Greater Negros-Panay rain forests
Bandila-an, Siquijor Island, Philippines Photograph by Tom Brooks
Introduction Catingas, Philippines. (Source: Photograph by © Cynthia Gneiser/Zegrahm Expeditions (Greater Negros-Panay rain forests) )
The Greater Negros-Panay Rain Forests ecoregion, including the Western Visayas and parts of additional political regions, appears as a number of isolated islands, but during the last ice ages these islands were (for the most part) part of one continuous island. The islands contain a unique mix of Sundaic and Philippine mammals and birds, including leopard cats and endemic pigs and deer species. Sibuyan, a small mountainous island surrounded by deep water, contains five endemic mammals and several restricted-range birds and nearly qualifies as an ecoregion in itself.
Location and General Description
The ecoregion includes the large island of Negros, Panay, and Cebu and the smaller islands of Masbate, Ticao, and Guimaras; Sibuyan, Romblon, Tablas, and Siquijor are moderately isolated and distinctive. The climate of the ecoregion is tropical wet. The Visayas receive approximately 2,419 millimeters (mm) of rainfall annually. July and August are the wettest months. The west coasts of Panay and Negros experience a dry season between November and February.
WWF
Most of these islands have been uplifted above water in the last 6 million years or less. Sibuyan Island contains pre-Tertiary schists, marble, volcanics (Igneous rock), and ultramafics. Cebu contains a rugged mountain spine, and 73 percent of the island contains slopes greater than 18 percent. The geology of Cebu includes limestones, marls, and karst topography. Negros contains a string of volcanic mountains. The channel between Greater Negros-Panay and the surrounding islands of Luzon and Greater Mindanao is more than 120 meters (m) deep. During the last ice age (late Pleistocene), sea level was approximately 120 m below current levels and Greater Negros-Panay was separated from ice age Luzon and the Eastern Visayas by a narrow channel. Except for the eastern portion of Panay and much of Masbate, the islands generally are fairly rugged, with the highest elevation being 2,465 m Mt. Canlaon in north-central Negros.
Vegetation types in the ecoregion are diverse and include beach vegetation, mangroves, tropical lowland rain forest, montane forests, and grasslands and heath forests. Beach forest merges with other forest types away from the coast and includes Casuarina and Barringtonia mixed with other lowland species. Palms, vines, bamboo, and Pterocarpus indicus are present only in rare back-beach swamps. This habitat type is extremely rare because of coastal habitation.
The lowland evergreen dipterocarp rain forest was once the dominant vegetation of the ecoregion and contained Dipterocarpus spp., Shorea spp., Hopea spp., Pterocarpus indicus, and pandans. Philippine dipterocarp forest is quite tall (45-65 m) and dense, with three layers of canopy. Lianas and bamboo are rare in mature forest but common in poorly developed evergreen forest. Ferns, orchids, and other epiphytic plants are found on the larger trees. At higher elevations there are only two canopy layers, tree stature is lower, and there are more epiphytes. Upper hill dipterocarp forest is found at elevations of 650-1,000 m and contains dominant Shorea polysperma and oaks, chestnuts, and elaeocarps. At approximately 1,000 m the montane forest contains oaks and laurels. The mossy upper montane forest generally is found at elevations over 1,200 m, where humidity is constantly high. This stunted, single-story moss- and epiphyte-covered forest contains tree ferns up to 10 m high.
Biodiversity Features
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Table 1. Endemic and Near-Endemic Mammal Species. Family Species Sorcidae Crocidura mindorus Sorcidae Crocidura negrina* Muridae Apomys sp. A* Muridae Apomys sp. B* (Sibuyan only) Muridae Apomys sp. C* (Sibuyan only) Muridae Chrotomys sp. A* (Sibuyan only) Muridae Crateromys heaneyi* Muridae Tarsomys sp. A* (Sibuyan only) Pteropodidae Nyctimene rabori* Pteropodidae Dobsonia chapmani* Pteropodidae Haplonycteris sp. A* (Sibuyan only) Suidae Sus cebifrons* Cervidae Cervus alfredi* An asterisk signifies that the species' range is limited to this ecoregion Greater Negros-Panay contains a unique mix of Sundaic and Philippine mammals and birds, including leopard cats and endemic pig and deer species. Fifty-eight mammals inhabit the ecoregion (Greater Negros-Panay rain forests) , and thirteen mammal species are endemic or near endemic (Table 1). Six of these species (Crocidura mindorus, two Apomys spp., and Chrotomys, Tarsomys, and Haplonyteris spp.) are limited to Sibuyan Island within the ecoregion (Crocidura mindorus is also found on Mindoro); most of these species have yet to be named. Two endemic large vertebrates are especially notable: the Philippine spotted deer (Cervus alfredi) and the Visayan warty pig (Sus cebifrons). The Visayan warty pig is critically endangered, and the Philippine spotted deer is endangered. One found only on Negros and Cebu, the Philippine bare-backed fruit bat (Dobsonia chapmani), is now believed to be extinct because of guano mining, deforestation, and hunting. Sibuyan, a small mountainous (to 2,052 m) island surrounded by deep water within the ecoregion, is outstanding in itself. Sibuyan contains six endemic mammals (five strict endemics) and is considered a Secondary Area by BirdLife International because of the existence of three restricted-range birds. These restricted-range birds are also found elsewhere but have no clear affinities. One hundred thirty-one bird species have been recorded on the island, a high number for an isolated island of only 463 km2. Sibuyan still contains about half of its original forest cover (100-150 km2), including some extremely rare (in the Philippines) lowland forest; unfortunately, logging threatens the remainder. Sibuyan Island is also a Centre of Plant Diversity (CPD), containing beach vegetation, mangroves, lowland rain forest, montane forests, and grasslands and heath forests. There are an estimated 700 vascular plant species on the island, including 54 endemic species. The flora is closely related to that of Luzon. Sibuyan contains valuable timber trees, almaciga (Agathis philippensis) resins, and ornamental plants and has good potential for tourism.  Bandila-an, Siquijor Island, Philippines. (Source: Photograph by Tom Brooks) The Asian leopard cat (Prionailurus bengalensis), an Asian species, is found on Negros, Panay, and Cebu within the ecoregion. Also found on Palawan, the Negros leopard cat is a subspecies. Threatened endemic or near-endemic mammals include the critically endangered Negros shrew (Crocidura negrina) and Philippine tube-nosed fruit bat (Nyctimene rabori), the endangered Mindoro shrew (Crocidura mindorus) and Panay bushy-tailed cloud rat (Crateromys heaneyi), and the widespread but endangered golden-crowned fruit bat (Acerodon jubatus). The Visayan warty pig has been extirpated from Masbate, Guimaras, Cebu, and Siquijor and now lives only in isolated areas of Negros and Panay, where hunting of them is still intense. There are no effective protected areas in the fragmented range of S. cebifrons. The Visayan warty pig is smaller than its closer relative, the Philippine warty pig (Sus philippensis), which the IUCN considers rare and declining. The Visayan warty pig once inhabited both lowland and montane rain forests and may have thrived in disturbed areas as well. The Philippine spotted deer (Cervus alfredi) has been extirpated from Guimaras, Cebu, and Siquijor and is now limited to the Mt. Madja-Mt. Baloy area of west Panay and some scattered forest fragments on Negros. A very small population apparently was located on Masbate in 1991. Small populations are protected in Mt. Canlaon National Park, North Negros Forest Reserve, and the Mount Talinis/Lake Balinsasayao Reserve. The Philippine spotted deer prefers dipterocarp rain forests but also frequents open grassland patches and secondary forest. The population has been reduced by habitat loss and hunting, which are still the main threats.
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