Recorded summer crustacean groups at Trout Bog differed more from six other Wisconsin lakes in 2014–2025 than in 2002–2013

We tested whether summer crustacean composition became more similar among seven northern Wisconsin lakes. We used open NTL LTER density data and fixed June–August samples in 2002–2025. We pooled copepod orders and cladoceran genus groups to reduce changes in identification detail. The panel had 159 complete lake-years and 454 observed pair-years. The primary mean change in annual Bray–Curtis dissimilarity across 21 fixed pairs was +0.024, with a nominal 95% three-year block interval of −0.011 to +0.059. This did not show a clear regional change. A follow-up found larger differences for all six pairs with Trout Bog. Their mean change was +0.202; the simultaneous lake-check interval was +0.099 to +0.305. The other 15 pairs had a mean change of −0.047, with a simultaneous interval of −0.078 to −0.015. Bosminidae supplied about 70% of the Trout Bog pair change. Fixed-date and common-year checks kept the local contrast. Native taxon codes gave a smaller Trout Bog estimate whose interval included zero. Distances between period-average compositions did not show clear convergence among the other six lakes. These results apply to recorded broad-group density shares. They do not identify an environmental cause or establish species-level change. The package preserves source data, code, all estimates, search records, figures and internal repeat checks.

zooplankton · lake communities · spatial composition · taxonomic resolution · Bray-Curtis · North Temperate Lakes · Bosminidae · reproducible analysis