Recent land use and vegetation history from soil pollen analysis: Testing the potential in the lowland humid tropics

Impact of Cotyledon and Leaf Removal on Seedling Survival in Three Tree Species with Contrasting Cotyledon Functions1

“…Together, these three genera account for 9 percent of the total pollen enumerated in five samples prepared from sediment associated with site 1 macrofossils. This percentage of ''extralocal'' pollen is higher than we have found under modern closed forest canopies at La Selva (Horn et al 1998;S. Horn, pers.…”

“…Analyses of pollen grains and charcoal fragments in swamp sediments and soils have provided information on the last few millennia of vegetation history. This includes episodes of forest clearance, maize agriculture, and widespread fires associated with pre-Columbian human activity and possible late-Holocene droughts (Horn & Sanford 1992, pers. obs.…”

Stratigraphic palynology in porous soils in humid climates: An example from Pouerua, Northern New Zealand

“…Given the relatively recent arrival of Europeans in New Zealand (after c. 1800 A.D.), much finer resolution of sampling should thus be carried out on these soil types in future to give more precise temporal control. Horn et al (1998) analysed the pollen in soil profiles from the lowland tropics of Costa Rica and concluded that downwash of pollen at their sites was too rapid to allow the development of stratigraphies. Annual rainfall in their study area is extremely high, averaging almost 4 m per annum, two and a half times that of Pouerua.…”

Vegetation Dynamics of a Permanent Pasture Plot in Puerto Rico1

“…obs. ; Kennedy & Horn 1997;Kennedy 1998;Horn & Kennedy 2001). The new plant fossil assemblages we report here extend the time frame of ecological studies at La Selva into the Pleistocene, beyond the limit of radiocarbon dating.…”

“…While microfossils (pollen and spores) can be carried long distances by wind, our previous studies of pollen in surface soils at La Selva (Horn et al 1998) and elsewhere in Costa Rica (Rodgers & Horn 1996) indicate that soil pollen spectra within forests are to a large degree dominated by the pollen of local plants. If the Puerto Viejo and Pozo La Guaria macrofossil assemblages represent ancient forests buried in place, the associated pollen and spore assemblages should primarily reflect the plants that once grew at the sites.…”