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)

Abstract

Many rivers are intensely managed due to anthropogenic influences such as dams, channelization, and water provision for municipalities, agriculture, and industry. With this growing pressure on fluvial systems comes a greater need to evaluate the state of their ecosystems. The purpose of this research is to use a geospatial model of the Qu'Appelle River in Saskatchewan to distinguish instream macroinvertebrate habitats at the family level. River geomorphology was assessed through the use of ArcGIS and digital elevation models; with these tools, the sinuosity, slope, fractal dimension, and stream width of the river were processed. Subsequently, Principal Component Analysis, a clustering technique, revealed areas with similar sets of geomorphological characteristics. These similar typology sequences were then grouped into geomorphological response units (GRUs), designated a color, and mapped into a geospatial model. Macroinvertebrate data was then incorporated to reveal several relationships to the model. For instance, certain GRUs contained more highly sensitive species and healthier diversity levels than others. Future possibilities for expanding on this project include incorporating stable isotope data to evaluate the food-web structure within the river basin. Although GRUs have been very successful in identifying fish habitats in other studies, the macroinvertebrates may be too sessile and their habitat too localized to be identified by such large river units. Units may need to be much shorter (250 m) to better identify macroinvertebrate habitat.

Geospatial Modeling of River Systems

“…Hosseini et al [75] and Meissner et al [76,77] used different modelling approaches to determine the effects of spatial variability and indicators on aquatic ecology. Hosseini et al [75] applied a deterministic water quality model to determine the impact of location along a river on the sensitivity of ecological parameters (e.g., oxygen demand and growth rate) to water-quality variables (e.g., dissolved oxygen and chlorophyll-a concentrations).…”

“…Meissner et al [76,77] developed a geospatial model to easily identify fish and invertebrate habitat along another Prairie river to assist water and wildlife managers to rapidly identify fisheries habitat in need of protection. The study concentrated on fluvial geomorphology (metrics included channel sinuosity, width and slope and fractal dimension) and examining the hydrological and geological processes that shape certain fluvial geomorphological structures and patterns, as developed by Lindenschmidt and Long [66].…”

“…Multivariate-derived geomorphic response units (GRU) that categorized reaches along river systems that exhibit similar geomorphic structures were established, thus providing a link between the hydrological regime and species habitat preference. Meissner et al [76] focused on macro-invertebrate genus groupings as the ecological indicator, whereas the better-performing macroinvertebrate species groups are described in Meissner et al [77].…”

“…[76,77] papers, Doll et al [78] also used macroinvertebrate community metrics, but extended their correlation with in-stream geomorphological features (e.g., bankfull channel cross-sectional area, width-to-depth ratio, channel sinuosity and channel slope) to include morphological features in the river basin (e.g., width of the flood prone area, valley width, valley slope, and substrate). They, too, used principal component analyses to determine correlations between landscape features with macroinvertebrate indices.…”

Erosion processes on different relief units: the relationship of form and process

“…Until today the ERU concept has only been applied for the identification of areas prone to gully development and their subsequent use in gully-growth models. Recent studies aim at relating topographic characteristics to current processes and their prediction (Anders et al, 2009;Carr et al, 2015;Meissner et al, 2016). If recent efforts for automatic identification of relief units from digital terrain models (Anders et al, 2011;Martins et al, 2016;Smith et al, 2011) are taken into account, it is clear that relief units offer great potential for quantifying the current processes that shape the earth surface.…”