Hierarchical spatial structuring of stream insect diversity through DNA barcoding
Biodiversity is often studied in the context of species distributions across spatial scales. Diversity components analysis—the partitioning of total diversity into local diversity and distributional heterogeneity measures—assesses the spatial structure of biodiversity. While previous works have relied on morphological specimen identifications, here, DNA barcoding is coupled with additive diversity partitioning to assess stream larval Trichoptera (caddisfly) species diversity across spatial scales ranging from m2 to Canadian sub-arctic vs. temperate USA regions, and is used in conjunction with checkerboard analyses at a small spatial extent to investigate the importance of biotic interactions. I found that taxonomic resolution influenced the interpretation of results. In addition, Trichoptera diversity was similarly structured at two disparate regions, suggesting similar underlying mechanisms govern how regional diversity is distributed. Interspecific competition was important at small spatial scales. My thesis illustrates the utility of DNA-based species identification coupled with diversity partitioning in the study of biodiversity.