Macroinvertebrate instream flow studies after 20 years: a role in stream management and restoration

Abstract

Over the past two decades of refinement and application of instream flow evaluations, we have examined the hydraulic habitat of aquatic macroinvertebrates in a variety of conditions, along with the role of these macroinvertebrates in sustaining ecosystem integrity. Instream flow analyses assume that predictable changes in channel flow characteristics can, in turn, be used to predict the change in the density or distribution of lotic species or, more appropriately, the availability of useable habitat for those species. Five major hydraulic conditions most affect the distribution and ecological success of lotic biota: suspended load, bedload movement, and water column effects, such as turbulence, velocity profile, and substratum interactions (near-bed hydraulics). The interactions of these hydraulic conditions upon the morphology and behavior of the individual organisms govern the distribution of aquatic biota. Historically, management decisions employing the Physical Habitat Simulation (PHABSIM) have focused upon prediction of available habitat for life stages of target fish species. Regulatory agencies have rarely included evaluation of benthos for flow reservations. Although 'taxonomic discomfort' may be cited for the reluctant use or creation of benthic criteria, we suggest that a basic misunderstanding of the links between benthic macroinvertebrate and the fish communities is still a problem. This is derived from the lack of a perceived 'value' that can be assigned to macroinvertebrate species. With the exception of endangered mussel species (for which PHABSIM analysis is probably inappropriate), this is understandable. However, it appears that there is a greater ability to predict macroinvertebrate distribution (that is, a response to the change in habitat quality or location) and diversity without complex population models. Also, habitat suitability criteria for water quality indicator taxa (Ephemeroptera, Plecoptera, and Trichoptera; the so-called 'EPTs') may also provide additional management options to stream regulators. The greatest application for macroinvertebrate criteria will be in low-order streams where a more immediate link to fish communities can be established. We present an example from Queens Creek, in North Carolina, USA, in which monthly allocations required to preserve the integrity of the benthic macroinvertebrate community were significantly higher than for the target benthic fish species, Cottus bairdi. In the months when both Cottus and community diversity of macroinvertebrates were the 'bottleneck' life stages, preservation of only fish species could result in an additional 5-25% loss in macroinvertebrate habitat. We suggest that, as there becomes an increased emphasis on maintaining macroinvertebrates as monitors of stream health, there will be a concurrent emphasis on incorporating hydraulic habitat conditions as a part of bioassessment.

Effects of flow reduction and spillways on the composition and structure of benthic macroinvertebrate communities in a Brazilian river reach

“…In fact, they have properly applied instream flow incremental methodology (IFMI) for some fish groups (e.g. salmonids) (Dewson et al, 2007a), but its development and use for benthic macroinvertebrates have still been limited by restrictions in collection of adequate samples (large numbers), accurately taxonomic identification of species and construction of habitat suitability curves (Gore et al, 2001).…”

Meetprogramma Overijsselse Vecht : nulsituatie 2017 en effecten maatregelen

“…Habitatheterogeniteit is in tegenstelling tot wat vaak wordt aangenomen minder afhankelijk van korrelgrootteverdeling (o.a. Tolkamp 1980) maar veel meer van substraatdiversiteit (Beisel et al 1998, de stroomsnelheid in de lagere range van 10 tot 40 cm/s (Gore et al 2001), voedselkwaliteit (Allan & Castillo 2007) en de inrichting van de oeverzone (Petersen et al 2004). …”

Assessing ecological land use and water demand of river systems: a case study in Luanhe River, North China

“…And these suitability requirements can be defined by suitability curves of physical habitat parameters (Gore et al, 2001;Jowett and Richardson, 1990;Quinn and Hickey, 1990). Suitability curves are derived from a fit of some order polynomial to a plot of cumulative mean number of individuals of a taxon per sample as a function of an arbitrarily chosen increment of each physical habitat parameter (Gore and Judy, 1981;Gore et al, 2001). Substrate histograms can be plotted as the mean number of individuals of per substrate category and normalized to one, as described by Bovee (1986).…”