Implications of Streamflow Variability and Predictability for Lotic Community Structure: A Regional Analysis of Streamflow Patterns

Abstract

Long-term discharge records (17–81 yr) of 78 streams from across the continental United States were analyzed to develop a general quantitative characterization of streamflow variability and predictability. Based on (1) overall flow variability, (2) flood regime patterns, and (3) extent of intermittency, 11 summary statistics were derived from the entire record for each stream. Using a nonhierarchical clustering technique, nine stream types were identified: harsh intermittent, intermittent flashy, intermittent runoff, perennial flashy, perennial runoff, snowmelt, snow + rain, winter rain, and mesic groundwater. Stream groups separated primarily on combined measures of intermittency, flood frequency, flood predictability, and overall flow predictability, and they showed reasonable geographic affiliation. A conceptual model that incorporates the nine stream clusters in a hierarchical structure is presented. Also, the positions of the 78 streams in a continuous three-dimensional flow space illustrate the wide range of ecologically important hydrologic variability that can constrain ecological and evolutionary processes in streams. Long-term daily streamflow records are a rich source of information with which to evaluate temporal and spatial patterns of lotic environments across many physiographic and ecographic regions. Relative positions of streams in flow space provide a conceptual framework for evaluating a priori the relative importance of abiotic and biotic factors in regulating population and community processes and patterns.

Macroinvertebrate community response to inter‐annual and regional river flow regime dynamics

“…This demonstrates that the hydrology and ecology of different river 'types' interact in a variety of ways and also that additional factors (i.e. other than the flow regime such as climatology, catchment characteristics, habitat availability, water chemistry and biological interactions) may be important in structuring instream macroinvertebrate communities (Allan et al, 1997;Doisy and Rabeni, 2001;Hughes and James, 1989;Poff and Ward, 1989;Rabeni and Doisy, 2000;Richards et al, 1997;Richards and Minshall, 1992;Sponseller et al, 2001). In the case of RM2, the 'region' is widely distributed across the study area and the variable LIFE scores recorded and high variance of the 'most significant hydrological descriptor (lnQ 10 /Q 90 -from the magnitude of flow events category within the IHA methodology) (Figure 4c) may reflect these 'additional' factors.…”

Application of the ELOHA Framework to Regulated Rivers in the Upper Tennessee River Basin: A Case Study

“…The need for standardized flowecology relationships provided the motivation for creating flow classifications where streams are grouped according to similar hydrologic properties (e.g., Poff and Ward 1989;Poff 1996;Kennard and others 2010). Instead of developing management recommendations for every individual river, classes of rivers within a given region can be used to develop standards for managing flow needs (Poff 1996;Arthington and others 2006).…”

Macroinvertebrate communities along a third-order Iberian stream

“…Variations in stream flow are seen as a major disturbance in these systems (e.g. Poff & Ward 1989, Yount & Niemi 1990, Robinson & Minshall 1998. The influence of floods on biotic communities seems to be related with their intensity, frequency and predictability (e.g.…”