Seed dispersal and seed predation between natural forest and restored forest area in Mae Rim District, Chiang Mai

ABSTRACT: Seed dispersal and seed predation are natural mechanisms reflecting natural regeneration. The objective of this study was to compare seed dispersal and the effect of seed predators in a natural and restored forests at Mon Cham in Mae Rim District, Chiang Mai. For the seed dispersal study ten hanging-mesh seed traps were installed in each forest. The traps were 50x50 cm in length and were 100 cm above the ground. Tree seeds deposited in the traps were collected once a month. In the natural forests, there were seeds of 11 tree species of 5 families and 1 unknown species. In the restored forest there were seeds of 7 tree species of 5 families.; Fagaceae was the most common family found. All 7 species found in the restored can be found in the natural forest. A similarity index of species found were 74%. This suggested that seed from the natural forest can be dispersed into the adjacent restored area.

For seed predation study, 3 plots were established in each forest. Four seed trays (35.6 x 54.6 cm) were installed in each plot. Seeds of 4 tree species were placed on the trays - Acrocarpus fraxinifolius Wight ex Arn., Prunus cerasoides D.Don, Bauhinia purpurea Linn. and Spondias pinnata ( L.f. ) Kurz. The number of seeds removed were recorded. A. fraxinifolius and P. cerasoides with smaller seed size had high percent seed removal (93%), while S. pinnata with larger seed size had low percent seed removal (1%). The finding indicates that seed character and size affect seed predation. My study shows that although seeds are dispersed into an area, the seeds are at risk of predation by seed predators that may slow down natural regeneration.