(^28) an environmenTal hisTory of Wildlife in england
or salad burnet (Poterium sanguisorba).^42 Because the layers of acid sand
overlying the chalk were thin, they were more easily reclaimed than heaths
of more conventional form, which overlay deeper deposits of sand or gravel.
Therfield Heath in Hertfordshire and Newmarket Heath in Cambridgeshire
lie some 30 kilometres apart but both are fragments of what was, until the
nineteenth century, a continuous tract of chalk heath extending all along the
scarp of the East Anglian Heights.^43
Heaths are important not so much because they host a wide range of
plants and animals – most are relatively species-poor – but because they
are home to species which are rare elsewhere, such as the natterjack toad.
Dry, open land with few trees to impede sunlight, their soils are warmer
than those of neighbouring habitats, allowing species to flourish which
are not normally found this far north, such as smooth snakes and sand
lizards; heaths provide the principal English home for the adder.^44 Loose,
sandy soils, and the low-growing gorse and heather also afford shelter for
invertebrates rarely found elsewhere, such as the silver-studded blue moth.
The very openness of the landscape, moreover, is and was attractive to a
number of bird species, such as the stone curlew and the Dartford warbler.
Nightjar and woodlark are heathland birds, although they also favour
woodland edges and may have been a particular feature of wood-pasture
heaths. In the seventeenth and early eighteenth centuries, the great bustard
and red-backed shrike would also have been common – the former now
extinct and the latter hovering on the edge of extinction in England. Those
heaths in which the amount of soil disturbance was greatest – either because
they boasted high densities of rabbits, or because they were regularly dug
for heather turfs or sporadically cultivated – displayed a distinctive flora,
including spiked and fingered speedwell (Veronica spicata and V. triphyllus),
perennial knawel (Scleranthus perennis) and field wormwood (Artemisia
campestris), and were particularly favoured by invertebrates like the tawny
wave moth.
The most extensive tracts of unploughed ground in the seventeenth
century were the moors which were to be found in the higher, wetter areas
of northern and western England, above c.300 metres. Like heaths, moors
were more extensive then than today. Even in 1773 Arthur Young was able
to assert, admittedly with some exaggeration, that ‘you may draw a line
from the north point of Derbyshire to the extremity of Northumberland of
150 miles as the crow flies, which shall be entirely across wastelands; the
exceptions of small cultivated plots, very trifling’.^45 And like heaths, moors
were (and are) of varied character. Those on lower ground, and towards
the drier east of the country, shade almost imperceptibly into lowland
heaths. They are formed over podzols or brown earths, and are largely
dominated by heather, only locally out-competed by coarse grasses such as
Nardus stricta.^46 Bilberry and bracken are also widespread. Many moors,
however, occur on higher or wetter land, on broad and poorly draining
plateaux. Here deposits of peat, many metres deep, have formed, as plant
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