Adjusting the effect of seasonal variability in the bioassessment of streams

• Published in: Environmental monitoring and assessment Vol. 187; no. 1; p. 4107
• Main Authors: Serra, Sónia R. Q, Calapez, Ana Raquel, Pérez-Bilbao, Amaia, Feio, Maria João
• Format: Journal Article
• Language: English
• Published: Cham Springer-Verlag 2015; Springer International Publishing; Springer Nature B.V
• Subjects: anthropogenic activities; Anthropogenic factors; Atmospheric Protection/Air Quality Control/Air Pollution; Autumn; biological assessment; Calibration; Creeks & streams; Discriminant analysis; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental Management; Environmental monitoring; Environmental Monitoring - methods; Invertebrates; Macroinvertebrates; Monitoring/Environmental Analysis; Precipitation; Prediction models; Rivers; Rivers - chemistry; seasonal variation; Seasonal variations; Seasons; Spring; Streams; Studies; Winter; Portugal; Multimetric index; Rivers; Invertebrates; Streams; Predictive model; Seasonality
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-014-4107-9

Bioassessment tools should distinguish between the effects of anthropogenic degradation in communities and natural temporal changes. The present study tests the influence of natural seasonal variability on macroinvertebrate stream communities assessed by a predictive model (PORTRIV) and a multimetric index (IPtI) calibrated for spring. The scores of PORTRIV decreased significantly between spring and autumn, and between spring and winter (ca. 37 to 53 %, respectively), while those of IPtI did not change significantly between seasons. For non-reference samples, the results of the predictive model also indicate no significant differences. A correction factor (CF) was calculated to adjust the existing differences in the model assessments between seasons, based on the percentage of variation of reference site scores from spring to autumn and winter. After the application of the CF to the OE50 scores of spring reference samples, the differences were no longer significant. Independent reference validation sites confirmed this tendency. This method has the advantage of avoiding large efforts required for the construction of databases from other seasons and the development of new models to allow the assessment of streams in seasons other than spring. Further tests with models developed in regions with more marked seasonal changes should be done to confirm its wider applicability.