Spatial and temporal variability in the littoral macroinvertebrate communities of selected Irish lakes

Abstract

Five replicate samples were collected from five exposed stony shoreline sites in three low, mid and high alkalinity lakes within a narrow temporal window in order to assess the spatial variation in littoral invertebrate communities Five replicate samples from five stony shoreline sites in one lake of each alkalinity type were collected over three seasons to assess temporal variability. All samples were collected using a 2 minute kick sweep method with a 670 μ mesh pond net, preserved in situ in 70% alcohol and subsequently sorted and identified to the lowest level of taxonomic resolution practicable. Non-metric multidimensional scaling (MDS), cluster analysis and TWINSPAN classification methods were used to examine the potential for using the littoral invertebrate fauna to differentiate among sites, among lakes, among seasons and among alkalinity types. Given that the underlying structure in the data was known, the efficacy of three common classification methods was assessed. The effect of sampling effort and the influence of rare species on the classification of biological invertebrate samples were also examined.