In the parts of the uplands where till is shallower and overlies limestone there are thousands of subsidence dolines (“shake-holes”), where the till has foundered into solution cavities in the limestone. The shake-holes, being in the till, are often water-tight, providing another suite of natural wetlands. They are not to be confused with the numerous shell holes on the Otterburn artillery ranges in northwest Northumberland, often also containing water-bodies. However, the more acidic pools are generally unfavourable for amphibians.
River floodplains have oxbow lakes and backswamp pools, and the braided reaches of upland rivers have temporary pools in unused channels, as have upland streams at their margins. Alluvial flats beside lowland rivers flood in winter. The restoration of old oxbows has been part of habitat management for Otter Lutra lutra recovery in north Northumberland.
The natural post-glacial vegetation over much of the region was woodland of various types, although in the higher uplands, with precipitation above 1,000 mm, extensive treeless blanket peat gradually accumulated, as did raised bogs replacing former shallow lakes. Other non-wooded habitats were unstable coastal dune systems of Northumberland and southern Durham, the offshore islands (owing to exposure and salt-spray), salt-marshes (especially at Teesmouth and in the sheltered strait behind Holy Island, and in Budle Bay), inland crags and other rock surfaces with only open tree cover, river shingles, and some limited areas above the upper tree-line.
However, this is a part of Britain where a particularly high proportion of native woodland has been lost. A main cause was the strenuous efforts of agricultural improvers in the 18th and 19th centuries to remodel the landscape, continued in a different context by coniferisation of native woodland on landed estates in the mid-20th century. The result is that, for Northumberland, only 0.5% of the county is ancient, semi-natural woodland (woods of over 2 ha) and for Durham 1.3%. However, Northumberland in particular now has a high total proportion of tree cover, 16%, partly because of 18th and 19th-century estate woodland planting, but mainly because of the establishment in the uplands by the Forestry Commission of the vast Kielder Forest, mainly between the 1930s and 1980. There are other substantial 20th century plantations, both state and private; Hamsterley is the main County Durham Forestry Commission forest, while a series of smaller plantations front the North York Moors above Guisborough. Durham has only 6.4% woodland cover, as has the former Cleveland county, and the former Tyne and Wear 5.4%. Over the North East as a whole the proportion of woodland and forest in the landscape is 12.0%. The large modern plantations are almost entirely coniferous (with Sitka Spruce Picea sitchensis the main species) and account for Northumberland’s low proportion of broad-leaved woodland, about 13%. In County Durham, on the other hand, broad-leaved woodland somewhat exceeds conifer woodland in area, and is a feature of the coastal denes and the Derwent valley. Similarly much Cleveland woodland is in the steep-sided coastal gills. The conifer plantations themselves, other than their edges, have little value for amphibians and reptiles while being vital for the survival in the region of Red Squirrel Sciurus vulgaris, but broad-leaved woods support Slow Worms Anguis fragilis and, in the uplands, Adders Vipera berus, as well as the normal suite of woodland mammals.
In the uplands, above the moorland edge, are various types of semi-natural moorland vegetation: acidic grassland, bracken, heathland dominated by heather, and peat bog – the latter mainly blanket bog on the higher ground. Land use here, apart from forestry, is extensive hill grazing and Red Grouse Lagopus lagopus scotica game shooting. The elevation of the moorland edge varies markedly across the region, being much higher in the lead mining area of the North Pennines than elsewhere, owing to past land reclamation by the miner-small-holders. In this book an association between Common Lizard Lacerta vivipara and the mosaic of moorland edge habitats is noted, partly because rotational burning of the heather moors above is detrimental to reptiles. Only limited areas of lowland heath survive, the most important being Waldridge Fell and Eston Moor. Moorland and lowland heath in general provide relatively undisturbed habitats for reptiles. The other main semi-natural habitats, apart from woods and wetlands, are calcareous and neutral grasslands, the coastal dune systems (where brackish pools in dune slacks provide Common Toad Bufo bufo habitat), salt marsh, and cliff and island ecosystems.
There was a period of relative peace and economic development from the mid-12 century AD. Royal hunting forests were established, collectively occupying vast tracts of the uplands as well as parks, such as Hulne Park at Alnwick and the Bishop of Durham’s Stanhope Park in Weardale. The hunting forests, for a time, preserved woodland, and Red Deer Cervus elaphus and Roe Deer Capreolus capreolus, and the parks were stocked with Fallow Deer Dama dama. Chillingham Park had been enclosed by the 13th century and the feral white park cattle may have been there then, but are first mentioned in 1646. (The sub-fossil horns of the extinct aurochs, which inhabited the native forests, are unearthed from time to time, particularly from upland peat.)
All changed with the outbreak of the Scottish wars at the end of the 13th century and, particularly in Northumberland, more than three centuries of misery and decivilisation ensued. Disruption and insecurity of life and property prevailed. A powerful brake was put on agricultural progress and settlement, and cultivation retreated from the hills. There was periodic official or semi-official warfare, raiding and reprisal between England and Scotland, and in the dales on either side of the Border there developed during these anarchic times a lawless, clan-based way of life based upon predatory cattle-rustling (reiving) to supplement subsistence agriculture. The hills and valleys nearest to the Border were abandoned for permanent settlement. Harrying penetrated deep into Northumberland and was ruinous to agriculture. This was less the case further from the Border in County Durham where, at least by the 16th century, conditions were more settled.
Defensible stone buildings such as castles, pele towers and bastle houses (strong farmhouses) proliferated, providing bat roosts and hibernacula, and there are summer roosts of Daubenton’s Bat Myotis daubentonii in the roofs of bastles and castles, near to the rivers and burns over which they forage.
In uplands near to the Border, land abandonment or reduced stocking levels brought about extensive secondary regeneration of woodland and scrub, and natural and semi-natural habitats survived, or became re-established, which would not otherwise have done so, including wetland as well as woodland. It is possible that these upland ecosystems survived in this way after the 17th century, following enclosure into ultra-extensive hill farms, so that in places they have persisted to the present. Certainly ground predators survived longer here than in more peaceful areas: Northumberland was the last English county to lose the Wild Cat Felis silvestris, in 1863.
By the later 17th century, however, the region was re-emerging to civilisation. The agricultural essayist, John Grey of Dilston, claimed (1841) that the peasant farming population had been so weakened by the centuries of warfare, raiding and destruction, and therefore unable to resist change, that once the brakes were released agricultural reform, though starting late, was carried further in Northumberland than anywhere else in Britain. Durham shared these trends. Certainly by the middle of the 19th century, landscape and society had been transformed. Enclosure of the lowlands had been completed, with the lowlands being laid out anew into large rectangular fields. (In modern times there has been less impulsion to clear away hedgerows than in other parts of England where fields were not already as large.) On the heavy clayey soils underground drainage was imperative, and the drains led into new field ditches. Some farms, especially in north Northumberland, had ponds to supply water power for threshing machines, and field ponds were fed from drains and streams, or were dug down to the water table, to be replaced in the 20th century by pipe fed troughs.Perhaps because of previous Border military need, a very high proportion of the region was, and still is, held in large estates, some later coming into the hands of families whose wealth was founded on coal or industry. Country houses were built amidst parks, some descended from medieval hunting parks. Lakes and ponds, for amenity and fishing, and arboreta were created.
Hunting foxes replaced hunting deer as the preferred life style of the better off, and fox (and pheasant) coverts planted. Numerous plantations, many of conifers (Norway Spruce Picea abies, Scots Pine Pinus sylvestris and, especially, European Larch Larix decidua) were established in the lowlands for estate timber, and also on the lower moorlands for stock shelter. The opening up of numerous large and small quarries for building stone and limestone created new habitats, especially ponds. Mills by rivers had mill ponds.
Systematic game management, including control of “vermin”, was practised by the end of the 18th century. Mammals which were slaughtered were Polecat Mustela putorius, Pine Marten Martes martes and Wild Cat. However, as both Rossiter (1998, 1999) and Yalden (1999) have pointed out, reductions in the populations of species regarded as pests had not begun with game preservation by private estates. At parish level churchwardens had been offering bounties for the purpose since the 17th century.
Equally profound changes were occurring away from the land. Coal had been exported from the Tyne to London and elsewhere from medieval times, but with British population growth and the Industrial Revolution, the demand for coal exploded. Mines were sunk across the Northumberland and Durham coalfield and also to coal seams in rural areas. Early horse-drawn waggonways for coal transport evolved into railways with locomotive haulage. The availability of abundant cheap coal facilitated heavy industry, especially on Tyneside, Wearside and, after the mid-19th century, Teesside.
Numerous new habitats developed, especially for amphibians; hundreds of coal mining-subsidence ponds appeared in southeast Northumberland and central Durham, where pond clusters favour the survival of amphibian metapopulations. There were also ponds in colliery yards, for boiler feeds and other uses. Farmland was severed by waggonways, railways, mines, pit-heaps, quarries and factories, leading to countless patches of neglected or casually-managed grassland and scrub habitats, including along disused railways. These patches, where near to ponds, serve as amphibian hibernacula. In the North Pennines reservoirs supported mining activity and there are numerous larger and smaller water-supply reservoirs.
The flourishing industrial economy of Tyneside, Wearside and Teesside up to the outbreak of the First World War created densely built-up urban quarters but also brought about the growth of residential suburbs for the growing middle-class population. Market towns and villages within commuting range similarly expanded. Gardens and their ponds provided new habitat, greatly enlarged again with 20th century greenfield housing estate development. New roads such as the A1(M) provided wide grass verges, enhancing populations of widespread small mammals.
In the second half of the 20th century underground coal mining was gradually replaced by opencast working, and with increased emphasis on land restoration for nature conservation new wetlands have been created following cessation of operations, as they have also following river gravel-working. Examples of the former are at Hauxley and East Chevington, and of the latter at Witton-le-Wear and Caistron. The last two decades of the 20th century saw the planting of numerous broad-leaved woodlands between the Tees and the Tyne as part of Community Forest initiatives, usually close to settlements and limited in size, although some such as Cowpen Bewley Woodland Park on the outskirts of Billingham are quite substantial. These, together with woodland planting on restored mineral sites, will have aided the increase in deer populations, particularly on the urban fringes.
Written by Angus Lunn (last updated Nov 12)