Browsing by Author "Drummond, Jennifer A."

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    Cryptic diversity in the North American Dromochorus tiger beetles (Coleoptera: Carabidae: Cicindelinae): a congruence-based method for species discovery
    (Oxford University Press, 2019) Duran, Daniel P.; Herrmann, David P.; Roman, Stephen J.; Gwiazdowski, Rodger A.; Drummond, Jennifer A.; Hood, Glen R.; Egan, Scott P.
    A fundamental problem in biodiversity science is determining the number of species in any taxon, and there is a growing awareness that cryptic diversity contributes to this problem – even in well-studied groups. Discovering cryptic species requires several lines of evidence to elucidate congruent patterns across data-types, and distinguish unrecognized species. Tiger beetles are among the most well-studied insect groups; yet few new North American species have been described since the mid-20th century, suggesting that that the number of morphologically distinct species is reaching an asymptote. We explore the possibility that more species exist in the fauna as cryptic species, by analysing a broad geographic sample of all species in the genus Dromochorus. We employ a ‘taxonomic congruence’ approach, where we first generate species hypotheses from patterns of reciprocal monophyly across the mitochondrial and nuclear datasets, and test these hypotheses through congruence with population structure, morphological measures and ecological divergence. We find broad congruence that supports eight species of Dromochorus, more than doubling the known diversity. We also validate a previously ambiguous taxon, and re-describe previously named species. Lastly, we identify new diagnostic morphological characters, include an updated dichotomous key and provide updated natural history/ecological characteristics for the genus and individual species.
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    Diversity Metrics Are Robust to Differences in Sampling Location and Depth for Environmental DNA of Plants in Small Temperate Lakes
    (Frontiers Media S.A., 2021) Drummond, Jennifer A.; Larson, Eric R.; Li, Yiyuan; Lodge, David M.; Gantz, Crysta A.; Pfrender, Michael E.; Renshaw, Mark A.; Correa, Adrienne M.S.; Egan, Scott P.
    Environmental DNA (eDNA) analysis methods permit broad yet detailed biodiversity sampling to be performed with minimal field effort. However, considerable uncertainty remains regarding the spatial resolution necessary for effective sampling, especially in aquatic environments. Also, contemporary plant communities are under-investigated with eDNA methods relative to animals and microbes. We analyzed eDNA samples from six small temperate lakes to elucidate spatial patterns in the distributions of algae and aquatic and terrestrial plants, using metabarcoding of the Internal Transcribed Spacer-1 (ITS1) genomic region. Sampling locations were varied across horizontal and vertical space: sites in each lake included a mixture of nearshore and offshore positions, each of which was stratified into surface (shallow) and benthic (deep) samples. We detected the expected community variation (beta diversity) from lake to lake, but only small effects of offshore distance and sampling depth. Taxon richness (alpha diversity) was slightly elevated in nearshore samples, but displayed no other significant spatial effects. These diversity metrics imply that plant eDNA is more evenly distributed than its generating organisms in these small lake environments. Read abundances were heavily weighted toward aquatic macrophytes, though taxon richness was greatest in the algae and other nonvascular plants. We also identified representatives of many phylogenetically and ecologically varied plant taxa, including terrestrial species from surrounding areas. We conclude that freshwater plant eDNA surveys successfully capture differences among lake communities, and that easily-accessible, shore-based sampling may be a reliable technique for informing research and management in similar ecosystems.