Open Carboniferous Limestone Pavement Grike Microclimates in Great Britain and Ireland: Understanding the Present to Inform the Future
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Open Carboniferous Limestone pavement grike microclimates in Great Britain and Ireland: understanding the present to inform the future Item Type Thesis or dissertation Authors York, Peter, J. Citation York, P, J. (2020). Open Carboniferous Limestone pavement grike microclimates in Great Britain and Ireland: understanding the present to inform the future (Doctoral dissertation). University of Chester, UK. Publisher University of Chester Rights Attribution-NonCommercial-NoDerivatives 4.0 International Download date 10/10/2021 01:26:52 Item License http://creativecommons.org/licenses/by-nc-nd/4.0/ Link to Item http://hdl.handle.net/10034/623502 Open Carboniferous Limestone pavement grike microclimates in Great Britain and Ireland: understanding the present to inform the future Thesis submitted in accordance with the requirements of the University of Chester for the degree of Doctor of Philosophy By Peter James York April 2020 I II Abstract Limestone pavements are a distinctive and irreplaceable geodiversity feature, in which are found crevices known as grikes. These grikes provide a distinct microclimate conferring a more stable temperature, higher relative humidity, lower light intensity and lower air speed than can be found in the regional climate. This stability of microclimate has resulted in an equally distinctive community of flora and fauna, adapted to a forest floor but found in an often otherwise barren landscape. This thesis documents the long-term study of the properties of the limestone pavement grike in order to identify the extent to which the microclimate may sustain its distinctive biodiversity, to provide recommendations for future research which may lead to more effective management. Over a five-year study, recordings of temperature, relative humidity, light intensity and samples of invertebrate biodiversity were collected from five limestone pavements situated in the Yorkshire Dales and Cumbria in Great Britain, and The Burren in the Republic of Ireland. An extensive description of the grike microclimate was undertaken using the data collected to understand the extent of the microclimate stability of the grike and the conditions for variation in the grike microclimate. Further insights into the grike microclimate were gained through simulation techniques more commonly used in engineering, to explore the effects of air flowing over a grike, the light from the sun entering the grike and regression analysis to simulate the temperature within the grike in the present and projected for the future. This study has indicated that although the whole of the grike confers a degree of microclimatic stability, it is made up of a less stable upper zone and a more stable lower zone. The instability of the upper zone is hypothesised to result from the extent to which the majority of light and external air can enter the grike, whereas the stability of the lower zone may be governed by the thermal stability of the limestone surrounding it. Based on this zonation and the projections for the grike temperature, it is hypothesised that climate change will have the most substantial effects in the upper grike zone where species obligated to this area could be most heavily impacted. This study recommends a range of areas in which research may be employed so that the limestone pavement habitat may be successfully managed in Great Britain and the Republic of Ireland. III IV Acknowledgements This thesis would not have been possible without the support and guidance of several excellent people. Firstly, I would like to offer the greatest thanks to my supervisors and mentors Cynthia Burek, Lottie Hosie and Matt Geary. Each person has brought something distinctive and valuable to the development of this project, and without whom I would not be where I am today. I would also like to thank Serban Pop who, though not a PhD supervisor gave me valuable support in the use of COMSOL and CFD working. I would like to thank John Cross and John Jordan at the Species Protection Unit at the Irish National Parks and Wildlife Service, for providing the funding which made it possible to extend my study to encompass The Burren in the Republic of Ireland. Had I not been able to include these habitats, I would not have observed many of the more unique insights from this study. I would like to thank those who own and work on the limestone pavements on which I have worked including Graham Coates, Dan Crellin and especially Eamon Doyle, who made much of my work in the Republic of Ireland possible. I would like to thank Rob Petley-Jones and Liam O’Reilly from Natural England, Peter Welsh from the National Trust and Russel Hobson from Butterfly Conservation for their logistic support. Without these fine people, access and work on the limestone pavements from this study would not be possible. Great thanks to all the academics and amateur enthusiasts who have made each aspect of my study a new revelation. These include Stephen Foster, Peter Standing, Jake Ward, Sue Willis, John Cook, Marc Patterson and especially Adrian Norris. Special thanks for the patience and support from Jane Dodd, who kept me in sample pots and ethanol. Finally, I would like to thank my friends who have listened patiently to endless theories on the microclimate of grikes. These include Graham Bonwick and Cath Birch who have been the most supportive and flexible, managers and friends I could ever have asked for. I would especially like to thank my wonderful partner Kate Wright, for allowing me the space to complete this PhD by holding back life’s worries. Lastly, I would like to thank my parents Jane and David York, whose example of hard work is an inspiration every day. V Table of contents Abstract ................................................................................................................................................ III Acknowledgements ............................................................................................................................... V Table of contents ................................................................................................................................. VI List of figures ...................................................................................................................................... XIII List of tables ....................................................................................................................................... XXI List of abbreviations .......................................................................................................................... XXII Declaration ....................................................................................................................................... XXIII 1. Introduction and aims ................................................................................................................... 1 1.1 Limestone pavements ......................................................................................................... 1 1.1.1 Limestone Pavement formation and grike features .................................................... 2 1.1.2 Underlying geology and Distribution ........................................................................... 2 1.1.3 Limestone pavement and geodiversity ........................................................................ 3 1.1.4 Grike Microclimate ....................................................................................................... 3 1.1.5 Grike flora and fauna ................................................................................................... 3 1.1.6 Limestone pavement conservation status and management .............................. 4 1.1.7 Climate change, uncertainty and refugia ..................................................................... 4 1.2 Current gaps in knowledge ................................................................................................. 6 1.2.1 Microclimate ................................................................................................................ 6 1.2.2 Fauna ............................................................................................................................ 9 1.2.3 Call to action ................................................................................................................ 9 1.3 Aims and objectives .......................................................................................................... 10 1.3.1 Aims of the thesis ....................................................................................................... 10 1.3.2 Objectives of the thesis .............................................................................................. 10 1.4 Thesis synopsis .................................................................................................................. 11 1.4.1 Chapter One ............................................................................................................... 11 1.4.2 Chapter Two ............................................................................................................... 11 1.4.3 Chapter Three ............................................................................................................ 11 1.4.4 Chapter Four .............................................................................................................. 11 1.4.5 Chapter Five ..............................................................................................................