Arnold R. Salvacion

The Philippines experiences approximately 86% of its recorded disaster events from extreme precipitation, yet national-scale trend studies remain constrained by sparse station networks and narrow index coverage. This study mapped the spatial patterns and long-term trends of 12 extreme precipitation indices across the Philippine archipelago using 45 years of daily gridded precipitation data from the Climate Hazards Group InfraRed Precipitation with Stations dataset over the period 1981 to 2025. Trend magnitude and direction were estimated at each grid cell using the Theil-Sen slope estimator and assessed for statistical significance using the Mann-Kendall test; spatial clustering of trends was examined using the Local Indicator of Spatial Association. Field-significance testing (Monte Carlo permutation) and a Hamed-Rao (1998) autocorrelation correction were subsequently applied to determine which spatial trend patterns are distinguishable from spatially correlated noise. Significant increasing trends in total annual precipitation covered 71.9% of land grid cells (Hamed-Rao-corrected; 60.5% raw) with a median Sen's slope of 17.6 mm yr⁻¹, concentrated predominantly in Mindanao and the Visayas, with central Luzon and southern Luzon (Bicol) as secondary contributors, and this pattern was field-significant (p = 0.004). Heavy precipitation frequency showed the most spatially extensive and most robust signal, with significant increasing trends in heavy rainfall days covering up to 73.1% of land grid cells (R10; field-significant, p = 0.010). Re-analysis found mean daily rainfall intensity on wet days (SDII) to be predominantly increasing, not decreasing as initially reported, across 25.6% of land grid cells, though this pattern did not reach field significance (p = 0.058) and is therefore suggestive rather than conclusive. Rainfall days are consequently becoming more frequent across much of the country with high statistical confidence, while evidence for a corresponding change in per-event intensity remains inconclusive, a more conservative conclusion than a straightforward frequency-versus-intensity dichotomy. The contrasting trend directions between 3-day and 5-day maximum accumulations are suggestive of, but do not on their own demonstrate, a lengthening of sustained rainfall episodes, since the 5-day signal did not reach field significance (p = 0.115). Spatial clustering analysis, computed on the complete spatial field of Sen's slopes, identified hotspot clusters concentrated on the typhoon-exposed eastern seaboard, including western Mindanao and the Zamboanga Peninsula for the two most robust frequency indices (R10, R20), and a coldspot cluster concentrated in northern Luzon; these results inform flood risk management and agricultural water planning across the exposure-sensitive sub-regions identified.

Geospatial information science is the scientific discipline that focuses on the development and application of information technologies to address different societal and environmental problems. In the Philippines, there is limited information on the progress and utilization of geospatial techniques and tools. This study assessed the trends in geospatial information research in the country using bibliometric analysis of two (2) major scientific databases (i.e. Web of Science and Scopus). Results showed that around 55% of the initial 4,184 search entries from the two (2) scientific databases were discarded while further reducing the bibliographic records to 1,869. In addition, the analysis revealed that geospatial information research has grown tremendously in the Philippines in the last four (4) decades (1978–2024) with an annual growth rate of 16%. Funding from both local and international sources, along with active collaboration facilitated this trend. The Department of Science and Technology has funded the most research publications, while internationally, the Japanese government and its scientists provided significant support through funding, mentoring, and research collaborations. Among local universities, the University of the Philippines (UP) System has produced the most research publications in geospatial information research compared to other local universities and state colleges. The bibliographic records also revealed that geospatial information was minimally explored in the social sciences compared to research areas such as engineering, life sciences, and physical sciences. Hence, the recommendation is to adopt the old concept of spatially integrated social sciences research in the Philippines.

Research in human ecology and sustainability holds significant importance in addressing global challenges related to the environment, society, and the well-being of the current and future generations. There is an urgent need for a platform to inform new knowledge, practices, policies, and behaviors that contribute toward a more sustainable, resilient, and harmonious coexistence between humans and their environment. The Journal of Human Ecology and Sustainability (JHES) aims to publish interdisciplinary, multidisciplinary, and transdisciplinary research on all aspects of human-environment interactions, community development, and other fields of social science that link with the people, organizations, and government to achieve human-ecological security. This note, which summarizes the contributions in the first volume of the journal, provides a brief background of the transformation of the Journal of Human Ecology to JHES, the official academic publication of the College of Human Ecology, University of the Philippines Los Baños.

Contamination of crops by aflatoxins (AFs) is a real risk in the South-Eastern USA. Contamination risk at the county level based on soil type and weather in different years has been investigated. However, defining AFs contamination risk zones within fields has not yet been attempted. Drought conditions, particularly within the month of June have been linked to high levels of AFs contamination at the county level. Soil characteristics and topography are the factors influencing drought status that vary most within fields. Here, soil, plant, topography and remotely sensed information are used to define AFs contamination risk zones within two fields using different approaches. Normalized difference vegetation index (NDVI) data were used to indicate potential droughty areas and thermal IR data from LandSat imagery were used to identify hot areas. Topographic variables were also computed. Comparison tests showed that a combination of regression analysis of soil, plant and imagery data and bi-variate local Moran’s I analysis of NDVI and Thermal IR data from several years was the best way to define zones for mean and maximum AFs levels. An approach based on principal components analysis of soil, plant and imagery data from 2010, a high-risk year, was best for defining zones for minimum AFs levels. Analysis of imagery from several years suggested that the zones are likely to be relatively stable in time and could be defined using only freely available sensor, topographic and soil series data. Once defined, such zones can be managed to increase profitability and reduce waste.

Sustainable development goal (SDG) 3 promotes well-being and healthy lives for people of all ages. However, based on the literature, one of the main challenges to achieving SDG 3 is inequality in access to health care. In order to support the efforts of the local government of the province to contribute to the achievement of SDG thru equitable access to health care, this study measured the spatial accessibility of healthcare facilities in Marinduque, Philippines. It used distance-based (i.e., travel-time) and area-based (i.e., enhanced two-step floating catchment analysis or E2SFCA) metrics. The distance from each healthcare facility to different villages in the province was established using QGIS and Google Maps. The distance traveled was measured using three (3) modes of transportation: tricycle, jeepney, and private vehicle. The E2SFCA scores were calculated for different population groups: the general population, women, children, and the elderly. Based on the results, island villages and those areas in the inner portion of the province lack physical access to healthcare facilities. Such a limitation was apparent in the distance- and area-based accessibility metrics. Among the population group considered in this study, the women population showed the lowest accessibility scores.