Land Use/Land Cover Changes Assessment and Forest Fragmentation Analysis in the Baroro River Watershed, La Union, Philippines

Abstract

The Baroro River Watershed, like most watersheds in the Philippines, has been experiencing widespread land use changes. With the increasing interest on studies of watersheds as valuable water resources, this study attempted to assess the land use/land cover changes and forest fragmentation using landscape metrics. Three official land cover maps (2003, 2010, and 2015) were obtained. Cross-tabulation detection method in the Geographic Information System module was used to detect land cover changes during the first period (2003-2010) and second period (2010-2015). The landscape fragmentation tool (LFT v2.0) generated a forest fragmentation map, then analyzed patterns and changes in three time periods: 2003-2010, 2010-2015, and 2003-2015. The annual rate of change in the forest cover has a negative trend in all three time periods: 1.16%, 0.91%, and 1.06%, respectively. Conversely, forest fragmentation analysis revealed a markedly decrease of large forest areas and that the number of patches, percentage of land, and edge density of forest patch, edge and small core increased over time. Also, smaller patches (0 – 100 ha) in large forest areas increased rapidly (3 to 225 patches), indicating a more fragmented forest landscape. In 12 years, there were widespread land cover changes and forest fragmentation in the watershed mainly due to expansion in agricultural and built-up areas. It is hoped that results of this study, particularly the application of landscape metrics using spatial data, can serve as necessary inputs in crafting sustainable land use policies, plans, and interventions for effective and comprehensive watershed management.