The performance of trait-based indices in an estuarine environment

Abstract

The performance of several indices of benthic functioning, based on the traits of estuarine macroinvertebrates, was tested in the lower Mondego estuary (Portugal), whose two arms exhibit different disturbance levels related to hydromorphology. The results showed that some indices responded clearly to this type of disturbance and others not so well. We argue that the communityweighted mean (CWM) trait values in combination with the newly developed SR-FRED index provided the best overall picture of how the benthic communities might have been affected by hydromorphological disturbance. This study also showed that certain indices should be used with caution when dealing with communities with few and dominant species, such as in estuarine environments.

Environmental drivers of taxonomic, functional and phylogenetic diversity (alpha, beta and gamma components) in estuarine fish communities

“…| 409 preference and position in the water column. These traits are commonly used to reflect the ecological functions of species in estuaries, focusing on key elements determining species habitat preference and their position in the food web Henriques et al, 2017;van der Linden et al, 2016 Fish attributes were described at the most common life stage encountered in estuaries because these systems generally include large proportion of young fish using estuaries as nursery areas (Potter et al, 2015). The pairwise functional distances between species were then computed using the Gower distance and used to calculate functional diversity (De Bello et al, 2010).…”

Spatial and temporal response of multiple trait-based indices to natural- and anthropogenic seafloor disturbance (effluents)

“…The performance of Rao was also similar to that of genus richness and the Simpson index (strongly correlated). This reflects the relationship between species richness and trait (functional) diversity in that with the loss or addition of a species, unique traits were being lost or added to the community (Culhane et al, 2014;van der Linden et al, 2016). Most studies found a strong correlation between Rao and Simpson (e.g.…”

“…Most studies found a strong correlation between Rao and Simpson (e.g. Vandewalle et al, 2010;Culhane et al, 2014;van der Linden et al, 2016).…”

The Arctic Traits Database – a repository of Arctic benthic invertebrate traits

“…Reasons for the increasing popularity of these approaches are that they offer a variety of additional options to solely species-based methods: traits can be analyzed across wide geographical ranges and across species pools (Bernhardt-Römermann et al, 2011), and they can be used to calculate a variety of functional diversity indices (Schleuter et al, 2010), to estimate functional redundancy (Darr et al, 2014) or as indicators of ecosystem functioning (Bremner et al, 2006). Given the rapid changes we observe in many marine regions of the world, and especially in the Arctic Ocean (Wassmann et al, 2011), the potential to indicate vulnerability to climate change and biodiversity loss or to estimate climate change effects on ecosystem functions is another inherent advantage of trait-based approaches (Foden et al, 2013;Hewitt et al, 2016).…”