Effects of geomorphology, habitat, and spatial location on fish assemblages in a watershed in Ohio, USA

Abstract

In this paper, we evaluate relationships between in-stream habitat, water chemistry, spatial distribution within a predominantly agricultural Midwestern watershed and geomorphic features and fish assemblage attributes and abundances. Our specific objectives were to: (1) identify and quantify key environmental variables at reach and system wide (watershed) scales; and (2) evaluate the relative influence of those environmental factors in structuring and explaining fish assemblage attributes at reach scales to help prioritize stream monitoring efforts and better incorporate all factors that influence aquatic biology in watershed management programs. The original combined data set consisted of 31 variables measured at 32 sites, which was reduced to 9 variables through correlation and linear regression analysis: stream order, percent wooded riparian zone, drainage area, in-stream cover quality, substrate quality, gradient, cross-sectional area, width of the flood prone area, and average substrate size. Canonical correspondence analysis (CCA) and variance partitioning were used to relate environmental variables to fish species abundance and assemblage attributes. Fish assemblages and abundances were explained best by stream size, gradient, substrate size and quality, and percent wooded riparian zone. Further data are needed to investigate why water chemistry variables had insignificant relationships with IBI scores. Results suggest that more quantifiable variables and consideration of spatial location of a stream reach within a watershed system should be standard data incorporated into stream monitoring programs to identify impairments that, while biologically limiting, are not fully captured or elucidated using current bioassessment methods.

Geospatial Modeling of River Systems

“…Geomorphology has often been recognized as an important factor in defining biological [10,11] and ecological characteristics of rivers [12,13] and ultimately the shaping of aquatic habitat [13,14]. The term habitat refers to a location or environment where an organism is most likely to be found and can include physical, chemical and biological characteristics that allow the organism to achieve various life history requirements, such as spawning, feeding, and overwintering.…”

“…The majority of existing studies investigate relationships between habitat and geomorphology in relatively small, often wadeable, streams (order 1-5), where monitoring protocols tend to be well established and geomorphological variables can be measured with relative ease [11,13]. Such thorough data collection becomes less attainable in larger rivers, where greater depths, widths, discharge and flow velocities impede both active and passive data collection methods.…”

Use of Ecohydraulic-Based Mesohabitat Classification and Fish Species Traits for Stream Restoration Design

“…Literature indicates some species exploit food resources on the episodic submerged floodplain [52,184,188,223]. In general, the importance of flood refugia has been recognized in stream restoration for agricultural Midwest streams with two-stage cross-sectional designs [274][275][276]. Further research is needed to enhance of understanding of trait expression associated with these high-flow mesohabitat units.…”

Using a Geospatial Model to Relate Fluvial Geomorphology to Macroinvertebrate Habitat in a Prairie River—Part 2: Matching Family-Level Indices to Geomorphological Response Units (GRUs)

“…The fluvial environment is influenced by factors such as climate, vegetation, and geology, which leads to the formation of many different instream habitats [1,2]. Since the geomorphological structure of a river basin is a driving factor affecting biological responses, it plays a vital role in the functioning and habitat selection of many species within the river [1,3].…”

“…Since the geomorphological structure of a river basin is a driving factor affecting biological responses, it plays a vital role in the functioning and habitat selection of many species within the river [1,3]. Changes in river geomorphology influence the hydrological and ecological processes within the river ecosystem by creating these diverse instream habitats [4].…”