Small islands, complex realities: Advancing One Health in the Philippines

This correspondence is in response to the recent article by Koenig and colleagues (2026) in BioScience, which examines small islands as systems and scales for applying the One Health framework. The authors state that small islands can serve as natural laboratories that facilitate the examination of how human, animal, and environmental health interact. Small islands can serve as useful sites for understanding how human, animal, and environmental health interact. However, I argue that treating islands as bounded systems may underestimate their ecological and socio-environmental complexity. In an archipelagic nation such as the Philippines, island systems are deeply interconnected through mobility, trade, and resource exchange. As a result, health outcomes on one island are often shaped by processes extending beyond its geographic boundaries. This point is especially important in the Philippine context, where islands are far from homogeneous socio-ecological units. They differ markedly in ecological condition, biodiversity, degree of habitat transformation, exposure to environmental hazards, and local institutional capacity. Larger and more ecologically modified islands such as Luzon often experience more extensive habitat change and species turnover, while smaller and more remote islands in the Visayas and Mindanao may retain localized or endemic biodiversity but remain highly vulnerable to ecological disturbance. These differences matter because they shape how environmental risks are experienced and managed. Island communities across the Philippines face multiple and overlapping stressors, including typhoons, recurrent flooding, sea-level rise, biodiversity loss, and extreme heat. However, the severity and consequences of these hazards are uneven, depending on local ecological characteristics, infrastructure, governance capacity, and access to resources. For this reason, islands should not be approached as uniform, closed, or interchangeable systems but as diverse socio-ecological settings marked by uneven vulnerabilities.