Can Zooplankton Add Value to Monitoring Water Quality? A Case Study of a Meso/Eutrophic Portuguese Reservoir

Despite the key role of zooplankton communities in regulating water quality lentic ecosystems, they are absent from list biological elements Water Framework Directive (WFD) for assessment ecological status. Based on this, present work was a case study that aimed to understand relevance as bioindicator classifying reservoirs. For one year and each season, Torrão reservoir assessed using mandatory proposed by WFD sampling (second cycle) legislation currently applicable (third cycle). Additionally, samples were collected characterize community dynamic. The does not reach good potential. Furthermore, with updating criteria, classification tends get worse. Concerning zooplankton, occurrence Cyclopoida Bosmina associated lower quality, well collapse or low abundance Daphnia population, same periods. Low abundances better Shannon-Wiener diversity values decrease increase trophic state. High-efficiency feed filters macrofiltrator organisms dominate all seasons, which is quality. Calanoida/Cyclopoida ratio shows strong negative association species, diversity, functional groups (high efficiency macrofiltrators), different ratios (large Cladocera/total Cladocera Calanoida/Cyclopoida) promising valuable tools determine status, should be considered within metrics. Notwithstanding further research including reservoirs geographical areas various status pressures must analyzed.