Abstract

The species-area relationship (SAR) and the species-time relationship (STR) are two well-established macro-ecological patterns. Species richness has also been shown to follow a humped relationship with body size, suggesting that SAR and STR may also depend on body size. We test whether the pattern of increase in the number of species with time varies with species body size. We analyzed data on carnivorous and scavenger species collected in a shallow marine benthic megafauna community in Coliumo Bay, Chile. Body size data were tabulated into exponential body size classes using two binning strategies. Species-level binning represented all individuals of each species by their average body size. Individual-level binning tabulated all data into exponential body size classes, allowing species to potentially occupy multiple size classes. We determined empirical relationships between body size and species richness, as well as estimated temporal species accumulation curves (TSAC) and nested species-time relationships (NSTR). We also tested whether the increase of species richness within body size classes follows either a power-law relationship or a logarithmic function. We find that the number of species increases with the time span studied, both for a TSAC and in the NSTR, for both species-based and individual-based data, while also showing a unimodal relationship with body size for both species and individual-based data. Thus, the STR is a general pattern, which depends on body size, despite reproductive seasonal forcing and strong hypoxia disturbance in Coliumo Bay.