Environmental Engineering Reference
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of its Latin name
Galinsoga parviflora
, came to Kew Gardens from Peru in the 1790s but proliferated
unexpectedly in the bomb craters.
All this was documented by City of London banker and amateur botanist Ted Lousley, who reported
on more than 250 plant discoveries in his topic
The Natural History of the City
.
8
He treasured both alien
finds and the hybrids produced by illicit liaisons between aliens and natives. He often took samples and
planted them in his own garden in South London, which became for a time the country's largest private
herbarium.
9
Besides the craters, his favorite places to search were railway sidings, landfills, graveyards, and mar-
ket gardens, where horticulturalists used the finely shredded waste from the wool industry, known as
shoddy, as a cheap fertilizer. There were rich pickings here because the shoddy carried with it many
plant seeds from foreign climes that had become entangled in the fleece. Over the years, Lousley found
more than five hundred species trapped in shoddy, including Mediterranean plants that Merino sheep
from Spain had taken to Australia and New Zealand in the nineteenth century and that later came to Bri-
tain in their fleece.
10
Lousley's jottings started the botanical study of brownfield Britain. His successor was northern
lichen-hunter and botanist Oliver Gilbert of Sheffield University.
11
In 1993, Gilbert wrote the first gov-
ernment report anywhere in the world on the ecology of derelict urban sites, which he reckoned con-
tained more of the nation's rare insects than either ancient woodlands or chalk downs. “At least 40
invertebrate species are wholly confined to brownfields,” he wrote. Rare wasps and bee species love
abandoned quarries. The glowworm mostly lives now in old walls. “Butterfly species may now be more
likely to be found in suburban areas than in rural areas,” due to the sheer variety of habitats in sub-
urban gardens and parks. Less surprising, perhaps, bats inhabit buildings and tunnels. Indeed, many
now roost almost nowhere else.
12
A series of recent studies in France, Germany, and the United States
found the year-round flowers in suburban gardens supported more wild bees—and more species of wild
bees—than surrounding farmlands.
Nature's go-getters, carpetbaggers, and vagabonds end up in these badlands. Michael Crawley of Im-
perial College London ranked various types of British habitats according to how “invaded” they were by
alien flora. The top habitat for aliens was waste ground, with 78 percent of the flora made up of aliens,
followed by conifer plantations (56 percent) and walls (46 percent).
13
The warm and dry microclimates
in open spaces typical of brownfield sites are often the first stopping places for migrating Mediterranean
species. But in these novel ecosystems, the distinction between native and alien is particularly meaning-
less. No species is “native” to a chemical works or ash heap.
We should be wary of pushing the full panoply of environmental protection onto these places,
however. Not least because it wouldn't work. Brownfield sites do not have to be protected for the long
term. Their charms and biodiversity credentials are almost always ephemeral. No ecosystem is perman-
ent, but most brownfield sites, as homes of new colonists on often bare ground, are changing faster than
most. They are nature at its most dynamic but also most temporary. Preserving them for posterity is a
contradiction in terms, but while they are in bloom we should treasure them.
Around the world, nature is moving to the cities. “Ecological novelty pervades the urban environment,”
says Michael Perring of the University of Western Australia.
14
Gardens and cemeteries, abandoned in-
dustrial areas, transport corridors, and even suburban trash cans are all grist to nature's mill. Sometimes
cities provide specialist habitat. Buildings and bridges in cities from Budapest and Florence to Brussels
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