PARENT SESSION
Poster Session 2: Forest Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

The seed rain and seedling establishment in the Fushan subtropical rain forest, Taiwan.

Chang Yang, Chia-Hao¹, Lu, Chia-Ling¹, Hsieh, Chang-Fu¹, ¹ National Taiwan University, Taipei, Taiwan

ABSTRACT- We set up 87 stations in the 25-ha Fushan Forest Dynamics Plot (FDP). Each station included one 0.5-m² seed trap and three 1-m² seedling plots. The objectives of this study are to understand the temporal variation of the seed rain and seedlings of tree species, and the relationship between seed rain and seedling bank. We tried to probe into the regeneration strategies of the main tree species in the Fushan FDP. All seeds, fruits, and fruit fragments > 1 mm in dia. falling into the traps were counted and identified to species each week from Sept. 2002 to Mar. 2004. In Sept. 2002, all tree seedling < 1 cm DBH in the 261 seedling plots were tagged and identified to species. Survivors were re-measured and new recruits were tagged and identified each 3 months from Feb. 2003 to Feb. 2004. There were 9,580 seeds collected from 87 seed traps, belonging to 23 tree species. During 2003, species with the largest fruit amount was Limlia uraiana, the next was Castanopsis carlesii, but a large proportion of fruits were immature. Species with the highest mature fruit ratio was Lagerstroemia subcostata, and followed by Glochidion acuminatum. Seed viability percentages were quite different among species, ranging from 26% to 99%. A total of 4,794 new seedlings were found, belonging to 18 species. There were 15 species from which both seeds and seedlings were collected and recorded. The highest density of seedlings occurred in May 2003, and the highest number of species occurred in Aug. 2003. Most species had lower seed-to-seedling transition probabilities (mean seedling density / mean seed density). 5 species with a seed mass of less than 8 mg accounted for 73.4% of the seed rain but just 3.8% of the recruits in Feb. 2004. The species with smaller seeds, smaller seedlings and epigeal germination type had higher seedling mortalities. The regeneration strategies of the tree species were quite different from each other. Schefflera octophylla and G. acuminatum produced lots of seeds to ensure enough recruits. Machilus thunbergii, Machilus zuihoensis, and Litsea acuminate produced better quality seeds and had higher seedling survival rates. L. uraiana and C. carlesii had a few seeds and seedlings, and their regeneration probably relied on sprouting.

Key words: seed rain, seedling, subtropical rain forest