Linking WBS

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Linking WBS WBBS to other national river surveys

• Ian Vaughan Steve Ormerod
• Cardiff University

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• Quantifying the links between river birds and the
  riverine environment
• Distribution patterns and population trends
• Environmental and biological data sets
• vital stage in indicator development
• Examining the national picture (cf. local
  autecology)
• Clear correlates bird distributions (WBBS) and
  River Habitat Survey (Vaughan, Noble Ormerod,
  submitted)

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Data resources

• Physical habitat/hydromorphology
• RHS 4500 reference sites c. 12k others
  (England Wales)
• Water chemistry
• GQA 9000 sites 000s other monitoring sites
• Land use GIS-derived data
• Biology macroinvertebrates
• GQA 6000 sites 000s others

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Caveats

• Site matching
• Sampling is not coupled relatively few direct
  matches
• Preliminary analysis quantify the effects of
  matching tolerance
• Sampling schemes
• Often non-random potentially biased
• RHS reference sites random stratified
• Water chemistry often targeted for organic
  pollution

Mixture of statistical inference and less
rigorous descriptions
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Outline analysis
Two key aspects of WBS/WBBS

• How representative are WBS and WBBS sites of
  British rivers?
• Identify correlates of population and
  distribution changes of river birds

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Representativeness of WBS and WBBS

• Are the environmental conditions found across
  river bird sites consistent with a representative
  sample of British rivers?
• How do the two schemes compare?
• How has the representativeness changed over time
  with the turnover of observers/plots?

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Multivariate - sample of all British rivers
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River bird sites
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Environmental correlates of WBS/WBBS data

• In what ways do population trends for different
  species correlate with environmental conditions
  or river types?
• If/where data allowtime series of bird trends
  vs. water chemistry and invertebrate data series.
• Modelling population and environmental data
• Case-control methodology

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Conclusions

• Evaluation of two key components in using
  existing river bird monitoring to appraise river
  environments
• Do they appear to be an unbiased sample of
  British rivers?
• What environmental changes/features correlate
  with observed changes in bird populations?