Our objective was to quantify if macroinvertebrate assemblages in Indiana streams were better predicted from co-occurring fish assemblages or environmental variables. We used Canonical Correspondence Analysis (CCA) with forward-selection of variables to identify significant environmental predictor variables for macroinvertebrate and fish assemblages. A partial Mantel test was used to determine if fish assemblage composition and macroinvertebrate assemblage composition significantly co-vary while controlling for environmental effects. The CCAs resulted in two significant predictors of macroinvertebrate distribution and relative abundance, and four significant predictors of fish distribution and relative abundance. Similarity matrices of fish and macroinvertebrates were significantly correlated in the Mantel (r = 0.22, p = 0.019) and partial Mantel tests (r = 0.23, p = 0.013). Our results suggest that macroinvertebrates respond to local and regional environmental variation, and less to local presence of fishes. / Department of Biology

The objective of this study was to determine the relationship between fish assemblage structure and habitat in streams dominated by an agricultural landscape. Fishes from 20 natural and 20 channelized streams were sampled using electrofishing gear in East Central Indiana. Streams that had been channelized had a lower quality fish assemblage when compared to natural streams as measured by the Indiana V. Eastern Corn Belt Plain Index of Biotic Integrity (IBI). Stream habitat was evaluated using the Qualitative Habitat Evaluation Index (QHEI), which indicated that channelized streams had lower quality primarily due to a loss of heterogeneous habitat. Pearson correlation analysis relating ECB IBI and QHEI was positive and significant, and demonstrated that a reduction in riffle and pool areas associated with channelization was the most significant factor influencing the fish community. Furthermore, species lost when streams are channelized were predictable, and often represented environmentally sensitive species. The results of this study suggested that stream channel alterations have a negative and lasting influence on the fish assemblage which should be recognized prior to any stream development. / Department of Biology

Relationships between fish assemblage composition and substrate variation is poorly understood in large rivers. Information on fishes occurrence and behavior and substrate variation were examined in field observations for the Middle Wabash River and fine scale artificial streams experiments. The results from field observations suggested strong concordance for variation in abundance of fishes with habitat variation among sites, resulting in a longitudinal river gradient as dominant in the Middle Wabash River. In addition, shifts in fish behavior within artificial stream experiments demonstrated that species-specific habitat selection behaviors were influenced by interactions within a fish assemblage. The combination of artificial stream experiments and field observations can identify fine scale trends that bioassessment surveys cannot tease apart, and highlighting the need to examine species-habitat relationships at more than one scale. / Department of Biology

Agricultural practices may influence stream biological communities by removing riparian vegetation and modifying stream channel morphology, both which may reduce water retention time. I collected benthic invertebrates and fishes in seven headwater agriculturally-influenced streams in central Indiana, to quantify controls on invertebrate and fish community assemblage variation. Invertebrates were collected at 14 sites and fish were collected at 12 sites in Buck Creek watershed. The abundances of invertebrates and fishes were analyzed in Detrended Correspondence Analyses (DCA) in PC-ORD software and correlated with abiotic and biotic factors. The sites located in close proximity to Buck Creek have increased stability of biotic (fish assemblages) and abiotic (flow and water depth) factors. Abundances of invertebrates of headwater streams in east-central Indiana agricultural landscapes are influenced by distance between sites, distance to Buck Creek, and presence of fish species. Abundances of fishes were correlated with water quality and distance to Buck Creek. / Department of Biology

The local substrate composition of large rivers varies with local current velocity and high flow events. We evaluated effects of hydrology on local substrate variation for 28 Wabash River sites from 2005-08, and subsequent variation in fish assemblages using multivariate analyses. Sites were 500-m in length and fish were collected by boat electrofisher. Substrate collection methods were compared by way of habitat pole, developed by Ohio River Valley Sanitation Commission (ORSANCO), and substrate grabs. We characterized hydrologic variation with the Indicators of Hydrologic Alteration (IHA) software. We determined important driving variables of fish assemblages, substrates, and hydrology with Principle Components Analysis. Temporal effects of hydrology and substrate variation on taxonomic and functional fish assemblages were determined by repeated measures ANOVA. The analyses resulted in annual variation in fish assemblage structure, substrates and hydrologic variation. Significant relationships were found for fish assemblage structure, substrate variation, and hydrologic variation. . Our Mantel tests resulted in significant concordance among hydrology, local substrate variation, and fish assemblage structure variables in years 2005, 2006, and 2008, but not in 2007. These results demonstrated that Wabash River fish assemblages respond to substrate variation and substrate variation is controlled largely by hydrology. A comparison of substrate quantification approaches demonstrated that the habitat pole and substrate grabs are both effective ways to describe fish assemblages but the costs of grabs outweigh the cost of the pole method. / Department of Biology