Ecological and community‐wide character displacement: the next generation

Abstract

Ecological character displacement, mostly seen as increased differences of size in sympatry between closely-related or similar species, is a focal hypothesis assuming that species too similar to one another could not coexist without diverging, owing to interspecific competition. Thus, ecological character displacement and community-wide character displacement (overdispersion in size of potential competitors within ecological guilds) were at the heart of the debate regarding the role of competition in structuring ecological communities. The debate has focused on the evidence presented in earlier studies and generated a new generation of rigorous, critical studies of communities. Character displacement research in the past two decades provides sound statistical support for the hypothesis in a wide variety of taxa, albeit with a phylogenetically skewed representation. A growing number of studies are strongly based in functional morphology, and some also demonstrate actual morphologically related resource partitioning. Phylogenetic models and experimental work have added to the scope and depth of earlier research, as have theoretical studies. However, many challenging ecological and evolutionary issues, regarding both selective forces (at the inter-and intraspecific level) and resultant patterns, remain to be addressed. Ecological character displacement and community-wide character displacement are here to stay as the focus of much exciting research.

Limiting similarity, species packing, and the shape of competition kernels

“…Apart from the extinction and invasion of species, there can be evolutionary changes of the traits in a community, for instance, in the form of character displacement (Dayan and Simberloff, 2005), and this topic has often been brought up in discussions of species packing. Concerning the effects of competition kernel shape on character displacement, one might expect that strong clustering tendencies of a kernel, in the sense of a pronounced minimum of its Fourier transform, select more strongly for divergence between species.…”

“…Theoretical studies of community evolution under asymmetric competition point to an important distinction compared with symmetric competition (Taper and Case, 1992;Law et al, 1997). Asymmetric competition can promote continual change in a community, for instance in the form of taxon cycles (Taper and Case, 1992;Dayan and Simberloff, 2005;Dieckmann et al, 2007). In spite of such basic differences between symmetric and asymmetric competition, questions of species clustering and typical sizes of gaps in species distributions may have similar answers for the two types of communities.…”

Bergmann’s rule for Neomys fodiens in the middle of the distribution range

“…According to [25], morphological differences should reflect differences in resource use, mainly relating to the efficiency of food gathering and processing. The role of resources was also considered by [19].…”

Using phylogenetic trees to test for character displacement: a model and an example from a desert mammal community

“…However, this burgeoning field has developed, for the most part, independently from the large body of work that has focused upon ecological character displacement and the evidence for evolutionary divergence among interacting species (Dayan and Simberloff 2005; but see Davies et al 2007). In addition, the influence of phylogeny on the expected distribution of traits of cooccurring species has been largely overlooked in the literature on character displacement (but see Winkler 1984, andCumming andHavlicek 2002).…”

“…In particular, much effort has been invested in exploring evidence for limiting similarity in the distribution of traits among community members (Brown and Wilson 1956, Hutchinson 1959, Cody and Diamond 1975. Community-wide character displacement (here defined as even dispersion in ecological traits among community members through species sorting) and ecological character displacement (here defined as evolutionary divergence in ecological traits between interacting species) may be widespread (Dayan and Simberloff 2005), and have been interpreted as evidence for competition (Brown and Wilson 1956, Hutchinson 1959, Grant 1972. Traditionally, ecological character displacement is assessed by contrasting sympatric and allopatric populations of putatively competing species (but see Schluter and McPhail 1992).…”