Development of a benthic macroinvertebrate flow sensitivity index for Canadian rivers

Abstract

Widespread alteration of flow regimes requires guidelines for the protection of river ecosystems based on sound science. Preservation of the biodiversity within river ecosystems and sustaining natural ecological functions are key aspects of their management. However, the relationship between the biota and flow-related phenomena is poorly understood and, as a consequence, over-simplistic hydrologybased guidelines for river management have been adopted without establishing clear indicators of success. In the present paper, we aim to support the improvement of guidelines for flow (current velocity) management by developing a flow sensitivity index based on macroinvertebrates for Canadian rivers. Using benthic macroinvertebrate (BMI) samples collected by the Canadian Aquatic Biomonitoring Network (CABIN), current velocity preferences for the 55 most common invertebrate taxa across a range of reference and potential reference sites were derived. A Canadian Ecological Flow Index (CEFI) was developed based on these preferences. By testing the index against independent data, CEFI was found to respond mainly to changes in hydraulic conditions, and was minimally influenced by confounding factors (e.g. stream type, organic enrichment). The index was further validated using two independent data sets from the west and east of Canada, suggesting countrywide applicability of the method. In conclusion, we have developed a practical approach to evaluate relationships between hydrological regime and an important component of the river biota, permitting the development of an index which has good potential as an indicator for the effects of flow alteration. Moreover, we outline how the CEFI could be used as a tool for the development of holistic guidelines for the estimation of riverine flow needs.

Multivariate Modelling of Water Temperature in the Okanagan Watershed

“…One of the key outcomes of the NAESI program was to provide practical tools that can assist in evaluating potential impacts of agriculture on water quality and quantity. Under the NAESI Water Theme, the ecological instream flow needs (IFN) sub-component was an integral part of such an agri-environmental assessment (i.e., Armanini et al, 2010). IFN assessments should not be strictly based on the quantity of habitat available, but should also include alterations of habitat quality.…”

Cold-regions Hydrological Indicators of Change (CHIC) for ecological flow needs assessment

“…In combination with the Range of Variability Approach (RVA; see Richter et al 1997, for details), we consider that CHIC and RVA used together can support first-tier EFN assessments in Canada, as recently proposed by Peters et al (2012a), as they provide a "hydrological standard" and offer an approach focused on protection of the whole ecosystem when combined with an "ecological performance indicator". Given that cold-regions hydro-ecology is still a developing science, an important next step will be to explore the response of the macroinvertebrate community composition (Canadian Aquatic Biomonitoring Network; CABIN database) as quantified through the Canadian Ecological Flow Index (CEFI; Armanini et al 2011Armanini et al , 2012 to the CHIC variables, thus providing a basis for hypothesis development and testing. The CEFI summarizes the flow sensitivity preferences across the sampled macroinvertebrate community and is incorporated in the EFN framework as the ecological performance indicator (Armanini et al 2011, Peters et al 2012a.…”

“…Given that cold-regions hydro-ecology is still a developing science, an important next step will be to explore the response of the macroinvertebrate community composition (Canadian Aquatic Biomonitoring Network; CABIN database) as quantified through the Canadian Ecological Flow Index (CEFI; Armanini et al 2011Armanini et al , 2012 to the CHIC variables, thus providing a basis for hypothesis development and testing. The CEFI summarizes the flow sensitivity preferences across the sampled macroinvertebrate community and is incorporated in the EFN framework as the ecological performance indicator (Armanini et al 2011, Peters et al 2012a.…”

“…Through an exploration of flow-ecology relationships, numerous studies have demonstrated that several of these hydrological variables can explain observed ecological variability in riverine communities (e.g. Monk et al 2006, Monk and Wood 2008, Armanini et al 2011. Hydroecological variables, such as the IHA, typically quantify five facets of the hydrological regime: the magnitude, frequency, timing, duration and rate of change of events.…”

The hydro-morphological index of diversity: a tool for describing habitat heterogeneity in river engineering projects

“…Hence, the impacts of habitat degradation on river biota are receiving increasing attention (Vaughan et al, 2009;Armanini et al, 2010;Dunbar et al, 2010), whereas the majority of river restoration projects are conducted under the assumption that restoring physical habitat will increase biodiversity (Miller et al, 2009). However, the knowledge for the planning of hydromorphological measures in an appropriate way to enhance the ecological potential of a stream reach still offers large room for improvement.…”