Pollen Dispersal and Representation in a Neotropical Rain Forest

Abstract

Results of 3 years of pollen trapping samples close to large canopy gaps had exceptional abundances of 'disturbance' taxa. A preliminary on Barro Colorado Island, Panama, are presented. Minimum pollen dispersal distances are estimated for analysis of the representation of canopy components indicates that as much as 19% of pollen caught in the the most abundant pollen taxa. Dispersal distances for some taxa appear to be as low as 5m, while for other traps was derived from large tree species. taxa at least 50% of the trapped pollen had travelled more than 40m. No consistent pattern of spatial Key words. Barro Colorado Island, Panama, pollen dispersal, pollen trap, tropical rain forest. variation was reflected in the pollen rain, however, 0-5m Annona,

Palaeoecology and climate of the Amazon basin during the last glacial cycle

“…The prominent exceptions are in the family Moraceae, many of which are anemophilous. In the BCI study, canopy trees contributed about 19% to the total pollen rain, with individual species almost always Ͻ3%, some represented as single grains, and some entirely absent (Bush and Rivera, 1998). These results are echoed by the distribution of pollen types in lake sediments.…”

“…Both these fears were groundless. Pollen trapping in the forest reserve of Barro Colorado Island (BCI) in Panama by Bush and Rivera (1998) found pollen accumulation rates comparable to those of temperate forests, at about 22 000 g cm −2 yr −1 . We have used the same techniques to trap pollen over three consecutive years in the Cuyabeno forest reserve in Ecuadorian Amazonia and at the INPA (Instituto Naçional do Pesquias Amazô nicas) Smithsonian Biological Dynamics of Forest Fragments Project at Manaus, with similar results: pollen accumulates in traps at mean rates of Ͼ20 000 g cm −2 yr −1 (unpublished data).…”

Pollen‐based biome reconstructions for Colombia at 3000, 6000, 9000, 12 000, 15 000 and 18 000 14C yr ago: Late Quaternary tropical vegetation dynamics

“…Foremost, as the modern calibration is derived from the same sedimentary environment as the fossil analyses, the data sets are directly comparable. The temporal range negates the problem of the representation of parent vegetation by pollen being subject to high interannual variability (Behling et al, 1997), and therefore biased in the short-term pollen assemblages available from pollen traps, soils or moss pollsters (Bush, 1991;Bonnefille et al, 1993;Mancini, 1993;Kershaw and Bulman, 1994;Calcote, 1995;Bush and Rivera, 1998;Marchant and Taylor, 2000). Third, the palynological indicators of human disturbance, other than Poaceae, are commonly present only at low levels (commonly <5), and as such their numerical contribution to the affinity score is low.…”

Colombian vegetation at the Last Glacial Maximum: a comparison of model‐ and pollen‐based biome reconstructions

“…A second reason why the reconstructed biomes reflect the potential, rather than the actual vegetation, is that the surface samples can encompass a relatively wide time-frame (possibly as long as the last 200 years). This is useful for our reconstructions, both modern and fossil, as the modern calibration is derived from the same sedimentary environment as the fossil analyses, and the temporal range negates the problem of the representation of parent vegetation by pollen being subject to high inter-annual variability (Behling et al, 1997), and therefore biased in the short-term pollen assemblages available from pollen traps, soils or moss pollsters (Bush, 1991;Bonnefille et al, 1993;Mancini, 1993;Kershaw and Bulman, 1994;Calcote, 1995;Bush and Rivera, 1998;Marchant and Taylor, 2000). The generally correct biome assignments confirm the robust a priori assignment of our pollen taxa to PFTs and biomes.…”