Geology and Biodiversity- Making the Links
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Geology and biodiversity- making the links English Nature is the Government agency that champions the conservation of wildlife and geology throughout England. This is one of a range of publications published by: External Relations Team English Nature Northminster House Peterborough PE1 1UA www.english-nature.org.uk © English Nature 2004 Printed on Evolution Satin, 75% recycled post-consumer waste paper, Elemental Chlorine Free. ISBN 1 85716 803 8 Front cover photographs: Top left: Slade Brook, Gloucestershire. Catalogue code IN14.6 Roger Meade/English Nature working today Middle left: Moorland. Michael Murphy/English Nature Designed and printed by Bottom left: Stanground brickpit, Cambridgeshire. Peter Wakely/English Nature 14,727 Status Design & Advertising, 2.5M. Main: Cornwall rock. Michael Murphy/English Nature for nature tomorrow Carboniferous Peak District and the Yorkshire Geology and biodiversity- (354-290 million years ago) Dales. Thick deltaic and riverine sandstone forms the overlying Carboniferous rocks are a record Millstone Grit in the Midlands making the links of equatorial environments and and northern England, whilst the changing sea levels. Initially, swampy vegetation was under a warm, tropical sea compressed to form the coal extensive reefs of crinoids and seams of the adjacent, low-lying corals developed. As the sea Upper Carboniferous Coal level dropped, rivers brought in Measures. sands and silts from the land areas, forming vast sandy deltas. Just as importantly, this range On top of the deltas thick swamp of rocks provides a substrate for vegetation developed, including a range of habitats. The trees, ferns and horsetails. Carboniferous limestones of the Peak District, Yorkshire Dales Today the Carboniferous rocks and the Mendips support show this change. The early limestone grasslands and form a tropical limestones outcrop network of karst and caves, and widely, forming the Mendip Hills, the Millstone Grit underlies the the Avon Gorge, the Derbyshire moorlands of the Pennines. Crinoid fossils, Salthill and Bellmanpark Quarry SSSI, Clitheroe, Lancashire. Peter Wakely/English Nature 7,317 Dunstanburgh Castle, Northumberland. Anna Wetherell The landscapes of England These landscapes hold a diversity When working with ecosystems, of habitats and species, special we need to take a holistic are hugely varied. There are throughout Europe. We have approach in understanding the the lakes and mountains of woodlands and heathlands, chalk geology, the wildlife and how they grassland, rivers, fens and bogs. interact to shape the ecosystem. Cumbria, the rugged spine of But why do we have such variety the Pennines, the limestone in such a small space? The Past ecosystems answer lies in the diversity of the dales of the Peak District and underlying geology. Since the Earth was formed 4,600 Yorkshire, the rolling chalk million years ago it has never For all living organisms, including stood still. Plate tectonics (the downs of Wiltshire and the humans, our environment affects movement of the Earth’s crust) has Chilterns, and the flat the way we can live and the brought continents together and resources available to us. This pulled them apart. This has expanses of the Fens. The environment is fundamentally a continuously changed the pattern result of climate (rainfall, light of land, ocean and climate and has coastline ranges from the and temperature), the physical also driven evolution, extinction rocky shores of Devon and landscape (slope, aspect and and an ever-changing pattern of altitude), and substrate. The ecosystems. Cornwall to the vast combination of these factors, plus expanses of mudflats and the interactions of the living Britain vividly illustrates this organisms present in that dynamic Earth. Our oldest rocks saltmarsh within our environment, is the ecosystem. are 2,800 million years old. Since estuaries. the Cambrian (approximately 500 Geology is a critical factor. It million years ago), plate influences climate at global, movement has carried Britain regional and local scales. from 30 degrees south of the Landscape is determined by the equator to its present position. nature of the rocks that lie beneath Britain’s rocks record the vast the surface and the processes that changes of climate and have shaped and formed them. environment as Britain has Substrate and soil are closely changed from land to sea, and related to the nature of the rocks from tropical to temperate to from which they are derived. glacial. Peak Cavern and Peveril Castle, Castleton, Derbyshire. Anna Wetherell 2 Geology and biodiversity - making the links 3 Permian and Triassic (290-205 million years ago) Hot, arid desert conditions dominated the Permian and Triassic. Extensive red sandstones and mudstones were deposited, which now form the characteristic red rocks of the south coast between Exmouth and Sidmouth, the low-lying ground and linear ridges of the Cheshire Plains and the red sandstone cliffs of St Bees Head in Cumbria. Shallow seas existed in north east England during the Permian, containing limestone reefs which now form the north-south Magnesian Limestone escarpment. The evaporation of the seawater changed the limestone to dolomite, making it rich in magnesium rather than calcium. Valley of Stones NNR, Dorset. Peter Wakely/English Nature 21,939 Now the sandstones provide an Quaternary The major expanse of ice meant also from changes in atmospheric opportunity for heathland to (1.8 million years ago to present) that sea levels dropped and Britain composition, the circulation of flourish in Cheshire and the Wirral, was connected to mainland ocean currents and the rise and and underlie the rich pastures of The most recent major climatic Europe. Woolly mammoth and fall of sea level. Geology teaches Cheshire and Warwickshire. change has been the last Ice Age. woolly rhino lived here, along us just how interlinked and Magnesian limestone grassland Around 2.5 million years ago, with hyena, deer and bears. Man interdependent the environment occurs only where the Permian the Earth became colder and ice also arrived. Changing climates, and ecosystems are on Earth. evaporating seas once were. expanded from the poles. the gradual recolonisation by Northern Europe experienced plants, the changing fauna, and Understanding this Left: St Bees Head, Cumbria. rapid changes in climate. There the impacts of man, are all interdependence is essential to Peter Wakely/English Nature 21,304 were significant, cyclic fluctuations shown in pollen and sediment understanding how and why our Magnesian limestone, Cassop Vale NNR, Durham. Peter Wakely/English Nature 21,224 between colder temperatures records, often found in peat bogs environment is changing. Our when the ice advanced (glacials), or lakes. A major impact of the environment has changed in the and a warmer, more temperate ice was that much of Britain past and is continuing to change. climate (interglacials). Much of was literally ‘scraped clean’. Ecosystems react to this and Britain was periodically covered The landscape and environment provide a feedback loop into it. with glaciers and, beyond the ice, we know today has really only In this present period of climate tundra and permafrost. evolved over the last 10,000 change, part driven by our own years or so. interaction with our environment, The ice scraped off any soil such knowledge can guide us how which had developed, leaving Many of these ancient ecosystems to work within this. sculpted bare rock, or depositing sound familiar from environments clays, sands and gravels in its today, and indeed geological place in glacial landforms. What interpretation develops from soil was left blew around the understanding modern-day frozen landscape, forming deposits ecosystems. Geology is strongly known as loess. Rivers carried rooted in both the present and the glacial meltwaters, depositing past. We can learn much from the massive amounts of sediment in past for the future, especially about the sea and on land. River courses the impacts of climate change. The developed and changed as ice rock record shows that changes in advanced and retreated leaving climate occur not only as a result complex river terraces. As sea of the movement of continents levels rose and fell, coastlines around the planet, for example Woolly rhino skeleton found at Whitemoor Haye, Alrewas, Staffordshire. Field Archeology Unit, moved back and forth. Britain’s progress northwards, but Birmingham University 2 Geology and biodiversity - making the links 5 Substrate is also fundamental to an ecosystem and comprises the underlying rock or soil, in which the plants grow. In terrestrial ecosystems, the plants are the foundation of the food chain. Substrate is therefore the foundation of life. Soil derives from rock. As rock breaks down through weathering and erosion, the resulting particles form the basis for soil. Soil evolves as a result of physical and chemical processes, and biological activity. It can vary from a very thin cover, or none, to deep soils and peat. The source material is important in determining the chemical and physical nature of the developing soil. Chalks and Derwent Water, Lake District, Cumbria. Paul Glendell/English Nature 23,075A limestones lead to an alkaline, usually well-drained soil; Present-day ecosystems is a key influence on global climate. sandstones, sands and gravels lead At a local scale, the geology can to an acidic, well-drained soil; Ecosystems result from the affect regional weather patterns. while finely-grained rocks, such as interaction of climate, physical For example, the Pennine ridge clays, mudstones and shales, can landscape, substrate and living that runs through England forces lead to a poorly-drained soil. organisms. They develop at air to rise over it, which causes various scales. The planet can be water to condense, form clouds These variations in substrate regarded as an ecosystem, as can a and fall as rain. As a result, the are the foundation for the woodland, a peat bog or a rock north west of England is generally diversity of habitats and species pool. wetter than the east, which broadly that have developed in England.