M. Jane Bunting

Pollen–vegetation relationships in non-arboreal moorland taxa

Pollen assemblages from moss polsters from northwest Scotland are compared with the vegetation composition around the sampling points. Presence–absence data are used to calculate association, over- and under-representation indices for the relationship between plants and the pollen assemblages, and results are found to be broadly comparable with published results from Norway. Relevant pollen source areas for individual taxa are estimated using least-squares linear regression analysis of pollen percentage against distance-weighted plant abundance. The extended R-value model is applied to estimate the relevant pollen source area for the pollen assemblages. The results indicate relevant pollen source areas on the order of 2 m or less for Calluna vulgaris, Vaccinium type, Myrica gale, Cyperaceae, Poaceae, Potentilla type and Succisa pratensis. Changes in non-arboreal components of pollen assemblages from mire communities therefore appear to reflect predominantly local patch dynamics rather than wider landscape changes.

Estimates of‘relative pollen productivity’ and‘relevant source area of pollen’ for major tree taxa in two Norfolk (UK) woodlands

Surface sample pollen assemblages and vegetation data collected from two East Anglian fen carr sites with adjacent dry woodland belts are analysed to estimate the relevant source area of pollen (RSAP) and the relative pollen productivity (RPP) values for the major canopy trees. The‘relevant source area of pollen’ is found to be on the order of 50-150 m, comparable with but slightly greater than estimates for forest hollow contexts in dry woodlands. Estimates of pollen productivity relative to Quercus are then compared with published values from south Sweden. Betula and Corylus values are similar, but some values estimated for taxa characteristic of wetter habitats, and therefore competitively advantaged in the fen carr system (Alnus, Salix and Fraxinus), are substantially higher at one or both sites. The results suggest that palaeoecological records from fen carr systems should be interpreted as reflecting predominantly local vegetation signals once the tree canopy is established.

Can we characterise ‘openness’ in the Holocene palaeoenvironmental record? Modern analogue studies of insect faunas and pollen spectra from Dunham Massey deer park and Epping Forest, England

This paper examines the degree to which tree-associated Coleoptera (beetles) and pollen could be used to predict the degree of ‘openness’ in woodland. The results from two modern insect and pollen analogue studies from ponds at Dunham Massey, Cheshire and Epping Forest, Greater London are presented. We explore the reliability of modern pollen rain and sub-fossil beetle assemblages to represent varying degrees of canopy cover for up to 1000 m from a sampling site. Modern woodland canopy structure around the study sites has been assessed using GIS-based mapping at increasing radial distances as an independent check on the modern insect and pollen data sets. These preliminary results suggest that it is possible to use tree-associated Coleoptera to assess the degree of local vegetation openness. In addition, it appears that insect remains may indicate the relative intensity of land use by grazing animals. Our results also suggest most insects are collected from within a 100—200 m radius of the sampling site. The pollen results suggest that local vegetation and density of woodland in the immediate area of the sampling site can have a strong role in determining the pollen signal.

Pollen–vegetation–climate relationships in some desert and desert-steppe communities in northern China

In this paper, we consider the relationship between pollen assemblages, vegetation and climate in some desert and desert-steppe areas in northern China using both surface soil samples and pollen trap samples. Discriminant analysis shows that samples originating from different climatic or geographical regions can be separated reliably on the basis of pollen assemblage regardless of sample type. DCCA analysis indicates that surface soil pollen assemblages show significant correlations with climate parameters. DCCA Axis 1 is negatively correlated with the mean temperature in the warmest month (MTwa; r = −0.58), whilst axis 2 is positively correlated with mean annual precipitation (Pann; r = −0.73). Artemisia-to-Chenopodiaceae ratios are generally lower in desert areas than in desert-steppe areas. Pollen productivity relative to Chenopodiaceae (RChenopodiaceae) was estimated using least-squares linear regression of pollen influx data against vegetation data and ERV model analysis of percentage pollen data against vegetation data. Rank order of RChenopodiaceae is consistent regardless of data set or analysis method. Artemisia has RChenopodiaceae values greater than 3, whilst RChenopodiaceae Nitraria is around 0.1 and RChenopodiaceae Poaceae is below 0.1. Our results provide useful information for quantitative reconstructions of paleovegation and paleoclimate in arid or semi-arid Asia.

Complex hydroseral vegetation succession and ‘dryland’ pollen signals: a case study from northwest Scotland

Pollen assemblages from sediment systems developed in response to changing sea level provide potentially valuable archives of local landscape dynamics in the coastal zone. Changes in wetland vegetation structure associated with the successional transition from saline to freshwater communities, and subsequent terrestrialization, however, will have marked effects on the palynological signal from surrounding dry land communities by altering the taphonomic properties of the pollen-recruiting system. We present data from one such system, a coastal wetland on the Coigach Peninsula in northwest Scotland, focusing here on reconstructing the hydroseral processes of wetland development, and how they affect the interpretation of the dry pollen signal. This contribution highlights the often-unacknowledged ambiguities inherent in reconstructing past environments from complex sedimentary systems, and outlines strategies for clarifying them.

Adding time to the conservation toolkit: palaeoecology and long term wetland function dynamics

One of the many fascinating aspects of wetlands is their ability to preserve an archive of their own history in the accumulating body of sediments building up beneath the surface, particularly but not exclusively in peatlands. The sedimentary record can be thought of as an archive of monitoring data collected over centuries and millennia, waiting to be read. This special issue brings together a selection of papers presented at the 7th INTECOL Wetlands Meeting in Utrecht, The Netherlands, July 25th–30th 2004 (see also Verhoeven et al. 2006; Bobbink et al. 2006). These papers give a Xavour of the wide range of methodologies used, and the situations investigated by palaeoecologists, and demonstrate how a palaeoecological perspective can add to our understanding of contemporary issues of concern such as Xuctuations in biodiversity and the response of wetland systems to Xuctuations in hydrology, water quality, and overall climatic change. Palaeoecology, the study of this long-term record, takes a strongly interdisciplinary approach to reading this archive. The accumulating sediments within wetlands contain the remains of animals, plants and other organisms living in and around the wetland, as well as inorganic indicators of environmental processes such as soil erosion; a range of these proxies are represented in the papers in this special issue. Pollen and spores are produced by Xowering plants and ferns across the landscape in very large amounts, and in many cases have evolved to be widely dispersed, though some distribute pollen more locally. Consequently, the distribution of plants and communities is hard to extract from the pollen record alone. Bunting (this issue pp. 000–000) explores some current work aimed at better interpreting the pollen signal from the archive. Transport to the wetland is less important when studying groups of organisms that only live in the wetland, such as testate amoeba (Mitchell et al. this issue pp. 000–000) or diatoms, or that are represented by larger, less widely dispersed

Book Review: Biogeography: an ecological and evolutionary approach (sixth edition)

The story of British mammals extends back to the Late Triassic, and the first chapter provides a brief review of the first 210 million years of mammalian history and an overview of geological timescales, with particular emphasis on the stratigraphy of the Late Pleistocene and Holocene. The rest of the book represents an encyclopaedic account of the fauna from the Late Pleistocene onwards. This bias toward Glacial and Postglacial mammals seems a reasonable one – after all, the current fauna has had to be ‘restocked’ almost from scratch following the various glaciations experienced by the British Isles and includes few, if any, pre-Glacial remnants. Moreover, as the author points out, the history of Postglacial mammals falls between the different spheres of the zoologist, archaeologist and palaeontologist and has been somewhat neglected as a result. This volume goes a long way to rectifying this deficit, and utilizes a vast amount of disparate information to produce a comprehensive overview of the subject. Throughout the book, the author has tried diligently to disentangle the effects of natural environmental change and ‘unnatural’ human interference. Some of the most drastic changes to the fauna are purely the result of climatic and geographical changes. The demise of mammoths, reindeer, Irish elk and woolly rhinos seems to be closely linked to the marked warming at the end of the last glaciation, which severely reduced or even eliminated suitable habitats, rather than overkill by prehistoric hunters. Conversely, cooling at the end of the last interglacial removed lions, hippos and hyenas, and it has since been too cool for many of these now southerly animals to make a reappearance. In contrast, the extinction of many other mammals is the direct result of human interference. The advent of agriculture is shown to be by far the worst event in the history of British mammals – the widespread destruction of woodland habitats over the past five millennia has marginalized many species, leading to their decline, and in some cases extinction. Moreover, agriculture provided a dubious justification for the elimination of wild mammals that were viewed as pests or as a threat to livestock (notably the large carnivores). In comparison, hunting, for food or for ‘sport’, has had a much smaller impact on the fauna than many would imagine. Detailed documentation of archaeological sites has shown that wild mammals made up an insignificant proportion of the animal bones recovered – our forebears relied not so much on hunting as on the harvesting of domestic stock. Paradoxically, the desire to hunt game led to the preservation of many forest areas that would otherwise have fallen in the face of agricultural demands, thereby maintaining refuges for some species. Stocks of game animals were also protected by law, ensuring that the lord of the manor always had some ‘entertainment’ on hand. Such arguments play into the hands of the pro-hunting lobby, but it should be remembered that these decisions to preserve game were not based on highminded conservation ideals, but on a selfish desire to hunt. Another major issue tackled in the book is the question: what is the ‘true’ postglacial native fauna of the British Isles? A large number of introduced mammals have arrived in the British Isles by accident or design. Some of the more recent introductions are obviously not a part of our native fauna. These animals (including copyus, red-necked wallabies and Chinese water deer) are usually escapees from farms and parks and have established small breeding colonies in the wild. Other introductions have been in the British Isles for so long that many might mistakenly regard them as a part of the native fauna. Accidental arrivals include the black and brown rats (natives of southern Asia), while edible dormice, fallow deer and rabbits were deliberate introductions from mainland Europe for food or sport. Indeed, around 25% of the current mammalian fauna consists of introduced species. As well as being of historical ecological interest, establishing the composition of the true native fauna allows informed debate on issues relating to the reintroduction of locally extinct mammals and the eradication of introduced exotics. Yalden argues that it is important to support the native biodiversity of the British Isles, even if it is at the expense of some of the introductions. Although this might sound rather draconian, several examples support this approach. Water voles are currently under extreme pressure from habitat loss and predation by American mink; grey squirrels are ousting the native reds from all but a few strongholds in Scotland and southern England; and sika deer are interbreeding with red deer to produce a homogenized population that is neither one nor the other. It would be a tragedy if the native biodiversity of the British Isles was lost for ever as a result of a few accidental escapes. There are also more contentious debates regarding the reintroduction of wolves (partly as a good way of controlling deer numbers) and beavers. Moreover, exotics like the copyu and red-necked wallaby have been the targets of active eradication programmes. It is unlikely that any particular stance on reintroduction will please all the parties involved in protecting British wildlife – it would be anathema to some conservationists to suggest that all fallow deer should be culled, for example, while purists would prefer to see only roe and red deer roaming the woodlands. These are emotive issues, and consensus is probably impossible. We can only hope that, whatever decisions are taken, they are made sensibly on a case-bycase basis. Unfortunately, the history of British mammals is largely a depressing one, the story being that of a gradual decrease in native biodiversity, and increasing pressure on wild stocks by the demands of people and domestic animals. There is some good news – the escape of captive wild boar seems to have re-established a breeding population in the south of England, and otters and pine martens are making a strong recovery – but, unless politicians are willing to think about conservation matters more seriously, the future for British wildlife does not look good.