Two oceans, two taxa and one mode of development: latitudinal diversity patterns of South American crabs and test for possible causal processes

Abstract

The latitudinal gradient of species diversity is a widely recognized but poorly understood phenomenon. In marine systems, differences in dispersal abilities among species may pose an additional problem in identifying the processes that affect diversity. We compared latitudinal diversity gradients along two parallel continental coasts, the east and west coasts of South America, of two groups of Crustacea (Brachyura and Anomura), which exclusively exhibit planktonic development. We also evaluated the species-area and the energy-input hypotheses. Diversity decreased with increasing latitude for both groups in both oceans. Results suggest that the spatial structure of sea surface temperature (SST) explains diversity of both groups at large, but not small (< 5°), scales. Range size and latitude were not correlated. We hypothesize that SST differentially affects taxa with contrasting modes of development, influencing patterns of diversity. We suggest that developmental modes of marine organisms should be considered in future diversity analyses.

Species–energy relationships at the macroecological scale: a review of the mechanisms

“…Consequently, if high-energy areas are more extensive than low-energy ones, positive species-energy relationships may arise through the effects of area, rather than energy, on species richness. Area effects on species richness have been debated with reference to latitudinal species richness gradients, but without consensus (Rosenzweig & Sandlin, 1997 ;Rohde, 1997Rohde, , 1998Ruggiero, 1999;Hawkins & Porter, 2001 ;Astorga et al, 2003 ;Rosenzweig, 2003).…”

“…At the macro-scale (large plots, typically comprising hundreds of km 2 , spread throughout an entire geographical region) monotonically increasing species-energy relationships become more frequent and most authors conclude that they predominate (e.g. Currie, 1991 ;Wright, Currie & Maurer, 1993 ;Guegan, Lek & Oberdorff, 1998 ;Kerr, Vincent & Currie, 1998 ;Kerr & Packer, 1999 ;Waide et al, 1999;Gaston, 2000;Chase & Leibold, 2002;Astorga et al, 2003 ;Francis & Currie, 2003 ;Kaspari, Yuan & Alonso, 2003 ;Whittaker et al, 2003; but see Balmford et al, 2001;Mittelbach et al, 2001;Hawkins et al 2003).…”

Phenotypic covariance matrix in life-history traits along a latitudinal gradient: a study case in a geographically widespread crab on the coast of Chile

“…Interestingly, comparisons of matrices according to both methods are highly linked with the limits of the biogeographic province described for the coast of Chile (see Camus 2001, Astorga et al 2003, Thiel et al 2007). Thus, provinces share biotas, which are defined mainly by hydrographic characteristics (i.e.…”

Changing chain: past, present and future of the Scotia Arc's and Antarctica's shallow benthic communities

“…In gastropods (Roy et al, 1998) and bryozoans (Clarke and Lidgard, 2000) strong pole-ward declines have been established, but their data were restricted to particular northern coasts only. Recently complex but broadly poleward declines have been described in decapods around South America (Astorga et al 2003) and on North American coastlines (Boschi, 2000). A number of taxa, however, not only show no such decline in the southern hemisphere but even may have raised polar values.…”