Monitoring simplification in plankton communities using different ecological approaches

The existence of environmental monitoring programs is essential for the early detection of any disturbance in water resources. However, it is necessary to use simple, quick and low-cost methods. For this, substitute groups, numerical or taxonomic resolutions may be used. Objective: This study aimed to answer: (i) can phytoplankton communities be used as surrogate of zooplankton communities?; (ii) can we use ecological approaches as surrogate for phytoplankton species?; (iii) can we use substitute groups (cladocera, copepod, rotifer or testate amoebae) as surrogate for zooplankton species?; (iv) are the environmental variables’ ordination standards concordant with the ordering patterns of phytoplankton and zooplankton species?; and (v) for both communities, is the spatial pattern of ordination maintained using density data or presence/absence of individuals or lower taxonomic resolutions? Methodology: The study was conducted in 25 water bodies that supply central-pivot irrigation in the Federal District - Brazil (Rio Preto Basin). Results and Conclusions: Evaluating the use of substitute groups, comparisons between phytoplankton and zooplankton, FG and MBFG classifications and almost all the comparisons between zooplankton groups suggested consistent patterns. However, the values of r were low, all below 0.70. Biological analyses with phytoplankton and zooplankton can be performed using presence/absence of individuals without significant loss of information, except for MBFG classification and copepods. Data may also be used at genus or family level for copepods and testate amoebae and only data at genus level for cladocerans and rotifers. Different results were found concerning taxonomic resolution for phytoplankton considering that, while being significant, the r value was less than 0.70.