Report Number 562 Linking Geology and Biodiversity English Nature Research Reports working today for nature tomorrow English Nature Research Reports Number 562 Linking Geology and Biodiversity R Cottle Royal Haskoning, Rightwell House, Bretton, Peterborough PE3 8DW You may reproduce as many additional copies of this report as you like, provided such copies stipulate that copyright remains with English Nature, Northminster House, Peterborough PE1 1UA ISSN 0967-876X © Copyright English Nature 2004 Foreword Geology has strong ties with biodiversity, in that the nature of the substrate, as usually determined by the nature of the underlying rock, is a key factor in determining the distribution of habitats and species. An obvious example of this is the distribution of chalk grassland habitats with outcrops of chalk. As a signatory to the Convention on Biological Diversity drawn up at the World Summit held in Rio de Janeiro in 1992, the UK Government has a commitment to promoting and protecting biodiversity. This commitment has been focused through the identification of priority habitats and species and the development of a series of national targets which aim to maintain or enhance their conservation status. These have been published as part of the UK Biodiversity Action Plan (UKBAP). Biodiversity action groups have been set up locally and regionally to identify and promote how local initiatives can play a part in achieving the national targets and also enhance local biodiversity. This report investigates the links between biodiversity and geology. Some work had already been done in looking at how standard geological site management practices can benefit biodiversity and how some priority species may be associated with types of geological outcrop (report produced for English Nature - Geological conservation – benefits for biodiversity ENRR 561). This report takes this a step further, looking specifically at the link between rock type and biodiversity across England and thus how the achievement of biodiversity targets can be assisted through a better understanding of geology. The outcome is an examination of the key factors influencing and determining ecosystems, illustrated by examples of the links and factors from a number of countries, including England, to illustrate the work that has been done elsewhere. It is therefore a useful examination of this aspect of ecosystem studies and provides an extensive bibliography for those wishing to look at the subject in more detail. This report, along with English Nature Research Reports, No. 561 and English Nature Research Reports, No. 502 (Learning from the past to influence the future), has been summarised in a booklet by English Nature Geology and Biodiversity – making the links, available from the English Nature enquiry service. This is a research report and its findings have not necessarily been adopted as English Nature policy and practice. Anna Wetherell Senior Geologist – Stratigraphy Project Manager, Linking Geology and Biodiversity April 2004 Contents Foreword 1. Introduction....................................................................................................................9 2. Factors influencing the relationship between geology and biodiversity......................10 2.1 Soil formation..................................................................................................14 2.1.1 Parent material and weathering............................................................14 2.1.2 The influence of climate ......................................................................16 2.1.3 Biota.....................................................................................................16 2.1.4 Summary..............................................................................................17 2.2 Climate.............................................................................................................17 2.3 Relief and topography......................................................................................18 2.4 The recent past .................................................................................................20 2.5 Man’s influence ...............................................................................................21 3. Rock classification.......................................................................................................22 3.1 Introduction......................................................................................................22 3.2 Igneous rocks...................................................................................................23 3.3 Sedimentary rocks............................................................................................24 3.4 Metamorphic rocks..........................................................................................24 4. Plant-rock associations and the calicole-calcifuge issue .............................................25 5. Sedimentary rocks........................................................................................................26 5.1 Calcareous rocks..............................................................................................27 5.1.1 The chalk..............................................................................................27 5.1.2 Carboniferous Limestone.....................................................................30 5.1.3 The Jurassic Limestones ......................................................................33 5.1.4 The Magnesian Limestone...................................................................34 5.1.5 Calcareous heathland ...........................................................................36 5.2 Shales and mudstones ......................................................................................37 5.3 Sandstones........................................................................................................41 5.4 Sands and gravels.............................................................................................43 5.5 Drift and glacially derived deposits .................................................................45 6. Igneous rocks...............................................................................................................47 7. Metamorphic rocks......................................................................................................50 7.1 Introduction......................................................................................................50 7.2 Serpentine ........................................................................................................50 7.3 Other metamorphic rocks.................................................................................53 7.3.1 Calcareous mica-schist.........................................................................56 8. Mineralisation and mining ...........................................................................................56 9. The influence and role of geomorphological processes...............................................60 9.1 The influence of cliffs and cliff processes .......................................................60 9.2 Slope processes................................................................................................63 9.3 Karst systems ...................................................................................................66 9.3.1 Caves....................................................................................................67 9.4 The Influence of geology on fluvial habitats ...................................................67 9.4.1 Rivers ...................................................................................................68 9.4.2 Lakes and ponds...................................................................................70 9.4.3 Tufa and spring-fed alkaline fens ........................................................72 9.5 Coastal processes.............................................................................................73 9.5.1 Sand dunes...........................................................................................74 9.5.2 Coastal shingle.....................................................................................75 9.5.3 Rocky shorelines and reefs ..................................................................76 9.6 Bare ground......................................................................................................78 10. Comparative studies and links at the landscape level..................................................79 10.1 Introduction......................................................................................................79 10.2 Comparative studies.........................................................................................79 10.3 Natural Areas ...................................................................................................81 10.3.1 Isle of Wight ........................................................................................81 10.3.2 The East Thames corridor....................................................................82 11. Conclusions..................................................................................................................84 12. References....................................................................................................................87 1. Introduction Since the Earth