Ecological Archives E091-258-A1

Margaret R. Metz, Wayne P. Sousa, and Renato Valencia. 2010. Widespread density-dependent seedling mortality promotes species coexistence in a highly diverse Amazonian rain forest. Ecology 91:3675–3685.

Appendix A. Seedling plot network design: description and figures. Additional description of seedling plot network design.

The 600 seedling plots are established in sets of three, surrounding the 200 seed traps, such that a trap and its adjacent seedling plots comprise a census station (Fig. A1). The traps at the center of the stations were arrayed systematically every 13.5 m along the trails, on alternating sides of a trail, and at random distances of 4–10 m into the forest from a trail (Fig. A1). The stations are, on average, 16.6 m from the nearest neighbor; none is less than 10.3 m from the nearest neighbor, except for two stations near the junction of two trails that are 8.5 m apart. The distribution of the stations samples the major topographic habitats (characterized by Valencia et al. (2004) as valley, mid-slope and upper ridge) in representative proportions (χ2 = 12, df = 9, P = 0.2133; Metz 2007) (Fig. A2). The stratification of the seed traps in relation to the forest dynamic plot's trail network was intended to minimize trampling to the greater area caused by biweekly sampling of flowers and fruit collected by the trap. In a much more heavily trafficked research plot in Panama, Comita and Goldsmith (2008) found some localized effects of trails on seedling dynamics, but the influence was not substantial enough to bias characterizations of plot-wide seedling dynamics. Further, seedling dynamics within the research area were not significantly different from dynamics in areas outside the study plot, which experienced little to no research activity (Goldsmith et al. 2006).

References cited:

Comita, L. S., and G. R. Goldsmith. 2008. Impact of research trails on seedling dynamics in a tropical forest. Biotropica 40:251–254.

Goldsmith, G. R., L. S. Comita, L. L. Morefield, R. Condit, and S. P. Hubbell. 2006. Long-term research impacts on seedling community structure and composition in a permanent forest plot. Forest Ecology and Management 234:34–39.

Metz, M. R. 2007. Spatiotemporal variation in seedling dynamics and the maintenance of diversity in an Amazonian forest. PhD thesis, University of California, Berkeley, California, USA.

Valencia, R., R. B. Foster, G. Villa, R. Condit, J. C. Svenning, C. Hernandez, K. Romoleroux, E. Losos, E. Magard, and H. Balslev. 2004. Tree species distributions and local habitat variation in the Amazon: large forest plot in eastern Ecuador. Journal of Ecology 92:214–229.

 
   FIG. A1. Seedling plot study design. Seedling plots are grouped in sets of three surrounding a seed trap used in studies of flowering and fruiting phenology. Together the plots and trap comprise a census station. The stations are arrayed every 13.5 m along the trails in the Yasuní Forest Dynamics Plot, on alternating sides of the trail, and at random distances into the forest from the trail (4–9 m). The plots were established 2 m away from the trap along imaginary orthogonal axes centered at the seed trap but not coinciding with the path from the trail to the trap. Schematic not to scale.


 
   FIG. A2. Seedling census stations in the Yasuní 50-ha forest dynamics plot. The topography of the Yasuní forest dynamics plot and the layout of 200 seedling census stations along the trail system. Two ridges run west to east, and one ridge (on the eastern side of the plot) runs north to south.

LITERATURE CITED

Valencia, R., R. B. Foster, G. Villa, R. Condit, J. C. Svenning, C. Hernandez, K. Romoleroux, E. Losos, E. Magard, and H. Balslev. 2004b. Tree species distributions and local habitat variation in the Amazon: large forest plot in eastern Ecuador. Journal of Ecology 92:214–229.



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