sevenTeenTh-CenTury environmenTs: farmland^41pectin-veneris) and Venus’ looking-glass (Legousia hybrida) – all thrived.
Arable weeds are worthy of more attention than they usually receive. Only
around thirty of the more than 150 species characteristic of arable fields
are actually indigenous. Most are aliens, mainly introduced in prehistory
although with some later recruits from the Americas, such as pineappleweed
(Matricaria matioides), or from Asia, such as common field speedwell
(Vemica persica). Weeds survived repeated ploughing and harrowing
by employing a variety of strategies. Some produced seeds with similar
dimensions to cereal grains, and were thus winnowed and stored with these,
a proportion returning to the soil with the seed crop. Others, like couch grass
(Elymus repens), can regenerate from tiny fragments of stem or root. Most,
however, produce seed that can lie dormant in the soil, sometimes for years,
so that species which germinate in the spring and emerge with the spring
crop are able to survive years when fields are sown in the autumn, and vice
versa: they can also often remain dormant for longer periods, where, for
example, land is laid to grass for several years.^18 Such plants often produce
vast quantities of seed – over 15,000 per plant, per annum, in the case of
the poppy. Whatever their particular modus operandi, the wealth of weeds
growing in the fields provided sustenance for large numbers of invertebrates,
and also for birds and mammals, feeding on these or on the seeds or leaves
of the plants themselves. Others of course fed off the grain itself, generally
when spilled on the ground at harvest.
Weeds were abundant in crops but they really flourished when the fields
lay uncultivated or ‘fallow’, and fallow fields also gave opportunities for
ground-nesting birds like the skylark, although most such species would
also take their chances in fields under grain. In clayland areas especially
the land was often ploughed and harrowed for much of the fallow year
(a ‘bare fallow’), but even so there was usually an extended period in the
winter during which weeds could grow undisturbed. It was usual to spread
the work of ploughing and sowing evenly between the autumn and spring,
with wheat especially being autumn-sown, ensuring that weeds also had a
chance to flourish for a while on spring-sown land, during late autumn and
early spring, something which further increased the range and numbers of
invertebrates. In addition to all this, crops harvested by hand left longer
stubbles than those cut by modern machines. These remained standing in
the spring-sown fields as well as on the fallows over winter, providing cover
for ground-nesting birds such as the song thrush, skylark, yellowhammer
and lapwing.
Arable fields thus provided an abundance of food for birds and mammals.
This said, their importance to biodiversity increased considerably if
adjacent habitats, providing shelter from the activities of cultivators and
additional sources of food, also existed: in the seventeenth century, the
character and density of such habitats displayed marked variations from
district to district. I noted in Chapter 1 the broad distinction between
‘woodland’ and ‘champion’ countryside: the former the landscapes of