Nicki J. Whitehouse

'Islands' in Holocene Forests: Implications for Forest Openness, Landscape Clearance and 'Culture-Steppe' Species

Received January 2004; revised manuscript accepted February 2004. Authors’ addresses: Nicki Whitehouse, School of Archaeology and Palaeoecology, Queen’s University Belfast, Belfast BT7 1NN, Northern Ireland, UK, Email: n.whitehouse@qub.ac.uk; David Smith, Institute of Archaeology and Antiquity, University of Birmingham, Edgbaston, Birmingham B15 2TT, England, UK, Email: d.n.smith@bham.ac.uk Abstract Human activity has undoubtedly had a major impact on Holocene forested ecosystems, with the concurrent expansion of plants and animals associated with cleared landscapes and pasture, also known as ‘culture-steppe’. However, this anthropogenic perspective may have underestimated the contribution of autogenic disturbance (e.g. wind-throw, fire), or a mixture of autogenic and anthropogenic processes, within early Holocene forests. Entomologists have long argued that the north European primary forest was probably similar in structure to pasture woodland. This idea has received support from the conservation biologist Frans Vera, who has recently strongly argued that the role of large herbivores in maintaining open forests in the primeval landscapes of Europe has been seriously underestimated. This paper reviews this debate from a fossil invertebrate perspective and looks at several early Holocene insect assemblages. Although wood taxa are indeed important during this period, species typical of open areas and grassland and dung beetles, usually associated with the dung of grazing animals, are persistent presences in many early woodland faunas. We also suggest that fire and other natural disturbance agents appear to have played an important ecological role in some of these forests, maintaining open areas and creating open vegetation islands within these systems. More work, however, is required to ascertain the role of grazing animals, but we conclude that fossil insects have a significant contribution to make to this debate. This evidence has fundamental implications in terms of how the palaeoecological record is interpreted, particularly by environmental archaeologists and palaeoecologists who may be more interested in identifying human-environment interactions rather than the ecological processes which may be preserved within palaeoecological records.

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.

Mire ontogeny, environmental and climatic change inferred from fossil beetle successions from Hatfield Moors, eastern England

Results of a fossil Coleoptera (beetle) fauna from a fen edge sequence from Hatfield Moors, Humber-head Levels, England, are presented. Mire ontogeny inferred from this location and others are discussed, particularly in the light of previous palynological and plant macrofossil investigations. Peat initiation across most of the site centres around 3000 cal. bc, characterized by a Calluna-Eriophorum heath with areas of PinusBetula woodland. The onset of peat accumulation on the southern margins of the site was delayed until 1520– 1390 cal. bc and appears to overlap closely with a recurrence surface at a pollen site (HAT 2) dated to 1610– 1440 cal. bc, suggesting that increased surface wetness may have caused mire expansion at this time. The faunas illustrate the transition from eutrophic and mesotrophic fen to ombrotrophic raised mire, although the significance of both Pinus- and Calluna-indicating species through the sequence suggests that heath habitats may have continued to be important. Elsewhere, this earlier phase of rich fen is lacking and mesotrophic mire developed immediately above nutrient-poor sands, with ombrotrophic conditions indicated soon after. Correspondence analysis of the faunas provides valuable insights into the importance of sandy heath habitats on Hatfield Moors. The continuing influence of the underlying coversands suggests these may have been instrumental in mire ontogeny. The research highlights the usefulness of using Coleoptera to assess mire ontogeny, fluctuations in site hydrology and vegetation cover, particularly when used in conjunction with other peatland proxies. The significance of a suite of extinct beetle species is discussed with reference to forest history and climatic change.

Fossil insects and ecosystem dynamics in wetlands: implications for biodiversity and conservation

We review the uses of fossil insects, particularly Coleoptera (beetles) and Chironomidae (non-biting midges) from ancient deposits to inform the study of wetland ecosystems and their ecological and restoration processes. In particular, we focus on two contrasting ecosystems, drawing upon research undertaken by us on British raised mire peats and shallow lake systems, one an essentially terrestrial ecosystem, the other aquatic, but in which wetland insects play an important and integral part. The study of raised mire peats suggests that faunal stability is a characteristic of these wetland systems, over what appear to be extensive periods of time (up to several millennia), whilst studies of shallow lake ecosystems over recent timescales indicates that faunal instability appears to be more common, usually driven by increasing eutrophication. Drawing upon a series of fossil Coleoptera records spanning several thousand years from Hatfield Moors, south Yorkshire, we reconstruct in some detail the mire’s ontogeny and fluctuations in site hydrology and vegetation cover, illustrating the intimate association between substrate, topography and peat development. A comparison between fossil and modern beetle populations indicates that the faunal characteristics of this mire and its adjacent neighbour, Thorne Moors, become established during the early phases of peat development, including its rare endemics, and that the faunal biodiversity on the sites today is dictated by complex site histories. The over-riding characteristic of these faunas is of stability over several thousand years, which has important implications for the restoration of degraded sites, especially those where refugial areas are limited. In contrast, analyses of fossil Chironomidae from shallow lakes allow researchers to track changes in limnological status and while attempts have been made to reconstruct changes in nutrient levels quantitatively, the chironomids respond indirectly to such changes, typically mediated through complex ecosystem dynamics such as changes in fish and/or macrophyte communities. These changes are illustrated via historic chironomid stratigraphies and diversity indices from a range of shallow lakes located across Britain: Slapton Ley, Frensham Great Pond, Fleet Pond, Kyre Pool and Barnes Loch. These sites have shown varying degrees of eutrophication over recent timescales which tends to be associated with a decline in chironomid diversity. While complex functional processes exist within these ecosystems, our evidence suggests that one of the key drivers in the loss of shallow lake chironomid diversity appears to be the loss of aquatic macrophytes. Overall, while chironomids do show a clear response to altered nutrient regimes, multi-proxy reconstructions are recommended for a clear interpretation of past change. We conclude that if we are to have a better understanding of biota at the ecosystem level we need to know more of the complex interactions between different insect groups as well as with other animal and plant communities. A palaeoecological approach is thus crucial in order to assess the role of insect groups in ecosystem processes, both in the recent past and over long time scales, and is essential for wetland managers and conservation organisations involved in long term management and restoration of wetland systems

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

A palaeoenvironmental context for Terminal Upper Palaeolithic and Mesolithic activity in the Colne Valley: Offsite records contemporary with occupation at Three Ways Wharf, Uxbridge

Abstract Multi-proxy analyses from floodplain deposits in the Colne Valley, southern England, have provided a palaeoenvironmental context for the immediately adjacent Terminal Upper Palaeolithic and Early Mesolithic site of Three Ways Wharf. These deposits show the transition from an open cool environment to fully developed heterogeneous floodplain vegetation during the Early Mesolithic. Several distinct phases of burning are shown to have occurred that are chronologically contemporary with the local archaeological record. The floodplain itself is shown to have supported a number of rare Urwaldrelikt insect species implying human manipulation of the floodplain at this time must have been limited or episodic. By the Late Mesolithic a reed-sedge swamp had developed across much of the floodplain, within which repeated burning of the in situ vegetation took place. This indicates deliberate land management practices utilising fire, comparable with findings from other floodplain sequences in southern Britain. With similar sedimentary sequences known to exist across the Colne Valley, often closely associated with contemporary archaeology, the potential for placing the archaeological record within a spatially explicit palaeoenvironmental context is great.

Farming and Foraging in Neolithic Ireland: An Archaeobotanical Perspective

Abstract Ireland has often been seen as marginal in the spread of the Neolithic and of early farming throughout Europe, in part due to the paucity of available data. By integrating and analysing a wealth of evidence from unpublished reports, a much more detailed picture of early arable agriculture has emerged. The improved chronological resolution reveals changing patterns in the exploitation of different plant species during the course of the Neolithic that belie simplistic notions of a steady intensification in farming, juxtaposed with a concomitant decline in foraging. It is possible that here, as in other areas of Europe, cereal cultivation became less important in the later Neolithic.

Evidence for the early onset of the Ipswichian thermal optimum: palaeoecology of Last Interglacial deposits at Whittlesey, eastern England

Fossiliferous deposits infilling a channel at Whittlesey, eastern England, are dated by amino acid racemization to the Last Interglacial, and pollen analysis indicates deposition in Ipswichian biozones Ip Ib and Ip IIb. Multidisciplinary palaeoenvironmental analyses of these deposits provide a rare insight into Ip Ib subzone conditions. Specifically, the Ip Ib deposits contain exotic thermophiles Naias minor, Belgrandia marginata, Bembidion elongatum, Pelochares versicolor, Caccobius schreberi, Onthophagus massai and Emys orbicularis, usually associated with Ip IIb. Combined palaeotemperature reconstructions based on beetle, ostracod and vertebrate assemblages of the Ip Ib deposits indicate that summers (mean July range +19 to +22°C) were at least 2°C warmer than at present, whereas winters (mean January air temperature range 0 to +7°C) were probably similar to those of today. These palaeotemperature ranges encompass those for Ip IIb deposits at Trafalgar Square (+20 to +21°C and +1.5 to +3°C), previously considered the only Ipswichian site to record temperatures significantly warmer than Holocene temperatures. Of particular significance is that thermal optimal conditions commenced in Ip Ib, rather than being confined to Ip IIb. This demonstrates rapid warming and biological response to early Ipswichian climate amelioration, which accords with the deep-sea Last Interglacial and European Eemian records. Supplementary material: Supplementary Tables S1-S7 are available at http://doi.org/10.6084/m9.figshare.c.3830221.

Early agriculture in uncertain climates: themes and approaches

Latin Binomial English Common Name AQUATIC TAXA Myriophyllum spp. 3 Water-milfoil Callitriche spp. 3 3 ? Water-starwort Alisma cf. plantago-aquatica L. 3 3 Possible Water-plantain Potamogeton spp. 3 Pondweed WATERSIDE TAXA Alnus glutinosa (L.) Gaertn. 3 3 Alder Lycopus europaeus L. 3 3 3 Gypsywort Carex spp. 3 3 Sedge WET/DAMP GROUND TAXA Filipendula ulmaria (L.) Maxim. 3 3 3 Meadowsweet Juncus sp. 3 Rush WOODLAND TAXA Urtica dioica L. 3 3 3 3 Common Nettle Betula pendula Roth 3 3 3 Silver Birch Betula pubescens Ehr. 3 3 3 Downy Birch Oxalis acetosella L. 3 3 3 3 Wood-sorrel TAXA OF VARIED ENVIRONMENTS/SOILS Galeopsis spp. ? 3 3 ? Hemp-nettle Stellaria media s.l. 3 3 Common Chickweed cf. Sanguisorba minor Scop. ssp. minor 3 3 3 3 Possible Salad Burnet

Plant controls on Late Quaternary whole ecosystem structure and function.

Plants and animals influence biomass production and nutrient cycling in terrestrial ecosystems; however, their relative importance remains unclear. We assessed the extent to which mega-herbivore species controlled plant community composition and nutrient cycling, relative to other factors during and after the Late Quaternary extinction event in Britain and Ireland, when two-thirds of the regions mega-herbivore species went extinct. Warmer temperatures, plant-soil and plant-plant interactions, and reduced burning contributed to the expansion of woody plants and declining nitrogen availability in our five study ecosystems. Shrub biomass was consistently one of the strongest predictors of ecosystem change, equalling or exceeding the effects of other biotic and abiotic factors. In contrast, there was relatively little evidence for mega-herbivore control on plant community composition and nitrogen availability. The ability of plants to determine the fate of terrestrial ecosystems during periods of global environmental change may therefore be greater than previously thought.