Laize, C.L.R.; Barker, L.J.; Edwards, F.K. (2018). Simulated monthly biological indicators for England and Wales 1964-2012. NERC Environmental Information Data Centre. (Dataset). https://doi.org/10.5285/2ad542be-e883-4c6e-b198-7d49da62208c
Monthly time series of simulated de-trended/de-seasonalised biological indicators at 86 bio-monitoring sites in England and Wales based on the modelled response of these indicators to discharge (represented by a standardised streamflow index, SSI) at 76 paired gauging stations. The biological indicators include:
(i) Average Score per Taxon (ASPT)
(ii) Lotic-invertebrate Index for Flow Evaluation (LIFE) calculated at family-level (LIFE Family)
(iii) LIFE calculated at species-level (LIFE Species).
Biological indicator ASPT and LIFE (family and species levels) were obtained for 86 sites from the EA Freshwater and Marine Biological Surveys for Invertebrates England database (commonly known as 'BIOSYS'). Biological records for the UK typically exhibit an annual positive trend and seasonal offset (higher values in spring); bio-indicators were therefore de-trended and de-seasonalised by fitting linear regression models (season and year as predictors) then subtracting the fitted bio-indicator values from the raw indicator data. Monthly SSI series for period 1964-2012 for the 76 gauging stations paired to the 86 BIOSYS sites were derived using 6-month accumulation period and Tweedy distribution. Seven predictors were assembled: SSI on same monthly date as biological indicators, and six lagged SSI (6, 12, 18, 24, 30, and 36 months prior to date of biological indicators). For each bio-indicator, a model of the indicator's response to the SSI predictors was fitted using Multi-Level modelling and Multi-Model Inference. Models were then run with the whole SSI dataset to produce the final dataset of simulated de-trended/de-seasonalised ASPT, LIFE Family and LIFE Species series for period 1964-2012.
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