Assessing biodiversity hotspots below the species-level in Canada using designatable units

• Main Authors: Gillian Muir, Elizabeth R. Lawrence, James W.A. Grant, Dylan J. Fraser
• Format: Article
• Language: English
• Published: Elsevier 2021-04-01
• Series: Global Ecology and Conservation
• Subjects: Designatable units; Hotspots; Intraspecific diversity; At-risk; Species richness; Endangered species
• Online Access: http://www.sciencedirect.com/science/article/pii/S2351989421000561

The biodiversity hotspot approach is commonly used to identify key regions of conservation priority based on species richness and uniqueness. Like other countries, Canada uses below species-level conservation units, called Designatable Units (DUs), for assessing extinction risk on a case-by-case basis. Researchers have yet to investigate conservation unit hotspots below the species level, despite the potential benefits to optimize the impact of conservation strategies. Across taxa, we: (i) identified at-risk DU hotspots, eco-geographic regions in Canada with a disproportionate number of at-risk DUs relative to species richness; and (ii) compared at-risk DU hotspots using two sets of eco-geographic maps adopted by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). DU richness counts were based on COSEWIC assessed species and hence biased towards at-risk DUs; species richness values were obtained from the International Union for Conservation of Nature (IUCN) Red List. At-risk DU hotspots were consistently found in the Pacific and Great Lakes regions. A positive correlation was observed between at-risk DUs and species richness using both eco-geographic maps, but important regional nuances were also detected, i.e., hotspots were not always found in regions of high species richness. Moreover, there were 3.45 at-risk DUs for every at-risk species across all taxa, providing greater resolution for refining conservation prioritization across regions. For Canada, the at-risk DU hotspot approach permits the identification of regions with a high number of at-risk DUs relative to species richness, enabling the targeting of multiple DUs and taxa in one management plan. More generally, these results emphasize the importance of incorporating below species-level metrics into conservation decisions to better account for different components of biodiversity and extinction risk.