Land cover change and its associated impacts on landscape fragmentation and flood exposure in Quinali A Watershed, Albay, the Philippines

Gifford Jay L. Agudo, University of the Philippines Resilience Institute
Josephine E. Garcia, University of the Philippines Los Banos
Juan M. Pulhin, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Jerico E. Mendoza, University of the Philippines Resilience Institute
Kyle Vincent R. Singson, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Alfredo Mahar Francisco A. Lagmay, University of the Philippines Resilience Institute
Rex Victor O. Cruz, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Joy T. Santiago, University of the Philippines Resilience Institute
Marc Anthony M. Moises, University of the Philippines Resilience Institute
Arge Louise Joy S. Esquivel, University of the Philippines Resilience Institute
Maricel T. Villamayor, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Rose Jane J. Peras, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Lorena L. Sabido, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Liezl B. Grefalda, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Catherine S. Anders, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Florencia B. Pulhin, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Asa Jose U. Sajise, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Marlo D. Mendoza, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management
Canesio D. Predo, University of the Philippines Los Baños Interdisciplinary Studies Center for Integrated Natural Resources and Environment Management

Issue Date

4-2025

Abstract

Detrimental land cover conversion has emerged as a pressing issue in the Quinali A Watershed, Albay, the Philippines. However, there has been a lack of monitoring regarding the change and its repercussions. Establishing baseline information is imperative to enable informed decisions and policies toward sustainable development. Landsat images were used to analyze the land cover changes in Quinali A Watershed from 1990–2020. Two-dimensional flood models and landscape metrics derived from FRAGSTATS were employed to assess the impacts of land cover change on flood exposure and landscape fragmentation. Results revealed that cropland, artificial surfaces, submerged vegetation, and inland water increased since 1990, but at the expense of forest, brushland, and barrenland. Generally, flooding occurs in areas of topographic lows of the watershed. The expansion of artificial surfaces took place in flood-prone areas, nearly doubling the flood exposure rates recorded in 1990. Despite cropland expansion, it decreased in the low-lying areas of the watershed, resulting in reduced exposure to flooding. The annual rate of change indicates substantial increases of 2.77 and 0.79% in NP for artificial surfaces and barren land, respectively, with ED increasing by 2.73 and 0.74%. AWM increased by 1.62% in non-forest areas, whereas forest areas showed an increase of 0.65%. Although the PAFRAC decreased by 0.02%, it maintained a high value of 1.53 in 1990 and 1.52 in 2020, indicating low stability of the land cover structure within the watershed landscape. Continuous monitoring of these changes is imperative to recommend sciencebased policies that can regulate resource utilization in Quinali A Watershed.

Source or Periodical Title

Philippine Journal of Science

ISSN

0031 - 7683

Volume

154

Issue

2

Page

287-300

Document Type

Article

Frequency

quarterly

Physical Description

illustrations, maps, chart, graphs, table, references

Language

English

Subject

flooding, landscape fragmentation, land cover change, multi-temporal analysis

En – AGROVOC descriptors

WATERSHED MANAGEMENT; LAND COVER CHANGE; LANDSCAPE; FLOODING TOLERANCE; TEMPORAL VARIATIONS

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