Endemic Avifauna in Caraga – the mining capital of Mindanao Island, Philippines: their preferred habitats and threats

Abstract

Caraga Region comprises most of the Eastern Mindanao Biodiversity Corridor in the Philippines which is known to be the center of endemism. However, it is popularly known as the “Mining Hub” in Mindanao Island where there is obvious overlapping of mining concessions with the remaining blocks of tropical rainforests. Habitat preference of endemic avifauna and their threats are least studied in the region. Hence, in this study, habitat characteristics across habitat types and responses of endemic birds to habitat alterations were assessed in four selected mining areas (Masabong and Philsaga in Rosario and Bunawan, Agusan del Sur and Claver, Surigao del Norte) using Canonical Correspondence Analysis, survival envelope, niche position and niche width analyses. High suitability areas in Caraga that potentially harbor viable populations of endemic birds and suitable habitats for the key forest-dependent endemic birds across the landscape were also predicted using species distribution modeling. Among the four selected mine sites in Caraga, Masabong and Claver are good representation of forest ecosystem, while Bunawan and Philsaga are dominated by agro-forests and cultivated areas. A total of 47 endemic birds were encountered in four selected key mine areas of Caraga. Fifty of which are Philippine-endemics (four are near-threatened, three vulnerable and one endangered) and seven of them are Mindanao-endemics (one near-threatened and three vulnerable). Most of the endemic birds prefer advance secondary forests especially the threatened endemics. Some can tolerate regenerating forests but not in the non-forest habitat e.g. cultivation and open, degraded areas which implies sensitivity to forest fragmentation. Most of the predicted high conservation value areas for forest-dependent endemic birds are overlapping with mining concessions and expanding perennial crop plantations. Failure to do effective policy reform and law enforcement in regulating land-use changes in Caraga will most likely compromise the niche requirements of the endemic bird specialists.