Assessing Climate Change Vulnerability in Canadian Marine Conservation Networks: Implications for Conservation Planning and Resilience
Laura Keen, Christine H. Stortini, Dan G. Boyce, Ryan R.E. Stanley
Code and data citation
Keen, L., Stortini, C.H, Boyce, D.G., and R.R.E. Stanley. Representing Climate Change Vulnerabilities in Canadian Marine Conservation Networks- code & data.
Abstract
Marine Protected Areas (MPAs) are critical in safeguarding biodiversity and ecosystem functions under climate change. The long-term effectiveness of these static conservation measures will depend on how well they represent current and future ocean changes. Here, we use the Climate Risk Index for Biodiversity to assess the vulnerability representation of marine ecosystems within the Canadian Marine Conservation Network (CMCN) under two divergent emissions scenarios. We found that MPAs best represent climate vulnerability in Atlantic Canada (85% representativity overall, and 93% in the Gulf of Saint Lawrence under low emissions), followed by the Pacific (78%) and Arctic (63%; lowest in the Eastern Arctic (41% under high emissions) regions. Notably, MPAs with lower climate vulnerability are proportionally overrepresented in the CMCN. Broad-scale geographic targets employed in the Scotian Shelf-Bay of Fundy network planning process achieve over 90% representativity of climate vulnerabilities, underscoring the importance of ensuring habitat representativity and geographic distribution in conservation planning to enhance climate resilience, even if not explicitly prioritized. Moving towards Canada’s target to protect 30% of its waters by 2030, prioritizing representativity and designation of MPAs in currently underrepresented climate-vulnerable regions may be crucial to enhancing the resilience of the CMCN amidst an ever-changing climate.
Figure 1 Map of the Canadian Exclusive Economic Zone (EEZ) overlaid with (a) outlines of conservation areas (Marine Protected Areas (MPAs), in blue, and Other Effective Conservation Measures (OECMs), in orange), (b) the 14 Canadian bioregions, (c) an aggregate climate vulnerability assessment by Boyce et al. 2022 for the Canadian EEZ under RCP 8.5 (the box on the lower right corner represents the area shown in panel d) and (d) outlines of the Scotian Shelf-Bay of Fundy Draft Conservation Network sites (Areas of Interest (AOIs) in red, draft sites in green, MPAs in blue, and OECMs in orange).
Figure 2 Within each 0.5° x 0.5° grid cell across the Canadian geographic distribution of a species (a), 12 standardized climate indices were calculated (b) and used to define the three dimensions of climate vulnerability (c) according to Boyce et al. 2022. These dimensions were used to calculate species’ vulnerability and combined to represent climate vulnerability for ecosystems. Marine Conservation Areas, including MPAs and Marine Refuges, are depicted in each map.
Figure 3 Density plots of climate vulnerability distributions for three oceans (Pacific, Arctic, and Atlantic) under two climate scenarios (RCP 8.5 and RCP 2.6) in ocean basins (in red) and within conservation networks (in blue-green). Vulnerabilities are weighted by cell area. Area-weighted medians of distributions are shown as vertical lines in their respective colours.
Figure 4 Box and whisker plots of climate vulnerabilities under high (RCP 8.5) and low (RCP 2.6) emissions subdivided by ocean basin, in entire bioregions (n=12) (in red) and within conservation networks (in blue-green). Vertical lines indicate area-weighted medians and circles represent outliers. Distributions are weighted by area.
Figure 5 (a) Representativity of the conservation network in a given bioregion (n=9), expressed as the percent overlap of the distributions of vulnerability in the network compared to the bioregion as a whole. (b) Changes in representativity between high emissions (RCP 8.5) and low emissions (RCP 2.6). Positive values indicate the conservation network will become more representative of bioregional vulnerabilities under RCP 8.5 compared to RCP 2.6. Colours represent weighted median vulnerability of the bioregion under RCP 8.5 and RCP 2.6. Shapes represent emissions scenarios.
Figure 6 Density plots of climate vulnerability distributions for the Scotian Shelf-Bay of Fundy for the current network and the draft network under two climate scenarios (RCP 8.5 and RCP 2.6) in the bioregion (in red) and the network (in blue). Vulnerabilities are weighted by cell area. Area-weighted medians of distributions are shown as vertical lines in their respective colours.
Figure 7 For Canadian ocean basins (n=3): (a) percentages of depth categories within the conservation network, (b) proportional representation of depth categories within the network where positive values and negative values represent percent over- or under-representation, and vulnerability by depth category under (c) RCP 8.5 and (d) RCP 2.6.