Relating streamflow characteristics to specialized insectivores in the Tennessee River Valley: a regional approach

Abstract

Analysis of hydrologic time series and fish community data across the Tennessee River Valley identified three hydrologic metrics essential to habitat suitability and food availability for insectivorous fish communities in streams of the Tennessee River Valley: constancy (flow stability or temporal invariance), frequency of moderate flooding (frequency of habitat disturbance), and rate of streamflow recession. Initial datasets included 1100 fish community sites and 300 streamgages. Reduction of these datasets to sites with coexisting data yielded 33 sites with streamflow and fish community data for analysis. Identification of critical hydrologic metrics was completed using a multivariate correlation procedure that maximizes the rank correlation between the hydrologic metrics and fish community resemblance matrices. Quantile regression was used to define thresholds of potential ranges of insectivore scores for given values of the hydrologic metrics. Increased values of constancy and insectivore scores were positively correlated. Constancy of streamflow maintains wetted perimeter, which is important for providing habitat for fish spawning and increased surface area for invertebrate colonization and reproduction. Site scores for insectivorous fish increased as the frequency of moderate flooding (3 times the median annual streamflow) decreased, suggesting that insectivorous fish communities respond positively to less frequent disturbance and a more stable habitat. Increased streamflow recession rates were associated with decreased insectivore scores. Increased streamflow recession can strand fish in pools and other areas that are disconnected from flowing water and remove invertebrates as food sources that were suspended during high-streamflow events. Published in

Streamflow characteristics from modeled runoff time series – importance of calibration criteria selection

“…A large number of endemic fish species and a unique assemblage of mussels, crayfish, and salamanders make the Tennessee River basin an excellent area for ecohydrological studies (Abell et al, 2000). From a study published by Knight et al (2008), 25 catchments in the Tennessee River basin with observed streamflow time series (U.S. Geological Survey, 2016b), pre-cipitation (U.S. Department of Commerce, 2007a), temperature (U.S. Department of Commerce, 2007b), and potential evaporation data (Rotstayn et al, 2006) were selected. The catchment areas range between 100 and 4800 km 2 with elevations ranging from 174 to 937 m (U.S. Geological Survey, 2016a).…”

“…Thirteen SFCs assessed in this study were chosen for use in model scenarios based on discernible functional connections with fish community diversity (Knight et al, 2008(Knight et al, , 2014. This set of 13 SFCs represents each of the major flow regime components commonly used in ecological studies (e.g., Olden and Poff, 2003;Arthington et al, 2006;Caldwell et al, 2015): magnitude, ratio, frequency, variability, and date (Table 1).…”

Multi-metric calibration of hydrological model to capture overall flow regimes

“…In this study, the overall flow regime was divided into high, middle and low flow events based on the daily flow duration curve and was characterized by 16 flow metrics including magnitude (5), frequency and variation (3), duration (3), timing (2) and rating (3) of flow events (Richter et al, 1996;Olden and Poff, 2003;Poff et al, 1997Poff et al, , 2010aKnight et al, 2008Knight et al, , 2012Kennard et al, 2010) (Table 1). All the 16 observed and simulated metric values were extracted from the observed and simulated daily streamflow series in the entire period (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005), respectively.…”

“…It is widely accepted that flow regimes play a critical role in flood control, domestic and production water supply (Bauwens and Vandewiele, 1989;Lehner et al, 2006), migration and transformation processes of nutrients (Poff et al, 1997;Ahmet et al, 2006;van Griensven and Meixner, 2007), variation of species habitat, as well as biodiversity and life history patterns in aquatic ecosystems (Poff et al, 1997;Bunn and Arthington, 2002;Knight et al, 2008;Arthington et al, 2010). Except for the traditional resource attribute of flow regimes, their environmental and ecological attributes were gradually paid more attention.…”

“…Similarly, the simulation performance of low flow events significantly affects the prediction errors of water quality concentrations (van Griensven et al, 2006). Thus, the term ''flow regime" was put forward (Langbein and Iseri, 1960), and the ecologically relevant metrics (ERMs) system was gradually formed to describe overall flow paradigm using magnitude, frequency, variability, timing, duration and rating of flow events (Richter et al, 1996;Olden and Poff, 2003;Poff et al, 1997Poff et al, , 2010aKnight et al, 2008Knight et al, , 2012Kennard et al, 2010). It is necessary and urgent to enrich WRIs to predict the entire flow regimes, which will provide hydrological foundations for the integrated water resources management, particularly for flood control, river environment improvement and restoration, and water project regulations.…”