Tuesday, August 3, 2010: 4:40 PM
408, David L Lawrence Convention Center
Background/Question/Methods Patterns of global scale diversity for soil animals are not well known, especially for mesofaunal and microfaunal metazoans. It is hypothesized that latitudinal gradients determined the distribution of soil animal biodiversity. We assessed the biodiversity of soil animal communities in twelve global sites, distributed from Pole to Pole. Sites included: grasslands (Kenya, Kansas), mediterranean ecosystem (South Africa), boreal forests and tundra (Alaska, Sweden), tropical forests (Costa Rica, Peru), temperate forest (New Zealand), shrub steppe (Argentina), and cold desert (Antarctica). At each site a 900m transect was established comprised of 4 evenly spaced plots (10 x10 m). Twenty soil cores were combined from each plot. DNA was extracted from the soil samples of each plot and 18S rDNA amplified with metazoan-specific primers. The PCR products were cloned into libraries and individual clones sequenced. Sequences were compiled into OTUs (operational taxonomic units) using a 99% match criterion and OTUs were identified provisionally by BLAST searching. Biodiversity was analyzed using rarefaction curves and communities at each site were compared by multivariate analysis of species (OTUs) compositions.
Results/Conclusions We obtained 18271 sequences for animals from the twelve sites. Sequences were assigned to 2286 OTUs based on 99% minimum matching percentage. The highest soil faunal diversity was observed in samples from Kenya grassland, Kansas tallgrass, and Swedish tundra sites; whereas, the lowest diversity was observed among the samples of Argentina shrub steppe and Antarctica cold desert. Our molecular approach provided information on endemic and cosmopolitan faunal species at the 12 sites. None of the 2286 OTUs were present at all sites, only 1 OTU was common to 8 sites and 5 OTUs were common to 6 sites. Most of the OTUs (78%) were represented by a single sequence and we estimate that 95% of the OTUs represent endemic “species” within our samples. We also compared diversity and community structure among samples from the different sites. The soil faunal composition under different ecosystems using molecular profiling indicates that soil animal diversity does not follow a latitudinal gradient and provides key information about global-scale patterns of diversity for the entire soil animal community.
Results/Conclusions We obtained 18271 sequences for animals from the twelve sites. Sequences were assigned to 2286 OTUs based on 99% minimum matching percentage. The highest soil faunal diversity was observed in samples from Kenya grassland, Kansas tallgrass, and Swedish tundra sites; whereas, the lowest diversity was observed among the samples of Argentina shrub steppe and Antarctica cold desert. Our molecular approach provided information on endemic and cosmopolitan faunal species at the 12 sites. None of the 2286 OTUs were present at all sites, only 1 OTU was common to 8 sites and 5 OTUs were common to 6 sites. Most of the OTUs (78%) were represented by a single sequence and we estimate that 95% of the OTUs represent endemic “species” within our samples. We also compared diversity and community structure among samples from the different sites. The soil faunal composition under different ecosystems using molecular profiling indicates that soil animal diversity does not follow a latitudinal gradient and provides key information about global-scale patterns of diversity for the entire soil animal community.
