More complexity does not always mean more accuracy: the case of IBMWP and METI in NW Spain

Abstract

Since the Water Framework Directive (WFD) implementation, new biological indices based on macroinvertebrates have been developed, mainly focusing on multimetric approaches. This work checks the relationship among several biotic indices [Iberian Biological Monitoring Working Party (IBMWP), Indice Biotico Esteso, Indice Biologique Global Normalisé] and one multimetric index (METI) proposed for NW Spain rivers, and their behaviour using different physicochemical parameters throughout the different typologies defined for NW Spain rivers according to the WFD. It is also tested whether the reference sites and conditions established are representative enough of each typology comparing the IBMWP and METI in reference and non‐reference sampling sites. As a whole, the METI showed the lowest correlations with the rest of the indices, whereas the IBMWP showed the highest and all indices displayed negative correlations with those variables, which caused pollution in all typologies. Furthermore, it has been found sites with an index value higher than that of the reference sites and therefore in a better status than the selected reference sites, revealing several shortcomings in the selection of the reference sites in NW Spain and proving that a good selection of the reference sites is extremely important to produce successful results. Finally, the IBMWP has proved to be a useful tool to assess freshwater ecosystems in NW Spain showing how a simple index can be satisfactorily used to monitor ‘Ecological status’. Copyright © 2014 John Wiley & Sons, Ltd.

EFFECT OF PHOTOPERIODS MANIPULATION ON GROWTH AND SOME REPRODUCTIVE ACTIVITIES OF NILE TILAPIA (Oreochromis niloticus)

“…These results are in agreement with Use of photoperiod manipulation to alter the incidence of sexual maturation and the time of spawning has been reported for a number of species (Duston et al, 2003;Imsland et al, 2003). Mendoza et al (2014) found significantly larger eggs under normal day length (12 L: 12 D). However, (Ridha and Cruz, 2000) found that fish reared under long day length (18 L: 6 D) exhibited higher total fecundity and relative fecundity, with a reduction in inter-spawnintervals.…”

How do low-abundance taxa affect river biomonitoring? Exploring the response of different macroinvertebrate-based indices

“…The IBMWP index is a single metric index (Munné and Prat, 2009) and the sample value is obtained by summing these family scores. This index is considered a simple one (Couto-Mendoza et al, 2015) with a multihabitat semi-quantitative kick procedure in the field (Jáimez-Cuéllar et al, 2002). IASPT represents a sensitive taxa index that is easily calculated for each sample as the IBMWP value divided by the number of scoring families detected.…”

Taxonomic changes and non-native species: An overview of constraints and new challenges for macroinvertebrate-based indices calculation in river ecosystems

“…Similarly, the potential advantages of multimetric indices over single metric indices should also be considered; this topic has already been subject of debate in some instances (e.g. Couto-Mendoza et al, 2015). To avoid criticisms associated with scoring systems limited to faunal tolerances in relation to a single parameter (a common criticism of the BMWP approach which focuses on organic contamination), a multimetric approach would facilitate the assessment of multiple stressors (e.g., potentially including the presence and impacts of new invaders).…”