Introduced frogs in buffer zone and adjacent areas of Mt. Banahaw de Lucban, Quezon Province, Luzon Island, Philippines Keywords: Invasive alien species, frogs, Mt. Banahaw, buffer zone Essex Vladimer G. Samaniego Faculty Southern Luzon State University Lucban, Quezon Email: eseks27@gmail.com Mt. Banahaw de Lucban, a part of the Mt. Banahaw San Cristobal Protected Landscape, is home to diverse endemic frogs including Platymantis banahao, P. montanus, P. naomii, P. luzonensis, P. pseudodorsalis, and P. indeprensa. This study was conducted to determine the occurrence of the 5 introduced frog species in the Philippines, namely: Rhinela marina (Linnaeus), Lithobates catesbeianus (Rana catesbeiana) (Shaw), Hoplobatrachus rugulosus (Wiegmann), Hylarana erythraea (Schlegel), and Kaloula pulchra Gray. Using quadrat methods and direct count of introduced frog populations in 5 barangays located at the foot of Mt. Banahaw de Lucban, a total of 373 frogs belonging to 4 species were counted. Rhinella marina has the highest occurrence (210 individuals) followed by K. pulchra (118), H. rugulosus (23), and H. erythraea (22). Lithobates catesbeianus was not observed during the survey. Interviews conducted with farmers and locals highlighted the sudden increase of K. pulchra population in the recent years. The species occurring nearest to the protected area was Hylarana erythraea. THE INTRODUCTION AND SPREAD OF NON-INDIGENOUS SPECIES HAVE signifcant negative impacts on biodiversity (McGeoch et al. 2016). Invasive alien species (IAS) have been identifed as a cause of major population decline and extinction of native species in various ecosystems worldwide (Zug GR and Zug PB 1979; Drake et al. 1989; Lodge 1993). Biological invasion is now widely considered as a form of global change (Vitousek et al. 1996). Factors such as increased trade volumes and increasingly Sylvatrop, The Technical Journal of Philippine Ecosystems and Natural Resources 25 (1 & 2): 57- 66