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Cryptic biodiversity in streams - a comparison of macroinvertebrate communities based on morphological and DNA barcode identifications
Citation:
Jackson, J. K., J. M. Battle, B. White, E. Stein, E. PILGRIM, P. E. Miller, AND B. W. Sweeney. Cryptic biodiversity in streams - a comparison of macroinvertebrate communities based on morphological and DNA barcode identifications. Presented at Society of Freshwater Science, Louisville, KY, May 20 - 24, 2012.
Impact/Purpose:
The objective of this task is to develop molecular indicators to evaluate the integrity and sustainability of aquatic fish, invertebrate, and plant communities. Specifically, this subtask aims to evaluate methods for the measurement of: fish and invertebrate community composition, especially for morphologically indistinct (cryptic) species population genetic structure of aquatic indicator species and its relationship to landscape determinants of population structure (to aid in defining natural assessment units and to allow correlation of population substructure with regional stressor coverages) genetic diversity within populations of aquatic indicator species, as an indicator of vulnerability to further exposure and as an indicator of cumulative exposure patterns of temporal change in genetic diversity of aquatic indicator species, as a monitoring tool for establishing long-term population trends.
Description:
Aquatic ecologists and entomologists have long known that species-level identifications were difficult, if not impossible, for many larval macroinvertebrates collected in streams. This study describes macroinvertebrate (primarily insect) communities from five coastal streams distributed across three neighboring drainages in Southern California based ons equences for cytochrome c oxidase subunit 1 (COI), and compares barcode results to traditional morphological identifications. A total of 5309 individuals were examined. Barcodes identified 97 more species than morphological taxa across streams (184 versus 87, a 111% increase). Totals for individual streams ranged from 37 to 87 barcode species, a 37-110% increase over morphology. Richness increases were greatest for Chironomidae (56 species, 193%), followed by Ephemeroptera (10 species, 77%), Acari (10 species, 200%), and Trichoptera (6 species, 50%). Many species (41%) were represented by one or two specimens at one or two streams, and only two species were collected at all five streams. Thus, DNA barcoding now makes it possible to differentiate consistently among species, and these results indicate that much of the macroinvertebrate biodiversity in streams has been underestimated in the past.