PARENT SESSION
Oral Session # 1: Ecological Theory I: Theory; Scaling.
Presiding: M Pascual
Monday, August 4. 8:00 AM to 11:30 AM, SITCC Meeting Room 100.

Indo-Pacific coral reefs and the neutral theory: A multi-scale comparison.

Dornelas, Maria^*,1, Connolly, Sean¹, Hughes, Terrence¹, ¹ Centre for Coral Reef Biodiversity, Townsville, QLD, AUSTRALIA

ABSTRACT- The neutral theory aims to explain patterns of biodiversity and community structure, and makes specific predictions about how species abundance distributions should vary across spatial scales. It has been proposed that coral assemblages are well described by the neutral theory. This study compares species abundance distributions generated by the neutral model to coral data over three spatial scales (site, island and region), for three reef habitats (flat, crest and slope), and five regions across the Indo-Pacific biodiversity gradient. The model′s parameters (the fundamental biodiversity number and immigration rate) are estimated by maximum likelihood fits to coral species abundance distributions. In contrast to the theory′s predictions, the shape of the species abundance distribution is almost invariant across spatial scales. At the reef crest and slope the distribution is log-series like, but at the reef flat it is frequently bimodal. Estimates of the fundamental biodiversity number, for the five metacommunities, vary predictably across the biodiversity gradient. Estimates of immigration rate for the local communities are orders of magnitude greater than published estimates from population genetic studies. These data suggest that the neutral theory, at this stage, is inconsistent with observed patterns in coral assemblages.

Key words: neutral theory, coral reefs, species abundance distribution , macro-ecology