Monitoring Changes in Freshwater Macroinvertebrate Communities Along a Salinity Gradient Using Artificial Substrates

Abstract

Scientists strive to develop efficient sampling protocols, reducing both the number of samples and processing time required, which can be adapted for use in a broad range of ecosystems. We investigated the accuracy and usefulness of artificial substrates in monitoring the impact of rising salinity on freshwater macroinvertebrate communities. We sampled seven sites along a salinity gradient (from 0.2gL(-1) to 2.6gL(-1)) over a 19-km stretch of the Meurthe River, in northeastern France. All other parameters remained stable in this section of the river. Artificial substrate samples, each consisting of six liters of pebbles, were removed from the river at one-month intervals and examined. Results obtained indicated the same qualitative impairments as those found in samples collected using a Surber net. The use of artificial substrates was found to be a viable alternative method for assessing biological changes in river quality due to increasing salinity disturbance when Surber sampling cannot be performed.

Impact of the Salinity Gradient on the Mollusc Fauna in Flooded Mine Subsidences (Karvina, Czech Republic)

“…According to these results, the optimum salinity for the species-rich malacocoenosis development is within the range of 200-1100 mg·l -1 . Piscart et al [38] suggested that the intermediate salinity levels may be conducive to both salt sensitive and salt tolerant species in accordance with the intermediate disturbance hypothesis of Connell [8]. This hypothesis assumes that in habitats with low salinity, salt tolerant species tend to be excluded from the competition.…”

“…The increasing salinity (as a concentration of dissolved inorganic ions, further referred to as TDS) in surface freshwater ecosystems is becoming a serious problem worldwide [38,52,21,22], including the Czech Republic, especially in post-industrial structures, such as fl ooded mine subsidences [25,43]. Salinity is also regarded as one of the most important environmental contamination types occurring in freshwater.…”

“…Although dissolved salts are natural components of freshwater and some aquatic systems have naturally high salinity levels the impact of excessive concentrations of dissolved salts derived from the human activity may have profound and measurable effects on freshwater aquatic ecosystems [15,50,19,21,31,13,14,27]. Human activities, such as removal of vegetation [51,40], irrigation, mining [45] and industrial discharges [36,37,38,39] may lead to a salinity increase.…”

Downward, upstream or downstream? Assessment of meio- and macrofaunal colonization patterns in a gravel-bed stream using artificial substrates

“…Stones were placed around and on top of each trap to avoid any displacement. Traps were left in situ for 36 days, which is considered an exposure time sufficient to allow the complete substrate colonization (Rosenberg and Resh, 1982;Piscart et al, 2006). After this period, traps were collected and their content was carefully sieved and washed, separating invertebrates from cobbles and organic debris; the rinse-out water was filtered with two nets (255 and 50 mm) in order to separate meiofauna from macrofauna.…”

Effects of salinity gradients on benthic invertebrate and diatom communities in a German lowland river

“…Salinity tolerance varies profoundly between species. While some species are known to be salt-tolerant, others react sensitively to increasing salinity levels sometimes even ending up in a decline or disappearance of the population (Williams and Williams, 1998;Piscart et al, 2006b). Accordingly, aquatic biota have been commonly classified by salinity preferences.…”