Page 233 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

[P59] HUDSON BAY LOWLANDS BRYODIVERSITY: A NATIONAL HERBARIUM INITIATIVE
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REVEALING TAXONOMIC AND GEOGRAPHIC GAPS IN OCCURENCE DATA. Adam J. Storey and
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Jennifer Doubt . National Herbarium of Canada, Natural Heritage Campus, Canadian Museum of Nature,
1740 Chemin Pink, Gatineau, QC, Canada, J9J 3N7
Correspondence to: adam28storey@gmail.com

The Hudson Bay Lowlands (HBL) form the largest wetland in Canada and the third largest wetland
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globally at 374,000 km . The region is known for its extensive peatlands — wetlands characterized by the
accumulation of partially decayed plants, providing many regulatory services including sequestering and
storing carbon. In arctic and northern boreal peatlands, bryophytes (mosses and liverworts) compose 90-
100% of the ground cover, influencing all other plant and animal life. Their growth and decomposition
rates, which are species- and climate-specific, heavily influence rates of carbon sequestration. Despite
their functional diversity and ecological importance, the diversity and distribution of HBL bryophytes
remain largely unassessed, even as development and other environmental changes call with increasing
urgency for data that support management decision-making. The goals of this project are to (1) use
existing data sources to generate the first bryophyte checklist for the entire HBL region and (2) produce a
referenced dataset of known bryophyte species occurrences for the HBL region, to serve as primary
resources for land managers. Bryophyte records from the HBL were compiled from 10,700 specimen
records (e.g., CANM, UBC, NY, QFA, DUKE, MICH) and literature. These records were reviewed for
errors and standardized to present-day taxonomy. At the Canadian Museum of Nature (CMN), these data
are supplemented through the identification of thousands of previously unprocessed specimens from
projects in Ontario’s Ring of Fire region (CMN) and Wapusk National Park, Manitoba (University of
Manitoba, Parks Canada). To date, 388 mosses (316 in CANM) and 145 liverworts (94 in CANM) are
known for the HBL. The most diverse genera to date are Sphagnum (at least 40 species), Dicranum (20),
and Ptychostomum (17) for mosses and Scapania (17), Fuscocephaloziopsis (7), and Cephaloziella (7)
for liverworts. At least two species so far have not previously been reported from Manitoba. Four species
are new to the HBL region due to taxonomic revisions, one of which is newly reported from Quebec, and
another which is newly reported for Ontario and Manitoba. The resulting dataset will enable identification
of geographical, taxonomic, and temporal gaps in search effort, and provide a foundation for future
bryological work in the HBL. All specimens held at the CMN will be publicly accessible via the Global
Biodiversity Information Facility. The checklist and occurrence records resulting from this study will be
shared with project partners (Parks Canada, Mushkegowuk Council, Environment and Climate Change
Canada) and conservation data managers in Manitoba, Ontario, and Quebec.

*[P60] TOTAL PHENOLIC COMPOUNDS AND HERBIVORE RESISTANCE IN HYBRID POPLAR
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EXPOSED TO SALINITY. Sandamini Bandara , Trinity Bredardt , Caleb Lavallée-Shrupka , Sylvie
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Renault , and German Avila- Sakar . Biological Sciences, University of Manitoba, Winnipeg, Canada,
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R3T 2N2; and Biology, University of Winnipeg, Canada, R3B 2G3

Correspondence to: udagemus@myumanitoba.ca

Salinity and herbivory, two factors commonly faced by plants, are usually detrimental to their growth and
reproduction. Salinity disrupts water and nutrient uptake and causes ionic and oxidative stress. Herbivory
decreases plant photosynthetic area and triggers defensive biochemical pathways. The sequential
exposure of plants to these factors may have contrasting outcomes. Plant responses to one stress may
prime the biochemical pathways involved in their response to a second stress, thus lessening the
detrimental effects of the latter. Alternatively, the allocation of resources involved in the response to one
stress could decrease the effectiveness of the plant response to a second stress due to resource
limitations. Phenolic compounds, known to provide plants with resistance against herbivores, are also
elicited by salinity. Thus, exposure to salinity may prime plant resistance against herbivores via increased
phenolic content. The objective of this study was to test whether hybrid poplar (Populus) cuttings exposed
to salinity have higher concentrations of leaf phenolic compounds and greater resistance to a generalist
herbivore, Orgyia leucostigma. Four-week-old hybrid poplar cuttings were irrigated with 0 or 100 mM NaCl
for four weeks in a greenhouse. Leaf disc assays were used to determine constitutive resistance (prior to
insect exposure) and induced resistance (after insect exposure). In-vivo feeding assays were also used to
assess constitutive resistance. Constitutive and induced resistance were not affected by exposure to
salinity. The total leaf phenolic content of plants exposed to salinity was greater than that of control plants

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