Dynamics of land cover transitions and agricultural abandonment in a mountainous agricultural landscape: Case of Ifugao rice terraces, Philippines

Abstract

Mountainous agricultural landscapes experienced large-scale land cover changes in the past decades due to traditional land modification practices and increasing permanent agricultural abandonment. However, there is lack of observation of short-period land cover transitions and paddy field dynamics of fallowing and recultivation. This study was implemented in the Philippines’ Ifugao rice terraces with three aims. The first aim is to analyze rapid land cover transitions by mapping land cover maps in consistent five-year intervals from 1990 to 2020. The second aim is to analyze paddy field dynamics that involve permanent abandonment, fallowing, first-time cultivations, and recultivation by developing an analysis framework involving time-series land cover maps. The third aim is to confirm the relationship between abundance of vegetation land covers and permanent abandonment of paddy fields by implementing regression analysis. Results show that a two-step process involving low vegetation as an intermediary land cover typically occurs in between agricultural abandonment and afforestation that was widely observed in mountainous agricultural landscapes. Observed temporal dynamics of paddy fields aligned with historical records such as high rates of permanent abandonment in the 1990s and recultivation (416% increase) in the 2000s. Regression analysis revealed that there is a significant correlation between low vegetation cover abundance and subsequent paddy field permanent abandonment (P = 0.0498), which confirms that afforestation in the landscape decreased the water yield and promoted agricultural abandonment. The findings suggest that planning of mountainous agricultural landscapes should address social and environmental driving factors to mitigate the land-transition feedback loop that further promotes agricultural abandonment.