Congruence of community structure between taxonomic identification and T-RFLP analyses in free-living soil nematodes

Molecular-based methods of community analysis are becoming a popular alternative to the traditional, highly specialized, and time-consuming taxonomic identifications especially for morphologically challenging groups like free-living soil nematodes. In particular, terminal restriction fragment length polymorphism (T-RFLP) analysis has become popular as a quick and efficient tool to provide researchers with broad-scale assessments of community structure. The majority of studies comparing T-RFLP with morphological-based assessments have used cultured or previously characterized communities. Here we compare morphological identification to T-RFLP analyses in a previously unexplored system for nematode diversity, the boreal forest of Ontario, Canada. Samples were collected from five silvicultural treatments over two sampling seasons with nematodes extracted using the Baermann funnel technique. We found significantly greater richness from T-RFLP analyses than morphological identifications at both sampling times, but in both cases silvicultural treatment had no effect. Despite differences in taxonomic richness, community compositional similarities were highly correlated between morphological and molecular methods for both sampling times. We suggest that both methods are reliable in studies of previously undescribed communities where the goal is community assessment under treatment.