Abstract
Climate change is affecting the ocean, altering the biogeography of marine species. Yet marine protected area (MPA) planning still rarely incorporates projected species range shifts. We used the outputs of species distribution models fitted with biological and climate data as inputs to identify trends in occurrence for marine species in British Columbia (BC), Canada. We assessed and compared two ways of incorporating climate change projections into MPA planning. First, we overlaid 98 species with modelled distributions now and by the mid-21st century under two contrasting (“no mitigation” and “strong mitigation”) climate change scenarios with existing Provincial marine parks in BC, to ask which species could overlap with protected areas in the future. Second, we completed a spatial prioritization analysis using Marxan with the projected future species ranges as inputs, to ask where priority regions exist for the 98 marine species. We found that many BC marine parks will lose species in both climate scenarios that we analyzed, and that protecting 30% of important marine species will be challenging under the “no mitigation” climate change scenario. Challenges included the coarse resolution of the data and uncertainty in projecting species range shifts.
Introduction
Marine ecosystems are at risk from the effects of climate change on marine species physiology, population and species diversity, and ecological interactions (Hoegh-Guldberg and Bruno 2010; Doney et al. 2012). As ectotherms, fish and invertebrate species are especially vulnerable to ocean warming, as their body temperature is largely determined by the surrounding environment (Sunday et al. 2011; Pinsky et al. 2019). Species ranges, an outcome of a species’ potential and realized habitat niche, are driven by environmental conditions and moderated by biological interactions such as competition, predation, and long-term interactions among species (such as mutualism, commensalism, parasitism, and others) (Ackerly et al. 2010). The distribution of many species and populations has already changed as species move in space, such as poleward or to deeper waters (marine species), higher altitudes (terrestrial species), and/or in time as the seasonality of species lifecycles shifts to earlier or later times of the year (Parmesan and Yohe 2003; Tingley and Beissinger 2009; Brown et al. 2015). Marine species range shifts are expected to continue under projected warming and other changes in ocean conditions, with consequences for ecosystems, economies, societies, and management (Cheung et al. 2015; Patrizzi and Dobrovolski 2018).
Climate change impacts on species ranges can change where marine protected areas (MPAs) should be situated (McLeod et al. 2009; Gerber et al. 2014) and can also disrupt connectivity between protected areas by changing dispersal pathways and species physiology (Álvarez‐Romero et al. 2017) and affecting adult movement (Friesen et al. 2021). Well-established conservation planning tools have been applied in response to climate change predictions, such as emphasizing MPA networks, increasing spatial connectivity, habitat heterogeneity, and improving management of the core and edges of reserves (Hannah et al. 2002). Designating new MPAs could augment the existing global network of MPAs and provide potential benefits of connectivity and redundancy for existing species ranges (Hannah 2008; Araújo 2009). However, adding more MPAs today might not provide future benefits to the specific species or habitats they were intended to protect because of climate change.
To date, others have proposed a range of methods to incorporate climate change into conservation planning (see reviews by Magris et al. 2014; Jones et al. 2016). Previous research has aimed to identify thermal refugia, or areas that may warm less rapidly and thus offer some protection from increasing temperatures (Ban et al. 2016; Lima et al. 2016). However, data limitations—especially in terms of understanding how protecting future habitat might increase species adaptive capacity to climate change—make these methods challenging and uncertain (Groves et al. 2012; Magris et al. 2014). Others make a case for “conserving the geophysical stage”, whereby conversation plans are defined by geophysical indicators such as topography as surrogates for biodiversity features (Groves et al. 2012), an appropriate approach for some but not all species. Others still promote incorporating ecological processes into systematic conservation planning, such as river flows, flood patterns, or animal migration patterns (McCook et al. 2009; Groves et al. 2012; D'Aloia et al. 2017). Typically, conservation planning methods and data have remained temporally static based on the current state of biodiversity; with climate change, much more adaptive and proactive adaptation strategies are necessary (Groves et al. 2012). Another technique is to ensure the protection of habitat distributions over time (temporal connectivity), which would allow species to track their climatic niche as habitats change with climate change (Hodgson et al. 2009). Ecological niche theory—the environmental conditions that an organism is dependent upon to survive and reproduce (Wiens et al. 2009)—can be applied to models to describe how species may respond to future environmental change by identifying habitats that are likely to be used in the future. These forecasts are called species distribution models (SDMs) or bioclimatic niche models (e.g., Cheung et al. 2015). These SDMs can then be applied to a spatial decision support tool such as Marxan or zonation to prioritize actions to protect those future habitat needs and species of interest (Magris et al. 2014; e.g., Alagador et al. 2014).
In this paper, we explored two ways that marine conservation planning could incorporate projected changes in species distributions using global climate projections available globally. We used the outputs of an existing dynamic bioclimate envelope model of shifting species distributions (Weatherdon et al. 2016b) to (1) determine where species ranges overlap within MPAs in the Northern Shelf Bioregion (see below) in the present and future (2060) and (2) use them as inputs into spatial prioritization software (Marxan) to identify priorities for MPAs to represent biodiversity now and into the future across the entire coast of BC (within the Canadian Pacific Exclusive Economic Zone (EEZ) and including the transboundary region of southeastern Alaska and Washington States). We also tracked challenges encountered and reflected on the usefulness of the results for MPA network planning.
We focused on two scales: (1) the Northern Shelf Bioregion, and (2) all of Canada's Pacific EEZ and northern neighbouring regions in Alaska and northern Washington State. The smaller focal region, the Northern Shelf Bioregion, is relevant because this is the part of Canada's Pacific EEZ where a network of MPAs is currently actively being pursued jointly by Federal, Provincial, and First Nations government representatives (Gale et al. 2019) (Fig. 1). The bioregion, approximately 100,000 square kilometres in size, is one of 13 ecologically defined bioregions in Canada's EEZ (Government of Canada 2011). It is the only bioregion (out of 4) in Pacific Canada that has an active MPA network planning process underway and one that involves multiple governments (McGee et al. 2022; Reid et al. 2022). There are 118 conservancies, ecological reserves, and parks with a marine component that are under the jurisdiction of the Provincial BC government through BC Parks (hereafter referred to as BC MPAs) and 6 Federal MPAs within the bioregion included in this analysis. We focused on Provincial MPAs as part of this project, which was funded by BC Parks. We worked closely with members of the technical team planning the Northern Shelf Bioregion MPA network, including sharing our approaches, results, and associated data. Understanding how well existing MPAs in the region might fare under climate change is important for the development of the planning process, which includes a climate change sub-committee. The broader focus, on Canada's Pacific EEZ and beyond, is important for understanding how future range shifts might affect Canada's ability to protect marine species in its Pacific EEZ.
