Functional classifications and their application in phytoplankton ecology

Abstract

SUMMARY1. Ecologists often group organisms based on similar biological traits or on taxonomic criteria. However, the use of taxonomy in ecology has many drawbacks because taxa may include species with very different ecological adaptations. Further, similar characters may evolve independently in different lineages. 2. In this review, we examine the main criteria that have been used in the identification of nine modes of classifying phytoplankton non-taxonomically. These approaches are based purely on morphological and/or structural traits, or on more complex combinations including physiological and ecological features. 3. Different functional approaches have proved able to explain some fraction of the variance observed in the spatial and temporal distribution patterns of algal assemblages, although their effectiveness varies greatly, depending on the number and characteristics of functional traits used. The attribution of functional traits to single species or broad groups of species has allowed a few classifications (e.g. Functional Groups, FG) to be used in the assessment of ecological status. 4. We stress that the misuse of functional classifications (by applying them under conditions other than those intended) can have serious consequences for interpreting ecological processes. Assigning functional traits or groups cannot be considered a surrogate for the knowledge of species or ecotypes, and the use of specific traits must always be justified and circumscribed within the limits of ecological questions and hypotheses. 5. An important future challenge will be to integrate advances in molecular genetics, metabolomics and physiology with more conventional traits; this will form the basis of the next generation of functional classifications.

Spatial heterogeneity and seasonal succession of phytoplankton functional groups along the vertical gradient in a mesotrophic reservoir

“…Phytoplankton morphological variability can thus supply important information on the ecological conditions (nutrient and light availability) of a given water body (Naselli-Flores, 2014). Moreover, the FGs approach (Reynolds et al, 2002;Padisa´k et al, 2009), based on the physiological, morphological and ecological attributes of the species, has been proved to be an efficient way to analyze seasonal changes in phytoplankton dynamics (Salmaso et al, 2015). The functional classification approach has been successfully applied in reservoirs (e.g., Crossetti and Bicudo, 2008;Becker et al, 2010;Rychteckyá nd Znachor, 2011) and can reveal the ecological status of aquatic ecosystems independently from their geographic location (Padisa´k et al, 2006).…”

Blowing in the wind: how many roads can a phytoplanktont walk down? A synthesis on phytoplankton biogeography and spatial processes

“…As demonstrated for other microorganisms (Heger et al, 2013), DNA taxonomy is a very promising tool to unravel the puzzle of distribution and diversity of phytoplankton species and strains (for the role of different ''cryptic adaptive traits'' found in different phytoplankton strains see Salmaso et al, 2015). However, as with all tools, it has to be used in a proper way (see Fontaneto et al, 2015) and the reliability of the results achieved by these new molecular methods still needs to be carefully checked and assessed (e.g., Morgan et al, 2014).…”

Morphology-based classification of functional groups for potamoplankton

“…Rivers are as important as lakes for water management (Wehr and Descy, 1998). MBFG is a potentially suitable tool for riverine study, but its misuse can have serious consequences for interpreting ecological processes (Salmaso et al, 2014). Thus a special version of MBFG for potamoplankton is required and the development of such a version would be meaningful.…”