SPATIAL PATTERNS AND PLANT SPECIES ASSOCIATIONS OF COFFEE (COFFEA SPP.) ALONG THE EASTERN SLOPES OF MOUNT MAKILING FOREST RESERVE, LUZON, PHILIPPINES

摘要

Non-native species can become invasive and threaten the biodiversity of natural ecosystems. In Mount Makiling Forest Reserve (MMFR), the non-native coffee plant was introduced in agroforestry farms in the 1980s. At present, it is observed growing abundantly inside the secondary growth forests. This study determined the factors that are related to the spatial distribution of coffee in MMFR, looked at the differences in plant community characteristics between sites with coffee and without coffee, and identified plant species that are associated with coffee. This study was conducted on the eastern slopes of MMFR, Philippines from November 2014 to March 2015. Data on vegetation and biophysical factors from 57 10 m × 10 m randomly established sample plots were subjected to regression analyses and redundancy analysis. Plant community characteristics were compared using the Mann-Whitney Test. Patterns of spatial distribution were visualized using a Geographic Information System. Results showed that the probability of coffee occurrence decreases with an increase in distance from sites of initial coffee introduction. Abundance increases with decreasing leaf litter and plant species diversity. Species richness, plant diversity, endemic and native species richness, and threatened species richness did not differ between plots with and without coffee; however it is worth mentioning that the number of endemic and threatened plant species was lower in plots with coffee. Coffea liberica was positively associated with Ficus nota and negatively associated with Nephelium ramboutanake and Arenga pinnata. On the other hand, Coffea canephora exhibited a highly negative association with Parashorea malaanonan. The results imply that: 1) coffee does not pose a threat to the reserve's flora at present, however future assessment efforts are needed, 2) if needed in the future, the population of coffee can be limited by manipulating the identified site factors, and 3) coffee can possibly limit or facilitate the growth of other plant species.