Mapping diversity in temporary aquatic habitats the distribution and occurrence

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					Mapping diversity in temporary aquatic habitats: the distribution and
occurrence of microphyte communities
Supervisors: Dr Roger Flower (Geography, UCL) and Professor John Birks (Visiting
Professor in Quaternary Palaeoecology, Geography, UCL)
Seasonally wet areas and especially temporary ponds constitute an important habitat
type that sustains a highly adaptable biota often comprising unusual and/or endemic
species. Although seasonal changes in water availability impose a major constrain on
these habitats, more usual characteristics of aquatic habitats (nature of the substratum,
water chemistry, morphometry and site aspect) are also influential factors affecting
species abundances.
The significance of temporary aquatic habitats for diversity has only recently been
recognised and is now a research topic within the new EU Framework Programme 7.
Initial research has focused on the relevance of these specialized habitats to
invertebrates and to amphibians but microphyte communities have received little
attention. Diatoms (micro-algae with siliceous cells walls) are one group of
microphytes that are excellent indicators of water quality and are used extensively in
environmental change research including biomonitoring of permanent waters, as
indicators of ecological quality (cf. the Water Framework Directive) and in
palaeoecology. Other microphyte groups include the bryophytes and green algae.
This research projects sets out to understand more about the distributions of, in the
first instance, diatom species in ephemeral wet habitats. It is proposed to sample and
enumerate diatom species in a variety of these sites, both natural and artificial, in
upland and lowland areas in the UK and in the seasonally drier country, Morocco. The
environmental factors that influence species occurrences and abundances are of
special interest as are those that control species diversity locally and regionally.
Various hypotheses about these controls and include environmental quality and niche
size, biogeography, and population dynamics will be tested using diatoms, and
possibly other microphytes, from an array of habitats types.
It is proposed to compare and evaluate and biodiversity patterns in various temporary
aquatic habitats using numerical techniques and identify the main factors influencing
species diversity in both climatic zones. Whilst the results will be most relevant to
assessing floristic diversity and interpreting the occurrences and abundances of
diatom species, they should also help test the ‘rules' which control community
composition. The work could also have relevance to other fields including
palaeoecology, forensic science and geoarcheaology where diatoms are used to infer
environmental attributes.

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