Temporal and spatial concordance in community composition of phytoplankton, zooplankton, macroinvertebrate, crayfish, and fish on the Precambrian Shield

Concordance among communities dictates how broadly we can extrapolate results derived from a set of eco- systems. We used Mantel tests to evaluate the degree of concordance in community composition among phytoplankton, zooplankton, benthic macroinvertebrate, crayfish, and fish in eight lakes near Dorset, Ontario, Canada. Spatial concor- dance across lakes at the decadal scale was stronger (mean Mantel r = 0.51, standard deviation (SD) = 0.20) than both intra-annual agreement (mean Mantel r = 0.38, SD = 0.20) and temporal concordance within a single lake (mean Man- tel r = 0.20, SD = 0.15). The degree of temporal concordance was not related to climatic fluctuations, with the excep- tion of increased spatial synchrony in phytoplankton communities in 1997. Strength of overall spatial concordance was most commonly related to variability in chemical attributes of the study lakes. An understanding of the determinants of concordance among taxon groups is germane to the advancement of ecology in general, as well as biodiversity conser- vation strategies, ecosystem monitoring, and impact diagnosis.