Among-habitat and Temporal Variability of Selected Macroinvertebrate Based Metrics in a Mediterranean Shallow Lake (NW Spain)

Abstract

According to the European Water Framework Directive, waterbodies have to be classified on the basis of their ecological status using biological quality elements, such as macroinvertebrates. This needs to take into consideration the influence of natural variation (both spatial and temporal) of reference biological communities as this may obscure the effects caused by anthropogenic disturbance. We studied the influence of among-habitat and temporal (seasonal and interannual) changes on the macroinvertebrate communities of an Iberian shallow lake and the variability of 21 measures potentially useful for bioindication purposes. Two series of data were examined: (a) macroinvertebrate samples taken on four occasions over an annual cycle were used to assess the effects of seasonality and among-habitat variability; (b) macroinvertebrate samples collected in three consecutive summers were used to assess interannual variability. Coefficients of variation, expressed as percentage, were used to quantify the effect of among-habitat and temporal variability on the selected metrics. According to our results, % Insecta, Shannon-Wiener diversity index and the qualitative taxonomic metrics (measures based on number of taxa) were robust in terms of temporal (seasonal and interannual) and among-habitat variability. Abundance ratio and some metrics based on functional feeding groups were highly variable. Therefore, qualitative taxonomic metrics may be promising tools in biomonitoring programs of Mediterranean shallow lakes due to their comparatively low variability.

Relevance of abiotic criteria used in German lake typology for macroinvertebrate fauna

“…Sampling in different seasons and years may cause a different dominance structure in the benthic fauna and different frequencies of several species (e.g. White, 2001;Trigal et al, 2006). These findings are inconsistent with our data where sampling of alpine lakes, for example, occurred in spring, summer and fall, and furthermore in three different years.…”

Development and validation of a macroinvertebrate index of biotic integrity (IBI) for assessing urban impacts to Northern California freshwater wetlands

“…We sampled different microhabitats present in lentic habitats in proportion to their relative abundance because taxonomic groups show strong affinities to vegetation and sediment structure (e.g., Garcia-Criado and Trigal 2005;Trigal et al 2006). Sampling was focused throughout the wadeable littoral zone because that area was accessible by wading and contains the majority of species found in lentic habitats (GarciaCriado and Trigal 2005;Trigal et al 2006). The sampling area was classified into four habitat types prior to sampling: emergent vegetation (e.g., Typha spp., Scirpus spp., Eleocaris spp.…”

“…In order to limit the effects of seasonality (i.e., intra-annual variability), we restricted sampling to a specific index period, as is recommended for aquatic macroinvertebrate biomonitoring protocols in streams and wetlands (Barbour et al 1999;Trigal et al 2006). Sample dates of the main study were restricted to late spring and summer (May 10-July 13), at which time most macroinvertebrates captured would be large enough to identify, but most taxa would not have already emerged.…”

Adaptation, phenology and disturbance of macroinvertebrates in temporary water bodies

“…Turlough species diversity has been postulated to depend on availability of colonisers at times of flooding, but there is an absence of studies on seasonal progression of their invertebrate communities (Reynolds et al, 2004). This is a fundamental knowledge gap that limits discriminating impact of natural compared with anthropogenic pressure, for example from nutrient enrichment (Cunha Pereira et al, 2010), and which hinders management and monitoring (Linke et al, 1999;Trigal et al, 2006).…”