Preston Bolen
Research Mentor: Alain Isabwe
Mentor Department: Cooperative Institute for Great Lakes Research, SNRE
Author(s): Preston Bolen, Benjamin Pecci, Alain Isabwe
Session: Session 1 (9:00 AM – 9:50 AM)
Presentation Type: Poster 54
Abstract
Although the latitudinal diversity gradient (LDG) is widely documented across terrestrial and marine ecosystems, its strength and uniformity in freshwater ecosystems worldwide remain less resolved. The LDG hypothesis describes the pattern in which species biodiversity increases toward lower latitudes, with peak richness near the equator. Using pre-existing collections of freshwater organism DNA sampled across multiple geographic regions, we analyzed biodiversity patterns across a global latitudinal gradient. We compiled sequence data from large nucleotide databases and standardized datasets to ensure comparability across sampling locations and taxonomic groups. Using R programming, we quantified species richness and assessed statistical relationships between latitude and biodiversity metrics. Contrary to classical LDG expectations, our results reveal a reverse LDG, with both richness and Shannon diversity increasing toward higher latitudes. Arctic and subarctic lakes exhibited the highest diversity, while subtropical lakes showed markedly lower richness, likely reflecting environmental constraints. Our findings suggest that freshwater microbial communities do not conform to macroecological LDG patterns and instead exhibit distinct biogeographic structuring shaped by local environmental conditions. Overall, we highlight the importance of incorporating molecular biodiversity data when evaluating large-scale ecological patterns and testing long-standing biogeographic hypotheses.
