ERIKA SCHNEIDER can scarcely contain her excitement. Standing on a muddy
embankment at Cernovca in the Danube delta, she has her eyes fixed on 400 pale
pink pelicans sitting placidly on the water less than 100 metres away. 鈥淭hat is
just fantastic,鈥� she says. 鈥淲here pelicans rest, there are fish.鈥� And if fish
are there, she knows that her plan to return the delta to nature is
succeeding.
Schneider is a Romanian ecologist who is based at the Floodplains Institute
of the World Wide Fund for Nature (WWF) at Rastatt in southern Germany. Put
bluntly, what she and her colleagues are trying to do is to reverse the tide of
recent Romanian history. Ten years ago, Cernovca was reclaimed from the marshes
to become a 1580-hectare polder, to be used for rice production. In April last
year, the dykes were breached to let the water in again in an attempt to return
the area to its natural state.
When Schneider visited the site last May, just a month after the flooding, it
was resplendent with wildlife. As well as the pelicans, 37 other species of bird
had been seen in the area, and there were 25 coot nests. Six pairs of roe deer,
two pairs of wild boar and a raccoon dog were also sighted: all signs that a
healthier ecosystem was re-establishing itself. What is remarkable, says
Schneider, is not the spectrum of birds and mammals that were found, but the
speed at which they returned from the other parts of the delta.
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Bill Niering, a botanist from Connecticut College in New London, and editor
of the journal Restoration Ecology, is less surprised. He sees
resemblances between the recolonisation of the Danube polders and what has
happened in older restoration projects, such as the marshlands of Long Island
Sound in the northeastern US (see 鈥淏ack to nature鈥�). 鈥淚t鈥檚 amazing how
fast everything comes back,鈥� he says. 鈥淚t seems so simple, but it works.鈥�
鈥淲etlands are the most regenerative ecosystem you can imagine,鈥� says Jerome
Van Wetten, a Dutch ecological consultant based in Amsterdam. They can recover
relatively quickly, he says, because in their natural state they are subject to
鈥渟hock dynamics鈥�, such as dramatic changes from annual flooding. But Schneider鈥檚
work at Cernovca is important, says Van Wetten, because it shows the governments
of Eastern Europe that damaged environments can be restored.
Schneider is working with Georgeta Marin, a senior soil scientist from the
Danube Delta Institute at Tulcea in Romania. They are part of an ambitious
$6-million scheme funded by the World Bank to protect and restore the
magnificent mosaic of water, trees and grass formed as the Danube spreads out
before merging with the Black Sea. The delta, which stretches across the border
into Ukraine, is home to more than 110 species of freshwater fish and 320 bird
species, including rarities such as the red-breasted goose, the Dalmatian
pelican and most of the world鈥檚 population of pygmy cormorants. Schneider and
Marin are now finalising a report that will highlight the successes already
achieved in their pilot project.
Their ambitious task is to restore the Danube delta to the state it was in
before it was wrecked by human interference. The Romanian part of the delta,
covering nearly 680 000 hectares, was the victim of a grand 20-year plan dreamt
up by the former Communist leader of Romania, Nicolae Ceausescu, and his wife
Elena. In 1975, they decided to start converting 180 000 hectares of the delta
to agriculture, fisheries and forestry production.
The Ceausescus set up 11 fishing companies and five agricultural companies
employing a total of 5700 people. Engineers erected dykes around vast areas of
the delta, creating giant polders for crops such as wheat, maize and rice, along
with a sprinkling of artificial lakes for use as fish farms. Elena Ceausescu was
particularly keen to transform parts of the wetlands into paddy fields so that
Romania could become self-sufficient in rice.
鈥淚t was the worst thing that could be done in the delta鈥攖urning wet
land into dry land,鈥� says Marin. 鈥淎nd it has comprehensively failed.鈥� The soil
was often too sandy or salty for crops. Irrigation proved too expensive, and the
projects were abandoned. The fish farms, too, were a spectacular flop as the
water drained away through the soil. Many have been abandoned, although a few
struggle on. 鈥淭he production of one kilo of fish cost more than one kilo of
caviar,鈥� says Marin. By 1989, when the Ceausescu regime collapsed, 40 000
hectares of the delta had been destroyed.
But now the dykes are being broken down. In 1991, the UN designated more than
half of the delta a World Heritage Site, an accolade that ranks it with areas
such as the Serengeti National Park in Tanzania and the Gal谩pagos Islands
in the Pacific. The following year, the new Romanian government created the
Danube Delta Biosphere Reserve under UNESCO鈥檚 Man and the Biosphere programme.
Advised by WWF, it is employing 100 wardens to enforce a ban on fishing and
farming in 鈥渃ore areas鈥� covering about 8.5 per cent of the reserve鈥檚 591 000
hectares. 鈥淲e want to replace Mrs Ceausescu with Mother Nature,鈥� says Phil
Weller, the coordinator of WWF鈥檚 Green Danube programme. 鈥淏y freeing the river
we will enable nature to restore itself. And it will do things that we can鈥檛
辫谤别诲颈肠迟.鈥�
The focus of Schneider and Marin鈥檚 report, due to be published by the WWF in
May, will be a 2100-hectare polder close to Cernovca called Babina, which was
dammed off for rice production in 1985. In May 1994 it became the first
agricultural polder to be flooded, when four breaches were bulldozed in the dyke
that encircles Babina鈥攖wo to the north and two to the south鈥攁llowing
the murky waters of the Danube to pour back in.
The results are encouraging, not to say astonishing. 鈥淚 was surprised by how
water flowed through the four holes,鈥� says Marin. 鈥淚 expected two to act as
inflows and two as outflows, but in fact all four act as both in a complex
pattern we have yet to fully understand.鈥� The area is constantly flooded and
drained in response to the changing levels of the Danube itself. Since 1994 the
volume of water in Babina has varied from 4.8 million to 35 million cubic
metres. This renewed ebb and flow restores some of the natural mechanisms
governing the delta landscape. Before Babina was made into a polder, up to 90
per cent of its area was flooded for 150 days each year.
The rate at which nature has recolonised Babina has amazed Schneider and
Marin. Within four months of flooding, Phragmites reeds were growing up
to 6 metres high. Up to 18 species of fish, including carp, bream and perch, are
now breeding in the area, which was previously devoid of wild fish. Many species
have a good range of ages, and prey outnumber their predators by a healthy
5-to-1 ratio鈥攂oth signs of healthy, sustainable populations. These are
important developments, for in addition to restoring wildlife habitats, one of
the aims of the Danube project is eventually to provide a sustainable harvest of
fish and reeds.
The number of bird species seen at Babina has more than doubled, from 34 to
72, of which 28 are breeding. During summer days the air is thick with
butterflies and dragonflies, while the night is filled with a deafening chorus
of frogs. According to Schneider and Marin鈥檚 draft report, mammal populations
are recovering, with raccoon dogs, foxes and wild boars returning. There are now
eight resident pairs of roe deer.
A separate study by the Institute of Biology in Bucharest, published in 1995,
found the restoration had also increased the diversity of plankton. In the first
year after the dykes were breached, the number of phytoplankton species had
increased by 20 per cent to 136 and the number of zooplankton species by 30 per
cent to 99. At the same time the mass of phytoplankton per litre of water
decreased almost by a factor of five, while the mass of zooplankton increased
sixfold. All signs, say the researchers, of the ecosystem returning to
health.
Babina has also resumed the traditional role of a delta as a natural
sedimentation bed. As water trickles through the flooded area, sediments rich in
nitrates and phosphates settle out. The Danube water flowing into Babina is
cloudy, but the outflow is crystal clear. Marin says that the delta halves the
concentration of nitrogen in the water to less than 2 milligrams per litre, and
cuts phosphorus levels from 0.6 to 0.15 milligrams per litre. 鈥淚t is good enough
to drink,鈥� she jokes, though she refrains from doing so.
As in any restoration project, there are still daunting problems. The delta
is by no means an isolated ecosystem. In the 2850 kilometres from the Danube鈥檚
source in southern Germany to the Black Sea, the cities and industries of a
dozen countries in Central and Eastern Europe disgorge heavy metals, chlorinated
hydrocarbons and other pollutants into its waters. Phosphates and nitrates from
agricultural fertilisers and sewage have produced a plague of algal blooms in
the delta. According to an internal report produced by the World Bank in 1994,
eutrophication has destroyed the natural vegetation in many delta lakes,
contributing to a decline in the populations of birds, fish and shellfish which
depend on it for food and shelter.
Like much of the rest of the Danube, the three main branches that flow
through the delta were straightened, confined by dykes and dredged in the 1970s
and 1980s, as engineers dug an extensive network of canals for shipping. This
altered the patterns of flooding, erosion and sedimentation. Dykes further
upstream, that were built to prevent flooding, have only made the problem worse,
by increasing river flow and depth, which further changed the hydrology of the
delta.
Both Babina and Cernovca used to be labyrinths of lakes, streams and islands,
but they were flattened as well as dammed by Ceausescu鈥檚 engineers. To recreate
the old landscape, some 40 kilometres of dyke would have to be removed. The cost
would be prohibitive. 鈥淚t is like my face at a beauty parlour,鈥� says Marin. 鈥淚
can recapture something of what I used to be, but not everything.鈥�
* * *
Back to nature
ECOLOGICAL restoration is a science in its infancy, and not surprisingly
still has teething troubles. Most of these stem from the need to understand
extraordinarily complex ecosystems. 鈥淓cosystems are not more complex than you
think, they are more complex than you can think,鈥� says Bill Niering, a botanist
from Connecticut College in New London.
Despite the initial success at Babina, it is doubtful whether this and other
attempts at ecological restoration can ever be completely successful. 鈥淧eople
have tried hard to fully restore a marsh and they can鈥檛 do it,鈥� Harold Mooney of
Stanford University in California told this year鈥檚 meeting of the American
Association for the Advancement of Science. 鈥淪o unless we learn how to restore
ecosystems we ought to be very careful about tearing them apart.鈥�
But where the damage has already been done, restoration is the only option,
and each case history adds much needed information about the process of
reconstruction. In the 1970s, the Connecticut Department of Environmental
Protection began to restore 600 hectares of the salt marshes that stretch more
than 200 kilometres along Long Island Sound. These had nearly all been damaged
by the creation of earth dykes and ditches by early colonists, who wanted to use
the land for hay, and later by unsuccessful attempts to control mosquitoes by
destroying their breeding pools.
Now the barriers have been removed, and the marshes are carefully managed to
restore, as far as possible, the natural ebb and flow of the tides. This
requires controlled opening of tidal gates to avoid overflooding the marsh,
which has been eroded by 30 to 40 centimetres from its natural level. Deep
pools, destroyed by ditches, have been re-established, allowing a
5-centimetre-long minnow called the mummichog to breed. The fish keeps
mosquitoes in check by feeding on their larvae, which it can reach when spring
tides flood mosquito breeding grounds.
According to Niering, fiddler crabs, salt marsh snails and other wild species
have returned in abundance. Native Spartina cord grasses are
recolonising the marshes, encouraged by the salty water flowing through the
tidal gates. 鈥淲e are bringing back much of the marsh we destroyed,鈥� Niering
says. 鈥淏ut it will never be the same as it was.鈥�