An Investigation of the History of Vegetation Change on Ballynahone Bog, County Londonderry using Pollen Analysis.

Transcription

1 An Investigation of the History of Vegetation Change on Ballynahone Bog, County Londonderry using Pollen Analysis. Aerial photo taken from the South of Ballynahone Bog and the Moyola River. Source: Friends of Ballynahone Bog (1991). Megan Noble BSc Environmental Science with DPP School of Environmental Science University of Ulster, Coleraine

2 Abstract A pollen diagram from a typical lowland raised bog in County Londonderry is presented. The recorded vegetation is assessed relative to the dating of zones of climatic/vegetation phases at Sluggan Bog, Co. Antrim. Peat cores were taken from two sites. Site 1 was an area of cutover bog and two cores were extracted from here. Five cores were taken from the dome of the bog which was site number two. The first core from site 1 reached the basal peat and the underlying lake sediments below the surface, the second core was taken above this at a depth of 2m. Betula (birch), Pinus (pine) and Alnus (alder) woodland started to colonise early in this sequence; around BP. However Calluna (heather) and Sphagnum grains were also present in these deep cores, and these species now grow on the surface of this area of the bog. Betula (birch) woodland also developed early in the sequence; around BP (Older Dryas period). The end of the Thermal Maximum, around BP, caused the decline of woodland and this is discussed. During the Woodgrange interstadial, Betula (birch) was susceptible to drought and therefore started to decrease as the peat dried out. Corylus (hazel) disappeared during this period representing a turning point in woodland development. During the Late Boreal period, Betula (birch) returned to the mire. The evidence of human activity and the impact it had to vegetation during the Boreal-Atlantic transition is considered. The first elm decline (Early Faming period) is suggested to have been caused by Neolithic forest clearance activity, the second by major forest clearances during the Bronze Age. The greatest impact on the bog happened during Viking to Late Anglo-Norman times. The changes caused on the bog by present human impacts are also discussed and why development of certain species has happened at the two sites. Key words: raised bog/mire, pollen, vegetation history, climatic change, human impacts.

3 Acknowledgements I would like to express many thanks to everyone who has helped me throughout the course of this project, especially my family who have had to listen to me talk about bogs every day, and my boyfriend Philip Leckey who constantly checked to make sure I was on track with my timing to complete my dissertation. I would firstly like to thank my dissertation supervisor, Dr. Peter Wilson for his advice, guidance and hands on approach to my topic. I would also like to thank Claire Mulrone from the Science Shop for helping me to find a topic of my interest. Thanks to the Ulster Wildlife Trust for granting me permission to take core samples from Ballynahone Bog. And a special thanks to Pól Mac Cana for the help he gave out in the field coring the bog. Thanks especially to Joerg Arnscheidt for helping set up the camera on the microscope to allow me to take pictures of my pollen grains. To Thomas Beattie, many thanks for carrying out the laborious task of writing out my sample bags and for keeping me company during my lab time, whilst being volunteered to be designated washer of my used apparatus.

4 Table of Contents Abstract I Acknowledgements II Chapter 1: Introduction.. 1 Study Rationale.. 2 Study Objectives and Aims 4 Chapter 2: Literature Review.. 5 Raised Bogs in Northern Ireland. 5 Peat-land system: an important proxy; of paeloenvironmental data.6 Tephra 7 The use of pollen analysis. 9 Sample collections. 10 Treatment of samples. 11 Interpreting pollen data: History of Raised Bog Vegetation. 12 Restoration and Conservation of Raised Bogs 14 Chapter 3: Site Description..16 Geology. 16 Definition of Raised mire 17 Peat.. 17 Hydrology 18 Climate.. 18 Vegetation.. 18 Site History. 19 Chronological sequence of events in the conservation history of Ballynahone Bog 20 Chapter 4: Methodology 22 Fieldwork.22 Study Area 22 Coring Risk Analysis 26 Description and preparation of cores 26 Treatment of samples.. 28 Microscopy work. 29 Pollen diagram. 29 Chapter 5: Results 30 Description of Cores. 30 Sampling 39 Identified Pollen Grains. 40 Pollen Count, Site Results. 40 Figures of Sampled Pollen Grains.. 49 Pollen Diagram. 56 Chapter 6: Discussion.. 58 Peat deposits.. 58 Pollen diagram; change in vegetation.. 59 Human or Climatic impacts?.. 62 Chapter 7: Conclusion.. 66

5 References 67 Appendices Appendix One Bogland. 78 List of Figures Figure 1.1 page 2 Figure 2.1 page 6 Figure 2.2 page 8 Figure 2.3 page 10 Figure 2.4 page 11 Figure 3.1 page 16 Figure 3.2 page 19 Figure 3.3 page 20 Figure 4.1 page 23 Figure 4.2 page 24 Figure 4.3 page 25 Figure 4.4 page 25 Figure 4.5 page 27 Figure 4.6 page 27 Figure 5.1 page 31 Figure 5.2 page 32 Figure 5.3 page 33 Figure 5.4 page 34 Figure 5.5 page 35 Figure 5.6 page 36 Figure 5.7 page 37 Figure 5.8 page 50 Figure 5.9 page 51 Figure 5.10 page 52 Figure 5.11 page 53 Figure 5.12 page 54 Figure 5.13 page 55 Figure 5.14 page 57 List of Tables Table 4.1 page 22 Table 5.1 page 39 Table 5.2 page 41 Table 5.3 page 42 Table 5.4 page 44 Table 5.5 page 45 Table 5.6 page 46 Table 5.7 page 47

6 Table 5.8 page 48 Abbreviations EHS Environmental and Heritage Service for Northern Ireland UWT Ulster Wildlife Trust NNR National Nature Reserve KOH Potassium hydroxide

7 Chapter 1: Introduction Ballynahone is an example of a raised bog located at the eastern foot of the Glenshane Pass. It is situated N, W, lying north of the Moyola River, 3km north-east of Tobermore and 3km south of Maghera in County Londonderry (Fig. 1.1). In 1987 Bulrush Peat Company Limited applied for planning permission to extract peat from Ballynahone. Although there were some objections raised against this scheme planning permission was granted in 1988 by the Department of the Environment. Shortly after this decision was made the Ulster Wildlife Trust invited its members to take a last walk on the bog now the fight to retain its ancient flora and fauna had been lost. The group Friends of Ballynahone Bog (FBB) was launched as a result of this walk. By 1991 Bulrush had already dug 13 miles of drains on the southern half of the bog, and flora in close proximity to the drains, began to come under threat. Two years after this FBB started the process of declaring Ballynahone a National Nature Reserve. Planning permission was revoked from Bulrush and they dammed their drains in December By 1995 the bog was declared an Area of Special Scientific Interest (ASSI). Ballynahone Bog is currently the largest nature reserve at 244 hectares, incorporating the second largest area of intact raised bog in Northern Ireland. It is an Area of Special Scientific Interest (ASSI), as-well as a designated National Nature Reserve (NNR). The vegetation on the bog is extremely interesting, species include; rare sphagnum mosses, liverworts and bog rosemary. The bog and surrounding birch woodland also support a variety of birds, butterflies and dragonflies. The remaining drains were dammed by the end of 1994.

8 Crown Copyright Figure 1.1: Ordnance Survey map showing the location of Ballynahone Bog Study Rational The value of pollen analysis as a tool for the reconstruction of past vegetation and environments, and its applications in such areas as climate change studies, archaeology, geology, honey analysis and forensic science, is now widely known (Moore et al., 1991). One of the most highly exploited uses of palynology is the investigation of vegetation history (Godwin, 1975; Bryant and Holloway, 1985). Most effort has certainly been expended on the reconstruction of changes during the last 11,000 years (the Holocene) during which the Earth has recovered from the last glaciation, and human pressures upon global vegetation have become increasingly intense (Moore et al., 1991). Peat extraction at Ballynahone Bog never came to completion and extraction of peat was never taken from the surface of the dome. Therefore a full reconstruction of the history of vegetation change as Ballynahone Bog developed can be carried out from pollen retrieved from the dome.

9 The use of pollen analysis helps to understand the environmental setting, the economy and the way of life of prehistoric human cultures (Dimbley, 1985). Further study of modern agricultural communities and the pollen rain may assist in understanding the effect that mankind had on the vegetation in the past (Moore et al., 1991). Studies have been carried out on numerous raised bogs. According to Habitas (2010), over the last thirty five years, no lowland raised bog in N. Ireland has been the subject of more palaeoenvironmental study than Sluggan Bog, Co. Antrim. Ballynahone Bog has not had the same amount of research carried out on it than other bogs in Northern Ireland. This presents an opportunity to study the change in past vegetation on this bog using pollen analysis.

10 Study Objective and Aims Study Objective The objective of this project is to investigate the history of vegetation change that has taken place on Ballynahone Bog, Co. Londonderry, as well as finding out if these changes are significant. Aims A number of aims need to be fulfilled to meet this objective: To take cored samples to from Ballynahone Bog and to use pollen analysis to reconstruct the vegetation change of the bog Analyse any significant relationships that could have occurred between the environment and past vegetation. To reciprocate feedback from my data and findings. Increase personal taxonomic knowledge of raised bog vegetation species; past and present. To familiarise myself with identification of specific pollen grain types.

11 Chapter 2: Literature Review This section is dedicated to providing on overview and synopsis of the reconstruction of Quaternary environmental change using biological evidence in the form of plant and animal remains. Particular emphasis will be put on the use of pollen analysis regarding the identification of historical vegetation transformation. Discussion will also include the current condition and status of raised bogs within Northern Ireland. A brief insight into the growing interest of tephra and how volcanic eruptions could have affected local vegetation will also be explored. Further investigation will consist of additional scrutiny of restoration and conservational ideas within these fragile landscapes. Raised Bogs in Northern Ireland Many past surveys of lowland raised bogs in Northern Ireland have been carried out (Hammond, 1979; Leach and Corbett, 1987; Cruickshank and Tomlinson, 1990). One of these surveys showed that raised bogs are concentrated along the valleys of the Main (Antrim), Bann (Antrim/Londonderry), Fairy Water (Tyrone), and Arney (Fermanagh) and to the north of Ballymoney (Antrim). Figure 2.1 shows that almost all peatland areas in Northern Ireland lie to the west and on the uplands of the north-east, in close association with wet, gleyed mineral soils (Hammond, 1979). The Environmental and Heritage Service (EHS) developed a policy statement in 1993 that estimates that over a quarter of the United Kingdom s resource of lowland raised bogs may be found in Northern Ireland. About 9%; 2,270 hectares is still intact. Many plant species that are found on peatland systems are unique, however certain species that are found on raised bogs can also be found within other habitats. There is a strong set of interactions that take place between the physical and chemical environment that controls the development of peatland ecosystems and vegetation (Bedford, 1992). The natural species type of many lowland raised bogs is seen to be Sphagnum (Money, 1995; Wheeler and Shaw, 1995). Sphagnum also plays an important role in successful restoration of bogs (Money, 1995). Heterogeneous surface microtopography such as pool complexes and hummocks can also be found on raised bogs (Dierssen, 1992). Vegetation composition studies are a good way to discover what effect environmental conditions have had on different types of vegetation species.

12 Figure 2.1: A simplied map of Northern Ireland showing the positions of peatlands. Source: Hammond (1979). The peatlands of Ireland. Peat-land systems: an important proxy of palaeoenvironmental data Peat archives have been widely employed to examine changes in climate over the Holocene in northwest Europe by numerous researchers e.g. Blundell et al., (2007). The search for reliable records of climatic change during the Holocene has involved much usage of proxyrecords e.g. Barber et al. (2003). All proxies have their advantages and disadvantages (Barber et al., 2003). Single proxy studies examining plant macrofossils have been examined greatly (Barber, 1981; Barber et al., 1994). However there are only a few multiproxy records from peat archives even in well studied regions (Charman et al., 1999; Chiverrell, 2001) and substantially fewer from Ireland e.g. Caseldine and Gearey (2005).

13 Plant and animal remains can sometimes be used to sub-divide the Quaternary record (biostratigraphy). Applications that are related to peat systems are also applicable to lake sediments, palaeosols, as well as marine and estuarine materials. With respect to radiocarbon dating, tephra and dendrochronology, peat systems are extremely valuable. The rather small body of evidence for Ireland s ancient fauna contrasts markedly with the wealth of evidence for Ireland s past vegetation (Hall, 2011). Britain and Ireland s earliest mires began forming after the last glaciation, around 15,000 BP. Most mires developed during the Holocene: since 11,700 BP; however blanket mires started to develop at different times. Local conditions were affected when these mires started to form. Evidence for environmental change is often found in ombrogenous mires by examination of peat stratigraphy. Climate played an important role as an allogenic forcing factor in bog growth and therefore in peat stratigraphy as a proxy climate record (Barber et al., 1994; Chambers et al., 1997; Charman et al., 1991; Chiverrell; 2001). Often found in Irish bogs are rather abrupt changes from dark peat found at the bottom of the mire to less well humified light peat at the top. These are known as recurrence surfaces. They are potentially useful as palaeoclimatic indicators if, the recurrence surfaces are synchronous over various areas, meaning a climatic origin may be valid. What were also found at the bottom of Ballybetagh Bog in County Wicklow were the bones of the now extinct Great Irish deer (Megaloceros giganteus) (Hall, 2011). Tephra Tephra is volcanic ash. It is the product of a volcanic event (Hall et al., 1994). Tephrostratigraphers and tephrochronologies are used by Quaternary scientist; mostly in areas where tephra layers are visible to the naked eye (Hall et al., 1994). Using layers of micro-tephra as an isochrone marker has only recently been considered. (Persson, 1971; Buckland et al. 1981). According to Hammer (1984) laborious work needs to be carried out to trace fine tephra from peat bogs. Tiny particles of volcanic ash from volcanoes that have erupted almost entirely in Iceland are carried to Ireland by weather systems that originate in the Icelandic region, only small traces of volcanic ash or tephra have been found in Irish boglands (Hall, 2011). Tephra is present in Holocene peats and lake deposits. Figure 2.2 shows where these tephra layers have been found in Ireland (Hall et al. 1994). Not all tephra is colourless (Hall et al., 1993). Found in Sluggan Bog, Fallahogy Bog and Ballynahone

14 Bog was a layer of flaky light brown volcanic glass found above the Hekla 4 layer of these peats (Pilcher and Hall, 1992). This layer was also found in Garry Bog along with a number of other well defined layers (Hall et al, 1993). It is only recently that replicated studies of tephrostratigraphy in lowland raised bogs in the north of Ireland have been published (Hall et al., 1993). Figure 2.2: Sites in Ireland at which tephra layers have been found in peat. Source: Hall et al. / The Journal of the Association for Environmental Archaeology 11, (1994) pp

15 These show that although tephra events occurred throughout the Holocene, their frequencies have increased within the past 4000 years (Thorarinsson, 1981). Ash was found to be present in lowland peats from Sluggan Bog; it was linked geochemically to eruptions of Hekla in AD 1104 and Öræfajökull in AD 1362 (Hall et al, 1994). Local vegetation may have been impacted from the eruption of Hekla 4 (Bennet et al. 1992; Blackford et al. 1992; Hanna, 1993; McVicker, 1993; Hall et al ) The loss of native pines in Ireland was hastened by very poor weather after a volcanic eruption far from Ireland (Hall, 2011). This area of research is growing in interest, palynologists now investigate what influence past volcanic activity could have had on vegetation (Hall et al. 1994). Evidence that volcanic eruptions in Iceland have affected the weather in Ireland have even been evident more recently with mass disruption caused by eruptions from Eyjafjallajökull in The use of pollen analysis Levels of diversity, or differences in the number of organisms between areas, can be used to indicate the nature of past environments where high diversity and endemism are facilitated by relative environmental stability (Fjeldså and Lovett, 1997). Various pollination strategies influence and decide the number of pollen grains ultimately at disposal for analysis, and their distribution (Faegri and Iverson, 1989). One of the main ways to reconstruct the environmental past is through data produced by pollen analysis. The composition and distribution of past vegetation, and changes that may have happened can be determined by the pollen that has been preserved within mires or sedimentary basins. Palynology is one of the most widely used research tools in Quaternary studies (Edwards, 1983). It can be defined as a technique for reconstructing former vegetation by means of the pollen grains it produced (Faegri and Iverson, 1989). Palynology is concerned with both the structure and the formation of pollen grains and spores, and also with their dispersal and their preservation under certain environmental conditions (Moore et al., 1991). Pollen analysis was first developed in Sweden by a botanist, Professor Lagerheim, however it was the success of von Post s pioneering experiments in 1916, which enabled pollen analysis to become recognized and used to document long-term vegetation dynamics. (Birks, 1993). It was introduced to Ireland in the 1920 s and 1930 s by the Danish scientist, Knud Jessen, who worked on tracing Irish woodland development since the end of the last glaciation (Hall,

16 2011). It has also been used in a wide variety of Quaternary applications including chronostratigraphic correlation, palaeoecology, palaeoclimatology and archaeology (Macdonald, 1988). Pollen analysis is an extremely versatile method; inferences can be made about changing vegetation patterns over broad, spatial and temporal scales. The influences that man had on the landscapes can also be detected. Sample collection Many applications of pollen analysis depend upon the sampling of stratified sequences of peat, lake sediments or soil. These samples can be taken from exposed surfaces e.g. cliff or peat erosion faces (Moore et al., 1991). Where exposed sections of a deposit are not available, cores must be extracted from the surface of the site. Figure 2.3 shows the various types of coring equipment that have been devised to suit the different situations and the types of sediment (Moore et al., 1991). Figure 2.3: Different types of samplers that can be used to core section of sites. Source: Moore et al. (1991). Pollen Analysis.

17 Diagram (a) is a chamber sampler known as a Hiller, it is fitted with an auger head, allowing it to be twisted as it penetrates the sediment (Moore et al. 1991). Diagram (b) is a Russian, it is widely used for peat stratigraphic work because of its clean action and its speed of operation and cleaning. It also has a great advantage in that the sediment that it passes through is not disturbed (Moore et al., 1991). Diagram (c) is a Dachnowski and (d) is known as a Livingstone (Moore et al., 1991). The field work provides not only the material basis for the work that is to follow, but also the foundation upon which conclusions are built (Faegri and Iverson, 1989). Treatment of samples The various chemical processes developed for the treatment of pollen samples relate to the different matrix materials in which the pollen may be embedded (Moore et al., 1991). Treatment with Potassium hydroxide digestion on its own can produce a reasonable concentration of pollen from certain peats. To remove the cellulose; which is a polysaccharide, effectively, acid hydrolysis should be used (Moore et al., 1991). Hydrochloric acid treatment can be used if there is an abundance of calcium carbonate in the sediment. However if there is an abundance of silica present in the sample then Hydrofluric acid treatment can be used. The removal of silica is essential to avoid the pollen being obsured when mounted (Moore et al., 1991). When the pollen is mounted, the most appropriate magnification for routine scanning and counting is X400, i.e. X40 objective and X10 eyepiece (Moore et al., 1991). This provides sufficient magnification for the identification of many pollen grains. Figure 2.4 shows some of the pollen grains that can be seen through the microscope. Figure 2.4: Different types of pollen grains; from left to right: Betula (birch), Ulmus (elm), Alnus (alder), Pinus (Pine) and Poaceae (grass) Source: Faegri, K. and Iverson, J. (1989). Textbook of pollen analysis.

18 Interpreting pollen data: History of Raised Bog Vegetation It is useful to think of pollen analysis as a remote sensing technique, which records the past and present composition of vegetation (Webb et al., 1978). By accessing lake or bog sediments; that preserve pollen, it is possible to reconstruct plant communities of the past. The long story of Ireland s past landscape is not in history s pages but locked away within the peat bogs and lake sediments in which Ireland abounds (Hall, 2011). Each individual plant species is enclosed within a specific environmental envelope; temperature, moisture, seasonality, soil type and other factors that support the plants growth and reproduction, if the environment changes (Jolly et al., 1997). Radiocarbon dating can be used on these pollen grains, so that a reconstruction can be determined of how vegetation has changed over time. For example Ireland s changing landscape took 14,000 years to unfold, beginning with an account of happenings as the last glaciation terminate (Hall, 2011). There are difficulties with representation of different species as some taxa produce greater amounts of pollen that can be more widely dispersed (Birks and Birks, 2005) therefore many plants may be under represented. Pollen stratigraphy provides a record of the changing vegetation of the past; it supplies information on past climates and land use history (Moore et al., 1991). The interpretation of peat diagrams allows past vegetation types to be reconstructed. It consists of two steps: (1) establishing the composition of the vegetation that delivered the pollen, and reconstructing it; (2) drawing inference from the vegetation data back to the agents behind them e.g. climate, ecology and human interference (Faegri and Iverson, 1989). However careful interpretation of pollen diagrams can be tricky, it requires knowledge of differences in pollen production and dispersal, source areas, differential preservation and relationships between pollen and former plant communities (Faegri and Iverson, 1989). The reconstruction of the history of human vegetation management has proven to be just as difficult as reconstructing climate history (Moore et al., 1991). Interpretation is therefore dependent on the use of indicator species whose ecology can be linked to man-induced aspects of the environments, such as fire, disturbed soils, open canopies, nitrogen and phosphorus flushing, to name but a few (Moore et al., 1991). Almost everything known about the arrival of the trees to Ireland comes from pollen analytical studies (Hall, 2011). The early Boreal Period ( BP) was a time of real vegetation significance. The birch woods of the early post-glacial were subject to a set-back

19 at approx BP due to unstable soil characteristics of earlier times. Woodland development went through a turning point because of a decline of hazel at approx BP (Smith and Goddard, 1990). The spread of vast birch and oak woodland and later the subsequent spread of agriculture may be traced by pollen analytical studies (Hall, 2011). Studies carried out on pollen show that the Irish climate entered a period of reduced rainfall about 8,300 years ago, causing the water table in the boglands to fall and bog surfaces to dry up enabling pine seeds to germinate. (Hall, 2011). In Sluggan Bog, a densely packed layer of fossilised timber gives the impression of a great pine wood. Trees began to spread on the bog surface around 8361 BP. (Hall, 2011). The presence of pine stumps in the peat suggests a dry phase in the bog development (Smith and Goddard, 1990). Around 8,200 years ago the weather in Northern Ireland deteriorated. The Northern Hemisphere cooling event is believed to represent the last known major freshwater pulse into the North Atlantic (Head et al., 2005). Because of this collapse of the North American ice sheet that had covered much of eastern Canada, the North Atlantic region, the next 40 to 50 years experienced a period that was cold and wet (Hall, 2011). Using the peat sequence at Dooagh, Achill Island on the west coast of Ireland, clear evidence is found for a climatic oscillation in the early Holocene using various measures of pollen, indicating a disruption in the vegetation leading to a grassland dominated landscape, which is probably due to the climatic shift to drier and probably colder conditions which lasted for several hundred years (Head et al., 2005). Conversely there is a lack of peat-based palaeoclimatic studies from Ireland (Blackford and Chambers, 1995; Barber et al., 2003). Blackford and Chambers (1995) noted a shift from drier to wetter conditions in Ireland during AD 1300 s from humification data covering the last thousand years. The decline of birch woodland in BP represents the end of the thermal maximum of the late glacial inter-stadial (Smith and Goddard, 1990). Following pine, the tree species that found a new niche on bog surfaces was oak, dating from the period BP (Hall, 2011). Pollen records from Irish lowlands show that around 7000 years ago, increasing amounts of alder pollen was preserved in peat (Hall, 2011). Pollen analysis and radiocarbon dating have also assisted in showing that there is less than 6,000 years since farming and agriculture was introduced to Ireland. Cereal grains that have been dated show that between BP the first cereals were grown in Ireland and Britain (Hall, 2011). According to Chiverrell et al. (2004), pollen data and archaeological evidence reveals a complicated pattern of human activity

20 and associated vegetation change during what are conventionally termed the Bronze Age times ( BP). During this period several temporary woodland clearances were recorded in Northern Ireland (Chiverrell et al., 2004). The Bronze Age was an important period of landscape evolution in regards to an increase in settled mixed farming and associated woodland removal, soil erosion, blanket bog development and heathland expansion all of which caused significant and permanent changes (Chiverrell et al., 2004). The precision with which human influence can be detected from the pollen record is greatly facilitated by the practice of agriculture (Moore et al. 1991). In agricultural communities one expects to find elements of destruction of the natural vegetation, the introduction of crop species and the presence of weed species associated with arable and pastoral activities (Behre, 1981). An event known as the elm decline happened around 5840 BP. Pollen diagrams have recorded these vegetation changes. The decline in elm might be linked to the new farming practices (Hall, 2011). As agriculture expanded and climate worsened, woodland depleted further, soils became damaged and drainage became impeded (Hall, 2011). Neolithic forest clearance activity on a minor scale is attested at the elm decline which at Sluggan, falls rather late in the usual range for this horizon at around 4900 BP. (Smith and Goddard, 1990). The early farming period (4900 BP) ends with the final decline of Pine, which coincides with the onset of the Bronze Age clearances on Sluggan. The Bronze Age was an important period of landscape evolution in regards to an increase in settled mixed farming and associated woodland removal, soil erosion, blanket bog development and heathland expansion, all of which caused significant and permanent changes (Chiverrell et al., 2004). The spread of blanket peat probably owed much to the effects of human activity and land use (Chiverrell et al., 2004). Around 2,200 years ago bog woodland had almost disappeared from Ireland, making those that remained north of Lough Neagh and at Garry Bog in County Antrim the last of their kind (Hall, 2011). Restoration and Conservation of Raised bogs The protection of peatlands, especially blanket and raised bogs, is regarded as one of the top objectives for nature conservation in Northern Ireland. Due to the unique environmental conditions of bogs, highly specialised plants and animals that are not found in other habitats are able to colonize here. Blanket and raised bogs are listed as priority

21 habitats in the EC Directive on the conservation of natural habitats and of Wild Flora and Fauna. Surveys were conducted for the Environmental Service for Northern Ireland of raised bogs (Cruickshank and Tomlinson, 1988; Leach and Corbett, 1987) to increase awareness for the need to protect the peatlands of Northern Ireland for their scientific, wildlife, landscape and cultural value. These surveys were carried out to establish the extent of degradation of bogs in Northern Ireland and their potential for conservation. After 1985 the Nature Conservation and Amenity Lands (NI) Order (1989) introduced the ASSI Area of Special Scientific Interest designation (Corbett and Seymour, 1997). Restoration of bogs can have serious problems in terms of the relationship between peat, vegetation, hydrology and topography due to the complexity of them within bog habitats and how they are interlinked. According to Wheeler and Shaw (1995) the conservation and restoration of raised bogs are either mire centred or species centred. Many voluntary groups such as the Ulster Wildlife Trust (UWT) work to restore and conserve large sections of sites in Northern Ireland. The aims of groups such as the UWT are to try and maintain or recreate developing raised bog ecosystems and also to re-establish the populations of species that are typical of raised bogs. Many species may require human interference however species of Sphagnum may restore spontaneously. Most interest in peatland systems is with regards to legal protection of intact bogs. According to Crowley et al. (2003) anthropogenically disturbed sites including cutover bogs have yet to receive such legislative protection. However in terms of conservation, research on cutover bogs has now increased. From the literature it can be seen that pollen analysis is a very effective and versatile method, in regards to reconstructing past vegetation. It is also widely used; certain bogs in Northern Ireland have had a lot of work carried out on them to trace their vegetation history. Knowledge of the past history of mires can also help to restore and conserve these systems. The next section will describe the sites under investigation as well as their conditions which make it possible to carry out this study.

22 Chapter 3: Site Description Geology The Landscape Character Area known as the Moyola River Floodplain consists of three ages of rock strata according to the EHS (1994). The oldest layer is the Carboniferous including Iniscairn, Altagoan and Desert martin, these clastic and carbonate sediments are around 350 million years old and cover approximately 50% of the south-east area. The Triassic Sherwood Sandstone Group is 240 million years old, which runs in a strip from east to west. The Tertiary Lower Basalt Formation is about 55 million years old, covering around 50% of the north-east area. The drift geology of this area is made up from lacustrine alluvium and alluvial deposits that were laid down by the Moyola River and underlying glacial deposits. As last Ice Age ended around 16,000 ago Ballynahone Bog started to develop, Fig 3.1 shows the development of fen into a raised bog. Figure 3.1: Transverse section of peatland types. Profile (A) shows fen and (B) shows the development into a raised bog.

23 Tephra has been found within the peat column; a layer of flaky light brown volcanic glass from past volcanic activity (Pilcher and Hall, 1992). On such layer dates to AD1104 from the eruption of Hekla volcano in Iceland (Hall et al., 1994), tephra from this eruption has been recorded at many sites within the British Isles. Definition of Raised mire The Definition of raised mire from the Dictionary of Physical Geography (Thomas and Goudie, 2000): An acid peatland dominated by Sphagnum mosses and supplied by precipitation solely from atmospheric source (rain, snow, fog etc). Raised mires form characteristic shallow domes of peat where the topography is typically convex, with gently sloping land away from its centre toward the surrounding moat-like drainage channel or lag (Swedish terms describing margin of raised bog, typically with a stream and/or minerotrophic poor-fen or fen woodland) surrounding the bog. This mire type is primarily a lowland system, and mainly occurs in broad, flat(ish) valleys or basins. Raised mires have a wide distribution in Britain but predominate in the cooler, wetter north and west. In lowland Britain raised mires are recorded in basins, floodplains and at the heads of estuaries. Peat Ballynahone Bog has around 60 hectares of uncut bog making it the second largest area of uncut lowland raised bog in Northern Ireland. The storage of organic matter is greater than the rate of decomposition, resulting in this area of peat having a positive energy balance (Dierssen, 1992). According to Bellamy (1986), peat can be scientifically defined as partially decayed matter consisting mainly of plant origin. Ballynahone Bog is considered to have the best examples of raised bog habitats in the United Kingdom due to the area of uncut peat taking the shape of the classic dome profile. Pools, hummock hollows and lawn complexes can also be found within this area.

24 Hydrology The nearest point of the Moyola River to Ballynahone Bog is 150m south of it. The Black Burn River which is a tributary of the River Moyola is situated approximately 350m from the bog. However this bog is a rain-fed system despite its close proximity to the river, making this an ombrotrophic bog. Lindsay (1995) states that the wetland conditions of the bog and consequently the nutrient supply are derived from direct atmospheric precipitation alone. The hydrological status of the bog is dependent on a number of factors; annual precipitation, local climate, water movement on and off the body of the bog and also the amount of human disturbance etc. Bearing the above factors in mind it is understandable how the hydrology of Ballynahone Bog has been altered in the past by hand peat cutting but more significantly by the drainage ditch excavation put in place by the Bulrush Peat Company in preparation for mechanical peat cutting. The EHS in 1994 dammed the drains using peat in order to restore the hydrological condition of the bog. Climate The estimated amount of rainfall needed for peat formation is 475mm annually (Lindsay, 1995). Northern Ireland is ideally suited to provide a climate beneficial to the production of bog peat; in 2011 the annual amount of rainfall was 1356mm (Met Office, 2012), almost triple the average for the formation of peat. According to Lappalanien (1995) ombrogenous mires are entirely dependent on atmospheric inputs for their water and solute supply; they can only develop in regions which have an annual surplus of precipitation over evaporation, and not too great a deficit of precipitation during any season of the year. Vegetation As mentioned previously a full range of lowland raised bog characteristic structural features such as the classic domed profile, along with pools, hummocks and lawn complexes are found on Ballynahone Bog. A further mosaic of habitats have developed on this site due to past disturbances; Purple Moor-grass grasslands, poor fen, regeneration of the bog and Downy Birch woodland etc. This structural variation supports a wide range of vegetation, mainly dominated by Sphagnum mosses. The abundance and composition of vegetation species is dependent on local edaphic conditions (EHS, 1994). Prominent species found on

25 the dome of the bog include; Heather, Deer grass, Common cotton grass. Bog Myrtle and White beaked sedge are also widespread on the bog. Bog rosemary is rare; however it can be found growing on Ballynahone Bog alongside only one other lowland raised bog in Northern Ireland (EHS, 1994). woodland as shown in Figure 3.2. Ballynahone Bog is also surrounded by a young Birch Figure 3.2: The cut-over part of the Ballynahone Bog surrounded by Birch trees Site History Man has exploited Ballynahone Bog in the past through peat cutting by hand, commercial peat cutting in the 1980s and through drainage in preparation for this. Clay pigeon shooting that has taken place on the bog has caused ground contamination. Resulting from the peat extraction that took place on the Ballynahone bog, over 38.5 hectares of the approximately 100 hectare total of the National Nature Reserve were cutover. In the 1990s increased

26 awareness of raised bog ecology and vulnerability to disturbance resulted in the government designation of Ballynahone Bog as an ASSI. Figure 3.3: The cut-over section of Ballynahone Bog Chronological sequence of events in the conservation history of Ballynahone Bog Between August and October of 1985, Ballynahone Bog was considered one of the top ten lowland raised bogs after being surveyed by the Countryside and Wildlife Branch (DOENI). By 1988 a horticultural company known as Bulrush Peat Company had acquired a large part of the bog. Despite objections planning permission was granted to Bulrush to extract peat for commercial use. Drains were put in place on the southern part of the bog in During the 6 year period from 1988 to 1994 opposition to the commercial use of peat

27 extraction came from locals, which then caused Friends of Ballynahone Bog to start a campaign against Bulrush which drew in a lot of support from local environment groups and celebrities. Planning permission was then revoked from the site as a result from the local campaign and also from a further site survey carried out by the EHS; who then bought the area that was owned by Bulrush. By January 1995 the 244 hectares of Ballynahone Bog was designated an Area of Special Scientific Interest (ASSI) by the EHS, who then proposed it as a candidate for designation as a Special Area of Conservation (csac) under the EU Habitats Directive (92/43EEC). During September 2000, 98.5 hectares of the bog was designated as a National Nature Reserve; 60 hectares as uncut bog and 38.5 hectares as cutover bog. EHS declares NNRs under the Nature Conservation and Amenity Lands (Northern Ireland) Order (1985). Ballynahone Bog is now managed by the Ulster Wildlife Trust.

28 Chapter 4: Methodology This section includes details in each aspect of the investigation including; field work, lab work, identification of pollen grains and construction of a pollen diagram. Fieldwork Study Area Before samples could be taken from Ballynahone Bog, consent had to be received from NIEA; Northern Irelands Environment Agency. Permission was granted on the 5 th of January 2012 for samples to be collected. On Monday 23 rd of January 2012, the process of collecting primary data began. Seven 50cm cores were taken in total from two different locations of the bog. Two cores were extracted from the cut-over part of the bog (site 1) and 5 were taken from the dome of the bog (site 2) (Table 4.2). Table 4.1: Depth and location of each core. Co-ordinates Site Core Depth (m) 1H ± 5m 1H ± 5m Coring No exposed sections of Ballynahone Bog were available to take samples from therefore cores had to be extracted from the bog s surface. The 7 cores were extracted using a Russian Sampler; the main advantage of using this corer is because the sediment in which it passes through is not disturbed by churning action (Moore, et al., 1991). The only

29 disadvantage of using this corer is that it is limited to be used in soft materials as it lacks an auger head. The main blade of the sampler passes the material to be sampled as it pushed lower in to the bog, the movable chamber rotates 180 and cuts a semi-cylinder of peat which remains intact as it is pulled up to the surface. Figure 3.1 shows that to pull the sampler back up to the surface is a two person job. Figure 4.1: Removal process of sampler from the bog to extract core. When the chamber of the sampler is opened, the entire core is in a complete and undisturbed condition (Fig 3.2). No dismantling of the Russian sampler was needed. The length of time the cores were exposed to air and pollen rain was limited as they were quickly cover (put in bags).

30 Figure 4.2: Intact core taken from site 1, showing the changes in colour from light lake sands to dark peat. To keep the cores intact, and to store them, they were transferred into plastic guttering (Fig 3.3) that measured around 60cm in length. The guttering was labelled appropriately so that the top and bottom ends, respectively, could be easily recognised (Fig 3.4). These were then wrapped them in thick plastic bags to transport them back to the Laboratory. The whole coring process was quick and efficient; took around three and half hours.

31 Figure 4.3: Transferal of core into guttering for storage. Figure 4.4: Labelling of guttering for easy recognition in the lab.

32 Risk Analysis Before starting to core the bog Willie McNaire from the Ulster Wildlife Trust met with us to see where the cores would be extracted from in order to make sure the location was feasible. Certain parts of the bog were saturated and would be unable to extract cores from; these areas had to be identified. Willie then advised where the best places to take the cores from the dome were (site 2), so that the drains that had been dug by the Bulrush Company could be avoided. He advised this as he said that it would be a nasty experience to fall down one of these. He made us aware of the drains locations so that we were conscience of their whereabouts. He then left us to do some birdwatching on the bog and stayed nearby so that if any problems arose he would be on hand to help. Description and preparation of cores Due to the decent storage and protective nature of the guttering, descriptions of the cores were easy to record as the cores remained in an excellent condition. Core logs were drawn up to describe what could be seen on the surface of each core e.g. the presence of roots and fragments of wood. The colour of each core was recorded using the Munsell colour scheme. After the colour was recorded for each core it was visible the change in humification of peat with increasing depth down the bog. After each core was described they had to be divided in to 1cm segments (Fig 3.5). This was done by having a tape measure running the length of the core and using a knife to cut each section at 1cm intervals. Each segment was put into a labelled plastic bag recording the location of the core, where it was taken from and the core and site number (Fig 3.6). They were then stored in the fridge. The cores were cut into these small sections so that when it came to extracting the pollen, the smaller amounts of peat were easier to digest and break up, along with humic material being dissolved.

33 Figure 4.5: Core being divided into 1cm segments. Figure 4.6: Example of labelled bag with recorded site information, containing 1cm segment.

34 Treatment of samples Peat samples for pollen analysis need chemical pre-treatments in order to concentrate the pollen, these must be done in a fume cupboard and the reagents handled with great care. A laboratory coat, safety glasses and rubber gloves must be worn. Plenty of water should be used for washing away any waste. The idea for my method is mostly derived from Pollen Analysis by Moore, et al., There are 3 stages to the procedure. Stage 1 is Peat Digestion. Start by placing 1g of peat into a boiling tube and add 10ml of 10% KOH. After this test tubes are placed into a water bath for 30 minutes and continually stirred with a glass rod to break up any lumps. Distilled water may be added if needed to maintain the volume. This digestion process breaks up the matrix and dissolves humic materials to produce a dark brown solution. Next, the solution is filtered through a 100µm sieve, into a centrifuge tube where the pollen will pass through the sieve thus leaving plant debris to remain. The final part to this first stage is to centrifuge all 8 tubes for 3 minutes at 3000 rpm. The produced supernatant liquid is then decanted and this procedure is repeated until supernatant is clear. This should result in the deposition of a small pellet of material at the base of the tube. Care must be taken when decanting as this material can easily be lost. The second stage is Cellulose Removal. Cellulose is a polysaccharide and can be removed most effectively by acid hydrolysis (acetolysis). The technique below is basically a replica of that of Erdtman (1960). The reagents used in acetolysis are concentrated sulphuric acid and acetic anhydride which are both corrosive and react vigorously with water (Moore, et al., 1991). Extreme caution needs to be taken at this stage of the procedure as both are corrosive and irritant to the skin. 10ml of glacial acetic acid is added to the centrifuge tube, stirred with a glass rod, centrifuged again and then decanted. The added 10ml of acetolysis mixture is placed in a boiling water bath for one minute. This is then centrifuged and decanted carefully in to running water. Repeat step one by adding 10ml of glacial acetic acid and centrifuge and decant once more. Finally add 10ml of distilled water and a few drops of KOH, centrifuge and decant. Then repeat with more water and KOH.

35 Microscopy work The final stage to the procedure is to identify the pollen grains. The residue is mounted onto a glass slide, a drop of glycerine oil is added and spread out, and the coverslip is placed on top. Immersion oil is spread on top of the coverslip to seal it to prevent drying to reduce the degeneration process. The precision with which pollen grains can be identified depends upon the quality of microscope used for observing them (Moore et al., 1991). According to Moore et al (1994) the most appropriate magnification for routine scanning and counting is 400 i.e. a 40 objective and 10 eyepiece. This provides sufficient magnification for the identification of many pollen grains, and an adequate field of view for comfortable counting in all. A total of fifty pollen grains were counted for each slide, the process for this is to move from left to right across the slide counting pollen visible pollen grains and stopping whenever fifty have been counted. Pollen Diagram Quaternary palynology originated in temperate regions and was initially a technique for geological correlation and relative dating. Techniques of absolute dating have become more available recently and emphasis has switched to vegetation and environmental reconstruction (Flenley, 1985). From the data compiled after counting pollen grains, a pollen diagram was constructed, to show the changing proportions of plant species throughout the history of the mire. This was constructed through POLPAL, which is a computer system for palynological analysis. Each horizontal line of the diagrams represents the pollen result from a single slide. Each slide corresponds to a different depth of each core. The results of the graph are organised in order of depth. The total land pollen is tallied when the number of pollen grains recorded from each plant species is converted into a percentage. The increases and decreases in the amount of each plant species in the diagram shows that environmental conditions have changed over time. This enables the impact, climate and humans have had on past vegetation to be seen.

36 Chapter 5: Results Description of Cores A description was taken of each core to visually apparent characteristics. The bog is split into different layers and zones which run from the top of the bog to the base. The top cores are lighter; reddish brown/dark brown in colour whereas the deeper cores are a darker colour; black. The change in colours show that the lower darker peat is well humified and separated by the overlying lighter less humified Sphagnum peat. KEY: Key to show different features that are visible in each core Silt and Mud Peat mixed with Silty Mud Fragments of wood Thick woody roots Roots Disturbance

37 Site 1, Core 1 Top 0-1cm Bottom 50 cm Figure 5.1: Representation of vertical core arrangement from site 1. From top of the core 1cm to 48cm, the peat is all the same colour at: HUE 7.5YR 2.5/1 Black (Munsell colour system). When the peat is cut, the centre of the core is a different colour: 10YR 2/1 Black cm segment in the middle- reddish- brown colour: 7.5YR 2.5/2.5/3 Very Dark Brown cm piece of wood below peat cm and 44.5cm wood is very common in the core, fragments can be seen cm peat mixed with silt, can hear a crunching sound when cut cm light sandy mud. 10YR 4/2 Dark Greyish Brown.

38 Site 1, Core 2 Top 0-1cm Bottom 50 cm Figure 5.2: Representation of vertical core arrangement from site 1. Core same colour throughout: 10YR 2/1 Black. When core was cut colour changed: 7.5YR 2.5/1 Black. Fragments of wood throughout core cm chunks of wood running diagonally across peat cm- lots of wood, have to cut through it cm alot of wood is visible. Around 40% of core has visible wood flakes. Some disturbance to core when moving in from the corer to guttering.

39 Site 2, Core 1 Top 0-1cm Bottom 50 cm Figure 5.3: Representation of vertical core arrangement from site 2. Slight colour change throughout core. Roots are present throughout whole core, most abundant 26-41cm. Top 1-10cm- 7.5YR 2.5/2. Some roots through top part of core cm 2.5 3/1 Reddish Brown. Abundance of roots in this part of the core cm; most located in a cluster between cm. Bottom cm 10YR 2/1 Black cm and 49-50cm roots are visible. Max 15% of roots are visible on the surface of the core. Three colour changes throughout core which are not that obvious. Bottom section is a darker colour and therefore the change in colour is more noticeable in this section.

40 Site 2, Core 2 Top 0-1cm Bottom 50cm Figure 5.4: Representation of vertical core arrangement from site cm darker peat on top: 10YR 2/1 Black. Hard to cut this core apart as roots ran through it. 5-31cm: 2.5YR 2.5/1 Reddish Black cm: 2.5YR 2.5/2. Very slight variation in colour throughout the core cm is disturbed, light brown than the section above it. Less than 10% of the core had visible roots.

41 Site 2, Core 3 Top 0-1cm Bottom 50cm Figure 5.5: Representation of vertical core arrangement from site cm: /2 Very Dark Brown. 8-17cm: 5YR 2.5/1 Black cm: 7.5YR 2.5/1 Black cm: 10YR 2/1 Black cm: 10YR 2/2 Very Dark Brown. Very slight colour change throughout core. Most roots down the right side of the core. Very tough to cut through the roots, hard to separate different samples of the core. 8-10% of core had visible roots.

42 Site 2, Core 4 Top 0-1cm Bottom 50cm Figure 5.6: Representation of vertical core arrangement from site cm 10YR 2/2 Very Dark Brown cm 2.5YR 2.5/1 Reddish Brown. The middle of 13-14cm is a different colour: 7.5YR 2.5/3 Very Dark Brown. The middle of 38-39cm is a lighter reddish brown in the middle: 2.5YR 3/2 Dusty Red. Apart from the first 6.5cm s the core is intact, smooth. At a closer glance some roots can be seen at the top 7cm. Many roots are scattered through the top of the core until 23cm then they are harder to notice. Some roots visible at the bottom 4cm.

43 Site 2, Core 5 Top 0-1cm Bottom 50cm Figure 5.7: Representation of vertical core arrangement from site 2. Core is the same colour throughout: 7.5YR 2.5/1 Black. 0-8cm some visible roots. 32cm core has split so roots are more visible between the peat cm - more roots are visible in the section of the core. 39cm onwards hard to cut sections of the peat due to allot of roots being located here cm allot of thick wooden roots cm most of this section of the core is not made up of peat but of soft bark. Most of the roots are located down the right side of the core.

44 Main Observation Site 1, core 1 which is from the very bottom of the bog, lake sands were present in core, is very dark in colour HUE 10YR 2/1 Black, also a lump of wood was found in this core. Site 1, core 2 was also dark in colour with lots of wooden roots and flakes throughout it. Site 2, cores 1-4 are lighter in colour and have thin roots running through each of the cores, possibly from Sphagnum and heather etc. Site 2, core 5 is a lot darker in comparison to the cores above it. There are also a lot of wooden roots through out this core. This core shows the change in zones of peat, this core is a lot more humified than the 4 cores above it.

45 Sampling The table below records which parts of each core that were used as samples to carry out pollen grains analysis. Eight random samples from each core were selected from approximately equal distances down the core. Table show the location of each of the samples taken from each core. Table 5.1: Table showing position of samples taken from each of the seven cores. Sample number Site 1, Core 1 (Depth: 2.5m) Location of position of core Sample number Site 2, Core 2 (Depth: 1.0m) Location of position of core Sample 1 4-5cm Sample cm Sample cm Sample 2 6-7cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample number Site 1, Core 2 (Depth: 2.0m) Location of position of core Sample number Site 2, Core 3 (Depth:1.5m) Location of position of core Sample 1 0-1cm Sample 1 3-4cm Sample 2 6-7cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample number Site 2, Core 1 (Depth: 0.5m) Location of position of core Sample number Site 2, Core 4 (Depth: 2.0m) Location of position of core Sample 1 0-1cm Sample 1 0-1cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm

46 Site 2, Core 5 (Depth: 2.5m) Sample number Location of position of core Sample 1 2-3cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Sample cm Identified Pollen Grains Pollen Count, Site Results The following tables include the number of different pollen grain types that was found on each single slide. Each of these slides was created using sediment samples taken at regular intervals along each core. The total amount of pollen grains that was counted for each species and their total percentages from each sample of the core are noted below. During the investigation, site 1 had a sufficient number of pollen grains from tree species and these were prioritised, hence the low number of herb, shrub and spore pollen counts. However the cores from site 2 were taken from the top of the dome of the bog, where no trees where present, so herbs, shrubs and spores were counted alongside any tree species that was found. The result of each species was then turned into a percentage e.g. at 7cm, 21 Sphagnum grains where counted. 50 grains were counted in total. The percentage of the Sphagnum is shown below: (21 50) 100 = 42% Therefore 42% of the total pollen at 7cm depth was from Sphagnum.

47 Site 1, Core 1 = taken from the part of cut over bog at a depth of 2.5m, reached mud from ancient lake and start of peat formation. Table 5.2: The total amount of pollen grains for each species, and total percentage that has been found in different samples taken from Core 1. Slide 1 4-5cm Slide cm Pine (Pinus) 30 = 60% Pine (Pinus) 20 = 40% Birch (Betula) 10 = 20% Alder (Alnus) 20 = 40% Alder (Alnus) 8 = 16% Birch (Betula) 5 = 10% Elm (Ulmus) 1 = 2% Hazel (Corylus) 3 = 6% Oak (Quercus) 1 = 2% Elm (Ulmus) 2 = 4% Slide cm Slide cm Pine (Pinus) 23 = 46% Pine (Pinus) 23 = 46% Birch (Betula) 14 = 28% Alder (Alnus) 17 = 34% Alder (Alnus) 10 = 20% Birch (Betula) 9 = 18% Hazel (Corylus) 3 = 6% Hazel (Corylus) 1 = 2% Slide cm Slide cm Birch (Betula) 20 = 40% Birch (Betula) 19 = 38% Pine (Pinus) 17 =34% Pine (Pinus) 18 = 36% Alder (Alnus) 11 = 22% Alder (Alnus) 11 = 22% Hazel (Corylus) 2 = 4% Hazel (Corylus) 2 = 4% Slide cm Slide cm Birch (Betula) 24 = 48% Pine (Pinus) 28 = 56% Pine (Pinus) 19 = 38% Birch (Betula) 13 = 26% Alder (Alnus) 7 = 14% Alder (Alnus) 9 = 18%

48 Site 1, Core 2 = taken from cut over bog at a depth of 2.0m. Table 5.3: The total amount of pollen grains for each species, and total percentage that has been found in different samples taken from Site 1 Core 2. Slide 1 0-1cm Slide 2 6-7cm Birch (Betula) 19 = 38% Birch (Betula) 23 = 46% Pine (Pinus) 10 = 20% Sphagnum 17 = 34% Sphagnum 8 = 16% Pine (Pinus) 5 = 10% Elm (Ulmus) 5 = 10% Elm (Ulmus) 3= 6% Oak (Quercus) 4 = 8% Ling Heather (Calluna) 1 = 2% Ling Heather (Calluna) 4 = 8% Oak (Quercus) 1 = 2% Slide cm Slide cm Birch (Betula) 22 = 44% Birch (Betula) 20 = 40% Sphagnum 12 = 24% Sphagnum 10 = 20% Pine (Pinus) 11 = 22% Pine (Pinus) 10 = 20% Elm (Ulmus) 3 = 6% Elm (Ulmus) 8 = 16% Ling Heather (Calluna) 2 = 4% Ling Heather (Calluna) 2 = 4% Slide cm Slide cm Birch (Betula) 24 = 48% Birch (Betula) 16 = 32% Pine (Pinus) 13 =26% Pine (Pinus) 13 = 26% Sphagnum 10 = 20% Sphagnum 12 = 24% Elm (Ulmus) 2= 4% Elm (Ulmus) 7 = 14% Ling Heather (Calluna) 1 = 2% Ling Heather (Calluna) 2 = 4% Slide cm Slide cm Birch (Betula) 19 = 38% Birch (Betula) 17 = 34% Pine (Pinus) 17 = 34% Pine (Pinus) 14 = 28% Sphagnum 9 = 18% Sphagnum 8 = 16% Elm (Ulmus) 3 = 6% Alder (Alnus) 5 = 10% Alder (Alnus) 1 = 2% Elm (Ulmus) 4 = 8% Ling Heather (Calluna) 1 = 2% Ling Heather (Calluna) 2 = 4%

49 Main Observations Site 1. Site 1 s results shows of a mixed forest made up mostly of Pinus (Pine). The results of the pollen count of site 1 show that Pinus (Pine) usually makes up half of the pollen found there. Pine is not a dominant species of site 2; however it still exists in quite high quantity. The general trend from the bottom of the bog; slide 8 from site 1 to slide 1 of site 2 shows a gradual decrease in Pinus (Pine). Sphagnum and Calluna (Ling Heather) become present in site 2. The further up core 2 Alnus (Alder) disappears. It is found is slide 7 and 8 but in very low percentages.

50 Site 2, Core 1 = taken from the top of the dome at a depth of 0.5m. Table 5.4: The total amount of pollen grains for each species, and total percentage that has been found in different samples taken from Site 2 Core 1. Slide 1 0-1cm Slide cm Ling Heather (Calluna) 18 = 36% Sphagnum 19 = 38% Sphagnum 16 = 32% Ling Heather (Calluna) 15 =30% Oak (Quercus) 6 = 12% Fern (Filicales) 5 = 10% Hazel (Corylus) 4 = 8% Oak (Quercus) 4 = 8% Fern (Filicales) 3 = 6% Sedge (Cyperaceae) 4 = 8% Sedge (Cyperaceae) 3 = 6% Birch (Betula) 3 = 6% Slide 2 6-7cm Slide cm Sphagnum 21 = 42% Sphagnum 18 = 36% Oak (Quercus) 10 = 20% Ling Heather (Calluna) 13 = 26% Ling Heather (Calluna) 9 = 18% Oak (Quercus) 12 = 14% Sedge (Cyperaceae) 4= 8% Sedge (Cyperaceae) 5 = 10% Fern (Filicales) 3 = 6% Fern (Filicales) 4 = 8% Hazel (Corylus) 3 = 6% Hazel (Corylus) 3 = 6% Slide cm Slide cm Sphagnum 20 = 40% Ling Heather (Calluna) 20 = 40% Ling Heather (Calluna) 17 = 34% Sphagnum 15 = 30% Oak (Quercus) 8 = 16% Oak (Quercus) 10 = 20% Sedge (Cyperaceae) 2 = 4% Sedge (Cyperaceae) 2 = 4% Birch (Betula) 2 = 4% Fern (Filicales) 2 = 4% Fern (Filicales) 1 = 2% Birch (Betula) 1 = 2% Slide cm Slide cm Ling Heather (Calluna) 20 = 40% Sphagnum 17 = 34% Sphagnum 13 = 26% Ling Heather (Calluna) 15 = 30% Oak (Quercus) 6 = 12% Oak (Quercus) 10= 20% Birch (Betula) 4 = 8% Birch (Betula) 4 = 8% Sedge (Cyperaceae) 3 = 6% Sedge (Cyperaceae) 2 = 4% Fern (Filicales) 3 = 6% Fern (Filicales) 1 = 2% Hazel (Corylus) 1 = 2% Hazel (Corylus) 1 = 2%

51 Site 2, Core 2 = taken from the dome of the bog at a depth of 1.0m. Table 5.5: The total amount of pollen grains for each species, and total percentage that has been found in different samples taken from Site 2 Core 2. Slide 1 1-2cm Slide cm Sphagnum 17 = 34% Sphagnum 19 = 38% Ling Heather (Calluna) 9 = 18% Ling Heather (Calluna) 16 = 32% Birch (Betula) 9 = 18% Oak (Quercus) 6 = 12% Elm (Ulmus) 6 = 12% Sedge (Cyperaceae) 4 = 8% Oak (Quercus) 4 = 8% Fern (Filicales) 2 = 4% Fern (Filicales) 2 = 4% Birch (Betula) 1 = 2% Hazel (Corylus) 2 = 4% Hazel (Corylus) 1 = 2% Sedge (Cyperaceae) 1 = 2% Elm (Ulmus) 1 = 2% Slide 2 6-7cm Slide cm Sphagnum 15 = 30% Ling Heather (Calluna) 16 = 32% Ling Heather (Calluna) 10 = 20% Sphagnum 14 = 28% Birch (Betula) 8 = 16% Fern (Filicales) 6 = 12% Oak (Quercus) 8 = 16% Oak (Quercus) 6 = 12% Elm (Ulmus) 4 = 8% Sedge (Cyperaceae) 4 = 8% Fern (Filicales) 2 = 4% Birch (Betula) 2 = 4% Hazel (Corylus) 2 = 4% Hazel (Corylus) 1 = 2% Sedge (Cyperaceae) 1 = 2% Elm (Ulmus) 1 = 2% Slide cm Slide cm Sphagnum 19 = 38% Ling Heather (Calluna) 15 = 30% Ling Heather (Calluna) 15 = 30% Sphagnum 14 = 28% Fern (Filicales) 5 = 10% Sedge (Cyperaceae) 8 = 16% Birch (Betula) 4 = 8% Fern (Filicales) 6 = 12% Oak (Quercus) 3 = 6% Oak (Quercus) 5 = 10% Sedge (Cyperaceae) 3 = 6% Birch (Betula) 1 = 2% Birch (Betula) 1 = 2% Hazel (Corylus) 1 = 2% Slide cm Slide cm Sphagnum 18 = 36% Sphagnum 22 = 44% Ling Heather (Calluna) 15 = 30% Ling Heather (Calluna) 20 = 40% Sedge (Cyperaceae) 8 = 16% Sedge (Cyperaceae) 3 = 6% Oak (Quercus) 5 = 10% Fern (Filicales) 2 = 4% Fern (Filicales) 2 = 4% Oak (Quercus) 2 = 4% Birch (Betula) 2 = 4% Birch (Betula) 1 = 2%

52 Site 2, Core 3 = taken from the dome of the bog at a depth of 1.5m. Table 5.6: The total amount of pollen grains for each species, and total percentage that has been found in different samples taken from Site 2 Core 3. Slide 1 3-4cm Slide cm Elm (Ulmus) 16 = 32% Elm (Ulmus) 19 = 38% Oak (Quercus) 10 = 20% Oak (Quercus) 11 = 22% Birch (Betula) 7 = 14% Birch (Betula) 6 = 12% Sphagnum 4 = 8% Sphagnum 5 = 10% Pine (Pinus) 3 = 6% Fern (Filicales) 3 = 6% Ling Heather (Calluna) 3 = 6% Pine (Pinus) 2 = 4% Fern (Filicales) 3 = 6% Hazel (Corylus) 2 = 4% Alder (Alnus) 2 = 4% Ling Heather (Calluna) 1 = 2% Hazel (Corylus) 2 = 4% Alder (Alnus) 1 = 2% Slide cm Slide cm Elm (Ulmus) 20 = 40% Sphagnum 17 = 34% Oak (Quercus) 8 = 16% Elm (Ulmus) 13 = 26% Birch (Betula) 6 = 12% Oak (Quercus) 11 = 22% Sphagnum 6 = 12% Birch (Betula) 4 = 8% Ling Heather (Calluna) 6 = 12% Hazel (Corylus) 2 = 4% Fern (Filicales) 2 = 4% Fern (Filicales) 1 = 2% Hazel (Corylus) 1 = 2% Ling Heather (Calluna) 1 = 2% Pine (Pinus) 1 = 2% Pine (Pinus) 1 = 2% Slide cm Slide cm Elm (Ulmus) 23 = 46% Birch (Betula) 15 = 30% Oak (Quercus) 12 = 24% Sphagnum 12 = 24% Birch (Betula) 5 = 10% Elm (Ulmus) 9 = 18% Ling Heather (Calluna) 4 = 8% Oak (Quercus) 5 = 10% Fern (Filicales) 3 = 6% Alder (Alnus) 5 = 10% Hazel (Corylus) 1 = 2% Fern (Filicales) 2 = 4% Sphagnum 1 = 2% Hazel (Corylus) 1 = 2% Alder (Alnus) 1 = 2% Ling Heather (Calluna) 1 = 2% Slide cm Slide cm Elm (Ulmus) 20 = 40% Birch (Betula) 12 = 24% Sphagnum 14 = 28% Elm (Ulmus) 10 = 20% Oak (Quercus) 7 = 14% Oak (Quercus) 9 = 18% Pine (Pinus) 3 = 6% Sphagnum 7 = 14% Birch (Betula) 2 = 4% Alder (Alnus) 6 = 12% Fern (Filicales) 2 = 4% Fern (Filicales) 5 = 10% Ling Heather (Calluna) 2 = 4% Ling Heather (Calluna) 1 = 2%

53 Site 2, Core 4 = taken from the dome of the bog at a depth of 2.0m. Table 5.7: The total amount of pollen grains for each species, and total percentage that has been found in different samples taken from Site 2 Core 4. Slide 1 0-1cm Slide cm Birch (Betula) 16 = 32% Birch (Betula) 19 = 38% Elm (Ulmus) 13 = 26% Sphagnum 13 = 26% Sphagnum 8 = 16% Elm (Ulmus) 7 = 14% Fern (Filicales) 6 = 12% Fern (Filicales) 4 = 8% Ling Heather (Calluna) 4 = 8% Ling Heather (Calluna) 4 = 8% Hazel (Corylus) 2 = 4% Oak (Quercus) 2 = 4% Oak (Quercus) 1 = 2% Alder (Alnus) 1 = 2% Slide cm Slide cm Sphagnum 15 = 30% Birch (Betula) 20 = 40% Elm (Ulmus) 14 = 28% Sphagnum 11 = 22% Oak (Quercus) 8 = 16% Ling Heather (Calluna) 6 = 12% Hazel (Corylus) 5 = 10% Elm (Ulmus) 4 = 8% Birch (Betula) 4 = 8% Hazel (Corylus) 4 = 8% Fern (Filicales) 3 = 6% Fern (Filicales) 3 = 6% Ling Heather (Calluna) 1 = 2% Oak (Quercus) 2 = 4% Slide cm Slide cm Birch (Betula) 15 = 30% Birch (Betula) 18 = 36% Sphagnum 12 = 24% Sphagnum 13 = 26% Elm (Ulmus) 7 = 14% Ling Heather (Calluna) 5 = 10% Ling Heather (Calluna) 6 = 12% Elm (Ulmus) 4 = 8% Hazel (Corylus) 4 = 8% Alder (Alnus) 4 = 8% Fern (Filicales) 4 = 8% Hazel (Corylus) 3 = 6% Oak (Quercus) 2 = 4% Fern (Filicales) 3 = 6% Slide cm Slide cm Birch (Betula) 21 = 42% Birch (Betula) 15 = 30% Sphagnum 13 = 26% Sphagnum 8 = 16% Elm (Ulmus) 7 = 14% Ling Heather (Calluna) 7 = 14% Ling Heather (Calluna) 5 = 10% Alder (Alnus) 7 = 14% Fern (Filicales) 2 = 4% Elm (Ulmus) 6 = 12% Hazel (Corylus) 1 = 2% Fern (Filicales) 4 = 8% Oak (Quercus) 1 = 2% Hazel (Corylus) 3 = 6%

54 Site 2, Core 5 = taken from the dome of the bog at a depth of 2.5m. Table 5.8: The total amount of pollen grains for each species, and total percentage that has been found in different samples taken from Site 2 Core 5. Slide 1 0-1cm Slide cm Birch (Betula) 16 = 32% Birch (Betula) 13 = 26% Hazel (Corylus) 9 = 18% Sphagnum 11 = 22% Sphagnum 8 = 16% Alder (Alnus) 7 = 14% Elm (Ulmus) 7 = 14% Pine (Pinus) 7 = 14% Ling Heather (Calluna) 4 = 8% Fern (Filicales) 6 = 12% Pine (Pinus) 4 = 8% Elm (Ulmus) 3 = 6% Fern (Filicales) 2 = 4% Ling Heather (Calluna) 3 = 6% Slide cm Slide cm Birch (Betula) 16 = 32% Birch (Betula) 12 = 24% Sphagnum 10 = 20% Sphagnum 11 = 22% Elm (Ulmus) 8 = 16% Pine (Pinus) 9 = 18% Hazel (Corylus) 8 = 16% Ling Heather (Calluna) 8 = 16% Ling Heather (Calluna) 5= 10% Fern (Filicales) 6 = 12% Fern (Filicales) 2 = 4% Alder (Alnus) 3 = 6% Pine (Pinus) 1 = 2% Hazel (Corylus) 1 = 2% Slide cm Slide cm Birch (Betula) 15 = 30% Birch (Betula) 16 = 32% Sphagnum 11 = 22% Sphagnum 10 = 20% Elm (Ulmus) 8 = 16% Pine (Pinus) 7 = 14% Ling Heather (Calluna) 7 = 14% Fern (Filicales) 6 = 12% Hazel (Corylus) 6 = 12% Ling Heather (Calluna) 6 = 12% Fern (Filicales) 3 = 6% Alder (Alnus) 5= 10% Slide cm Slide cm Birch (Betula) 15 = 30% Birch (Betula) 23 = 46% Sphagnum 12 = 24% Sphagnum 11 = 22% Fern (Filicales) 5= 10% Ling Heather (Calluna) 7 = 14% Elm (Ulmus) 5 = 10% Pine (Pinus) 3 = 6% Alder (Alnus) 5= 10% Hazel (Corylus) 3 = 6% Hazel (Corylus) 4 = 8% Fern (Filicales) 2 = 4% Ling Heather (Calluna) 4 = 8% Alder (Alnus) 1 = 2%

55 Main Observations Site 2 Sphagnum and Calluna (Ling Heather) are the dominant species of core 1. Core 1 is mainly made up of shrubs (Hazel), Herbs (Sedge) and spores (Ferns and Sphagnum). Only two tree species found in core 1, in very low percentages; Oak- less than 16% and Birch less than 8%, Core 2 has the same species being dominant as core 1. The species have also been found in core 2 as in core 1. However Ulmus (Elm) has also been found in core 2 which is the only addition species found. Core 3 differs from the two previous cores. Ulmus (Elm) is now the dominant species. There is a more varied amount of species in core 3, more tree species have been found. Vegetation found in core 3 indicates a woodland as Ulmus (Elm) Quercus (Oak) and Betula (Birch) have the highest percentages. Pinus (Pine) and Alnus (Alder) are now present in core 3. In core 4 the amount of pollen grains found for Quercus (Oak) has decreased. Ulmus (Elm) has also decrease in numbers found. Betula (Birch) is now the dominant species of core 4 The amount of Sphagnum has also increased. Pinus (Pine) has completely disappeared, no pollen grains were found in this core. In core 5 Betula (Birch) and Sphagnum are still the dominant species of this, same as core 4. Core 5 has similar species and percentages as core 4, only difference is Pinus (Pine) is now present Figures of sampled pollen grains The following six figures show pollen grains of the following species; Betula (Birch), Pinus (Pine), Calluna (Ling Heather), Sphagnum, Quercus (Oak) and Cyperaceae (Sedge). These are actual samples that I have collected from the cores.

56 Figure 5.8: Pollen grain (circled) of Betula (Birch).

57 Figure 5.9: Pollen grain (circled) of Pinus (Pine).

58 Figure 5.10: Pollen grains (circled) of Calluna (Ling Heather).

59 Figure 5.11: Pollen grain (circled) of Sphagnum.

60 Figure 5.12: Pollen grains (circled) of Quercus (Oak).

61 Figure 5.13: Pollen grain (circled) of Cyperaceae (Sedge)

62 Pollen diagram The data from the above tables was used to produce a pollen diagram (Fig 5.14). This pollen diagram will allow us to visualise how the abundance of different pollen grains has changed over time, which then in turn gives an indication of how the abundance of the different plant types, that produced these pollen grains, has changed over time. The following factors that may have impacted on the past vegetation: Depositional environments. Palaeoclimate. Human impact pollen provides a record of land use change e.g. woodland expansion, deforestation or arable agriculture. The information about the ecology of these different plants can be used to chart changes in environmental conditions over time. The plant species with the highest abundance in a pollen diagram shows that their ecological requirements are being met by the prevailing environmental conditions at that time. By referring to the ecological requirements of these species, then the environmental conditions can be reconstructed

63 Pollen diagram (cm) Figure 5.14: Pollen diagram of percentage of pollen grains found at Ballynahone Bog