Reproductive ecology and pollen representation among neotropical trees

Abstract

Three years of pollen trapping data from Barro Colorado Island, Panama, are compared with local vegetation inventories. Two hypotheses relating pollen representation to 'messy' pollination and flower form are tested. Dioecious taxa were found to be over-represented in pollen spectra compared with their occurrence in local forests. Similarly, anemophilous and 'messy' pollination types were found to be over-represented. While anemophilous taxa were the best dispersed pollen types, zoophilous taxa were also well-represented in dispersal classes of 20-40 m and > 40 m. Thus pollen arriving to lake sediments is most likely to be from anemophilous species or those zoophilous species exhibiting 'messy' pollination syndromes. Pollination mechanisms will predictably bias the fossil record against certain flower morphologies. These data are of significance to those using the fossil pollen record to reconstruct the timing and sequence of angiosperm evolution. These data help prioritize plants to be included in modern pollen reference collections and to focus the search for 'unknown' types on most-likely candidate families.

Amazonian paleoecological histories: one hill, three watersheds

“…If Podocarpus and the other taxa had invaded the bottomlands, rather than just the plateau of the inselberg, then a vegetation descent of 1000 to 1100 m is required, which translates to a temperature depression of 5-6 °C. This estimate of cooling is entirely consistent with other pollen data (Bush and Rivera, 2001;Colinvaux et al, 1997;Liu and Colinvaux, 1985) and with isotopic analyses of groundwater (Stute et al, 1995).…”

“…Pennington et al (2000) argued that many of the pollen taxa documented by Colinvaux et al (1996) in the Pata record could equally come from caatinga as from mesic forest. Of course, many taxa are shared between habitats, but Pennington et al (2000) ignore the quantitative aspect of the pollen record and the wealth of modem pollen rain data from savanna and caatinga (Bush, 2000;Salgado-Labouriau, 1979;Salgado-Labouriau, 1997;Salgado-Labouriau et al, 1997) and many types of mesic tropical forest (Behling et al, 1997;Bush, 1991;Bush, 2000;Bush and Rivera, 2001;Bush and Rivera, 1998;Grabandt, 1980;Grabandt, 1985;Rodgers and Horn, 1996;Salomons, 1986). In savanna systems Poaceae pollen often reach values of 50-90% (Salgado-Labouriau et al, 1997ab), and in open woodland settings Poaceae pollen is seldom <20%.…”

Pollen-vegetation richness and diversity relationships in the tropics

“…The reason for the lower diversity values is likely due to the poorer taxonomic resolution of the palynological data (typically genus and family) compared to the vegetation (usually species) (Bush and Rivera 2001), and the tendency for artificial pollen traps to be 'swamped' by one taxon, usually a wind pollinated plant, or one very close to that trap . The loss of diversity information in the fossil record demonstrates the need for the development of improved taxonomic tools if we are going to be able to use fossil pollen to provide an accurate window into past diversity change, e.g.…”

Three millennia of vegetation and environmental dynamics in the Lagunas de Mojanda region, northern Ecuador

“…Moraceae/Urticaceae is anemophilus and can be overrepresented in the pollen record (Bush & Rivera 2001); it is an example of the long-distance pollen transport that has been studied along the Andes (Reese & Liu 2005, Ortuño et al 2011, Jantz et al 2013. The different taxa shown in the pollen record of the UMF ecological group indicate that it was diverse during the late Holocene.…”