Environmental Engineering Reference
In-Depth Information
FIG
134.
Fringed water lily, a native of eastern England and a rare alien in Wales. Introduced to Broad Pool during
the late 1940s or early 1950s. (Harold Grenfell)
By 1970 the fringed water-lily had almost completely covered the pool and the Trust was considering
ways to halt its spread. At the same time other vegetation was encroaching, mainly soft-rush
Juncus ef-
fusus
and sharp-flowered rush together with marsh pennywort
Hydrocotlyle vulgaris
, bog-bean and in
places common spike-rush
Eleocharis palustris
and bulrush. During the late 1970s the bog-moss
Sphag-
num auriculatum
started to increase, together with
S. squarrosom, S. fimbriatum, S. recurvum
and
S. sub-
nitens
. By 1982 the mats of
Sphagnum auriculatum
were so extensive that they were visible over a large
part of the water surface, even during the winter, and it seemed as though the pool might turn into a bog.
Following the work in 1984 clumps of pondweed
Potamogeton
spp. appeared together with one small
clump of the white water-lily
Nymphaea alba
, which had been previously recorded from the site but not
seen for a number of years, and floating club-rush
Eleogiton fluitans
. Other plants recorded from the site
include lesser bladderwort, lesser marshwort
Apium inundatum
and alternate water-milfoil
Myriophyllum
alterniflorum
.
