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Functional groups are non-phylogenetic, aggregated units of species sharing an important ecological characteristic and playing an equivalent role in the community (Cummins, 1974; Smith et al., 1997; Steneck, 2001; Blondel, 2003). In other words, Functional groups are defined as sets of species showing either similar responses to the environment or similar effects on major ecosystem processes (Gitay and Noble, 1997). In addition, FGs can be identified as clusters in trait space through multivariate statistics, without a priori of classifications regarding to particular responses to environment or influences on ecosystem processes (Hooper et al.,2002 ). Functional diversity refers to the range and value of organismal traits that influence ecosystem properties (Tilman 2001). This can be expressed in a variety of ways, including the number and relative abundance of functional groups (e.g. Tilman et al., 1997; Hooper, 1998), the variety of interactions with ecological processes (Martinez, 1996), or the average difference among species in functionally related traits (Walker et al., 1999).
A loss of biodiversity may, both directly and indirectly, affect ecosystem function and service (Chapin et al., 2000). As FGs provide a link between species diversity and ecosystem function (Grimm, 1995; Bengtsson, 1998; McCann, 2000). The FG approach can be applied to investigate and predict global environmental change impacts and feedbacks on ecosystem structure and function (Steffen et al., 1996; Diaz and Cabido, 1997; Woodward et al., 1997; Grime et al., 2000).
To a first approximation, FGs respond as a unified whole to their environment. As FGs are independent of any specific species composition they allow comparison to be made between different communities or communities at different stages of their development (Simberloff and Dayan, 1991; Tilman, 2001).
FG traits do not necessarily need to be taxonomic characteristics; although if connected to a particular morphological trait all members of a certain taxon tend to hold the same ecological function. FGs based on different form-of-feeding traits are differentially sensitive to environmental change and are potentially good indicator species.
The co-existence of species within a FG is only possible because of spatially and temporally different exploitation of food and environmental resources (Ritchie & Olff, 1999; Wilson, 1999; van der Putten et al., 2004); species within FGs exhibit interchange ability redundancy) (Blondel, 2003). If environmental conditions change, while species composition within FGs may alter the FG itself may persist. The more extreme the environmental change the fewer the number of common species present before and after the perturbation (-advantages of FGs, Voigt et al., 2007).
Improving our understanding of diversity–function relationships across ecosystems will require a categorization of species, or of species attributes, that can be related to function (Walker et al., 1999).
- Bengtsson J (1998) Which species? What kind of diversity? Which ecosystem function? Some problems in studies of relations between biodiversity and ecosystem function. Applied Soil Ecology, 10, 191–199
- Blondel J (2003) Guilds or functional groups: does it matter? Oikos, 100, 223–231.
- Chapin FS, Zavaleta ES, Eviner VT et al. (2000) Consequences of changing biodiversity. Nature, 405, 234–242.
- Cummins KW (1974) Structure and function of stream ecosystems. Bioscience, 24, 631–641
- Diaz S, Cabido M (1997) Plant functional types and ecosystem function in relation to global change. Journal of Vegetation Science, 8, 463–474
- Gitay H, Noble IR (1997) What are functional types and how should we seek them? In: Plant Functional Types (eds Smith TM, Shugart HH, Woodward FI), pp. 3–19. Cambridge University Press, Cambridge.
- Grime JP, Brown VK, Thompson K et al. (2000) The response of two contrasting limestone grasslands to simulated climate change. Science, 289, 762–765
- Grimm NB (1995) Why link species and ecosystems? A perspective from ecosystem ecology. In: Linking Species and Ecosystems (eds Jones CG, Lawton JH), pp. 5–15. Chapman & Hall, New York.
- McCann KS (2000) The diversity-stability debate. Nature, 405, 228–233
- Ritchie ME, Olff H (1999) Spatial scaling laws yield a synthetic theory of biodiversity. Nature, 400, 557–560
- Simberloff D, Dayan T (1991) The guild concept and the structure of ecological communities. Annual Review Ecology and Systematics, 22, 115–143
- Smith TM, Shugart HH, Woodward FI (eds) (1997) Plant Functional Types. Their Relevance to Ecosystem Properties and Global Change, 1st edn. Cambridge University Press, Cambridge.
- Steffen WL, Chapin FS III, Sala OE (1996) Global change and ecological complexity: an international research agenda. Trends in Ecology and Evolution, 11, 186
- Steneck RS (2001) Functional groups. In: Encyclopedia of Biodiversity, Vol. 3 (ed. Levin SA), pp. 121–139. Academic Press, San Diego.
- Tilman D (2001) Functional diversity. In: Encyclopedia of Biodiversity, Vol. 3 (ed. Levin SA), pp. 109–120. Academic Press, San Diego.
- Van der Putten WH, de Ruiter PC, Bezemer TM et al. (2004) Trophic interactions in a changing world. Basic and Applied Ecology, 5, 487–494.
- Voigt, W., Perner, J. and Jones, H. 2007. Using functional groups to investigate community response to environmental changes: two grassland case studies. Global Change Biology 13: 1710–1721
- Wilson JB (1999) Guilds, functional types and ecological groups. Oikos, 86, 507–522
- Woodward FI, Smith TM, Shugart HH (1997) Defining plant functional types: the end view. In: Plant Functional Types (eds Smith TM, Shugart HH, Woodward FI), pp. 355–359. Cambridge University Press, Cambridge.
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