Cuatro Islas in Leyte: The pristine tropical paradise

 Protected Landscape/Seascape 

The four islands collectively known as the Cuatro Islas—Apid, Digyo, Himokilan, and Mahaba—were proclaimed on April 23, 2000, as a protected landscape/seascape under the NIPAS Act of 1992 by President Joseph Ejercito Estrada through Proclamation No. 270. The protected area is under the administrative jurisdiction of the municipalities of Inopacan and Hindang, Leyte.

Location of Cuatro Islas off the coast of Inopacan and Hindang, Leyte

 Geologic Origin 

The Cuatro Islas are believed to be remnants of a barrier reef system located off the coast of Inopacan and Hindang in Leyte. In a study conducted during the International Tropical Ecology Workshop in 1999 organized by the ViSCA-GTZ Tropical Ecology Program, we proposed that these coral reef islands are underlain by a volcanic basement connected to the extinct Mt. Sacripante on the Leyte mainland (Grenz et al., 1999). Geological evidence suggests that the islands formed during the Upper Pleistocene epoch of the Quaternary period, as indicated by the presence of coralline limestone of Quaternary age. During the Last Glacial Maximum, approximately 15,000 years ago, sea levels across Southeast Asia dropped by about 100 to 150 meters. This significant decline exposed large portions of the continental shelf, creating conditions favorable for coral growth in newly formed shallow tropical marine environments. In addition, ongoing tectonic uplift in Leyte and other parts of the Philippines further facilitated reef development, as corals thrive in shallow, sunlit warm waters. This combination of falling sea levels and gradual tectonic uplift contributed to the emergence and present configuration of the barrier reef system. Similar uplifted coral reef formations can also be found in the northwestern and southwestern regions of Leyte Island (Grenz et al., 1999). 

Digyo Island, a pristine tropical paradise

 Digyo, the Jewel of the Cuatro Islas 

 Among the four islands, Digyo stands out for its relatively flat, low-lying topography, rising only about 2 to 3 meters above the present sea level. It suggests that Digyo is geologically younger than the other islands, having formed more recently. Its crystal-clear turquoise water and fine white sand, derived from coralline limestone and the shells of marine organisms, make Digyo a favorite destination for tourists. Many people call it the jewel of the Cuatro Islas. 

The stunning white sandbar 

 Digyo Soils are Sandy and Undeveloped 

 The soils of Digyo Island are dominated by sand (largely calcium carbonate) and show no signs of pedogenesis. Roots of coconut trees, the main vegetation on the island, hold the sandy soil but contribute little humus. The soils belong to the Entisols order in Soil Taxonomy, and Arenosols in the World Reference Base (WRB). 

The young, sandy, & undeveloped soil of Digyo Island showing roots of coconut trees

Reference 

Grenz, J., Zukunft, S., & Asio, V. B. (1999). Geomorphology and soils of Apid Island, Inopacan, Leyte, Philippines. Annals of Tropical Research, 21, 1-8.