Twelve-year changes in palm populations from a tropical lowland forest in the Philippines

Abstract Arecaceae (Palmae) is an ecologically and economically important family characteristic of the vegetation in tropical and subtropical regions, with at least 125 species occurring in the Philippines, most of them endemics. We monitored changes in stem density, mortality and recruitment of palm populations for twelve years within a 16-ha Forest Dynamic Plot located in northern Luzon, the Philippines. We recorded a total of 4,060 stems, dominated by Pinanga insignis (46%) and P. maculata (34%), followed by Caryota cumingii (19%), and a few stems (< 1%) of Orania decipiens and Areca whitfordii. Half (51%) of the initially recorded stems in the 2004 census died after the 2016 census, while an additional 1,086 (36%) stems were recorded in the same period. Overall palm population declined with the decreasing populations of P. insignis and P. maculata due to higher mortality than recruitment during the 2004–2010 and 2010–2016 census intervals while C. cumingii population increased in the same period. Regarding topographic position, the stem density of P. maculata is higher in valleys > midslopes > ridges across censuses, higher in valleys and midslopes than ridges for C. cumingii across censuses, and higher in midslopes than valleys for P. insignis during the 2016 census only. Mortality and recruitment were weakly observed along topographic positions between species and across censuses. Our result presents how palm population may change within twelve years with population trends differing between species, indicating the importance of palms in understanding the population dynamics of plant communities in a fast-changing environment.