Freshwater fish and mussel biodiversity hotspots for conservation priorities in Southwestern Ontario


Anas, M.U.M., A. Drake, T. Morris and N. Mandrak.

Area-based conservation approaches require identification of priority areas for conservation, for which the biodiversity hotspots concept is well known. We applied a systematic hotspots approach to freshwater fish and mussel diversity at a sub-basin level in Southwestern Ontario - an area characterized by the richest freshwater biodiversity in Canada and high intensity of anthropogenic pressures. We used three ecological criteria (i.e., irreplaceability, representativeness and vulnerability) in five templates (i.e., 3 proactive, 1 reactive and 1 representative) to prioritize sub-basins for alternative conservation strategies. We used comprehensive datasets of fish and mussel species distributions in the region to estimate irreplaceability (based on at-risk species diversity) and representativeness (based on native species diversity) of sub-basins, while the vulnerability (level of cumulative threats) was estimated based on intensity of human pressures (extracted from several national, continental, and global datasets) and invasive fish species richness in sub-basins. The prioritization of the sub-basins differed based on the conservation-strategy template. The high priority sub-basins identified by proactive 1 template (that only focuses on vulnerability) had the lowest diversity of both fishes and mussels and thus, offer limited biodiversity benefits. Interestingly, high priority sub-basins of reactive and proactive (2 and 3) templates can provide similar conservation value as they host similar diversity of at-risk fish and mussel species. The sub-basins prioritization in each templates varied depending on whether a single taxon (i.e., fishes OR mussels) or a multi-taxon (i.e., fishes PLUS mussels) approach was used in irreplaceability and representativeness criteria. Not only is current protected area coverage inadequate (only 0.36% of study region), but the distribution of protected areas is not optimised with respect to proposed spatial prioritization for proactive conservation. Our findings indicate that proactive conservation approaches can maximize conservation gains across multiple taxa in contrast to commonly used species-specific reactive strategies.