drivers play different roles in initiating, starting, and sustaining WPE, which is crucial for understanding and managing this phenomenon. The WPE is considered a structural change in social-ecological systems, focusing on the interactions between fundamental feedback processes, particularly the interactions between social and ecological processes. The analysis of existing studies indicates that humans have a local and global impact on grasslands and that this increasing shift from grass to woody plant communities may be largely related to population growth. Given the current preferences and consumption technologies, population growth is associated with increased demand for livestock production as a food source and increased CO2 emissions through various human activities. Additionally, there is a direct correlation between human population growth and fire suppression. All these factors have a greater impact on grassland systems, increasing the likelihood of WPE.

Conclusion
Identifying pivotal points in the form of feedback loops and direct and indirect local and global drivers is a key strength of the comprehensive social-ecological system change framework for effective management of grassland systems. Efficient management requires finding points in the system where changes will have the greatest benefit, which necessitates a better understanding of interactions between ecological and social systems. Future studies can address this.