Reliability analysis of fish traits reveals discrepancies among databases

Abstract

Trait‐based approaches are commonly used in ecology to understand the relationship between biodiversity and ecosystem functioning, environmental filtering or biotic responses to anthropogenic perturbations. However, little is known about the reliability of assigned traits and the consistency of trait information among different databases currently in use. Using 99 native and alien Iberian inland fish species, we investigated a total of 27 biological and ecological traits for their consistency among 19 different databases and identified less reliable traits, that is, traits with high disagreement among databases. Specifically, we used generalised linear models and inter‐rater reliability statistics (Krippendorff's α) to test for differences in trait values among databases. We also identified well‐studied versus data‐deficient traits and species. Our results show notable discrepancies and low reliability for several biological and ecological traits such as microhabitat preference, omnivory, invertivory, rheophily, and limnophily. Least reliable traits were mainly categorical (rather than continuous) and established by expert judgment and without a clear definition or a common methodology. Interestingly, categorical traits such as rheophily or limnophily, which showed significantly lower reliability, concurrently showed higher data availability and use than continuously scaled traits. Such uncertainties in trait assignments could affect bioassessment and other ecological analyses. Species with smaller distributional ranges and those that have been described more recently, presented lower coverage and data availability in trait databases. We encourage further standardisation of fish trait measurement protocols to help improve the robust application of bioassessment indices and trait‐based approaches.

Key factors explaining critical swimming speed in freshwater fish: a review and statistical analysis for Iberian species

“…By contrast, native species, mostly cypriniforms, are considered more adapted to lotic habitats with naturally more fluctuating flow regimes and, in particular, with frequent occurrence of high-flow events 23 , 94 – 96 . However, several invasive species that are often classified as limnophilic 97 showed relatively high swimming capacities (e.g. zander, northern pike [ Esox lucius ], common bleak [ Alburnus alburnus ]).…”

“…Moreover, issues of data availability also affected the selection of predictors. For example, we were not able to analyze the effect of some variables like fish weight, which is often not provided in swimming performance studies, or habitat preference which is often rather unclear for the endemic species of the Iberian Peninsula 97 .…”

A workflow for standardising and integrating alien species distribution data

“…This clearly shows that not only does the merging of individual databases have to be standardised as proposed here, but the integration of primary data from the original sources needs to be done in a more reproducible and transparent way as well (Vanderhoeven et al 2017;Pagad et al 2018). Our case study also highlights that the SInAS workflow and the associated scripts could be used to assess the reliability of different databases and their components (e.g., Cano-Barbacil et al 2020) and to identify potential areas of improvement for the respective databases.…”

OUP accepted manuscript

“…The articles are grouped into five categories: basic biology ( n = 80), aquaculture ( n = 61), climate change ( n = 36), invasive species ( n = 9) and fisheries management ( n = 7). This assessment demonstrates that the potential applications of this project, as expected in 2007, go well beyond aquaculture and that many researchers are looking for open-access data ( 12 , 16 ). In addition, three of the four articles using the data in STOREFISH were much more cited than the original publication, which partly explains the reluctance of data holders to make data available because of the lack of proper citation ( 16 ).…”

“…Trait-based approaches first require gathering data on several traits, which could be defined as measurable ecological, life history, morphological, physiological and behavioural expressions of species’ adaptations to their environment ( 11 ). Cano-Barbacil et al ( 12 ) recognized two types of traits (1): biological traits describing life cycle, physiological and/or behavioural characteristics including maximum body size, longevity, or feeding and reproductive strategies and (2) ecological traits or requirements that are linked to habitat preferences, water flow, pollution or temperature tolerances ( 12 ). This essential step is time-consuming and usually considered tedious and tricky to perform because no efficient automatic system exists ( 17–19 ).…”