Comment: Testing the Independence of Microhabitat Preferences and Flow (Part 1)

Williams, John G.

doi:10.1577/1548-8659-126.3.536

“…Contrary to the present results, velocity preference was independent of discharge for brown trout at the mesohabitat (Heggenes, 1988) and rainbow trout Oncorhynchus mykiss (Walbaum) at the microhabitat (Beecher et al, 1995) scales [but see also Beecher et al (1997)]. However, Williams (1997) and Jager & Pert (1997) criticized the work of Beecher et al (1995), on the grounds of methodological and statistical concerns. Conversely, although not explicitly deriving suitability curves, Armstrong et al (1998) found that Atlantic salmon parr studied at the pool-riffle scale remained in areas which were clearly highly unsuitable (i.e.…”

Section: Velocity Usecontrasting

confidence: 97%

“…Furthermore, methodological difficulties have been encountered (Beecher et al, 1995;Jager & Pert, 1997;Williams, 1997). Although the majority of workers have concluded that velocity preference varies with Q, the consequence for modelling habitat quantity has not been calculated.…”

Section: Introductionmentioning

confidence: 99%

Investigating a major assumption of predictive instream habitat models: is water velocity preference of juvenile Atlantic salmon independent of discharge?

Holm

¹

,

Armstrong

²

,

Gilvear

³

2001

Journal of Fish Biology

View full text Add to dashboard Cite

The mean column velocity preference of juvenile Atlantic salmon Salmo salar (L F 30-55 mm) was investigated by observing their spatial pattern of habitat use in a laboratory flume while varying discharge (Q) over a 18-fold range (Q=2·6-46·8 l s 1 ). Based on 341 fish observations at three discharges (Q=2·6, 15·0 and 46·8 l s 1 ), three separate velocity preference curves were developed using standard procedures. The mean column velocities measured at 0·6 depth for the fish positions at the set low, medium and high discharges had medians of 7, 10 and 24 cm s 1 , respectively, and varied significantly between the discharges. Across the range of flows, the fish utilized mean column velocities between 0 and 56 cm s 1 , but the three velocity preference curves differed. Differences between juvenile Atlantic salmon use of habitat, defined according to mean column velocities at different discharges, were greatest at the lower end of the available range of velocities (<20 cm s 1 ). Weighted usable area (WUA), the output of the instream flow model PHABSIM that is used to describe the available habitat at a given discharge, was calculated for the flume using the preference curves built at the three set discharges. The model was highly sensitive to differences between the three preference curves and WUA varied by up to a two-fold difference. Furthermore, habitat-discharge relationships derived from the three preference curves were very different. Predicted habitat losses across the modelled range of discharges varied by up to 150% depending upon which velocity preference curve was used in the model. Thus, the assumption that a single preference curve can be applied across a range of discharges is not valid and is likely to result in large errors when employing PHABSIM and other models that use similar principles.

show abstract

“…For example, investigations on microhabitat use by young fish have benefited from methods such as Point Abundance Sampling by Electrofishing (PASE: Copp and Penáz, 1988;Garner, 1997a;Cowx et al, 2001), whereas amongst IFN techniques, the Instream Flow Incremental Methodology (IFIM: Bovee et al, 1998) traditionally has been considered state-of-the-art, in spite of continuing criticism (e.g. Mathur et al, 1985Mathur et al, , 1986Shirvell, 1986Shirvell, , 1989Shirvell, , 1994Gan and McMahon, 1990;Castleberry et al, 1996;Williams, 1996Williams, , 1997Williams, , 1999Jager and Pert, 1997;Van Winkle et al, 1997;Kondolf et al, 2000). Mathur et al (1985, p. 827) pointed to some limitations of suitability curves, arguing that their shape 'can be highly dependent on the site, stream, and time of collection', and that this would result in large biases in calculation of Weighted Usable Areas (WUAs) (Mathur et al, 1986).…”

Section: Introductionmentioning

confidence: 99%

Assessing variation in suitability curves and electivity profiles in temporal studies of fish habitat use

Vilizzi

¹

,

Copp

²

,

Roussel³

2004

River Research & Apps

View full text Add to dashboard Cite

Under experimental conditions, we tested whether variations in preference curves, weighted usable areas, and electivity profiles for velocity of 0þ juvenile barbel Barbus barbus could be attributed to environmental variables (discharge, water depth, time of day) and/or time of sampling. We elaborated preference curves and weighted usable areas according to the Instream Flow Incremental Methodology, as well as electivity profiles. Variation among preference curves, weighted usable areas and electivity profiles was always observed, regardless of time of day, water depth, or discharge combinations. Our results support published concerns that the shape of preference curves is highly dependent on the time of data collection, and that curves derived from a single field sampling excursion can be viewed as representative for that moment in time only, whereas curves generated as composites from typological or time-series samples may provide an approximation for a study area, but at the expense of between-site and/or between-date variation. Spatial/temporal variation is an important aspect of fish habitat studies and should be incorporated as a (layered) component into descriptive/predictive models. To this end, we illustrate how a PCA-based technique and log-linear modelling can be used to assess temporal patterns in collections of preference curves and electivity profiles, respectively.

show abstract

“…Several studies have dealt with the effects of variations in discharge (Q) on velocity preference, or use, by salmonids, but remain difficult to interpret because of the interactions between Q and season (Heggenes & Saltveit, 1990;Rincón & Lobó n-Cerviá, 1993), or close links between velocity and mesohabitat (Greenberg, 1994). Furthermore, methodological difficulties have been encountered (Beecher et al, 1995;Jager & Pert, 1997;Williams, 1997). Although the majority of workers have concluded that velocity preference varies with Q, the consequence for modelling habitat quantity has not been calculated.…”

Section: Introductionmentioning

confidence: 99%

Investigating a major assumption of predictive instream habitat models: is water velocity preference of juvenile Atlantic salmon independent of discharge?

Holm

¹

2001

Journal of Fish Biology

View full text Add to dashboard Cite

The mean column velocity preference of juvenile Atlantic salmon Salmo salar (L F 30-55 mm) was investigated by observing their spatial pattern of habitat use in a laboratory flume while varying discharge (Q) over a 18-fold range (Q=2·6-46·8 l s 1 ). Based on 341 fish observations at three discharges (Q=2·6, 15·0 and 46·8 l s 1 ), three separate velocity preference curves were developed using standard procedures. The mean column velocities measured at 0·6 depth for the fish positions at the set low, medium and high discharges had medians of 7, 10 and 24 cm s 1 , respectively, and varied significantly between the discharges. Across the range of flows, the fish utilized mean column velocities between 0 and 56 cm s 1 , but the three velocity preference curves differed. Differences between juvenile Atlantic salmon use of habitat, defined according to mean column velocities at different discharges, were greatest at the lower end of the available range of velocities (<20 cm s 1 ). Weighted usable area (WUA), the output of the instream flow model PHABSIM that is used to describe the available habitat at a given discharge, was calculated for the flume using the preference curves built at the three set discharges. The model was highly sensitive to differences between the three preference curves and WUA varied by up to a two-fold difference. Furthermore, habitat-discharge relationships derived from the three preference curves were very different. Predicted habitat losses across the modelled range of discharges varied by up to 150% depending upon which velocity preference curve was used in the model. Thus, the assumption that a single preference curve can be applied across a range of discharges is not valid and is likely to result in large errors when employing PHABSIM and other models that use similar principles.

show abstract

Comment: Testing the Independence of Microhabitat Preferences and Flow (Part 1)

Cited by 5 publications

References 4 publications

Investigating a major assumption of predictive instream habitat models: is water velocity preference of juvenile Atlantic salmon independent of discharge?

Investigating a major assumption of predictive instream habitat models: is water velocity preference of juvenile Atlantic salmon independent of discharge?

Assessing variation in suitability curves and electivity profiles in temporal studies of fish habitat use

Investigating a major assumption of predictive instream habitat models: is water velocity preference of juvenile Atlantic salmon independent of discharge?

Contact Info

Product

Resources

About