Moss-associated epiphytic diatom (Bacillariophyta) occurrences in the Hudson Bay Lowlands: a proof of concept for non-destructive sampling of herbarium specimens

Diatoms constitute important components of moss microbiomes. In the peatlands of the Hudson Bay Lowlands (HBL), where bryophytes (mosses and liverworts) cover most of the landscape, epiphytic diatoms are sensitive ecological indicators that contribute to primary productivity and biodiversity. However, they remain largely uninventoried and collecting from remote regions such as the HBL is resource-intensive. Sampling epiphytic diatoms traditionally uses destructive techniques on invaluable herbarium specimens. A simple, non-destructive technique for sampling and documenting epiphytic diatoms in herbarium specimens was tested and found to yield similar results in terms of species detection as common destructive acid digestion techniques. Diatoms were observed in 49/66 subsamples. Fifty-five genera were detected, including Eunotia, Nitzschia, Pinnularia, Navicula, Encyonema, Kobayasiella and Gomphonema. These results demonstrate that herbarium specimens can provide a viable complement to field collection in biodiversity studies, in ways that not only preserve but also extend the value of the original specimen. This approach adds to the growing array of applications of physical herbarium specimens and extended herbarium data in support of current and future efforts to address challenges related to nature and natural resources.