Fen Management Handbook - Scottish Natural Heritage

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Vegetation establishment at Kingfisher Bridge
At Kingfisher Bridge near Ely in Cambridgeshire, a private scheme
attempted to create herbaceous fen vegetation and reedbeds (Beecroft
1998). Several hay crops were taken over a period of a month to collect
seed from a wide range of species from nearby Chippenham Fen. The
hay was then strewn onto the prepared area. The biggest problems
were dominance by weeds from the seed bank in the former agricultural
soil, and the high nutrient status allowing these plants to outcompete
seedlings from the hay crop. Hand collected seed from Chippenham
Fen was also germinated in a poly tunnel before planting out as plugs
in the spring of 1997; these seedlings established well. Further
information on this case study can be found on www.kfbweb.info.
Hay crops have been successfully used to re-establish a fen in an area
that had been drained and used for intensive agriculture for more than
200 years in southern Germany (Patzelt et al. 2001). As conditions for
restoration were unfavourable, fen meadow hay from nature reserves
in the region thought to contain enough viable seeds to assist the
development of target communities was spread out on bare peat.
Repeated vegetation analysis showed that a combination of topsoil
removal to reduce fertility and hay transfer resulted in the establishment
of 70% of the species present in the donor material. The dormancy of
the seeds was found to be broken by a combination of fluctuating light
and temperature cycles and stratification pre-treatment. Germination
of the seeds is therefore likely to occur in the spring after an autumn
sowing.
A similar process was used in northern Germany (Rasran et al, 2006).
Between 40% and 70% of the 29 to 41 species per 25 m 2 plot in the
above-ground vegetation of the donor hay meadow were present as
seeds in the hay. A cluster analysis showed a high similarity between
the species composition of the sward and the seeds present in the hay
material. The number of seeds ranged from about 2,000 to 12,000
per m 2 . The viability of the seeds of both herbs and sedges was high
(approximately 80%) whereas the viability of grasses was only about
40%. Due to dormancy the germination percentage was much lower in
all groups (20–50%).
9.10 Seedling survival
In the early stages of fen colonisation, self-sown and introduced plants are
vulnerable to a number of factors which can result in poor establishment rates. The
commonest factors are drought, flooding, frost heave and erosion, grazing by ducks,
geese, swans, rabbits and hares. The following mechanisms can help improve
seedling survival.
9.10.1 Reduction of wave action
Wave action can be reduced by using temporary breakwaters, such as plastic
sheeting or hurdles (Garbisch 2005). More permanent breakwaters such as rock or
sandy islands could also be used.