Channel Unit Use by Smallmouth Bass: Do Land‐Use Constraints or Quantity of Habitat Matter?

Abstract

I examined how land use influenced the distribution of Smallmouth Bass Micropterus dolomieu in channel units (discrete morphological features—e.g., pools) of streams in the Midwestern USA. Stream segments (n = 36), from four clusters of different soil and runoff conditions, were identified that had the highest percent of forest (n = 12), pasture (n = 12), and urban land use (n = 12) within each cluster. Channel units within each stream were delineated and independently sampled once using multiple gears in summer 2006. Data were analyzed using a generalized linear mixed model procedure with a binomial distribution and odds ratio statistics. Land use and channel unit were strong predictors of age‐0, age‐1, and age‐>1 Smallmouth Bass presence. Each age‐class was more likely to be present in streams within watersheds dominated by forest land use than in those with pasture or urban land uses. The interaction between land use and channel unit was not significant in any of the models, indicating channel unit use by Smallmouth Bass did not depend on watershed land use. Each of the three age‐classes was more likely to use pools than other channel units. However, streams with high densities of Smallmouth Bass age >1 had lower proportions of pools suggesting a variety of channel units is important even though habitat needs exist at the channel‐unit scale. Management may benefit from future research addressing the significance of channel‐unit quality as a possible mechanism for how land use impacts Smallmouth Bass populations. Further, management efforts aimed at improving stream habitat would likely be more beneficial if focused at the stream segment or landscape scale, where a variety of quality habitats might be supported.Received September 10, 2012; accepted December 23, 2012

Landscape Prediction and Mapping of Game Fish Biomass, an Ecosystem Service of Michigan Rivers

“…In a study of Ohio streams, Miltner and Rankin (1998) observed the highest fish abundances at intermediate nutrient concentrations, whereas abundances of sensitive species were reduced at higher concentrations. Smallmouth Bass and Brook Trout have both been shown to be sensitive to habitat degradation (Sowa and Rabeni 1995;Argent and Flebbe 1999;Curry and MacNeill 2004;Stranko et al 2008;Brewer and Rabeni 2011;Brewer 2013), pointing to one mechanism by which nutrient enrichment could be a stressor on fish. High concentrations of growth-limiting plant nutrients have been linked to an excessive growth of algae, macrophytes, and phytoplankton, which in turn can change habitat structure, flow velocities, dissolved oxygen concentration, and pH (Welch et al 1992;Dodds and Biggs 2002).…”

MultinomialN‐Mixture Models Improve the Applicability of Electrofishing for Developing Population Estimates of Stream‐Dwelling Smallmouth Bass

“…We electrofished areas that were at least 0.2 m deep in an upstream direction with a zigzag pattern. The depth limitation of the tow-barge electrofisher excluded most riffle areas, but the use of that habitat by Smallmouth Bass larger than 80 mm TL is very uncommon (Brewer 2013; Oklahoma Department of Wildlife Conservation [ODWC], unpublished snorkel data). Care was taken to thoroughly electrofish areas with structure (e.g., large wood, root wads, and boulders).…”

A Review of Urban Water Body Challenges and Approaches: (1) Rehabilitation and Remediation

“…So what are resource managers to do? It may be best to focus on riparian rehabilitation because that habitat has the most well-documented effects on stream condition (Naiman and Decamps 1997), and it also confers local habitat benefits at the reach scale (Brewer 2013). However, we note three caveats: (1) riparian rehabilitation can take many forms, depending on local physiographic conditions (a.k.a.…”

“…(2) in many watersheds extensive impervious surface coverage can override riparian services (Coles et al 2012); and (3) extensive pipe networks can bypass riparian zones (Brewer 2013).…”

“…In forest streams, those alterations usually increased physical habitat complexity, but their biological effects are uncertain because of insufficient monitoring, method and stream variability, and study design flaws that make increased fish production indistinct from increased fish concentration (e.g., Roni et al 2005Roni et al , 2006Roni et al , 2008Thompson 2006;Stewart et al 2009;Whiteway et al 2010). In addition, urban streams experience more flashiness and poorer water quality than forest streams, which together may override hydromorphological complexity (Larson et al 2001;Booth 2005;Brewer 2013). Most studies reviewed suggest that local rehabilitation actions have little effect.…”