The species–area relationship (SAR) is the oldest and most frequently documented law in ecology. In a community, the SAR is regulated by the abiotic environment and biotic interactions and depends on the individual–spatial distribution of species (ISD) and the species–abundance
distribution (SAD). In this study, we explored the effects of aggregation of ISDs and unevenness of SADs on SARs in forests of China by comparing the empirical and simulated SARs of 32 nested plots distributed along an extensive latitudinal gradient. Both aggregation and unevenness affected
the shape of SARs significantly: ISDs accounted for 12.6 ± 4.0% of the incremental increase in species richness with area, and SADs accounted for 18.7 ± 3.8 and 23.5 ± 3.9% under the broken‐stick model and even abundance model, respectively. Effects of both aggregation
and unevenness decreased as temperature increased, suggesting that individuals of a species were spatially more aggregated than random, and the individuals among species were more discrepant from the null distribution (broken‐stick model and even abundance model in this study), in the
cold than in the warm areas. Taken together, our results demonstrate that ISDs and SADs within communities can shape SARs, but these effects vary along latitudinal gradients, and are likely mediated by temperature.
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Document Type: Research Article
Dept of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking Univ., Beijing 100871, China.
December 1, 2012