Rajah Sikatuna Protected Landscape: Mapping the Biodiversity and Karst Terrain of Bohol

Rajah Sikatuna is best known as the largest remaining block of natural forest on Bohol and as one of the Philippines' premier birdwatching sites. Its importance stems from the combination of intact limestone karst forest, numerous caves, endemic bird species and the rare presence of six species of large mammals, including the iconic Philippine tarsier. The park also stands out for its scenic and recreational offerings: an observation tower atop Bilar Peak provides panoramic views over Bohol, the nearby island of Panglao and even Cebu on clear days, while a network of more than 30 kilometres of marked trails supports wildlife observation and nature-based tourism.

Rajah Sikatuna was first gazetted as a national park on July 10, 1987, initially covering approximately 9,023 hectares of forested limestone terrain in southern Bohol. Its early designation reflected recognition of the area as the largest remaining tract of natural forest on the island and as habitat of significant conservation value.

On April 23, 2000, the park was reclassified and expanded under the National Integrated Protected Areas System as a protected landscape, bringing its total area to roughly 10,452.6 hectares. This change broadened the management mandate from strict national park protection toward a balanced approach that acknowledges the surrounding communities, agricultural lands and water resources.

Since its reclassification, the park has been administered by the Department of Environment and Natural Resources and has continued to be promoted as both a conservation area and a destination for nature-based tourism, with infrastructure such as trails, an observation tower at Bilar Peak, and visitor facilities developed to support public access.

The landscape of Rajah Sikatuna is shaped by the southern Bohol karst, a series of rolling, steep-sided limestone hills rising out of the interior of the island. The terrain has an average elevation of around 400 metres, with the highest point at Bilar Peak reaching about 510 metres above sea level. The scenery shifts between forested ridges, exposed rocky slopes, grassy clearings and pockets of plantation and farmland, giving the area a patterned, mosaic appearance typical of upland Bohol.

Much of the park's surface is karst limestone, deeply weathered into ridges, sinkholes and cave systems. More than 100 caves have been identified within the protected area, contributing to the broader geological identity of Bohol, which is known for its karst formations and islet-studded coastlines. Four major springs, Logarita, Anislag, Mabugnao and Aghuban, emerge from this karst system and channel fresh water outward into the surrounding valleys and communities.

From the Bilar Peak observation tower, the surrounding countryside opens into a broad panorama of agricultural lowlands interspersed with forested hills, with the distant silhouettes of Panglao Island and Cebu visible on clear days. This combination of karst topography, forested ridges and distant sea views defines the visual character of Rajah Sikatuna.

The ecology of Rajah Sikatuna Protected Landscape is defined by its dominance of limestone forest, which supports the largest area of native lowland and submontane forest remaining on Bohol. The forest cover is built around native dipterocarp trees such as molave, along with other hardwood species adapted to thin, well-drained soils over limestone bedrock. These forests form a backdrop for the park's reputation as a stronghold of Philippine biodiversity.

Surrounding and interspersed with the forested core are areas of grassland, plantation forest and agricultural land, producing an ecological gradient that ranges from closed-canopy habitat to more open, edge environments. The karst system beneath the surface, with its more than 100 caves and numerous springs, adds a subterranean dimension to the park, providing roosting and breeding habitat for bats and cave-dwelling swiftlets.

The combination of mature limestone forest, open grassland and a heavily karstified underlay creates conditions that support many endemic Philippine species. The result is an unusually rich ecological mosaic for an island that has otherwise lost much of its original forest cover to agriculture and settlement.

Rajah Sikatuna is one of the most important bird areas in the Philippines, with records of more than 120 bird species, many of which are endemic to the country. The park's avifauna includes the endangered Philippine cockatoo and streaked reed warbler, as well as a broad cast of forest specialists such as the Philippine hawk-eagle, Visayan broadbill, Samar hornbill, Philippine eagle-owl, Philippine frogmouth, azure-breasted pitta, rufous-tailed jungle flycatcher, rufous-lored kingfisher, southern silvery kingfisher and the Philippine trogon. This diversity has made the park a key destination for birdwatchers from across the region.

Mammals are also a defining feature of the park. Six species of large mammals are present, including the Philippine tarsier, one of the world's smallest primates, along with the long-tailed macaque, Philippine flying lemur (colugo), Malayan civet, Asian palm civet and Philippine warty pig. A number of rodent species, including the Philippine forest rat, rice-field rat and Mindanao hairy-tailed rat, also inhabit the area.

The caves of Rajah Sikatuna host colonies of bats and swiftlets, adding another important component to the park's wildlife profile. The mix of endemic birds, primates, civets, cave-roosting bats and forest rodents gives the landscape a layered, biologically significant character that goes well beyond its reputation for scenery alone.

Rajah Sikatuna Protected Landscape is of major conservation significance because it contains the largest remaining block of natural forest on Bohol, an island where much of the original forest cover has been converted to agriculture and settlement. Its limestone forest, karst systems and grassland mosaic collectively sustain a high proportion of the island's remaining native biodiversity, including numerous endemic and threatened species.

The park's protected status under the National Integrated Protected Areas System recognises both its ecological and hydrological value. Beyond providing habitat for wildlife, the area's four mountain springs supply water to surrounding communities, making the conservation of the forest cover directly tied to local water security.

Recognition as an important bird area, combined with the presence of threatened species such as the Philippine cockatoo and the Philippine tarsier, gives the park a strong national profile within Philippine conservation. The combination of formal protection, biological richness and water-resource value places Rajah Sikatuna among the cornerstone conservation landscapes of the Central Visayas.

Beyond its ecological role, Rajah Sikatuna carries deep cultural meaning for Bohol. The protected landscape is named after Datu Sikatuna, a Boholano chieftain who, in 1565, entered into a blood compact, or sandugo, with the Spanish conquistador Miguel López de Legazpi. This compact is one of the most celebrated symbols of friendship and indigenous-Hispanic accord in Philippine history and is commemorated annually in Bohol through the Sandugo Festival.

By bearing the name of this chieftain, the park links contemporary environmental protection to a broader identity of the island, in which natural heritage and cultural memory are closely intertwined. The park's presence in southern Bohol, a region rich in both karst landscapes and historical sites, reinforces this connection between landscape and local heritage.

Rajah Sikatuna Protected Landscape combines Bohol's largest remaining natural forest with one of the country's most important birdwatching destinations, set amid limestone karst hills just east of the famous Chocolate Hills. Its network of more than 30 kilometres of marked trails, with over 100 documented caves, provides sustained opportunities for both birding and exploration.

Equally distinctive are the panoramic views from the Bilar Peak observation tower, the freshwater springs that supply surrounding communities, and the chance to encounter flagship species such as the Philippine tarsier, Philippine cockatoo and a wide range of endemic forest birds. The park's blend of biodiversity, karst scenery and cultural symbolism makes it a defining natural landmark of southern Bohol.

The most favourable conditions for visiting Rajah Sikatuna generally coincide with the drier months in the Central Visayas, when forest trails are more accessible, visibility from Bilar Peak is clearer and birdwatching is rewarding. The park's low mountain setting means temperatures are typically moderate, and morning hours are particularly productive for bird activity along the forest edges and along marked trails.

Wet-season months bring heavier rainfall and can make trails muddy and viewpoints obscured by cloud, though they also maintain lush forest conditions and active spring flows. Birdwatchers often find the forest especially lively year-round due to the park's high species diversity, while visitors focused on panoramic views from Bilar Peak benefit from the clearer skies of the drier season.