Wildlife and conservation review 2002
concluded that subspecies is the appropriate level of taxonomic separation at present. However, it
was suggested that, following further studies, full species status should be considered.
Finally, back to marine matters, the EU announced drastic cuts in the North Sea fishing quotas
(including Cod, down by 45%), causing consternation in both camps - too drastic said the fishermen
(naturally), too little said many conservationists. By the year's end, the PDV outbreak had claimed
3652 victims in the UK, of which just 23 were in Essex. Numbers of dead seals had dropped
steadily since September, and the epidemic was considered to be over. And as if to highlight the
good news, a Grey Seal with pup was seen in Hamford Water for the second year running.
Literature review
During the course of the year, a number of scientific papers have been published which have a
bearing on Essex wildlife, and I feel that a brief summary of their key points might be interesting to
those who do not have access to the scientific literature. It is not a comprehensive review, as it
covers just the papers I have been sent, but I would like to repeat this in the future, and so would
welcome copies of any papers to include in future reviews.
Chris Mason and Sheila Macdonald of Essex University have been studying changes in the ground
flora of Stour Wood, using permanent quadrats, for 11 years, in both coppiced plots and a widened
ride. This may be the only long-term study of its type, and presents information on the changes in
species richness, the performance of particular species, and changes in environmental parameters
such as light availability and temperature. Species richness was found to peak in the second or third
year after coppicing; the dominant species Wood Anemone showed little response to the coppice
cycle in terms of frequency, but showed a fourfold increase in flowering intensity, again two to
three years after coppicing. The results are discussed in the context of possible future management
alternatives: the continuation of coppicing provides historical continuity, benefits the aesthetically
valuable sward of Wood Anemones, and helps sustain the White Admiral population, but for greatest
conservation gain, a programme of tree-felling (Sweet Chestnut), stump killing and natural
recolonisation may be advantageous.
MASON, C.F. & MACDONALD, S.M. (2002) Responses of ground flora to coppice management in an
English woodland - a study using permanent quadrats. Biodiversity & Conservation 11: 1773-1789.
Turning to south Essex, Steve Colclough and others, on behalf of the Environment Agency, reported
the recent recover}' of the Thames Estuary as a major nursery ground for both economic and
conservation fish. Among the species important from a conservation perspective are: Smelt, which
has now established a large breeding stock in the Estuary; Twaitc Shad, increasingly common
below West Thurrock; Sea Lamprey, which appears to be re-establishing itself; and River Lamprey,
reported for the first time in 2001. The Environment Agency has developed a unique, focused
survey programme to inform its management policies, and produced a Fisheries Management Action
Plan to protect and enhance the fish (and fisheries) of the Thames.
COLCLOUGH, S.R., CRAY, G., BARK, A. & KNIGHTS, B. (2002) Fish and fisheries of the tidal Thames:
management of the modern resource, research aims and future pressures. Journal of Fish Biology 61
(Supplement A): 64-73.
30
Essex Naturalist (New Series) 20 (2003)