A voucher flora of diatoms from fens in the Tanana River floodplain, Alaska
On this page:
Climate change and human activities may alter the structure and function of boreal peatlands by warming waters and changing patterns in hydrology. Algal assemblages, especially diatoms can be used to assess or track these changes. However, effective biomonitoring requires consistent, reliable identification. To address the need for resources to support biomonitoring, this study evaluated the distribution of diatom species across a boreal fen gradient with the goal of building a voucher flora for interior Alaskan peatlands. Composite diatom samples were collected weekly during the summer growing season in 2017 from three peatland complexes (a rich, moderate, and poor fen), using natural transitions in water chemistry (e.g., pH) and vegetation assemblages that distinguish fen types. Cleaned diatom samples were imaged and assembled to capture the morphological range of each taxon. The fen diatom flora contained 35 genera comprised of 184 unique taxa. Across all peatland types, the most prevalent genera included Eunotia (45), Gomphonema (24), and Pinnularia (23). Tabellaria was common in the rich and moderate fens but became sparse in the poor fen. Eunotia showed the opposite trend. Twenty-five percent of the species matched those with at risk or declining status on the diatom Red List (developed in Germany), highlighting the conservation value of boreal wetland ecosystems. This voucher flora not only expands the regional knowledge of diatom biodiversity, but also provides an updated source of verifiable taxonomic information of inland Alaskan diatoms to build on Foged’s treatment in 1981. This flora strengthens the potential to effectively track changes in water quality in boreal ecosystems sensitive to climate-related temperature and hydrological shifts and anthropogenic stressors.