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Robert
was awarded a distinction for his dissertation
Abstract
Artificial
modifications to an urban stream, Bourne Stream, Dorset, as part of a
Sustainable Urban Drainage System (SUDS), were investigated for their
contribution to habitat quality as measured by macroinvertebrate and
macrophyte diversity. The specific objectives were to investigate the
environmental conditions prevailing in the three major freshwater
habitats – stream, ponds and SUDS; to investigate macroinvertebrate
and macrophyte species diversity within these habitats; to investigate
the relationship between the environmental conditions and species
diversity; to compare the stream quality over time in order to assess
any changes and to assess the habitats in terms of conservation value.
Diversity indices, multivariate statistics and two nationally recognised
predictive methodologies (RIVPACS and PSYM) were used to categorise the
habitats.
Species
richness and diversity were not found to differ significantly between
the stream itself, the existing ponds and the constructed wetlands.
Habitat quality as measured by macroinvertebrate diversity was related
to the pH of the water and the emergent vegetation. RIVPACS analysis
showed the condition of the stream to be grade B, good, in the upper
reaches. This shows an improvement in the uppermost sample point
immediately below the constructed wetlands compared with previous
published analysis. The lower sample point showed a slight degradation,
factors which may account for this are discussed. It is concluded that
the conservation value of constructed wetlands can be high, this site
having several Notable water beetle species and uncommon dragonflies.
Robert can be contacted via his web site at
www.aquilina-environmental.co.uk
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