Linking Excess Nutrients, Light, and Fine Bedded Sediments to Impacts on Faunal Assemblages in Headwater Agricultural Streams¹

Abstract

Griffith, Michael B., F. Bernard Daniel, Matthew A. Morrison, Michael E. Troyer, James M. Lazorchak, and Joseph P. Schubauer‐Berigan, 2009. Linking Excess Nutrients, Light, and Fine Bedded Sediments to Impacts on Faunal Assemblages in Headwater Agricultural Streams. Journal of the American Water Resources Association (JAWRA) 45(6):1475‐1492. Abstract: Biological impairments in streams are typically defined by regulatory agencies in terms of altered invertebrate or fish assemblages. While nutrients, canopy cover, and sediment fines contribute to these impairments, these stressors are often defined, at least in part, by their impacts on periphyton. Path analysis can extend these assessments to impacts on invertebrates and fish by characterizing the direct and indirect relationships among variables along defined model pathways. With data from headwater tributaries in the Little Miami River, Ohio, we tested models of the impacts of nutrients [total nitrogen (TN), total phosphorus (TP), and the nitrogen to phosphorus (N/P) ratio], the percentage of (%) open canopy, and the % sand and fines on three periphyton metrics [periphytic ash‐free dry mass (AFDM), the percent abundance of cyanobacteria (% cyanobacteria), and the percent abundance of Chlorophyta (% Chlorophyta)] and, in turn, on selected invertebrate or fish metrics. Our objective was to develop and evaluate a statistical model that assesses the direct and indirect impacts of excess nutrients on macroinvertebrate and fish in these streams and demonstrate how this approach might be applicable elsewhere. The results suggest indirect pathways for the influences of nutrients, canopy cover, and fine bedded sediments on invertebrates or fish that are mediated by their influences on periphyton. This is in addition to any direct impacts of these stressors on the invertebrate and fish metrics. In most models, all three periphyton metrics increased with % open canopy. Periphytic AFDM increased with TN, while % cyanobacteria decreased. The % cyanobacteria also decreased with % sand and fines, but % Chlorophyta increased. The metrics, percent abundance of (%) three most dominant (macroinvertebrate) taxa, % Trichoptera, and % herbivorous fish all increased with periphytic AFDM, while % climbers, % swimmers, and %Lepomis cyanellus Rafinesque decreased. Lepomis cyanellus is an indicator species, because it is generally common in these streams and relatively tolerant to various common environmental stressors. The % three most dominant macroinvertebrate taxa increased while % Hydropsychidae (Trichoptera) and %L. cyanellus decreased with % cyanobacteria. The % Trichoptera and %L. cyanellus increased with % Chlorophyta. Some macroinvertebrate metrics, such as the % burrowers and number of burrower taxa, did not have any statistically significant relationships with the periphyton metrics but did exhibit a direct pathway with % sand and fines. These analyses illustrate how path analysis can be used to estimate the relationships among the variables in a conceptual model, modify the ...

Genetic diversity and species diversity of stream fishes covary across a land-use gradient

“…Nonetheless, responses observed in the LMR basin more likely reflect suites of in-stream attributes that change when stream condition becomes impaired. Support for this comes from work by Griffith et al (2009) showing that fish species richness in the LMR basin varies according to complex interactions between canopy cover, nutrients and sedimentation.…”

“…Measures of nitrogen, phosphorus and turbidity, which all loaded positively on to PC1 W (Online Resource 1), are associated with agricultural land use in the LMR basin (Griffith et al 2009;Daniel et al 2010; this study), particularly in unglaciated watersheds (e.g., TKN: unglaciated r = 0.79, p \ 0.001; glaciated, r = 0.39, p = 0.10).…”

Boosted Regression Tree Models to Explain Watershed Nutrient Concentrations and Biological Condition

“…Both factors (latitude, HSG D) were important predictor variables in the nutrient and IBI BRT analyses and are indicative of the Level IV Ecoregion gradient across the watershed (Predictor Variables: Derivation of Watershed and RBA Metrics). The Ecoregion gradient trends from permeable glacial till soils in the northern part of the watershed to clayey, less permeable soils in the south from the Pre-Wisconsinan Drift Plain (i.e., where HSG D soils are more prevalent) (Griffith et al, 2009;Daniel et al, 2010).…”

Seasonal Manure Application Timing and Storage Effects on Field‐ and Watershed‐Level Phosphorus Losses

“…Additionally, short time intervals between manure application and rainfall in spring can lead to significant nutrient runoff losses (Smith et al, 2007; Vadas et al, 2007; Komiskey et al, 2011). Such losses, particularly when coinciding with extreme precipitation or flooding events, can be detrimental to stream ecology and downstream water quality (Wang et al, 2007; Griffith et al, 2009). …”