Clouds over Sheffield © Paul Richards Sheffield Overview “The setting of Sheffield in its ‘golden frame’, with its hills and valleys and the heritage of trees and parks, continues to be a major asset that is appreciated by residents and visitors alike. The natural environment with its variety of wildlife is valuable in its own right but can also contribute to the economic and social vitality of the city. The green spaces within the built- up areas make an important contribution to the life of the city. The challenge is to protect and enhance the city’s natural assets both to support the regeneration of the city and as features of value in their own right.” Challenge 13: A city that prizes its green environment Adopted Sheffield Local Plan/Sheffield Development Framework, Core Strategy Sheffield City Council, 2009 7 Sheffield in context: landscape and topography For the purpose of this report, the ‘Sheffield district’ is the whole Sheffield region, including areas of the Peak District National Park in Sheffield, and is shown below (Figure 1). Sheffield sits within the south-west corner of South Yorkshire with a third of its area falling within the Peak District National Park boundary (shaded area). The district is defined by the Unitary Authority boundary (Sheffield City Council; SCC) but is divided between two planning authorities: SCC and the Peak District National Park Authority (PDNPA) which covers the western area. Figure 1 (left): the Sheffield district as covered by the report. The green shaded area lies within the Dark Peak region of the Peak District National Park; map credit 3 - see Appendix for credit details Figure 2 (below): National Character Areas (NCAs) within which Sheffield lies. These regions have been based on both geological and ecological assessments as well as the culture and heritage that has helped to shape the landscape; National and Landscape Character Areas map credit 2 The district straddles three National Character Areas: ‘Nottinghamshire, Derbyshire and Yorkshire Coalfield’, ‘Yorkshire Southern Pennine Fringe’ and part of the ‘Dark Peak’1. At a more local level, SCC undertook a preliminary Landscape Character Assessment of its green belt and countryside areas 2. The assessment has categorised 16 character types further divided into four broad ‘Character Areas’: ‘Upland’; ‘Valley’; ‘Lowland’ and ‘Highly Maintained’2. On an even more local level, north- west Sheffield (known as the Sheffield Lakeland area, see case study) has recently been categorised into four ‘Landscape Character Types’: ‘Enclosed Gritland Uplands’; ‘Slopes and Valleys with Woodlands’; ‘Moorland, Moorland Slopes & Cloughs’; and ‘Developed’, with detailed descriptions of each 3. 8 View from Ringinglow © Paul Richards Sheffield contains a huge variety of landscapes for a city, ranging from the dense urban centre, through the built- up housing and industrial areas of the city, to its hills, lakes and moorlands 4. The countryside in Sheffield ranges from exposed upland heath and moorland fringes, with deep valleys to the west, to gentler rolling wooded farmlands and former marshland in the eastern lowlands. These landscapes have been shaped by variations in geology and landform as well as the city’s industrial history 5. The latter has resulted in a large urban conurbation centred on the meeting of five rivers: the Don; Sheaf (after which the city is named); Porter; Rivelin, and Loxley. A sixth, the Rother, forms the boundary between Sheffield and Rotherham. The underlying geology and deep cut valleys carved by these watercourses create an east-facing amphitheatre formed by the ‘seven hills’, with a 500m high, western upland backdrop (maximum: High Stones, 550m) sloping down towards the eastern lowlands of around 30m (minimum: Blackburn Meadows, 29m). From every part of Sheffield the hills dominate the skyline; over 12% of the district is above 400m high and over 52% lies above 200m 2. In Sheffield, 94% of all housing land is over 100m and 15% is over 200m (the normal limit for development in the UK is 200m)4. There are strong advantages for wildlife in the way in which these hills and valleys form natural green corridors and help to connect areas of woodland and domestic gardens, reducing urban fragmentation 6. The varied topography and landscape means that, 35% as a city, Sheffield supports a surprisingly wide 4 range of natural habitats and biodiversity , as 30% 29.4% detailed in this report. Sheffield has often been described as the ‘greenest city’ in the UK or in Europe and a study undertaken by A. Middleton 25% 22.0% provided some evidence to support this 6. A wide 20% range of statistics were used to determine levels 17.6% 17.8% of ‘greenness’ by comparing against population size, wooded areas, open country etc. and the 15% study found that Sheffield did perform well when 10.6% compared to other major population centres 6. For 10% more general information about Sheffield and its population, please see the ‘State of Sheffield 2018’ 7 5% report . 2.2% 0% Figure 3 (right) : amount of land at various heights within the Sheffield district. Most land lies between 100-300m. 100-200 100-200 metres Land over over Land 500m 200-300metres 300-400 300-400 metres metres 400-500 Land under100 Land m 9 Sheffield in context: geology The surface geology of the Sheffield area is of Silesian, Upper Carboniferous origin (333-299 million years ago) with some more recent alluvial deposits along the river valleys. Travelling from west to east across the district, the underlying landscape of the Eastern Pennine Anticline consists of the mudstone, shale and coarse sandstone (and minor coal seams) of the Millstone Grit (Namurian) of the Dark Peak, giving way to the more widespread Coal Measures (Westfalian). These also comprise mudstone, shale and sandstone, with rich workable seams of coal. Prominent features of the landscape are the inland cliffs or ‘edges’, the longest of which is Stanage Edge at 6km in length, part of which forms the western boundary of the district and runs south-east into the Derbyshire Peak District. This is formed by the hard sandstone horizon of the Millstone Grit where the softer shales and mudstones have eroded away. The Lower Coal Measures form the fine sandstone edges of Sky Edge in the heart of the city and Wharncliffe at the northern boundary with Barnsley. The variation in the coarseness of these sandstones offered different grades of abrasive gritstone in recent times for many uses including the grinding of high quality knife blades. The major consequence of the coming together of the geological characteristics of the region is the steel industry upon which Sheffield is built. The combination of coal for heat, multiple fast flowing streams running down from the upland watershed for power generation, locally occurring iron ore and the charcoal provided by the many forests provide the perfect combination for the creation of steel. The seat earths, fire-clay and ganister beneath the coal seams also provided ideal materials for furnaces. Stanage Edge 10 © Paul Richards Sheffield in context: climate and the effects of climate change on nature Sheffield’s position in the UK, combined with its varied landscape and topography means that the climate across the district varies considerably from the colder, wetter uplands of the western moorland to the relative warmth of the urban heat island within the city centre. The rain shadow that is cast by the Pennines sees the Sheffield area experiencing drier conditions than Manchester, but topography and valley direction deliver variations in temperature that are dramatically different locally depending on altitude, forestation, exposure and aspect 8. This range has a significant impact on the wildlife that the area can support and the extent to which species can disperse and flourish. The increase in mean temperature and sun hours per day over time is shown in Figure 4 (right) 8,9 . Vegetation growth and the diversity of plant species within the Sheffield region are strongly linked to climate because of how it influences the growing season. According to the Met Office, in 2016 the national growing season had increased by an average of 29 days from pre-1990 figures 10 . Sheffield figures reflect this and since 1989 there has been a marked extension to the growing season of around a month (Figure 5)8,9 . This greater local capacity for growth and flowering times has a significant impact further up the food chain as consumers from insects to birds benefit from this extended feeding season. Consequently, there is a longer Figure 4 (above): annual mean temperature and annual number of sun hours recorded at Weston Park between 1880 and 2010. period for reproduction and dispersal, which Figures are smoothed +/- 7 years 8,9 . may influence the introduction of new species as well as potentially strengthen populations. In recent years long-term changes in climate - such as increased average winter temperatures since around 1989 (Figure 4) - suggest possible effects on overwintering success of species such as dragonflies (see Odonata case study, Waterways & Standing Water chapter)8,9 . Other factors, including increased rainfall and temperature extremes, can be detrimental to some species. Non-native species can sometimes flourish in a changing climate. In some urban Sheffield locations some non-native flowering plants are carefully selected to make use of and extend flowering seasons and provide a stable resource for invertebrates (see next case study). Fig ure 5 (above): length of growing season as a smoothed figure (+/- 7 years) and annual variation from the 1961-1990 mean 8,9 . Wyming Brook 11 © Sarah Sidgwick Case study: Pollinators, flowering seasons and urban meadows Jack Brodie and Sue France, Green Estate The much reported decline in insect pollinators is due to several factors but the single most important is believed to be the greatly reduced number of flowers in the landscape.