Spatial heterogeneity of the soil seed bank in the tropical semi ...

PERERA 85by Hurlburt’s rarefaction method with 95% confidencelimits (Also see the Figure 2a for the soil seed banktypes).Ecology and seed dispersal patterns of forestspeciesAll woody species found at the forestgrasslandecotone area were forest pioneerspecies (sensu Whitmore 1990), but seeds of bothpioneer and climax species were found in theforest interior (Table 3). Seeds of wind dispersedpioneerstem twiner Aristolochia indica L. werefound in both forest and grassland. Seeds of mostwoody forest species were dispersed by animalsand they were not found in the grassland interior(Table 3). In contrast, the grassland species weredispersed by both wind and animals, and thesewere also found in the forest and at the forestedge. Seeds of invasive agricultural weed species:Chromalaena odorata and Lantana camara L.were present at the ecotone area in largequantities.Table 3. Abundance of seeds of woody species in the soil seed bank along transects, the ecology of seeds and theirmajor dispersal agent (The first digit indicates the frequency of seeds out of 4 replicated (transects) while the latterdigit indicates the total number of seeds found). fp is the distance to the furthest point that sampled within thegrassland.Sampling distance from forest-grassland boundary (m)Species Ecology Dispersal Forest GrasslandTreesAgent 3125 625 125 25 5 0 0 5 25 125 625 fpLepisanthes tetraphylla Climax Mammal 2/3Streblus asper Pioneer Bird 1/1Berrya cordifolia Climax Wind 2/4 1/1Cassia fistula Climax Mammal 1/1Vitex altissima Climax Bird 1/1 2/3 1/1 1/2Walsura trifoliolata Climax Bird 2/3 1/5 1/3Diplodiscus verrucosus Pioneer Bird 1/3 1/2 1/10 1/15Premna tomentosa Pioneer Bird 1/2 1/2ShrubsMemecylon umbellatum Climax Bird 1/4 2/7Salacia oblonga Pioneer Bird/ 3/9 1/1 1/1MammalHelicteres isora Pioneer 1/2 1/1 1/2Glycosmis mauritiana Climax Bird 1/1Toddalia asiatica Pioneer Bird 1/1Carmona retusa Climax Bird 1/2 2/3Flueggea leucopyrus Pioneer Bird/ 3/11 3/6 3/11 3/15 3/48 3/26 1/7MammalChromolaena odorata* Weed Wind 1/7 2/17 2/23 3/55Polyalthia korinti Climax Mammal 1/1Ziziphus oenoplia Pioneer Bird/1/1 1/1MammalLantana camara Weed Bird 1/1Phyllanthus reticulatus Pioneer Mammal 2/2 1/2 2/2 1/4 1/14 3/10 1/1 1/1Calotropis gigantea* Pioneer Wind 1/1ClimbersAristolochia indica * Pioneer Wind 2/2 1/1 1/2 1/1* semi-woody speices