Which trait dissimilarity for functional diversity: traitmeans or trait overlap?

View/ Open
Issue date
2013Suggested citation
de Bello, Francesco;
Carmona, Carlos P.;
Sebastià, Ma. T.;
Leps, Jan;
Mason, Norman W. H.;
.
(2013)
.
Which trait dissimilarity for functional diversity: traitmeans or trait overlap?.
Journal of Vegetation Science, 2013, vol. 24, núm. 5.
https://doi.org/10.1111/jvs.12008.
Metadata
Show full item recordAbstract
Question: Many functional diversity indices require the calculation of functional
trait dissimilarities between species. However, very little is known about
how the dissimilarity measure used might affect conclusions about ecological
processes drawn from functional diversity.
Methods: We simulated real applications of functional diversity, to illustrate
the key properties of the two most common families of dissimilarity measures:
(1) ‘Gower’ distance, using only ‘mean trait’ value per species and then standardizing
each trait, e.g. relative to its range; (2) ‘trait overlap’ between species,
which takes into account within-species trait variability.We then examine how
these approaches could affect conclusions about ecological processes commonly
assessed with functional diversity. We also propose a new R function (‘trova’,
i.e. TRait OVerlAp) which performs computations to estimate species trait
dissimilaritywith different types of data.
Results: The trait overlap approach generally produces a less context-dependentmeasure
of functional dissimilarity. For example, the results are less dependent
on the transformation of trait data (often required in empirical datasets)
and on the particular pool of species considered (i.e. trait range, regularity and
presence of outliers). The results therefore could bemore easily compared across
studies and biomes. Further, trait overlap more reliably reproduces patterns
expected when niche differentiation structures communities. The Gower
approach, on the contrary,more reliably detects environmental filtering effects.
Conclusion: The two approaches imply different conceptions of how species
dissimilarities relate to niche differentiation. Trait overlap is suitable for testing
the effect of species interactions on functional diversity within local communities,
especiallywhen relatively small differences in species traits are linked to different
resource acquisition. Gower is better suited to detecting changes in
functional diversity along environmental gradients, as greater differences in trait
values reflect increased niche differentiation. Combining trait overlap and Gower
approachesmay provide a novel way to assess the joint effects of environmental
filtering and niche complementarity on community assembly. We suggest
that attention should be given not only to the index of functional diversity
considered but also whether the dissimilarity used is appropriate for the study
context.
Is part of
Journal of Vegetation Science, 2013, vol. 24, núm. 5European research projects
Collections
Related items
Showing items related by title, author, creator and subject.
-
Partitioning of functional diversity reveals the scale and extent of trait convergence and divergence
de Bello, Francesco; Wilfried, Thuiller; Jan, Leps; Choler, Philippe; Clément, Jean-Christophe; Macek, Petr; Lavorel, Sandra; Sebastià, Ma. T. (Wiley, 2009)Questions: Trait differentiation among species occurs at different spatial scales within a region. How does the partitioning of functional diversity help to identify different community assembly mechanisms? Location: ... -
Functional Trait Changes, Productivity Shifts and Vegetation Stability in Mountain Grasslands during a Short-Term Warming
Debouk, Haifa; de Bello, Francesco; Sebastià, Ma. T. (Public Library of Science, 2015-10-29)Plant functional traits underlie vegetation responses to environmental changes such as global warming, and consequently influence ecosystem processes. While most of the existing studies focus on the effect of warming only ... -
Functional Trait Changes, Productivity Shifts and Vegetation Stability in Mountain Grasslands during a Short-Term Warming [Research data]
Debouk, Haifa; de Bello, Francesco; Sebastià, Ma. T. (Universitat de Lleida, 2015)Plant functional traits underlie vegetation responses to environmental changes such as global warming, and consequently influence ecosystem processes. While most of the existing studies focus on the effect of warming only ...