Seed limitation in a Panamanian forest
Article first published online: 15 JUN 2005
Journal of Ecology
Volume 93, Issue 5, pages 853–862, October 2005
How to Cite
SVENNING, J.-C. and WRIGHT, S. J. (2005), Seed limitation in a Panamanian forest. Journal of Ecology, 93: 853–862. doi: 10.1111/j.1365-2745.2005.01016.x
- Issue published online: 15 JUN 2005
- Article first published online: 15 JUN 2005
- Received 12 October 2004; revision accepted 28 February 2005 Handling Editor: David Burslem
- community ecology;
- dispersal assembly;
- seed addition experiment;
- seed limitation;
- seed size;
- seedling ecology;
- seedling recruitment;
- tropical ecology;
- tropical forest
- 1The role of seed limitation in tropical forests remains uncertain owing to the scarcity of experimental evidence. We performed seed addition experiments to assess seed limitation for 32 shade-tolerant tropical forest species and monitored the natural seed rain of 25 of these species for 17 years.
- 2One, two or five seeds were sown into 0.0079-m2 plots for large- (n = 5 species), medium- (n = 5) and small-seeded species (n = 22), respectively. The experiment was replicated at 69 sites, placed in groups of three at 23 locations. Seedling establishment was evaluated after 1 and 2 years in paired seed addition and control plots. Natural seedling emergence and understorey plant density were also measured.
- 3Median natural seed rain was 0.31 seeds m−2 year−1 per focal species.
- 4Seed addition enhanced seedling establishment in 31 and 26 of the 32 species after 1 and 2 years, respectively. Mean number of focal species’ seedlings after 2 years was 0.002 seedlings in control plots and 0.12, 0.37 and 0.60 seedlings in seed addition plots for large-, medium- and small-seeded species, respectively.
- 5A 25 seeds added treatment increased seedling establishment by ≥ 2.0-fold over the five seeds added treatment after 2 years.
- 6Community-wide recruitment and understorey plant density were strongly seed-limited. The natural density of understorey plants averaged 12 plants m−2 and was significantly less than for seedlings of the single focal species in plots with ≥ 2 seeds added 2 years earlier.
- 7The number of established seedlings per seed added was independent of seed size.
- 8Treatment (adding zero or five seeds), species identity and location all affected seedling establishment for the 11 small-seeded species represented at all sites, with treatment and its interactions accounting for 86% of the explained variation.
- 9Our results suggest that seed limitation plays a dominant role in seedling recruitment and understorey plant community assembly in tropical forests. Although strong seed limitation may set the stage for species-neutral community assembly, the species differences in seedling establishment rate and its spatial variation demonstrate an important role for species-specific processes.