Pollen dispersal and deposition models Pollen surface sample PrenticeeSugita model of pollen dispersal and deposition Remote sensing data Sutton model Vegetation data processing a b s t r a c t 1. Quantitative reconstruction of past vegetation distribution and abundance from sedimentary pollen records provides an important baseline for understanding long term ecosystem dynamics and for the calibration of earth system process models such as regional-scale climate models, widely used to predict future environmental change. Most current approaches assume that the amount of pollen produced by each vegetation type, usually expressed as a relative pollen productivity term, is constant in space and time.2. Estimates of relative pollen productivity can be extracted from extended R-value analysis (Parsons and Prentice, 1981) using comparisons between pollen assemblages deposited into sedimentary contexts, such as moss polsters, and measurements of the present day vegetation cover around the sampled location. Vegetation survey method has been shown to have a profound effect on estimates of model parameters (Bunting and Hjelle, 2010), therefore a standard method is an essential pre-requisite for testing some of the key assumptions of pollen-based reconstruction of past vegetation; such as the assumption that relative pollen productivity is effectively constant in space and time within a region or biome.3. This paper systematically reviews the assumptions and methodology underlying current models of pollen dispersal and deposition, and thereby identifies the key characteristics of an effective vegetation survey method for estimating relative pollen productivity in a range of landscape contexts.4. It then presents the methodology used in a current research project, developed during a practitioner workshop. The method selected is pragmatic, designed to be replicable by different research groups, usable in a wide range of habitats, and requiring minimum effort to collect adequate data for model calibration rather than representing some ideal or required approach. Using this common methodology will allow project members to collect multiple measurements of relative pollen productivity for major plant taxa from several northern European locations in order to test the assumption of uniformity of these values within the climatic range of the main taxa recorded in pollen records from the region.

A 3 m core from the New River Lagoon, adjacent to the Maya city of Lamanai, Northern Belize, contains a continuous record of vegetation change between c. 1500 bc and ad 1500. Inferred changes in forest abundance and plant community assemblage build on previous palaeolimnological analysis of the same core reported by Metcalfe et al. (2009). A near-complete, abundant record of Zea mays grains provides a detailed account of field-based agriculture local to Lamanai, in the context of a regional record obtained from a large lake (13.5 km2) with a substantial catchment. Three periods ( c. 170 bc–ad 150, c. ad 600–980 and c. ad 1500) of extraction of Pinus from pine savannas adjacent to the east of the New River Lagoon, can be distinguished from clearance of seasonal broadleaf forest for agriculture. An increased palm signal is observed during c. 1630–1150 bc and 100 bc–ad 1100 and may be indicative of Maya cultivation. This record shows that during the late Classic period the Maya actively managed the vegetation resources using a combination of field-based agriculture, arboreal resources and perhaps, palm cultivation. There is no evidence from the vegetation history of drying during the late Classic coincident with the Maya ‘collapse’ and this is consistent with the palaeolimnological and archaeological records of continuous occupation of the Maya at Lamanai. Both the decline in palms c. ad 1400 and the increase in Pinus extraction c. ad 1500 are consistent with changes in vegetation associated with European arrival, however further analysis of material from the last 1000 years will enable a better understanding of vegetation change pre- and post-European encounter.

A. AbstractWe present a simple sieving methodology to aid the recovery of large cultigen pollen grains, such as maize (Zea mays L.), manioc (Manihot esculenta Crantz), and sweet potato (Ipomoea batatas L.), among others, for the detection of food production using fossil pollen analysis of lake sediments in the tropical Americas. The new methodology was tested on three large study lakes located next to known and/or excavated pre-Columbian archaeological sites in South and Central America. Five paired samples, one treated by sieving, the other prepared using standard methodology, were compared for each of the three sites. Using the new methodology, chemically-digested sediment samples were passed through a 53 µm sieve, and the residue was retained, mounted in silicone oil, and counted for large cultigen pollen grains. The filtrate was mounted and analysed for pollen according to standard palynological procedures. Zea mays (L.) was recovered from the sediments of all three study lakes using the sieving technique, where no cultigen pollen had been previously recorded using the standard methodology. Confidence intervals demonstrate there is no significant difference in pollen assemblages between the sieved versus unsieved samples. Equal numbers of exotic Lycopodium spores added to both the filtrate and residue of the sieved samples allow for direct comparison of cultigen pollen abundance with the standard terrestrial pollen count. Our technique enables the isolation and rapid scanning for maize and other cultigen pollen in lake sediments, which, in conjunction with charcoal and pollen records, is key to determining land-use patterns and the environmental impact of pre-Columbian societies.

If citing, it is advised that you check and use the publisher's definitive version for pagination, volume/issue, and date of publication details. And where the final published version is provided on the Research Portal, if citing you are again advised to check the publisher's website for any subsequent corrections.

Elizabeth A.C. Rushton has worked within education as a high school teacher, as Director of Evaluation for an education charity that supports school student participation in STEM research and is currently a Lecturer in Geography Education at King's College London. Her research considers young people's experience of science in formal and informal settings and teacher professional development through collaborations with researchers and mentoring school student research.