Conservation of threatened vascular plants in intensive agricultural landscapes in Canada

With a steadily shrinking natural landscape in the province of Saskatchewan, Canada, mainly caused by intensive agriculture, conservation of threatened plants in situ should become a priority to prevent their extinction. The aim of this study is to identify native vascular plants at risk in the Redberry Lake Biosphere Region (RLBR) to support evidence-based conservation management. Such criteria as species distribution, richness, population size, habitat affinities, existing threats, conservation status, and gaps in the current protection were applied to develop the conservation strategies. The field surveys were conducted during 2010–2025 in various habitats of the RLBR within the Prairie and Boreal Plain ecozones. In total, 46 taxa (31 species, 5 subspecies and 10 varieties) of conservation concern in 19 families and 34 genera were identified. The top represented families Orchidaceae, Cyperaceae, and Poaceae and such genera as Carex , Cypripedium , and Potentilla make the largest contribution to the threatened flora. The study revealed that the majority of species occurrences and richness hotspots with 5–10 species each are concentrated in the Aspen Parkland ecoregion of the Prairie ecozone. It was found that most threatened plants occur in a few isolated sites, and their survival depends on the small population size as the consequence of recent habitat loss due to human activities. The conducted analysis identified seven hotspots of species richness, including three of them outside of the core area and the buffer zone of the RLBR designated for biodiversity protection. Threatened plants were categorized under the NatureServe criteria at the subnational (provincial) level as follows: S1– Critically Imperiled/Extremely rare (2 taxa), S2– Imperiled/Very rare (7), and S3– Vulnerable/Rare to uncommon (37). Among them, five species were assessed at the national level (N3) and two species at the global level (G3). Two S3 species from this listing are simultaneously ranked as VU– Vulnerable and NT– Near Threatened under the IUCN criteria. It was found that threatened plants are vulnerable to habitat loss, successional overgrowth, spread of invasive alien species, and wetland interventions. These threats are resulting from land use history, current unsustainable agricultural practices, and a lack of proper conservation management. The RLBR is one of the areas in Canada with the most heavily modified ecosystems where conservation management such as grazing, clearing, prescribed fire and invasive alien species control is needed in the majority habitats of threatened plants. This can be substantially enhanced by introducing novel conservation approaches, such as establishing Important Plant Areas in the buffer zone and recognising other effective area-based conservation measures in the transition area of the RLBR. These conservation strategies are important for raising public awareness and prompting political actions, but smaller-scale actions are also needed by local conservation practitioners.