Surface pollen‐vegetation relationships on the Atlantic seaboard: South Uist, Scotland

Abstract

Studies of modern pollen rain from remote islands have raised a number of interesting issues concerning the spatial precision of present‐day pollen spectra in relation to their parent plant community types. This paper examines the relationships and degree of correlation between a sequence of contemporary vegetation types, environments and their associated surface pollen spectra from a transect across the island of South Uist in the Outer Hebrides of Scotland. Paired data on both contemporary vegetation and associated surface pollen assemblages have been collected and analysed using methods of numerical classification and ordination. In general terms, the modern pollen rain on South Uist reflects the major changes in vegetation pattern and the major community types fairly closely. The major boundary between the alkaline machair sand dune communities and the various acidic upland vegetation types is particularly clear. However, both variability in the vegetation and the effects of the strong prevailing westerly and south‐westerly winds tend to blur the boundaries of the various communities within each of these larger categories. On average 86.6% of the palynomorphs come from in‐community quadrat sources, while only 1.3% are from off‐island sources. The limited present‐day tree distribution on the transect is discussed in the context of the more widespread distribution of arboreal pollen. Overall, there is a strong numerical correspondence between vegetation, pollen and environmental variables. The various problems inherent in examining surface pollen spectra are reviewed.

Historical Ecology on Sandoy, Faroe Islands: Palaeoenvironmental and Archaeological Perspectives

“…These values alone would be consistent with either a very low density of local woodland, or long-distance dispersal from Britain or the European mainland (cf. Randall et al, 1986;Brayshay et al, 2000;Tyldesley, 1973). However, a single sample from a short peat/soil profile in the Lítlavatn catchment, Lít-7, contains 16.3% B. pubescens pollen.…”

Modern pollen distribution and its relationship with environmental difference in southwestern China

“…There are many studies which have demonstrated good relationships between surface pollen and the environment from different sites or regions (e.g., Wright, 1967;Huntley and Birks, 1983;El-Moslimany, 1990;Guiot et al, 1993;Sugita, 1994;Hjelmroos and Franzen, 1994;Prentice and Webb, 1998;Hjelle, 1999;Prentice, 1985;Jackson and Kearsley, 1998;Brayshay, 2000;Yu et al, 1998Yu et al, , 2000Yu et al, , 2004Davies and Fall, 2001;Pardoe, 2001Pardoe, , 2006. In China, most studies undertaken so far have established the relationships between surface pollen and the major/indicative plants of the vegetation.…”

The relationships of modern pollen spectra to vegetation and climate along a steppe–forest–tundra transition in southern Siberia, explored by decision trees

“…The common approach to the calibration of the pollen/vegetation relationship relates pollen deposition to vegetation, land cover, land use and other environmental features, in order to search for common patterns. Frequently used statistical methods include correlation (Liu et al, 1999), regression (Webb et al, 1981;Bradshaw and Webb, 1985), cluster analysis (Hoyt, 2000;Stutz and Prieto, 2003) and ordination (eg, Gaillard et al, 1992Gaillard et al, , 1994Odgaard and Rasmussen, 2000;Brayshay et al, 2000;Fontana, 2005). All of these methods provide useful insights into the pollen/vegetation relationship, but face the problem of zero and close-to-zero values in percentage pollen data.…”