Functional traits in phytoplankton ecology

The term “trait” appeared very early in the biological literature and has been used as a proxy of organismal performance (Darwin 1859). Recently the traits are defined as morphological, physiological, phenological characteristics that can be measured or identified at the individual level (Violle et al. 2007). The recognition that the selection which determines the composition of the assemblages acts on traits rather than on species inspired the development of the trait-based approaches in the ecology. The approach became widespread in each level of biological organization, from individuals to ecosystems, and helped the understanding of the functioning of the systems.

In the common parlance of phytoplankton ecologists the term “trait” appeared only in the recent years, but in fact, the use of traits was always present in the phytoplankton studies. When relative abundance of heterocytic blue-greens, flagellated or vacuolated algae were contrasted with that of the other groups, performance of traits were compared. This however is not evident because in several cases taxonomic groups are compared in the studies, however, these groups might represent traits or trait combinations. Litchman and Klausmeier (2008) provided a conceptual framework that illustrates the nexus between various types of algal traits and their ecological function. This study was a great step towards the trait-based approaches. However in phytoplankton ecology, approaches, that are based on functional groups (FGs) had considerable attention in the recent years. In Reynolds’s system (Reynolds et al. 2002) the emphasis has been put on the habitat requirements of the taxa, thus species with different morphological properties could be assigned to the functional groups. In other proposals (Salmaso and Padisák 2007; Kruk et al. 2010) the groups were created by combination of morphological and physiological traits. Despite creation of the groups was different all three approaches were used successfully both in theoretical and practical studies. Partly this is the reason why the “classical” trait-based approaches received less attention in phytoplankton ecological studies.

The recent development in plant and animal community ecology was largely due to the widespread use of trait-based approaches, therefore the organizers would like to ask the potential participants to focus on these approaches, and to place their results in functional context. The aim of the 19th IAP meeting will be to enhance the communication among experts of each functional approach, and provide an elementary basis for combining the “group” and “trait” approaches for the development of phytoplankton ecology.

The organizers ask potential participants to focus primarily (i) on the “trait-based” functional approach in general, and (ii) on the combination of different functional approaches, especially of the functional group and the trait-based concepts. To avoid ambiguous definitions that are frequently found in the literature we listed some that might help the orientation of the participants.

  • Functional traits are defined as those components of an organism’s phenotype that determine its effect on ecosystem processes (Petchey and Gaston, 2006).
  • Functional traits are defined as the characteristics of an organism that determine its performance in response to the environment and/or its effects on ecosystem functioning (Bulleri et al., 2008).
  • Traits are defined here as species characters that are quantifiable. There are obviously a large number of potentially relevant traits for a given ecosystem process that are measured on a mixture of scales (binary, nominal, ordinal, and quantitative) (Ricotta and Moretti, 2011).
  • …, we suggest that traits be used at the level of the individual only, with the following definition: a trait is any morphological, physiological or phenological feature measurable at the individual level, from the cell to the whole-organism level, without reference to the environment or any other level of organization (Violle et al., 2007).


Although IAP meetings are considered as forums where phytoplankton ecologists share their new results and ideas with their colleagues, experts dealing with trait-based approaches in benthic algal assemblages are also welcome to join the symposium.


Bulleri, F., Bruno, J.F. and Benedetti-Cecchi, L., 2008. Beyond competition: incorporating positive interactions between species to predict ecosystem invasibility. PLoS biology, 6(6), p.e162.

Darwin, C., 1859. On the origin of species,

Kruk C., Peeters E.T.H.M., Van Nes E.H., Huszar V.L.M., Costa L.S. & Scheffer  M. (2011) Phytoplankton community composition can be predicted best in terms of morphological groups. Limnology & Oceanography, 56, 110-118.

Petchey, O. L., and K. J. Gaston. 2006. Functional diversity: back to basics and looking forward. Ecology Letters 9:741-758.

Reynolds C.S., Huszar V., Kruk C., Naselli-Flores L. & Melo S. (2002) Towards a functional classification of the freshwater phytoplankton. Journal of Plankton Research, 24, 417-428.

Ricotta, C. and Moretti, M., 2011. CWM and Rao’s quadratic diversity: a unified framework for functional ecology. Oecologia, 167(1), pp.181-188.

Salmaso N. & Padisák J. (2007) Morpho-Functional Groups and phytoplankton development in two deep lakes (Lake Garda, Italy and Lake Stechlin, Germany). Hydrobiologia, 578, 97-112.

Violle C., Navas M.-L., Vile D., Kazakou E., Fortunel C., Hummel I. & Garnier E. (2007) Let the concept of trait be functional! Oikos, 116, 882-892.


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